Oxidative and Anti-Oxidative Stress Markers in Chronic Glaucoma: A Systematic Review and Meta-Analysis

PubMed Central

Benoist d’Azy, Cédric; Pereira, Bruno; Chiambaretta, Frédéric

2016-01-01

Chronic glaucoma is a multifactorial disease among which oxidative stress may play a major pathophysiological role. We conducted a systematic review and meta-analysis to evaluate the levels of oxidative and antioxidative stress markers in chronic glaucoma compared with a control group. The PubMed, Cochrane Library, Embase and Science Direct databases were searched for studies reporting oxidative and antioxidative stress markers in chronic glaucoma and in healthy controls using the following keywords: “oxidative stress” or “oxidant stress” or “nitrative stress” or “oxidative damage” or “nitrative damage” or “antioxidative stress” or “antioxidant stress” or “antinitrative stress” and “glaucoma”. We stratified our meta-analysis on the type of biomarkers, the type of glaucoma, and the origin of the sample (serum or aqueous humor). We included 22 case-control studies with a total of 2913 patients: 1614 with glaucoma and 1319 healthy controls. We included 12 studies in the meta-analysis on oxidative stress markers and 19 on antioxidative stress markers. We demonstrated an overall increase in oxidative stress markers in glaucoma (effect size = 1.64; 95%CI 1.20–2.09), ranging from an effect size of 1.29 in serum (95%CI 0.84–1.74) to 2.62 in aqueous humor (95%CI 1.60–3.65). Despite a decrease in antioxidative stress marker in serum (effect size = –0.41; 95%CI –0.72 to –0.11), some increased in aqueous humor (superoxide dismutase, effect size = 3.53; 95%CI 1.20–5.85 and glutathione peroxidase, effect size = 6.60; 95%CI 3.88–9.31). The differences in the serum levels of oxidative stress markers between glaucoma patients and controls were significantly higher in primary open angle glaucoma vs primary angle closed glaucoma (effect size = 12.7; 95%CI 8.78–16.6, P < 0.001), and higher in pseudo-exfoliative glaucoma vs primary angle closed glaucoma (effect size = 12.2; 95%CI 8.96–15.5, P < 0.001). In conclusion, oxidative stress increased in glaucoma, both in serum and aqueous humor. Malonyldialdehyde seemed the best biomarkers of oxidative stress in serum. The increase of some antioxidant markers could be a protective response of the eye against oxidative stress. PMID:27907028

Lack of Association between Serum Vitamin B₆, Vitamin B12, and Vitamin D Levels with Different Types of Glaucoma: A Systematic Review and Meta-Analysis.

PubMed

Li, Shengjie; Li, Danhui; Shao, Mingxi; Cao, Wenjun; Sun, Xinghuai

2017-06-21

Although vitamins play a major role in health, and their deficiency may be linked to symptoms of optic-nerve dysfunction, the association between serum vitamin levels and glaucoma in humans remains controversial. In this study, articles in the PubMed, Web of Science, and EMBASE databases were searched up to 25March 2017. Nine studies on primary open-angle glaucoma (POAG), four studies on normal tension glaucoma (NTG), and six studies on exfoliative glaucoma (EXG) were retrieved. The combined results showed no differences in the levels of serum vitamin B₆ between POAG ( p = 0.406) and EXG ( p = 0.139) patients and controls. The weighted mean differences (WMDs) with 95% confidence intervals (CIs) were 2.792 ng/mL (-3.793 to 9.377) and 1.342 ng/mL (-3.120 to 0.436), respectively. There was no difference between POAG ( p = 0.952), NTG ( p = 0.757), or EXG ( p = 0.064) patients and controls in terms of serum vitamin B 12 . The WMDs with 95% CIs were 0.933 pg/mL (-31.116 to 29.249), 6.652 pg/mL (-35.473 to 48.777), and 49.946 pg/mL (-102.892 to 3.001), respectively. The serum vitamin D levels exhibited no differences ( p = 0.064) between POAG patients and controls; the WMD with 95% CI was 2.488 ng/mL (-5.120 to 0.145). In conclusion, there was no association found between serum vitamin B₆, vitamin B 12 , or vitamin D levels and the different types of glaucoma.

Microarray Analysis of Iris Gene Expression in Mice with Mutations Influencing Pigmentation

PubMed Central

Trantow, Colleen M.; Cuffy, Tryphena L.; Fingert, John H.; Kuehn, Markus H.

2011-01-01

Purpose. Several ocular diseases involve the iris, notably including oculocutaneous albinism, pigment dispersion syndrome, and exfoliation syndrome. To screen for candidate genes that may contribute to the pathogenesis of these diseases, genome-wide iris gene expression patterns were comparatively analyzed from mouse models of these conditions. Methods. Iris samples from albino mice with a Tyr mutation, pigment dispersion–prone mice with Tyrp1 and Gpnmb mutations, and mice resembling exfoliation syndrome with a Lyst mutation were compared with samples from wild-type mice. All mice were strain (C57BL/6J), age (60 days old), and sex (female) matched. Microarrays were used to compare transcriptional profiles, and differentially expressed transcripts were described by functional annotation clustering using DAVID Bioinformatics Resources. Quantitative real-time PCR was performed to validate a subset of identified changes. Results. Compared with wild-type C57BL/6J mice, each disease context exhibited a large number of statistically significant changes in gene expression, including 685 transcripts differentially expressed in albino irides, 403 in pigment dispersion–prone irides, and 460 in exfoliative-like irides. Conclusions. Functional annotation clusterings were particularly striking among the overrepresented genes, with albino and pigment dispersion–prone irides both exhibiting overall evidence of crystallin-mediated stress responses. Exfoliative-like irides from mice with a Lyst mutation showed overall evidence of involvement of genes that influence immune system processes, lytic vacuoles, and lysosomes. These findings have several biologically relevant implications, particularly with respect to secondary forms of glaucoma, and represent a useful resource as a hypothesis-generating dataset. PMID:20739468

Histopathologic evaluation of the anterior segment of eyes enucleated due to glaucoma secondary to primary lens displacement in 13 canine globes.

PubMed

Alario, Anthony F; Pizzirani, Stefano; Pirie, Christopher G

2013-07-01

PURPOSE  To describe histologic anterior segment changes in eyes affected with primary lens displacement (PLD) and secondary glaucoma. METHODS  Histologic sections stained with H&E from canine eyes enucleated because of PLD and secondary glaucoma were examined. RESULTS  Thirteen eyes from 12 patients were evaluated. Four dogs were castrated males and eight spayed females. Median age was 8 years of age (range 3-13). Breeds included seven terriers and five other breeds. All eyes examined demonstrated varying degrees of inflammation involving the iris and cleft. Mononuclear and melanophagic infiltration of the cleft was found in all specimens. Four globes also showed polymorphonuclear infiltrate. Pre-iridal fibrovascular membranes were clearly identified in 10 of 13 eyes. Total inflammatory score was significantly greater in all globes examined compared with an age-matched group of normal dogs. The posterior pigmented iris epithelium demonstrated a consistent pattern of hyperplasia and/or hypertrophy and cystic degeneration, more prominent in the more central regions. In some cases, hyperplasia was of greatest severity in the mid-iris and associated with thinning or flattening of the pupillary region. CONCLUSIONS  These results suggest that lens instability may be associated with chronic inflammation and secondary glaucoma. Mechanical irritation from an unstable lens may result in hypertrophy and/or hyperplasia of the posterior pigmented iris epithelium and subsequent cellular exfoliation and release of melanin. An inflammatory reaction directly or indirectly related to melanin release may obstruct the outflow pathways ultimately leading to glaucoma and loss of vision. Use of topical steroids may be warranted in dogs with PLD. © 2012 American College of Veterinary Ophthalmologists.

Assessment of Visual Status of the Aeta, a Hunter-Gatherer Population of the Philippines (An AOS Thesis)

PubMed Central

Allingham, R. Rand

2008-01-01

Purpose A screening study was performed to assess levels of visual impairment and blindness among a representative sample of older members of the Aeta, an indigenous hunter-gatherer population living on the island of Luzon in the Philippines. Methods Unrelated older Aeta couples were randomly invited to participate in a visual screening study. All consented individuals had ocular history, medical history, complete ophthalmic examination, height, weight, and blood pressure taken. Results A total of 225 individuals were screened from 4 villages. Visual acuity, both uncorrected and pinhole corrected, was significantly worse among older vs younger age-groups for women, men, and when combined (P < .001). Visual impairment was present in 48% of uncorrected and 43% of pinhole corrected eyes in the oldest age-group. Six percent of the screened population was bilaterally blind. The major causes of blindness were readily treatable. The most common etiologies as a proportion of blind eyes were cataract (66%), refractive error (20%), and trauma (7%). No cases of primary open-angle, primary angle-closure, or exfoliation glaucoma were observed in this population. Discussion Visual impairment and blindness were common in the Aeta population. Primary forms of glaucoma, a major cause of blindness found in most population-based studies, were not observed. The absence of primary glaucoma in this population may reflect random sampling error. However, based on similar findings in the Australian Aborigine, this raises the possibility that these two similar populations may share genetic and/or environmental factors that are protective for glaucoma.. PMID:19277240

A common variant mapping to CACNA1A is associated with susceptibility to Exfoliation syndrome

PubMed Central

Aung, Tin; Ozaki, Mineo; Mizoguchi, Takanori; Allingham, R Rand; Li, Zheng; Haripriya, Aravind; Nakano, Satoko; Uebe, Steffen; Harder, Jeffrey M.; Chan, Anita S.Y.; Lee, Mei Chin; Burdon, Kathryn P.; Astakhov, Yury S.; Abu-Amero, Khaled K.; Zenteno, Juan C.; Nilgün, Yildirim; Zarnowski, Tomasz; Pakravan, Mohammad; Safieh, Leen Abu; Jia, Liyun; Wang, Ya Xing; Williams, Susan; Paoli, Daniela; Schlottmann, Patricio G; Huang, Lulin; Sim, Kar Seng; Foo, Jia Nee; Nakano, Masakazu; Ikeda, Yoko; Kumar, Rajesh S; Ueno, Morio; Manabe, Shin-ichi; Hayashi, Ken; Kazama, Shigeyasu; Ideta, Ryuichi; Mori, Yosai; Miyata, Kazunori; Sugiyama, Kazuhisa; Higashide, Tomomi; Chihara, Etsuo; Inoue, Kenji; Ishiko, Satoshi; Yoshida, Akitoshi; Yanagi, Masahide; Kiuchi, Yoshiaki; Aihara, Makoto; Ohashi, Tsutomu; Sakurai, Toshiya; Sugimoto, Takako; Chuman, Hideki; Matsuda, Fumihiko; Yamashiro, Kenji; Gotoh, Norimoto; Miyake, Masahiro; Astakhov, Sergei Y.; Osman, Essam A.; Al-Obeidan, Saleh A.; Owaidhah, Ohoud; Al-Jasim, Leyla; Al Shahwan, Sami; Fogarty, Rhys A.; Leo, Paul; Yetkin, Yaz; Oğuz, Çilingir; Kanavi, Mozhgan Rezaei; Beni, Afsaneh Naderi; Yazdani, Shahin; Akopov, Evgeny L.; Toh, Kai-Yee; Howell, Gareth R; Orr, Andrew C.; Goh, Yufen; Meah, Wee Yang; Peh, Su Qin; Kosior-Jarecka, Ewa; Lukasik, Urszula; Krumbiegel, Mandy; Vithana, Eranga N; Wong, Tien Yin; Liu, Yutao; Ashley Koch, Allison E.; Challa, Pratap; Rautenbach, Robyn M; Mackey, David A.; Hewitt, Alex W; Mitchell, Paul; Wang, Jie Jin; Ziskind, Ari; Carmichael, Trevor; Ramakrishnan, Rangappa; Narendran, Kalpana; Venkatesh, Rangaraj; Vijayan, Saravanan; Zhao, Peiquan; Chen, Xueyi; Guadarrama-Vallejo, Dalia; Cheng, Ching Yu; Perera, Shamira A; Husain, Rahat; Ho, Su-Ling; Welge-Luessen, Ulrich-Christoph; Mardin, Christian; Schloetzer-Schrehardt, Ursula; Hillmer, Axel M.; Herms, Stefan; Moebus, Susanne; Nöthen, Markus M.; Weisschuh, Nicole; Shetty, Rohit; Ghosh, Arkasubhra; Teo, Yik Ying; Brown, Matthew A; Lischinsky, Ignacio; Crowston, Jonathan G; Coote, Michael; Zhao, Bowen; Sang, Jinghong; Zhang, Nihong; You, Qisheng; Vysochinskaya, Vera; Founti, Panayiota; Chatzikyriakidou, Anthoula; Lambropoulos, Alexandros; Anastasopoulos, Eleftherios; Coleman, Anne L; Wilson, M Roy; Rhee, Douglas J; Kang, Jae Hee; May-Bolchakova, Inna; Heegaard, Steffen; Mori, Kazuhiko; Alward, Wallace L.M.; Jonas, Jost B; Xu, Liang; Liebmann, Jeffrey M; Chowbay, Balram; Schaeffeler, Elke; Schwab, Matthias; Lerner, Fabian; Wang, Ningli; Yang, Zhenglin; Frezzotti, Paolo; Kinoshita, Shigeru; Fingert, John H.; Inatani, Masaru; Tashiro, Kei; Reis, André; Edward, Deepak P.; Pasquale, Louis R.; Kubota, Toshiaki; Wiggs, Janey L.; Pasutto, Francesca; Topouzis, Fotis; Dubina, Michael; Craig, Jamie E.; Yoshimura, Nagahisa; Sundaresan, Periasamy; John, Simon W.M.; Ritch, Robert; Hauser, Michael A; Khor, Chiea-Chuen

2015-01-01

Exfoliation syndrome (XFS) is the commonest recognizable cause of open angle glaucoma world-wide. To better understand the etiology of XFS, we conducted a genome-wide association study (GWAS) on 1,484 patients and 1,188 controls from Japan, and followed up the most significant findings on a further 6,901 patients and 20,727 controls from 17 countries across 6 continents. We discovered a significant association between a new locus (CACNA1A rs4926244) and increased susceptibility to XFS (Odds ratio [OR] = 1.16, P = 3.36 × 10−11). Although overwhelming association at the LOXL1 locus was confirmed, the key SNP marker (LOXL1 rs4886776) demonstrated allelic reversal depending on ethnic grouping (In Japanese: ORA-allele= 9.87, P = 2.13 × 10−217; In non-Japanese: ORA-allele= 0.49, P = 2.35 × 10−31). Our findings represent the first genetic locus outside of LOXL1 which surpasses genome-wide significance for XFS, and provides insight into the biology and pathogenesis of the disease. PMID:25706626

A common variant mapping to CACNA1A is associated with susceptibility to exfoliation syndrome.

PubMed

Aung, Tin; Ozaki, Mineo; Mizoguchi, Takanori; Allingham, R Rand; Li, Zheng; Haripriya, Aravind; Nakano, Satoko; Uebe, Steffen; Harder, Jeffrey M; Chan, Anita S Y; Lee, Mei Chin; Burdon, Kathryn P; Astakhov, Yury S; Abu-Amero, Khaled K; Zenteno, Juan C; Nilgün, Yildirim; Zarnowski, Tomasz; Pakravan, Mohammad; Safieh, Leen Abu; Jia, Liyun; Wang, Ya Xing; Williams, Susan; Paoli, Daniela; Schlottmann, Patricio G; Huang, Lulin; Sim, Kar Seng; Foo, Jia Nee; Nakano, Masakazu; Ikeda, Yoko; Kumar, Rajesh S; Ueno, Morio; Manabe, Shin-ichi; Hayashi, Ken; Kazama, Shigeyasu; Ideta, Ryuichi; Mori, Yosai; Miyata, Kazunori; Sugiyama, Kazuhisa; Higashide, Tomomi; Chihara, Etsuo; Inoue, Kenji; Ishiko, Satoshi; Yoshida, Akitoshi; Yanagi, Masahide; Kiuchi, Yoshiaki; Aihara, Makoto; Ohashi, Tsutomu; Sakurai, Toshiya; Sugimoto, Takako; Chuman, Hideki; Matsuda, Fumihiko; Yamashiro, Kenji; Gotoh, Norimoto; Miyake, Masahiro; Astakhov, Sergei Y; Osman, Essam A; Al-Obeidan, Saleh A; Owaidhah, Ohoud; Al-Jasim, Leyla; Al Shahwan, Sami; Fogarty, Rhys A; Leo, Paul; Yetkin, Yaz; Oğuz, Çilingir; Kanavi, Mozhgan Rezaei; Beni, Afsaneh Nederi; Yazdani, Shahin; Akopov, Evgeny L; Toh, Kai-Yee; Howell, Gareth R; Orr, Andrew C; Goh, Yufen; Meah, Wee Yang; Peh, Su Qin; Kosior-Jarecka, Ewa; Lukasik, Urszula; Krumbiegel, Mandy; Vithana, Eranga N; Wong, Tien Yin; Liu, Yutao; Koch, Allison E Ashley; Challa, Pratap; Rautenbach, Robyn M; Mackey, David A; Hewitt, Alex W; Mitchell, Paul; Wang, Jie Jin; Ziskind, Ari; Carmichael, Trevor; Ramakrishnan, Rangappa; Narendran, Kalpana; Venkatesh, Rangaraj; Vijayan, Saravanan; Zhao, Peiquan; Chen, Xueyi; Guadarrama-Vallejo, Dalia; Cheng, Ching Yu; Perera, Shamira A; Husain, Rahat; Ho, Su-Ling; Welge-Luessen, Ulrich-Christoph; Mardin, Christian; Schloetzer-Schrehardt, Ursula; Hillmer, Axel M; Herms, Stefan; Moebus, Susanne; Nöthen, Markus M; Weisschuh, Nicole; Shetty, Rohit; Ghosh, Arkasubhra; Teo, Yik Ying; Brown, Matthew A; Lischinsky, Ignacio; Crowston, Jonathan G; Coote, Michael; Zhao, Bowen; Sang, Jinghong; Zhang, Nihong; You, Qisheng; Vysochinskaya, Vera; Founti, Panayiota; Chatzikyriakidou, Anthoula; Lambropoulos, Alexandros; Anastasopoulos, Eleftherios; Coleman, Anne L; Wilson, M Roy; Rhee, Douglas J; Kang, Jae Hee; May-Bolchakova, Inna; Heegaard, Steffen; Mori, Kazuhiko; Alward, Wallace L M; Jonas, Jost B; Xu, Liang; Liebmann, Jeffrey M; Chowbay, Balram; Schaeffeler, Elke; Schwab, Matthias; Lerner, Fabian; Wang, Ningli; Yang, Zhenglin; Frezzotti, Paolo; Kinoshita, Shigeru; Fingert, John H; Inatani, Masaru; Tashiro, Kei; Reis, André; Edward, Deepak P; Pasquale, Louis R; Kubota, Toshiaki; Wiggs, Janey L; Pasutto, Francesca; Topouzis, Fotis; Dubina, Michael; Craig, Jamie E; Yoshimura, Nagahisa; Sundaresan, Periasamy; John, Simon W M; Ritch, Robert; Hauser, Michael A; Khor, Chiea-Chuen

2015-04-01

Exfoliation syndrome (XFS) is the most common recognizable cause of open-angle glaucoma worldwide. To better understand the etiology of XFS, we conducted a genome-wide association study (GWAS) of 1,484 cases and 1,188 controls from Japan and followed up the most significant findings in a further 6,901 cases and 20,727 controls from 17 countries across 6 continents. We discovered a genome-wide significant association between a new locus (CACNA1A rs4926244) and increased susceptibility to XFS (odds ratio (OR) = 1.16, P = 3.36 × 10(-11)). Although we also confirmed overwhelming association at the LOXL1 locus, the key SNP marker (LOXL1 rs4886776) demonstrated allelic reversal depending on the ancestry group (Japanese: OR(A allele) = 9.87, P = 2.13 × 10(-217); non-Japanese: OR(A allele) = 0.49, P = 2.35 × 10(-31)). Our findings represent the first genetic locus outside of LOXL1 surpassing genome-wide significance for XFS and provide insight into the biology and pathogenesis of the disease.

Oxidative stress in dry age-related macular degeneration and exfoliation syndrome.

PubMed

Chiras, Dimitrios; Kitsos, George; Petersen, Michael B; Skalidakis, Iosif; Kroupis, Christos

2015-02-01

Oxidative stress refers to cellular or molecular damage caused by reactive oxygen species, which especially occurs in age-related conditions as a result of an imbalance between the production of reactive oxygen species and the antioxidant defense response. Dry age-related macular degeneration (AMD) and exfoliation syndrome (XFS) are two common and complex age-related conditions that can cause irreversible vision loss. Two subtypes of AMD, which is the leading cause of blindness in the Western world, exist: the most prevalent dry type and the most severe wet type. Early dry AMD is characterized by formation of drusen, which are sub-retinal deposits, in the macular area and may progress to geographic atrophy with more dramatic manifestation. XFS is a systemic disorder of the extracellular matrix characterized by the accumulation of elastic fibrils that leads, in most cases, to glaucoma development with progressive and irreversible vision loss. Due to the aging population, the prevalence of these already-widespread conditions is increasing and is resulting in significant economic and psychological costs for individuals and for society. The exact composition of the abnormal drusen and XFS material as well as the mechanisms responsible for their production and accumulation still remain elusive, and consequently treatment for both diseases is lacking. However, recent epidemiologic, genetic and molecular studies support a major role for oxidative stress in both dry AMD and XFS development. Understanding the early molecular events in their pathogenesis and the exact role of oxidative stress may provide novel opportunities for therapeutic intervention for the prevention of progression to advanced disease.

A Comparison of Functional and Structural Measures for Identifying Progression of Glaucoma

PubMed Central

Xin, Daiyan; Greenstein, Vivienne C.; Ritch, Robert; Liebmann, Jeffrey M.; De Moraes, Carlos Gustavo

2011-01-01

Purpose. To compare glaucoma progression by functional and structural tests. Methods. The authors prospectively studied 33 glaucoma patients (55 eyes); 20 eyes (15 patients) had disc hemorrhage, and 35 eyes (18 patients) had exfoliation glaucoma. The following tests were performed at two baseline and three follow-up examinations: frequency doubling perimetry (FDT), 24-2 Humphrey visual fields (HVF), multifocal visual evoked potentials (mfVEP), and optical coherence tomography (OCT). To identify progression, the baseline measurements were averaged and compared to those obtained at the final examination. Stereophotographs of the optic disc were obtained at baseline and compared with those at the final examination. Results. Patients were followed up for 21.1 ± 1.8 months. For HVF there were significant changes in mean deviation (MD) in eight (14.5%) eyes but in pattern standard deviation (P/SD) in only two (3.6%) eyes. For FDT, there were significant changes in MD in 13 (23.6%) eyes. Five eyes showed changes in MD for HVF and FDT. For mfVEP, there was an increase in abnormal points in nine (16.4%) eyes. Six of these eyes did not show significant HVF or FDT changes. For OCT, RNFL average thickness values were significantly decreased in nine (16.4%) eyes. Nine (16.4%) eyes showed progression on stereophotography; four of these eyes did not show significant changes on OCT and functional tests. Conclusions. Each test showed evidence of progression in some eyes. However, agreement among tests and stereophotography regarding which eyes showed progression was poor, illustrating the importance of following up patients with a combination of functional and structural tests. PMID:20847115

Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci.

PubMed

Aung, Tin; Ozaki, Mineo; Lee, Mei Chin; Schlötzer-Schrehardt, Ursula; Thorleifsson, Gudmar; Mizoguchi, Takanori; Igo, Robert P; Haripriya, Aravind; Williams, Susan E; Astakhov, Yury S; Orr, Andrew C; Burdon, Kathryn P; Nakano, Satoko; Mori, Kazuhiko; Abu-Amero, Khaled; Hauser, Michael; Li, Zheng; Prakadeeswari, Gopalakrishnan; Bailey, Jessica N Cooke; Cherecheanu, Alina Popa; Kang, Jae H; Nelson, Sarah; Hayashi, Ken; Manabe, Shin-Ichi; Kazama, Shigeyasu; Zarnowski, Tomasz; Inoue, Kenji; Irkec, Murat; Coca-Prados, Miguel; Sugiyama, Kazuhisa; Järvelä, Irma; Schlottmann, Patricio; Lerner, S Fabian; Lamari, Hasnaa; Nilgün, Yildirim; Bikbov, Mukharram; Park, Ki Ho; Cha, Soon Cheol; Yamashiro, Kenji; Zenteno, Juan C; Jonas, Jost B; Kumar, Rajesh S; Perera, Shamira A; Chan, Anita S Y; Kobakhidze, Nino; George, Ronnie; Vijaya, Lingam; Do, Tan; Edward, Deepak P; de Juan Marcos, Lourdes; Pakravan, Mohammad; Moghimi, Sasan; Ideta, Ryuichi; Bach-Holm, Daniella; Kappelgaard, Per; Wirostko, Barbara; Thomas, Samuel; Gaston, Daniel; Bedard, Karen; Greer, Wenda L; Yang, Zhenglin; Chen, Xueyi; Huang, Lulin; Sang, Jinghong; Jia, Hongyan; Jia, Liyun; Qiao, Chunyan; Zhang, Hui; Liu, Xuyang; Zhao, Bowen; Wang, Ya-Xing; Xu, Liang; Leruez, Stéphanie; Reynier, Pascal; Chichua, George; Tabagari, Sergo; Uebe, Steffen; Zenkel, Matthias; Berner, Daniel; Mossböck, Georg; Weisschuh, Nicole; Hoja, Ursula; Welge-Luessen, Ulrich-Christoph; Mardin, Christian; Founti, Panayiota; Chatzikyriakidou, Anthi; Pappas, Theofanis; Anastasopoulos, Eleftherios; Lambropoulos, Alexandros; Ghosh, Arkasubhra; Shetty, Rohit; Porporato, Natalia; Saravanan, Vijayan; Venkatesh, Rengaraj; Shivkumar, Chandrashekaran; Kalpana, Narendran; Sarangapani, Sripriya; Kanavi, Mozhgan R; Beni, Afsaneh Naderi; Yazdani, Shahin; Lashay, Alireza; Naderifar, Homa; Khatibi, Nassim; Fea, Antonio; Lavia, Carlo; Dallorto, Laura; Rolle, Teresa; Frezzotti, Paolo; Paoli, Daniela; Salvi, Erika; Manunta, Paolo; Mori, Yosai; Miyata, Kazunori; Higashide, Tomomi; Chihara, Etsuo; Ishiko, Satoshi; Yoshida, Akitoshi; Yanagi, Masahide; Kiuchi, Yoshiaki; Ohashi, Tsutomu; Sakurai, Toshiya; Sugimoto, Takako; Chuman, Hideki; Aihara, Makoto; Inatani, Masaru; Miyake, Masahiro; Gotoh, Norimoto; Matsuda, Fumihiko; Yoshimura, Nagahisa; Ikeda, Yoko; Ueno, Morio; Sotozono, Chie; Jeoung, Jin Wook; Sagong, Min; Park, Kyu Hyung; Ahn, Jeeyun; Cruz-Aguilar, Marisa; Ezzouhairi, Sidi M; Rafei, Abderrahman; Chong, Yaan Fun; Ng, Xiao Yu; Goh, Shuang Ru; Chen, Yueming; Yong, Victor H K; Khan, Muhammad Imran; Olawoye, Olusola O; Ashaye, Adeyinka O; Ugbede, Idakwo; Onakoya, Adeola; Kizor-Akaraiwe, Nkiru; Teekhasaenee, Chaiwat; Suwan, Yanin; Supakontanasan, Wasu; Okeke, Suhanya; Uche, Nkechi J; Asimadu, Ifeoma; Ayub, Humaira; Akhtar, Farah; Kosior-Jarecka, Ewa; Lukasik, Urszula; Lischinsky, Ignacio; Castro, Vania; Grossmann, Rodolfo Perez; Sunaric Megevand, Gordana; Roy, Sylvain; Dervan, Edward; Silke, Eoin; Rao, Aparna; Sahay, Priti; Fornero, Pablo; Cuello, Osvaldo; Sivori, Delia; Zompa, Tamara; Mills, Richard A; Souzeau, Emmanuelle; Mitchell, Paul; Wang, Jie Jin; Hewitt, Alex W; Coote, Michael; Crowston, Jonathan G; Astakhov, Sergei Y; Akopov, Eugeny L; Emelyanov, Anton; Vysochinskaya, Vera; Kazakbaeva, Gyulli; Fayzrakhmanov, Rinat; Al-Obeidan, Saleh A; Owaidhah, Ohoud; Aljasim, Leyla Ali; Chowbay, Balram; Foo, Jia Nee; Soh, Raphael Q; Sim, Kar Seng; Xie, Zhicheng; Cheong, Augustine W O; Mok, Shi Qi; Soo, Hui Meng; Chen, Xiao Yin; Peh, Su Qin; Heng, Khai Koon; Husain, Rahat; Ho, Su-Ling; Hillmer, Axel M; Cheng, Ching-Yu; Escudero-Domínguez, Francisco A; González-Sarmiento, Rogelio; Martinon-Torres, Frederico; Salas, Antonio; Pathanapitoon, Kessara; Hansapinyo, Linda; Wanichwecharugruang, Boonsong; Kitnarong, Naris; Sakuntabhai, Anavaj; Nguyn, Hip X; Nguyn, Giang T T; Nguyn, Trình V; Zenz, Werner; Binder, Alexander; Klobassa, Daniela S; Hibberd, Martin L; Davila, Sonia; Herms, Stefan; Nöthen, Markus M; Moebus, Susanne; Rautenbach, Robyn M; Ziskind, Ari; Carmichael, Trevor R; Ramsay, Michele; Álvarez, Lydia; García, Montserrat; González-Iglesias, Héctor; Rodríguez-Calvo, Pedro P; Fernández-Vega Cueto, Luis; Oguz, Çilingir; Tamcelik, Nevbahar; Atalay, Eray; Batu, Bilge; Aktas, Dilek; Kasım, Burcu; Wilson, M Roy; Coleman, Anne L; Liu, Yutao; Challa, Pratap; Herndon, Leon; Kuchtey, Rachel W; Kuchtey, John; Curtin, Karen; Chaya, Craig J; Crandall, Alan; Zangwill, Linda M; Wong, Tien Yin; Nakano, Masakazu; Kinoshita, Shigeru; den Hollander, Anneke I; Vesti, Eija; Fingert, John H; Lee, Richard K; Sit, Arthur J; Shingleton, Bradford J; Wang, Ningli; Cusi, Daniele; Qamar, Raheel; Kraft, Peter; Pericak-Vance, Margaret A; Raychaudhuri, Soumya; Heegaard, Steffen; Kivelä, Tero; Reis, André; Kruse, Friedrich E; Weinreb, Robert N; Pasquale, Louis R; Haines, Jonathan L; Thorsteinsdottir, Unnur; Jonasson, Fridbert; Allingham, R Rand; Milea, Dan; Ritch, Robert; Kubota, Toshiaki; Tashiro, Kei; Vithana, Eranga N; Micheal, Shazia; Topouzis, Fotis; Craig, Jamie E; Dubina, Michael; Sundaresan, Periasamy; Stefansson, Kari; Wiggs, Janey L; Pasutto, Francesca; Khor, Chiea Chuen

2017-07-01

Exfoliation syndrome (XFS) is the most common known risk factor for secondary glaucoma and a major cause of blindness worldwide. Variants in two genes, LOXL1 and CACNA1A, have previously been associated with XFS. To further elucidate the genetic basis of XFS, we collected a global sample of XFS cases to refine the association at LOXL1, which previously showed inconsistent results across populations, and to identify new variants associated with XFS. We identified a rare protective allele at LOXL1 (p.Phe407, odds ratio (OR) = 25, P = 2.9 × 10 -14 ) through deep resequencing of XFS cases and controls from nine countries. A genome-wide association study (GWAS) of XFS cases and controls from 24 countries followed by replication in 18 countries identified seven genome-wide significant loci (P < 5 × 10 -8 ). We identified association signals at 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A). These findings provide biological insights into the pathology of XFS and highlight a potential role for naturally occurring rare LOXL1 variants in disease biology.

Scanning laser polarimetry in eyes with exfoliation syndrome.

PubMed

Dimopoulos, Antonios T; Katsanos, Andreas; Mikropoulos, Dimitrios G; Giannopoulos, Theodoros; Empeslidis, Theodoros; Teus, Miguel A; Holló, Gábor; Konstas, Anastasios G P

2013-01-01

To compare retinal nerve fiber layer thickness (RNFLT) of normotensive eyes with exfoliation syndrome (XFS) and healthy eyes.
 Sixty-four consecutive individuals with XFS and normal office-time intraocular pressure (IOP) and 72 consecutive healthy controls were prospectively enrolled for a cross-sectional analysis in this hospital-based observational study. The GDx-VCC parameters (temporal-superior-nasal-inferior-temporal [TSNIT] average, superior average, inferior average, TSNIT standard deviation (SD), and nerve fiber indicator [NFI]) were compared between groups. Correlation between various clinical parameters and RNFLT parameters was investigated with Spearman coefficient. 
 The NFI, although within normal limits for both groups, was significantly greater in the XFS group compared to controls: the respective median and interquartile range (IQR) values were 25.1 (22.0-29.0) vs 15.0 (12.0-20.0), p<0.001. In the XFS group, all RNFLT values were significantly lower compared to controls (p<0.001). However, they were all within the normal clinical ranges for both groups: TSNIT average median (IQR): 52.8 (49.7-55.7) vs 56.0 (53.0-59.3) µm; superior average mean (SD): 62.3 (6.7) vs 68.8 (8.2) µm; inferior average mean (SD): 58.0 (7.2) vs 64.8 (7.7) µm, respectively. TSNIT SD was significantly lower in the XFS group, median (IQR): 18.1 (15.4-20.4) vs 21.0 (18.4-23.8), p<0.001. There was no systematic relationship between RNFLT and visual acuity, cup-to-disc ratio, IOP, central corneal thickness, Humphrey mean deviation, and pattern standard deviation in either group. 
 Compared to control eyes, polarimetry-determined RNFLT was lower in XFS eyes with normal IOP. Therefore, close monitoring of RNFLT may facilitate early identification of those XFS eyes that convert to exfoliative glaucoma.

Glaucoma screening during regular optician visits: can the population at risk of developing glaucoma be reached?

PubMed Central

Stoutenbeek, R; Jansonius, N M

2006-01-01

Aim To determine the percentage of the population at risk of developing glaucoma, which can potentially be reached by conducting glaucoma screening during regular optician visits. Methods 1200 inhabitants aged >40 years were randomly selected from Dutch community population databases. A questionnaire was mailed to these inhabitants with questions on their latest optician visit and risk factors for glaucoma. A second questionnaire was sent to their opticians, who were asked about their willingness to conduct an additional glaucoma screening programme in the future. Results The questionnaire was returned by 959 of 1200 inhabitants and 37 of 50 opticians. The percentage of inhabitants who visited an optician during a 5‐year period was 83% (95% confidence interval (CI) 80% to 85%). This percentage was adjusted for the presence of risk factors for glaucoma to obtain the percentage of the population at risk of developing glaucoma. The percentage of opticians willing to cooperate in a glaucoma screening programme extended beyond a non‐contact tonometry measurement alone was 91% (95% CI 77% to 98%). Conclusion By conducting glaucoma screening during regular optician visits, a large section of the population at risk of developing glaucoma can be reached. PMID:16854829

Glaucoma screening during regular optician visits: can the population at risk of developing glaucoma be reached?

PubMed

Stoutenbeek, R; Jansonius, N M

2006-10-01

To determine the percentage of the population at risk of developing glaucoma, which can potentially be reached by conducting glaucoma screening during regular optician visits. 1,200 inhabitants aged >40 years were randomly selected from Dutch community population databases. A questionnaire was mailed to these inhabitants with questions on their latest optician visit and risk factors for glaucoma. A second questionnaire was sent to their opticians, who were asked about their willingness to conduct an additional glaucoma screening programme in the future. The questionnaire was returned by 959 of 1,200 inhabitants and 37 of 50 opticians. The percentage of inhabitants who visited an optician during a 5-year period was 83% (95% confidence interval (CI) 80% to 85%). This percentage was adjusted for the presence of risk factors for glaucoma to obtain the percentage of the population at risk of developing glaucoma. The percentage of opticians willing to cooperate in a glaucoma screening programme extended beyond a non-contact tonometry measurement alone was 91% (95% CI 77% to 98%). By conducting glaucoma screening during regular optician visits, a large section of the population at risk of developing glaucoma can be reached.

Clinical management outcomes of childhood glaucoma suspects.

PubMed

Greenberg, Matthew B; Osigian, Carla J; Cavuoto, Kara M; Chang, Ta C

2017-01-01

To investigate the outcomes of childhood glaucoma suspects. Retrospective case series. Records of childhood glaucoma suspects were identified using financial claims data; medical history, baseline biometric and exam findings were recorded. Conversion from suspect to glaucoma was determined based on the Childhood Glaucoma Research Network criteria. The study adheres to the tenets of the Declarations of Helsinki. 214 subjects were enrolled, with median age at initial presentation of 6.37 years (interquartertile range: Q1 = 2.46, Q3 = 8.90). 22 (10.2%) subjects developed glaucoma, 64 (29.9%) had ocular hypertension but no glaucoma, 9 (4.2%) had high-risk condition or syndrome without either ocular hypertension or glaucoma after a mean follow up of 39 +/- 34 months. Neither a family history of glaucoma nor patient gender was significantly different between the groups. 40.2% of subjects (86 of 214) had two or more episodes of intraocular pressure (IOP) > 21 mmHg, among which 25.6% (22 of 86) developed glaucoma after a mean duration of 32.8 +/- 33.5 months. Up to 25% of children with 2 or more episodes of elevated IOP may develop glaucoma. In 50% of suspects who converted to glaucoma, elevated IOP was not present at the initial evaluation. There is no significant difference in gender, family history, or baseline central corneal thickness between suspects who developed glaucoma compared to the rest. While suspects who converted to glaucoma had higher average, maximum and minimum IOP measurements, there is no clear cutoff between the groups.

Prospective evaluation of CO2 laser-assisted sclerectomy surgery (CLASS) with Mitomycin C.

PubMed

Cutolo, Carlo Alberto; Bagnis, Alessandro; Scotto, Riccardo; Bonzano, Chiara; Traverso, Carlo Enrico

2018-01-01

Our purpose was to evaluate the clinical safety and efficacy of CO 2 laser-assisted sclerectomy surgery (CLASS) with Mitomycin C (MMC) in open angle glaucoma (OAG). This was a prospective, uncontrolled, interventional case series. All subjects underwent CLASS procedure by a single surgeon. After the dissection of a partial thickness scleral flap, topical MMC 0.2 mg/ml was applied to the sclera and the conjunctiva for 3 min. The CO 2 laser with a beam-manipulating system was used to ablate the scleral tissue and expose the Schlemm's canal area. Primary outcomes: intraocular pressure (IOP) change, number of IOP-lowering medicaments change. Adverse events were evaluated as secondary outcomes. Twenty-one eyes of 21 patients underwent the CLASS procedure. Thirteen were primary OAG (62%), two normal pressure glaucoma (10%), three exfoliative glaucoma (14%) and three others secondary OAG. With a mean (SD) follow-up of 15.3 (5.9) months, the IOP changed from 25.4 (6.7) mmHg at baseline to 10.9 (3.4) mmHg al the last visit. Mean reduction of IOP was -14.5 mmHg (95% CI, -17.7 to -11.2, P < 0.001). The median (IQR) number of IOP-lowering medication decreased from 3 (3-3) at baseline to 1 (0-1) at the last visit (P < 0.001). Visual acuity did not change significantly. Adverse events: five eyes (24%) developed iris adhesion to the filtration area that was successfully managed with office-based procedures. In one case (5%), CLASS was converted to trabeculectomy due to intraoperative perforation of the ablated area. There was one case of hypotony maculopathy successfully treated with placement of additional transconjunctival scleral flap sutures. The CLASS procedure with MMC is clinically safe and effective maintaining a large reduction in IOP and in the number of IOP-lowering medications with a mean follow-up of 15 months. Iris adhesion at the filtrating area warrants further evaluation and possibly reflects the surgeon's learning curve.

A Plasma Metabolomic Signature of the Exfoliation Syndrome Involves Amino Acids, Acylcarnitines, and Polyamines.

PubMed

Leruez, Stéphanie; Bresson, Thomas; Chao de la Barca, Juan M; Marill, Alexandre; de Saint Martin, Grégoire; Buisset, Adrien; Muller, Jeanne; Tessier, Lydie; Gadras, Cédric; Verny, Christophe; Amati-Bonneau, Patrizia; Lenaers, Guy; Gohier, Philippe; Bonneau, Dominique; Simard, Gilles; Milea, Dan; Procaccio, Vincent; Reynier, Pascal

2018-02-01

To determine the plasma metabolomic signature of the exfoliative syndrome (XFS), the most common cause worldwide of secondary open-angle glaucoma. We performed a targeted metabolomic study, using the standardized p180 Biocrates Absolute IDQ p180 kit with a QTRAP 5500 mass spectrometer, to compare the metabolomic profiles of plasma from individuals with XFS (n = 16), and an age- and sex-matched control group with cataract (n = 18). A total of 151 metabolites were detected correctly, 16 of which allowed for construction of an OPLS-DA model with a good predictive capability (Q2cum = 0.51) associated with a low risk of over-fitting (permQ2 = -0.48, CV-ANOVA P-value <0.001). The metabolites contributing the most to the signature were octanoyl-carnitine (C8) and decanoyl-carnitine (C10), the branched-chain amino acids (i.e., isoleucine, leucine, and valine), and tyrosine, all of which were at higher concentrations in the XFS group, whereas spermine and spermidine, together with their precursor acetyl-ornithine, were at lower concentrations than in the control group. We identified a significant metabolomic signature in the plasma of individuals with XFS. Paradoxically, this signature, characterized by lower concentrations of the neuroprotective spermine and spermidine polyamines than in controls, partially overlaps the plasma metabolomic profile associated with insulin resistance, despite the absence of evidence of insulin resistance in XFS.

What is the risk of developing pigmentary glaucoma from pigment dispersion syndrome?

PubMed

Siddiqui, Yasmin; Ten Hulzen, Richard D; Cameron, J Douglas; Hodge, David O; Johnson, Douglas H

2003-06-01

To determine the probability of converting from pigment dispersion syndrome to pigmentary glaucoma. Retrospective community-based study of all newly diagnosed cases of pigment dispersion syndrome or pigmentary glaucoma. Subjects were patients newly diagnosed with pigment dispersion syndrome or pigmentary glaucoma from 1976 to 1999 in Olmsted County, Minnesota. Criteria for pigment dispersion syndrome were two of three signs: midperipheral, radial iris transillumination defects; Krukenberg spindle; heavy trabecular meshwork pigmentation. Criteria for pigmentary glaucoma were pigment dispersion syndrome and two of three findings: intraocular pressure (IOP) greater than 21 mm, optic nerve damage, or visual field loss. Kaplan-Meier survival curves were used to determine the probability of conversion to pigmentary glaucoma. A total of 113 patients were newly diagnosed with pigment dispersion syndrome over the 24-year period. Of these, 9 persons developed pigmentary glaucoma or elevated IOP requiring therapy. The probability of converting to pigmentary glaucoma was 10% at 5 years and 15% at 15 years. An additional 23 patients were found to have pigmentary glaucoma at their initial examination. The mean age at diagnosis of pigmentary glaucoma was 42 +/- 12 years; 78% of patients were male, whereas 58% of patients with pigmentary dispersion syndrome glaucoma were male. The most significant risk factor for conversion to pigmentary glaucoma was an IOP greater than 21 mm Hg at initial examination, whereas age, refractive error, and family history of glaucoma were not correlated with conversion. The risk of developing pigmentary glaucoma from pigment dispersion syndrome was 10% at 5 years and 15% at 15 years. Young, myopic men were most likely to have pigmentary glaucoma. An IOP greater than 21 mm Hg at initial examination was associated with an increased risk of conversion.

Ocular hemodynamics and glaucoma: the role of mathematical modeling.

PubMed

Harris, Alon; Guidoboni, Giovanna; Arciero, Julia C; Amireskandari, Annahita; Tobe, Leslie A; Siesky, Brent A

2013-01-01

To discuss the role of mathematical modeling in studying ocular hemodynamics, with a focus on glaucoma. We reviewed recent literature on glaucoma, ocular blood flow, autoregulation, the optic nerve head, and the use of mathematical modeling in ocular circulation. Many studies suggest that alterations in ocular hemodynamics play a significant role in the development, progression, and incidence of glaucoma. Although there is currently a limited number of studies involving mathematical modeling of ocular blood flow, regulation, and diseases (such as glaucoma), preliminary modeling work shows the potential of mathematical models to elucidate the mechanisms that contribute most significantly to glaucoma progression. Mathematical modeling is a useful tool when used synergistically with clinical and laboratory data in the study of ocular blood flow and glaucoma. The development of models to investigate the relationship between ocular hemodynamic alterations and glaucoma progression will provide a unique and useful method for studying the pathophysiology of glaucoma.

Large Area Atomically Flat Surfaces via Exfoliation of Bulk Bi 2Se 3 Single Crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melamed, Celeste L.; Ortiz, Brenden R.; Gorai, Prashun

In this paper, we present an exfoliation method that produces cm 2-area atomically flat surfaces from bulk layered single crystals, with broad applications such as for the formation of lateral heterostructures and for use as substrates for van der Waals epitaxy. Single crystals of Bi 2Se 3 were grown using the Bridgman method and examined with X-ray reciprocal space maps, Auger spectroscopy, low-energy electron diffraction, and X-ray photoelectron spectroscopy. An indium-bonding exfoliation technique was developed that produces multiple ~100 um thick atomically flat, macroscopic (>1 cm 2) slabs from each Bi 2Se 3 source crystal. Two-dimensional X-ray diffraction and reciprocalmore » space maps confirm the high crystalline quality of the exfoliated surfaces. Atomic force microscopy reveals that the exfoliated surfaces have an average root-mean-square (RMS) roughness of ~0.04 nm across 400 μm 2 scans and an average terrace width of 70 um between step edges. First-principles calculations reveal exfoliation energies of Bi 2Se 3 and a number of other layered compounds, which demonstrate relevance of our method across the field of 2D materials. While many potential applications exist, excellent lattice matching with the III-V alloy space suggests immediate potential for the use of these exfoliated layered materials as epitaxial substrates for photovoltaic development.« less

Large Area Atomically Flat Surfaces via Exfoliation of Bulk Bi 2Se 3 Single Crystals

DOE PAGES

Melamed, Celeste L.; Ortiz, Brenden R.; Gorai, Prashun; ...

2017-09-12

In this paper, we present an exfoliation method that produces cm 2-area atomically flat surfaces from bulk layered single crystals, with broad applications such as for the formation of lateral heterostructures and for use as substrates for van der Waals epitaxy. Single crystals of Bi 2Se 3 were grown using the Bridgman method and examined with X-ray reciprocal space maps, Auger spectroscopy, low-energy electron diffraction, and X-ray photoelectron spectroscopy. An indium-bonding exfoliation technique was developed that produces multiple ~100 um thick atomically flat, macroscopic (>1 cm 2) slabs from each Bi 2Se 3 source crystal. Two-dimensional X-ray diffraction and reciprocalmore » space maps confirm the high crystalline quality of the exfoliated surfaces. Atomic force microscopy reveals that the exfoliated surfaces have an average root-mean-square (RMS) roughness of ~0.04 nm across 400 μm 2 scans and an average terrace width of 70 um between step edges. First-principles calculations reveal exfoliation energies of Bi 2Se 3 and a number of other layered compounds, which demonstrate relevance of our method across the field of 2D materials. While many potential applications exist, excellent lattice matching with the III-V alloy space suggests immediate potential for the use of these exfoliated layered materials as epitaxial substrates for photovoltaic development.« less

Incidence and Management of Glaucoma in Vogt Koyanagi Harada Disease.

PubMed

Pandey, Amit; Balekudaru, Shantha; Venkatramani, Devendra V; George, Amala E; Lingam, Vijaya; Biswas, Jyotirmay

2016-08-01

To analyse the prevalence, incidence, and risk factors of glaucoma in Vogt Koyanagi Harada (VKH) disease and study the changes in visual acuity and intraocular pressure (IOP) with treatment. Retrospective chart analysis of 448 eyes of 224 patients of Indian origin diagnosed with VKH disease from January 1990 to December 2013, who had a minimum follow-up of 3 months was performed. Seventy-one eyes (15.8%) developed sustained elevation in IOP. The prevalence of glaucoma at presentation was 15.8% and the cumulative incidence of glaucoma was 11.7%. The mechanisms of glaucoma were open-angle glaucoma in 46 eyes, (64.8%), angle closure in 21 eyes (29.6%), and of combined mechanisms in the remainder (4 eyes, 5.6%). Acute angle-closure crisis developed in 9 eyes (12.6%). Uveal effusion (odds ratio 9.47; confidence interval, 4.08-20.03) and increased number of recurrences (odds ratio 1.31; confidence interval, 1.13-1.53) were found to be significant risk factors for the development of glaucoma. Successful control of IOP was achieved in 64% at 12 months using medical/ laser treatment for glaucoma and was 50 % at 12 months following surgical management. Glaucoma is a frequent complication of uveitis in VKH disease. Presence of uveal effusion and increased number of recurrences of inflammation are significant risk factors.

Incidence of and risk factors for glaucoma in lost-to-follow-up normal-tension glaucoma suspect patients.

PubMed

Lim, Jong Hoon; Park, Jun Sang; Lee, So Yeon; Hong, Young Jae

2016-05-25

To investigate the incidence and risk factors of glaucoma in normal-tension glaucoma (NTG) suspect patients who had been lost-to-follow-up for at least 24 months. Seventy-two eyes of 72 NTG suspect patients who returned to the hospital after at least 24 months of follow-up loss were enrolled in this study between January 2009 and June 2013. The data were collected retrospectively. The incidence of glaucoma was investigated using a comprehensive glaucoma evaluation in lost-to-follow-up NTG suspect patients. The patients were classified into the glaucoma group, who developed glaucoma during the study period, and the glaucoma suspect group, who did not, to analyse the risk factors for glaucoma. The number of patients who developed glaucoma was 7 (9.7 %) out of the 72 NTG suspect patients who had been mean lost-to-follow-up for 44 months. The rate of progression from suspected to glaucoma was 2.6 %/year. In the glaucoma group, the baseline intraocular pressure (IOP) was 18.43 ± 2.44 mmHg, and the average retinal nerve fiber layer (RNFL) thickness was 78.14 ± 7.60 μm; in the glaucoma suspect group, the baseline IOP was 14.95 ± 2.47 mmHg, and the average RNFL thickness was 92.55 ± 7.65 μm. The study results showed that the glaucoma group had higher baseline IOP and a thinner average RNFL (p = 0.003; p < 0.001). The results of the multivariable logistic regression analysis showed that the risk factors for glaucoma were high baseline IOP (OR = 1.63; p = 0.037) and a thin average RNFL (OR = 0.841; p = 0.004). The incidence of glaucoma in the lost-to-follow-up NTG suspect patients was 9.7 % for approximately 44 months, at a rate of 2.6 %/year. The risk factors for glaucoma in these patients were high baseline IOP and a thin average RNFL.

Linkage analysis excludes the glaucoma locus on 1q from involvement in autosomal dominant glaucoma with iris hypoplasia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heon, E.; Sheth, B.P.; Kalenak, J.W.

1994-09-01

Genetic factors have been implicated in a variety of types of glaucoma including primary open-angle glaucoma, infantile glaucoma, pigmentary glaucoma, and juvenile open-angle glaucoma. We previously mapped the disease-causing gene for one type of juvenile open angle glaucoma to chromosome 1q21-31. Weatherill and Hart (1969) and Pearce (1983) each noted the association of iris hypoplasia and early-onset autosomal dominant glaucoma. We recently had the opportunity to study a large family (12 affected members) with this phenotype. Affected individuals developed glaucoma at an average age of 30 years. These patients also have a strikingly underdeveloped iris stroma which causes a peculiarmore » eye color. Linkage analysis was able to completely exclude the 1q glaucoma locus from involvement in the disorder that affects this family. A complete clinical description of the family and linkage results at additional candidate loci will be presented.« less

The Evonik-Mainz Eye Care-Study (EMECS): Development of an Expert System for Glaucoma Risk Detection in a Working Population.

PubMed

Wahl, Jochen; Barleon, Lorenz; Morfeld, Peter; Lichtmeß, Andrea; Haas-Brähler, Sibylle; Pfeiffer, Norbert

2016-01-01

To develop an expert system for glaucoma screening in a working population based on a human expert procedure using images of optic nerve head (ONH), visual field (frequency doubling technology, FDT) and intraocular pressure (IOP). 4167 of 13037 (32%) employees between 40 and 65 years of Evonik Industries were screened. An experienced glaucoma expert (JW) assessed papilla parameters and evaluated all individual screening results. His classification into "no glaucoma", "possible glaucoma" and "probable glaucoma" was defined as "gold standard". A screening model was developed which was tested versus the gold-standard. This model took into account the assessment of the ONH. Values and relationships of CDR and IOP and the FDT were considered additionally and a glaucoma score was generated. The structure of the screening model was specified a priori whereas values of the parameters were chosen post-hoc to optimize sensitivity and specificity of the algorithm. Simple screening models based on IOP and / or FDT were investigated for comparison. 111 persons (2.66%) were classified as glaucoma suspects, thereof 13 (0.31%) as probable and 98 (2.35%) as possible glaucoma suspects by the expert. Re-evaluation by the screening model revealed a sensitivity of 83.8% and a specificity of 99.6% for all glaucoma suspects. The positive predictive value of the model was 80.2%, the negative predictive value 99.6%. Simple screening models showed insufficient diagnostic accuracy. Adjustment of ONH and symmetry parameters with respect to excavation and IOP in an expert system produced sufficiently satisfying diagnostic accuracy. This screening model seems to be applicable in such a working population with relatively low age and low glaucoma prevalence. Different experts should validate the model in different populations.

Equine Glaucoma.

PubMed

Michau, Tammy Miller

2017-12-01

Glaucoma is a multifactorial neurodegenerative ocular disease leading to progressive loss of retinal ganglion cells and their axons that form the optic nerve, causing blindness. Knowledge of the pathogenesis and development of equine glaucoma is in its infancy compared with human glaucoma. Glaucoma occurs most commonly secondary to uveitis and may be underdiagnosed or misdiagnosed in horses suffering from uveitis. Recognition and clinical diagnosis of glaucoma in the horse is improved with clinician awareness and the availability of handheld tonometers. Therapy for glaucoma is aimed at decreasing aqueous humor production through medical and surgical means. Even with therapy, long-term prognosis for vision is poor. Copyright © 2017 Elsevier Inc. All rights reserved.

New pharmacotherapy for the treatment of glaucoma.

PubMed

Schehlein, Emily M; Novack, Gary; Robin, Alan L

2017-12-01

Glaucoma is the second leading cause of blindness in the world and current pharmacotherapies for glaucoma have remained relatively unchanged (with the exception of fixed combinations of previously available medications) since the mid-1990s with the development of prostaglandin analogues. Now, with both new formulations and new classes of medications with novel mechanisms of action, the medical therapy of glaucoma may be heralding a new dawn in medical management. Areas covered: This review outlines new topical therapies for intraocular pressure (IOP) lowering treatment, in addition to new formulations, preservative-free options, and advances in glaucoma medical therapy delivery. We performed a comprehensive search for published studies for glaucoma medical therapy using the electronic database PubMed. A manual search for each therapy or delivery system was also performed. Expert commentary: These advances in glaucoma therapy have the potential to overcome many barriers to glaucoma's medical care, particularly in terms of adherence. However, both time and research are needed to prove the relative efficacy and safety of these new pharmacotherapies and products, helping us decide their role in the treatment of elevated intraocular pressure. We are hopeful that these new developments in therapy may bring more options for glaucoma medical therapy.

[Bibliometric analysis of current glaucoma research based on Pubmed database].

PubMed

Huang, Wen-bin; Wang, Wei; Zhou, Min-wen; Chen, Shi-da; Zhang, Xiu-lan

2013-11-01

To survey the distribution pattern and subject domain knowledge of worldwide glaucoma research based on literatures in Pubmed database. Literatures on glaucoma published in 2007 to 2011 were identified in Pubmed database. The analytic items of an article include published year, country, language author, and journal. After core mesh terms had been characterized by BICOMS, the co-occurrence matrix was built. Cluster analysis was finished by SPSS 20.0. Then visualized network was drawn using ucinet 6.0. Totally 6427 literatures were included, the number of annual articles changed slightly between 2007 and 2011. The United States, England, Germany, Australia, and France together accounted for 77.63% of articles. There were 52 high-frequency subjects and hot topics were clustered into the following 10 categories: (1) Pathology of optic disc and nerve fibers and OCT application, (2) METHODS: of visual field (VF) and visual function examination, (3) Glaucoma drug medications, (4) Pathology and physiology of primary open angle glaucoma (POAG) including VF and intraocular pressure (IOP), (5) Glaucoma surgery, (6) Gene research related to POAG, (7) Glaucoma disease pathology and animal models, (8) Ocular hypertension (OHT) induced complications and corneal changes, (9) Etiology of congenital glaucoma and complications, (10) Etiology and epidemiology of glaucoma. The visualized domain knowledge mapping was successfully built. The pathology of optic disc and nerve fibers, medications, and surgery were well developed. Study on IOP and visual field was in the core domain, which have an important link to etiology, diagnosis, and therapy. The researches on glaucomatous gene, disease pathology model, congenital glaucoma, etiology and epidemiology were not developed well, which are of great promotion space. The distribution pattern and subject domain knowledge of worldwide glaucoma research in the recent five years were shown by using bibliometric analysis.Western developed countries play a leading role in the field of glaucoma research, the international influence of related research in China needs to be strengthened.

Improved systemic safety and risk-benefit ratio of topical 0.1% timolol hydrogel compared with 0.5% timolol aqueous solution in the treatment of glaucoma.

PubMed

Uusitalo, Hannu; Kähönen, Mika; Ropo, Auli; Mäenpää, Jukka; Bjärnhall, Gunilla; Hedenström, Hans; Turjanmaa, Väinö

2006-11-01

The purpose of the study was to compare the systemic safety and risk-benefit ratio of 0.1% timolol hydrogel and 0.5% aqueous timolol eye drops in the treatment of glaucoma. An 8-week randomised, double-blind, cross-over, multicentre study. A total of 25 patients with primary open-angle glaucoma, exfoliation glaucoma, or ocular hypertension was enrolled. After completing a wash-out period, patients were randomly chosen to receive either 0.1% timolol hydrogel once daily or 0.5% aqueous timolol eye drops twice daily. Intraocular pressure and heart rate during rest and exercise, head-up tilt test results, spirometry readings, and plasma concentrations of timolol were recorded. The risk-benefit ratio was determined by calculating the ratio between several heart rate endpoints and the change in intraocular pressure (IOP). The mean drug-induced change in the peak heart rate during exercise was -13.5 beats/min (SD 7.6) in the 0.5% aqueous timolol group and -5.1 beats/min (SD 6.7) in the 0.1% timolol hydrogel group (P<0.001; 95% CI 4.06-12.18). There was no significant difference in the IOP-reducing efficacy between these compounds. The risk-benefit ratio was significantly improved when 0.1% timolol hydrogel was used, compared with 0.5% aqueous timolol in the exercise test. In the head-up tilt test the risk-benefit ratio was significantly improved at rest (P<0.05), at 1 min (P<0.05) and at 5 min (P<0.001) after patients had received 0.1% timolol hydrogel. There were, however, no differences in spirometry readings. After patients had been treated with 0.1% timolol hydrogel, plasma concentrations of timolol were 1/6 (at peak) and 1/50 (at trough) of those of 0.5% aqueous timolol. Drug-induced changes in the peak heart rate, and head-up tilt test results as well as plasma concentrations of timolol, were significantly more pronounced after treatment with 0.5% aqueous timolol than with 0.1% timolol hydrogel. Because of the statistically similar IOP-reducing efficacy of these formulations the risk-benefit ratio was significantly improved when patients used 0.1% timolol hydrogel instead of 0.5% aqueous timolol.

Efficacy and tolerability of fixed-combination brinzolamide/timolol in Latin American patients with open-angle glaucoma or ocular hypertension previously on brimonidine/timolol fixed combination.

PubMed

Alezzandrini, Arturo; Hubatsch, Douglas; Alfaro, Rene

2014-09-01

Fixed-combination glaucoma medications are commonly used to achieve target intraocular pressure (IOP) reduction in patients uncontrolled with monotherapy; however, ocular discomfort associated with eye drops can decrease adherence. This study assessed the efficacy and tolerability of twice-daily fixed-combination brinzolamide 1%/timolol 0.5% (BRINZ/TIM-FC) in Latin American patients transitioned from fixed-combination brimonidine 0.2%/timolol 0.5% (BRIM/TIM-FC) because of insufficient IOP control or treatment intolerance. This 8-week, open-label, prospective study was conducted at six sites in Argentina, Chile, and Mexico. Enrolled patients were aged ≥18 years with open-angle glaucoma (including primary, exfoliative, or pigment-dispersion glaucoma) or ocular hypertension with IOP of 19-35 mmHg in ≥1 eye at baseline (on BRIM/TIM-FC). Patients self-administered BRINZ/TIM-FC to both eyes at 8 a.m. and 8 p.m. daily for 8 weeks. The primary and secondary efficacy endpoints were mean IOP change from baseline at week 8 and percentage of patients achieving target IOP (≤18 mmHg) at week 8, respectively. Exploratory endpoints included patient and investigator preference for treatment at week 8. Adverse events (AEs) were assessed as the safety endpoint. Fifty patients (mean ± SD age, 66.7 ± 11.5 years) received BRINZ/TIM-FC, and 49 were included in the intent-to-treat population. Mean ± SD IOP was significantly reduced from baseline after 8 weeks of treatment with BRINZ/TIM-FC (-3.6 ± 3.0 mmHg; P < 0.0001, Wilcoxon signed-rank test; 17.1% reduction). Overall, 55.3% of patients achieved IOP ≤18 mmHg at week 8. Significantly more patients (89.4%) and investigators (95.7%) preferred BRINZ/TIM-FC to BRIM/TIM-FC (both P < 0.0001, exact binomial test). Of the 13 AEs observed, 8 were related to BRINZ/TIM-FC; the most common treatment-related AEs were eye irritation (n = 4) and abnormal sensation in the eye (n = 2). BRINZ/TIM-FC provides an effective and well-tolerated treatment option for patients transitioned from BRIM/TIM-FC.

Potential applications of optical coherence tomography angiography in glaucoma.

PubMed

Dastiridou, Anna; Chopra, Vikas

2018-05-01

Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging modality that allows assessment of the retinal and choroidal vasculature. The scope of this review is to summarize recent studies using OCTA in glaucoma and highlight potential applications of this new technology in the field of glaucoma. OCTA studies have shown that retinal vascular changes may not develop solely as a result of advanced glaucoma damage. OCTA-derived measurements have provided evidence for lower retinal vascular densities at the optic nerve head, peripapillary and macula in preperimetric-glaucoma and early-glaucoma, as well as, in more advanced glaucoma, in comparison to with normal eyes. OCTA is a novel imaging modality that has already started to expand our knowledge base regarding the role of ocular blood flow in glaucoma. Future studies will better elucidate the role of OCTA-derived measurements in clinical practice, research, and clinical trials in glaucoma.

Current concepts on primary open-angle glaucoma genetics: a contribution to disease pathophysiology and future treatment

PubMed Central

Gemenetzi, M; Yang, Y; Lotery, A J

2012-01-01

Glaucoma is a common, complex, heterogenous disease and it constitutes the major cause of irreversible blindness worldwide. Primary open-angle glaucoma (POAG) is the most common type of glaucoma in all populations. Most of the molecular mechanisms leading to POAG development are still unknown. Gene mutations in various populations have been identified by genetic studies and a genetic basis for glaucoma pathogenesis has been established. Linkage analysis and association studies are genetic approaches in the investigation of the genetic basis of POAG. Genome-wide association studies (GWAS) are more powerful compared with linkage analysis in discovering genes of small effect that might contribute to the development of the disease. POAG links to at least 20 genetic loci, but only 2 genes identified in these loci, myocilin and optineurin, are considered as well-established glaucoma-causing genes, whereas the role of other loci, genes, and variants implicated in the development of POAG remains controversial. Gene mutations associated with POAG result in retinal ganglion cell death, which is the common outcome of pathogenetic mechanisms in glaucoma. In future, if the sensitivity and specificity of genotyping increases, it may be possible to screen individuals routinely for disease susceptibility. This review is an update on the latest progress of genetic studies associated with POAG. It emphasizes the correlation of recent achievements in genetics with glaucoma pathophysiology, glaucoma treatment perspectives, and the possibility of future prevention of irreversible visual loss caused by the disease. PMID:22173078

Glaucoma Suspect: Diagnosis and Management.

PubMed

Chang, Robert T; Singh, Kuldev

2016-01-01

Glaucoma suspect is a diagnosis reserved for individuals who do not definitively have glaucoma at the present time but have characteristics suggesting that they are at high risk of developing the disease in the future based on a variety of factors. This review provides a practical approach to individuals classified as glaucoma suspects caused by one or more of the following risk factors or indicators of disease: ocular hypertension, optic nerve features suggestive of glaucoma, visual field abnormalities, and other characteristics placing them at greater risk than the average population. In addition to diagnostic considerations, this overview provides information on therapeutic approaches to the glaucoma suspect.

Ocular-specific ER stress reduction rescues glaucoma in murine glucocorticoid-induced glaucoma

PubMed Central

Zode, Gulab S.; Sharma, Arti B.; Lin, Xiaolei; Searby, Charles C.; Bugge, Kevin; Kim, Gun Hee; Clark, Abbot F.; Sheffield, Val C.

2014-01-01

Administration of glucocorticoids induces ocular hypertension in some patients. If untreated, these patients can develop a secondary glaucoma that resembles primary open-angle glaucoma (POAG). The underlying pathology of glucocorticoid-induced glaucoma is not fully understood, due in part to lack of an appropriate animal model. Here, we developed a murine model of glucocorticoid-induced glaucoma that exhibits glaucoma features that are observed in patients. Treatment of WT mice with topical ocular 0.1% dexamethasone led to elevation of intraocular pressure (IOP), functional and structural loss of retinal ganglion cells, and axonal degeneration, resembling glucocorticoid-induced glaucoma in human patients. Furthermore, dexamethasone-induced ocular hypertension was associated with chronic ER stress of the trabecular meshwork (TM). Similar to patients, withdrawal of dexamethasone treatment reduced elevated IOP and ER stress in this animal model. Dexamethasone induced the transcriptional factor CHOP, a marker for chronic ER stress, in the anterior segment tissues, and Chop deletion reduced ER stress in these tissues and prevented dexamethasone-induced ocular hypertension. Furthermore, reduction of ER stress in the TM with sodium 4-phenylbutyrate prevented dexamethasone-induced ocular hypertension in WT mice. Our data indicate that ER stress contributes to glucocorticoid-induced ocular hypertension and suggest that reducing ER stress has potential as a therapeutic strategy for treating glucocorticoid-induced glaucoma. PMID:24691439

Glaucoma as an early complication of Hurler's disease.

PubMed Central

Nowaczyk, M J; Clarke, J T; Morin, J D

1988-01-01

We report three cases of Hurler's disease in which glaucoma developed in early childhood. We draw attention to the fact that glaucoma may be a commonly unrecognised early complication of this condition. PMID:3140740

The European Glaucoma Society Glaucocard project: improved digital documentation of medical data for glaucoma patients based on standardized structured international datasets.

PubMed

Schargus, Marc; Grehn, Franz; Glaucocard Workgroup

2008-12-01

To evaluate existing international IT-based ophthalmological medical data projects, and to define a glaucoma data set based on existing international standards of medical and ophthalmological documentation. To develop the technical environment for easy data mining and data exchange in different countries in Europe. Existing clinical and IT-based projects for documentation of medical data in general medicine and ophthalmology were analyzed to create new data sets for medical documentation in glaucoma patients. Different types of data transfer methods were evaluated to find the best method of data exchange between ophthalmologists in different European countries. Data sets from existing IT projects showed a wide variability in specifications, use of codes, terms and graphical data (perimetry, optic nerve analysis etc.) in glaucoma patients. New standardized digital datasets for glaucoma patients were defined, based on existing standards, which can be used by general ophthalmologists for follow-up examinations and for glaucoma specialists to perform teleconsultation, also across country borders. Datasets are available in different languages. Different types of data exchange methods using secure medical data transfer by internet, USB stick and smartcard were tested for different countries with regard to legal acceptance, practicability and technical realization (e.g. compatibility with EMR systems). By creating new standardized glaucoma specific cross-national datasets, it is now possible to develop an electronic glaucoma patient record system for data storage and transfer based on internet, smartcard or USB stick. The digital data can be used for referrals and for teleconsultation of glaucoma specialists in order to optimize glaucoma treatment. This should lead to an increase of quality in glaucoma care, and prevent expenses in health care costs by unnecessary repeated examinations.

Structural and Functional Evaluations for the Early Detection of Glaucoma.

PubMed

Lucy, Katie A; Wollstein, Gadi

2016-01-01

The early detection of glaucoma is imperative in order to preserve functional vision. Structural and functional methods are utilized to detect and monitor glaucomatous damage and the vision loss it causes. The relationship between these detection measures is complex and differs between individuals, especially in early glaucoma. Using both measures together is advised in order to ensure the highest probability of glaucoma detection, and new testing methods are continuously developed with the goals of earlier disease detection and improvement of disease monitoring. The purpose of this review is to explore the relationship between structural and functional glaucoma detection and discuss important technological advances for early glaucoma detection.

Structural and Functional Evaluations for the Early Detection of Glaucoma

PubMed Central

Lucy, Katie A.; Wollstein, Gadi

2016-01-01

The early detection of glaucoma is imperative in order to preserve functional vision. Structural and functional methods are utilized to detect and monitor glaucomatous damage and the vision loss it causes. The relationship between these detection measures is complex and differs between individuals, especially in early glaucoma. Using both measures together is advised in order to ensure the highest probability of glaucoma detection, and new testing methods are continuously developed with the goals of earlier disease detection and improvement of disease monitoring. The purpose of this review is to explore the relationship between structural and functional glaucoma detection and discuss important technological advances for early glaucoma detection. PMID:28603546

Open-angle glaucoma in patients with diabetic retinopathy at the Puerto Rico Medical Center.

PubMed

Cruz-lñigo, Yousef; Izquierdo, Natalio J; García, Omar; Pérez, Raúl

2012-01-01

The association of open-angle glaucoma (OAG) with diabetes mellitus remains controversial. We report on the frequency of open-angle glaucoma in patients having diabetic retinopathy in a population of the Puerto Rico Medical Center. A cross-sectional study of 1,442 patients was done. Only the chart of patients 40 years-of-age and older, with a diagnosis of diabetic retinopathy and/or open-angle glaucoma were included. Descriptive analysis was done. Unadjusted and gender-adjusted logistic regression analyses were used to estimate risk of developing open-angle glaucoma in patients with diabetic retinopathy for each subsequent decade. 1,040 patients were diagnosed with diabetic retinopathy from July 1, 2004 to June 30, 2009. Also, 402 patients were diagnosed with open-angle glaucoma from July 1, 2007 to June 30, 2009. Of the 1,040 patients with diabetic retinopathy, 64 patients (6.15%) also had OAG. According to our gender-adjusted logistic regression analysis the estimated risk of developing open-angle glaucoma for patients 40 years-of-age with diabetic retinopathy increased for each subsequent decade until the seventh decade, odds ratio = 5.07 (95% confidence interval: 1.62-15.86). Thereafter, it decreased, odds ratio = 2.07 (95% confidence interval: 0.36-11.82). Our findings suggest that Puerto Rico patients between 40 to 79 years of age with diabetic retinopathy have an increased risk of developing open-angle glaucoma with each subsequent decade. Screening for open-angle glaucoma in patients with diabetic retinopathy is of utmost importance in the aging Puerto Rico population to prevent blindness.

Making Basic Science Studies in Glaucoma More Clinically Relevant: The Need for a Consensus.

PubMed

Toris, Carol B; Gelfman, Claire; Whitlock, Andy; Sponsel, William E; Rowe-Rendleman, Cheryl L

2017-09-01

Glaucoma is a chronic, progressive, and debilitating optic neuropathy that causes retinal damage and visual defects. The pathophysiologic mechanisms of glaucoma remain ill-defined, and there is an indisputable need for contributions from basic science researchers in defining pathways for translational research. However, glaucoma researchers today face significant challenges due to the lack of a map of integrated pathways from bench to bedside and the lack of consensus statements to guide in choosing the right research questions, techniques, and model systems. Here, we present the case for the development of such maps and consensus statements, which are critical for faster development of the most efficacious glaucoma therapy. We underscore that interrogating the preclinical path of both successful and unsuccessful clinical programs is essential to defining future research. One aspect of this is evaluation of available preclinical research tools. To begin this process, we highlight the utility of currently available animal models for glaucoma and emphasize that there is a particular need for models of glaucoma with normal intraocular pressure. In addition, we outline a series of discoveries from cell-based, animal, and translational research that begin to reveal a map of glaucoma from cell biology to physiology to disease pathology. Completion of these maps requires input and consensus from the global glaucoma research community. This article sets the stage by outlining various approaches to such a consensus. Together, these efforts will help accelerate basic science research, leading to discoveries with significant clinical impact for people with glaucoma.

Conjunctival erosion after glaucoma drainage device surgery: a feasible option.

PubMed

Dubey, Suneeta; Prasanth, Baswati; Acharya, Manisha C; Narula, Ritesh

2013-07-01

Glaucoma drainage devices (GDDs) have been used in the management of complicated glaucomas. GDDs are associated with various complications such as tube migration, tube or plate exposure or extrusion, ocular motility disturbance and infection. Erosion of conjunctiva and exposure of the GDD remains a risk factor for the development of endophthalmitis. A wide range of materials have been used for this purpose, including sclera, dura, pericardium, fascia lata and cornea. However, there is no evidence to prove that any of these methods is superior to another for providing tectonic durability in the long term. In this report, we present a case of neovascular glaucoma, who developed conjunctival melting over the tube of an Ahmed Glaucoma Valve implant and was successfully managed with Cap Doxycycline.

Preference-based Glaucoma-specific Health-related Quality of Life Instrument: Development of the Health Utility for Glaucoma.

PubMed

Muratov, Sergei; Podbielski, Dominik W; Kennedy, Kevin; Jack, Susan M; Pemberton, Julia; Ahmed, Iqbal Ike K; Baltaziak, Monika; Xie, Feng

2018-05-12

To develop a descriptive system for a glaucoma-specific preference-based health-related quality of life (HRQoL) instrument: the Health Utility for Glaucoma (HUG-5). The descriptive system was developed in two stages: item identification and item selection. A systematic literature review of HRQoL assessment of glaucoma was conducted using a comprehensive search strategy. Purposeful sampling was used to recruit patients with different clinical characteristics. Relevant items were presented to glaucoma patients through face-to-face, semi-structured interviews. Framework methodology was applied to analyze interview content. The recurring themes identified through an iterative content analysis represented topics of most importance and relevance to patients. These themes formed the domains of the HUG-5 descriptive system. Three versions of the descriptive system, differing in explanatory detail, were pilot tested using a focus group. The literature review identified 19 articles which contained 266 items. These items were included for the full text review and were used to develop an interview guide. From twelve patient interviews, 22 themes were identified and grouped into five domains that informed the five questions of the descriptive system. The HUG-5 measures visual discomfort, mobility, daily life activities, emotional well-being, and social activities. Each question has five response levels that range from "no problem" to "severe problem". The focus group comprised of seven additional patients unanimously preferred the version that contained detailed, specific examples to support each question. A 5-domain descriptive system of a glaucoma-specific preference-based instrument, the HUG-5, was developed and remains to be evaluated for validity and reliability in the glaucoma patient population.

One-Pot Exfoliation of Graphite and Synthesis of Nanographene/Dimesitylporphyrin Hybrids

PubMed Central

Bernal, M. Mar; Pérez, Emilio M.

2015-01-01

A simple one-pot process to exfoliate graphite and synthesize nanographene-dimesitylporphyrin hybrids has been developed. Despite the bulky mesityl groups, which are expected to hinder the efficient π–π stacking between the porphyrin core and graphene, the liquid-phase exfoliation of graphite is significantly favored by the presence of the porphyrins. Metallation of the porphyrin further enhances this effect. The resulting graphene/porphyrin hybrids were characterized by spectroscopy (UV-visible, fluorescence, and Raman) and microscopy (STEM, scanning transmission electron microscopy). PMID:25984598

Secondary glaucoma after pediatric cataract surgery

PubMed Central

Şahin, Alparslan; Çaça, Ihsan; Cingü, Abdullah Kürşat; Türkcü, Fatih Mehmet; Yüksel, Harun; Şahin, Muhammed; Çinar, Yasin; Ari, Şeyhmus

2013-01-01

AIM To determine the incidence and risk factors of secondary glaucoma after pediatric cataract surgery. METHODS Two hundred and forty nine eyes of 148 patients underwent cataract surgery without intraocular lens (IOL) implantation (group 1), and 220 eyes of 129 patients underwent cataract surgery with IOL implantation (group 2) retrospectively, were evaluated between 2000 and 2011. The outcome measure was the presence or absence of post-cataract surgery glaucoma, defined as an intraocular pressure (IOP) ≥26mmHg, as measured on at least two occasions along with corneal or optic nerve changes. RESULTS The mean follow-up periods of group 1 and 2 were (60.86±30.95) months (12-123 months) and (62.11±31.29) months (14-115 months) respectively. In group 1, 12 eyes of 8 patients (4.8%) developed glaucoma. None of the patients developed glaucoma after surgery in group 2. The mean age of the patients at the cataract surgery was (2.58±0.90) months (1 month-4 months) and the average period for glaucoma development after surgery was (9.50±4.33) months (4-16 months) in group 1. Three of the 12 glaucomatous eyes were controlled with antiglaucomatous medication and 9 eyes underwent trabeculectomy+mitomycin C surgery. One patient underwent a second trabeculectomy + mitomycin C operation for both of his eyes. CONCLUSION The incidence of glaucoma after pediatric cataract surgery is very low in patients in whom IOL is implanted. The aphakic eyes after pediatric cataract surgery are at an increased risk for glaucoma development particularly if they underwent surgery before 4 months of age. PMID:23638427

Reducing the visual burden of glaucoma in Asia: what we know and what we need to know.

PubMed

Congdon, Nathan

2009-01-01

Despite great progress in elucidating risk factors and effective treatments for eye disease in the last decades, blindness prevalence in the developing and developed world is either static or rising. A research agenda is needed to develop and test specific strategies to reduce the burden of blindness from glaucoma and other common eye diseases. Current knowledge about open and closed-angle glaucoma is reviewed and a strategy to reduce glaucoma blindness in Asia is suggested. A critical component of this strategy is enhanced training in the detection of narrow angles and optic nerve damage by direct examination. Specific research topics that could inform such a strategy are outlined.

German register for glaucoma patients with dry eye. I. Basic outcome with respect to dry eye.

PubMed

Erb, Carl; Gast, Ulrike; Schremmer, Dieter

2008-11-01

The purpose of this register was to determine the links between glaucoma, age, concomitant disease, medication, and dry eye in a large group of glaucoma patients. A total of 20,506 patients from 900 centers across Germany were included. The first 30 consecutive glaucoma patients at each center were recruited. Epidemiological data as well as information on glaucoma, medication, concomitant diseases, dry eye, and local symptoms were elicited by means of a questionnaire. We analyzed primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and pigmentary glaucoma (PDG). According to the register data, more women develop dry eye and glaucoma than men (56.9 vs. 45.7%). The most frequent concomitant systemic diseases were hypertension (48.1%), diabetes mellitus (22.5%), and dry mouth, nose, and skin (11.3%). As expected, the highest incidence of dry eye was found in those patients with dry mouth, nose, and skin. Dry eye occurred with dissimilar frequencies in association with the various glaucoma types: PEX>POAG>PDG. The incidence of dry eye increases with age. The gender difference in the occurrence of dry eye becomes apparent from the age of 50. Dry eye occurred more frequently when three or more antiglaucoma drugs were used and increased with the duration of glaucoma disease. We publish the first results from the German Glaucoma and Dry Eye Register. We found that the occurrence of dry eye is linked to several factors. Thus, the type of glaucoma has an impact on the risk of dry eye. The quantity of eye drops applied also plays a role in the development of the dry eye syndrome if more than three medications are used. While POAG is usually treated with one drug, PEX and PDG tend to be treated with multiple drugs. The gender difference in the occurrence of dry eye becomes apparent from the age 50 years. Because of the vicious circle of dry eye, antiglaucoma eye drops containing benzalkonium chloride compromises patient compliance. The results of the register are therefore of key relevance for the care of glaucoma patients.

Glaucoma Medication Adherence among African Americans: Program Development

PubMed Central

Dreer, Laura E.; Girkin, Christopher A.; Campbell, Lisa; Wood, Andy; Gao, Liyan; Owsley, Cynthia

2014-01-01

Purpose To elucidate barriers and facilitators related to glaucoma medication adherence among African Americans (AA) with glaucoma and to elicit input from a community-based participatory research team in order to guide the development of a culturally informed, health promotion program for improving glaucoma medication adherence among AA’s. Methods The nominal group technique (NGT), a highly structured focus group methodology, was implemented with 12 separate groups of AA’s patients with glaucoma (N = 89) to identify barriers and facilitators related to glaucoma medication usage. Participant rank-ordering votes were summed across groups and categorized into themes. Next, an individually and culturally targeted health promotion program promoting appropriate medication adherence was developed based on focus group results and input from a community-based participatory research team. Results The top five barriers included problems with 1) forgetfulness, 2) side effects, 3) cost/affordability, 4) eye drop administration, and 5) the eye drop schedule. The most salient top five facilitators were 1) fear or thoughts about the consequences of not taking eye drops, 2) use of memory aids, cues, or strategies, 3) maintaining a regular routine or schedule for eye drop administration, 4) ability to afford eye drops, and 5) keeping eye drops in the same area. The resulting health promotion program was based on a multi-component empowerment framework that included glaucoma education, motivational interviewing, and problem-solving training to improve glaucoma medication adherence. Conclusions Barriers and facilitators related to glaucoma medication adherence among AA’s are multifactorial. Based on the NGT themes and input from the community-based participatory research team, a culturally informed, health promotion program was designed and holds great promise for improving medication adherence among this vulnerable population. PMID:23873033

A supramolecular strategy to leverage the liquid-phase exfoliation of graphene in the presence of surfactants: unraveling the role of the length of fatty acids.

PubMed

Haar, Sébastien; Ciesielski, Artur; Clough, Joseph; Yang, Huafeng; Mazzaro, Raffaello; Richard, Fanny; Conti, Simone; Merstorf, Nicolas; Cecchini, Marco; Morandi, Vittorio; Casiraghi, Cinzia; Samorì, Paolo

2015-04-08

Achieving the full control over the production as well as processability of high-quality graphene represents a major challenge with potential interest in the field of fabrication of multifunctional devices. The outstanding effort dedicated to tackle this challenge in the last decade revealed that certain organic molecules are capable of leveraging the exfoliation of graphite with different efficiencies. Here, a fundamental understanding on a straightforward supramolecular approach for producing homogenous dispersions of unfunctionalized and non-oxidized graphene nanosheets in four different solvents is attained, namely N-methyl-2-pyrrolidinone, N,N-dimethylformamide, ortho-dichlorobenzene, and 1,2,4-trichlorobenzene. In particular, a comparative study on the liquid-phase exfoliation of graphene in the presence of linear alkanes of different lengths terminated by a carboxylic-acid head group is performed. These molecules act as graphene dispersion-stabilizing agents during the exfoliation process. The efficiency of the exfoliation in terms of concentration of exfoliated graphene is found to be proportional to the length of the employed fatty acid. Importantly, a high percentage of single-layer graphene flakes is revealed by high-resolution transmission electron microscopy and Raman spectroscopy analyses. A simple yet effective thermodynamic model is developed to interpret the chain-length dependence of the exfoliation yield. This approach relying on the synergistic effect of a ad-hoc solvent and molecules to promote the exfoliation of graphene in liquid media represents a promising and modular strategy towards the rational design of improved dispersion-stabilizing agents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-yield exfoliation of tungsten disulphide nanosheets by rational mixing of low-boiling-point solvents

NASA Astrophysics Data System (ADS)

Sajedi-Moghaddam, Ali; Saievar-Iranizad, Esmaiel

2018-01-01

Developing high-throughput, reliable, and facile approaches for producing atomically thin sheets of transition metal dichalcogenides is of great importance to pave the way for their use in real applications. Here, we report a highly promising route for exfoliating two-dimensional tungsten disulphide sheets by using binary combination of low-boiling-point solvents. Experimental results show significant dependence of exfoliation yield on the type of solvents as well as relative volume fraction of each solvent. The highest yield was found for appropriate combination of isopropanol/water (20 vol% isopropanol and 80 vol% water) which is approximately 7 times higher than that in pure isopropanol and 4 times higher than that in pure water. The dramatic increase in exfoliation yield can be attributed to perfect match between the surface tension of tungsten disulphide and binary solvent system. Furthermore, solvent molecular size also has a profound impact on the exfoliation efficiency, due to the steric repulsion.

Developing standards for the development of glaucoma virtual clinics using a modified Delphi approach.

PubMed

Kotecha, Aachal; Longstaff, Simon; Azuara-Blanco, Augusto; Kirwan, James F; Morgan, James Edwards; Spencer, Anne Fiona; Foster, Paul J

2018-04-01

To obtain consensus opinion for the development of a standards framework for the development and implementation of virtual clinics for glaucoma monitoring in the UK using a modified Delphi methodology. A modified Delphi technique was used that involved sampling members of the UK Glaucoma and Eire Society (UKEGS). The first round scored the strength of agreement to a series of standards statements using a 9-point Likert scale. The revised standards were subjected to a second round of scoring and free-text comment. The final standards were discussed and agreed by an expert panel consisting of seven glaucoma subspecialists from across the UK. A version of the standards was submitted to external stakeholders for a 3-month consultation. There was a 44% response rate of UKEGS members to rounds 1 and 2, consisting largely of consultant ophthalmologists with a specialist interest in glaucoma. The final version of the standards document was validated by stakeholder consultation and contains four sections pertaining to the patient groups, testing methods, staffing requirements and governance structure of NHS secondary care glaucoma virtual clinic models. Use of a modified Delphi approach has provided consensus agreement for the standards required for the development of virtual clinics to monitor glaucoma in the UK. It is anticipated that this document will be useful as a guide for those implementing this model of service delivery. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Improving services for glaucoma care in Nigeria: implications for policy and programmes to achieve universal health coverage.

PubMed

Kyari, Fatima; Gilbert, Clare; Blanchet, Karl; Wormald, Richard

2017-05-01

Glaucoma in Africa is sometimes referred to as the silent thief of sight. In Nigeria, glaucoma is common, it is serious, ophthalmologists face many constraints in managing it, people do not even know they have it until it is advanced, patients do not understand or comply with treatment after they are diagnosed and the poor are more likely to be glaucoma blind. Available evidence indicates that the health system in Nigeria is failing to meet the needs of patients with glaucoma. Based on evidence, we propose future directions for improving services for glaucoma care in Nigeria, and the implications for policy and programmes to control glaucoma blindness, using a health system-oriented approach. Three complementary strategies are required: (i) strengthening clinical services for glaucoma-by developing models of glaucoma care, improving clinical treatment options, making medicines and equipment available, financing glaucoma care and training eye care workers; (ii) introducing initiatives for earlier detection of glaucoma in the clinic and approaches in the community and (iii) strengthening health system governance. Glaucoma is a complex disease to manage and addressing it as a public health problem is challenging. However, we need to change the paradigm to recognise that glaucoma is a potentially avoidable cause of blindness in Africa. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Using Genetic Mouse Models to Gain Insight into Glaucoma: Past Results and Future Possibilities

PubMed Central

Fernandes, Kimberly A.; Harder, Jeffrey M.; Williams, Pete A.; Rausch, Rebecca L.; Kiernan, Amy E.; Nair, K. Saidas; Anderson, Michael G.; John, Simon W.; Howell, Gareth R.; Libby, Richard T.

2015-01-01

While all forms of glaucoma are characterized by a specific pattern of retinal ganglion cell death, they are clinically divided into several distinct subclasses, including normal tension glaucoma, primary open angle glaucoma, congenital glaucoma, and secondary glaucoma. For each type of glaucoma there are likely numerous molecular pathways that control susceptibility to the disease. Given this complexity, a single animal model will never precisely model all aspects of all the different types of human glaucoma. Therefore, multiple animal models have been utilized to study glaucoma but more are needed. Because of the powerful genetic tools available to use in the laboratory mouse, it has proven to be a highly useful mammalian system for studying the pathophysiology of human disease. The similarity between human and mouse eyes coupled with the ability to use a combination of advanced cell biological and genetic tools in mice have led to a large increase in the number of studies using mice to model specific glaucoma phenotypes. Over the last decade, numerous new mouse models and genetic tools have emerged, providing important insight into the cell biology and genetics of glaucoma. In this review, we describe available mouse genetic models that can be used to study glaucoma-relevant disease/pathobiology. Furthermore, we discuss how these models have been used to gain insights into ocular hypertension (a major risk factor for glaucoma) and glaucomatous retinal ganglion cell death. Finally, the potential for developing new mouse models and using advanced genetic tools and resources for studying glaucoma are discussed. PMID:26116903

Level of agreement among Latin American glaucoma subspecialists on the diagnosis and treatment of glaucoma: results of an online survey.

PubMed

Grigera, Daniel E; Mello, Paulo Augusto Arruda; Barbosa, Wilma Lelis; Casiraghi, Javier Fernando; Grossmann, Rodolfo Perez; Peyret, Alejo

2013-01-01

The aim of this research was to assess the level of agreement among glaucoma experts in Latin America on key practices related to treatment and diagnosis of glaucoma. An online questionnaire was sent to a multinational panel of glaucoma experts. The questionnaire contained 107 statements on the medical treatment (Part 1) and diagnosis (Part 2) of glaucoma, and was developed in Spanish and translated into English. Agreement was defined as >70% of respondents. Fifty participants from 14 countries completed the questionnaire. For the medical treatment of glaucoma, nearly all respondents (98% or greater) confirmed that medical treatment as first-line therapy is preferred to surgery, prostaglandin analogs are the medication of first choice for primary open-angle glaucoma (POAG), longitudinal monitoring of efficacy should include intraocular pressure, structural and functional status, as well as if patients' quality of life is impaired by the high cost of medication. For the diagnosis of glaucoma section, all respondents confirmed that, after initial examination, gonioscopy should be repeated over time, standard automated perimetry is the most important functional examination for diagnosis and monitoring of primary open-angle glaucoma, central corneal thickness is important in assessment of glaucoma, and computerized imaging tests help in clinical evaluation of optic disc. This survey shows a high level of agreement on most aspects of glaucoma diagnosis and treatment among Latin American glaucoma experts. Areas of disagreement highlight the need for further evidence or education. These findings will be useful for guiding future efforts to optimize glaucoma practice by clinicians in Latin America.

Brain: The Potential Diagnostic and Therapeutic Target for Glaucoma.

PubMed

Faiq, Muneeb A; Dada, Rima; Kumar, Ashutosh; Saluja, Daman; Dada, Tanuj

2016-01-01

Glaucoma is a form of multifactorial ocular neurodegeneration with immensely complex etiology, pathogenesis and pathology. Though the mainstream therapeutic management of glaucoma is lowering of intraocular pressure, there is, as of now, no cure for the disease. New evidences ardently suggest brain involvement in all aspects of this malady. This consequently advocates the opinion that brain should be the spotlight of glaucoma research and may form the impending and promising target for glaucoma diagnosis and treatment. The present analysis endeavors at understanding glaucoma vis-à-vis brain structural and/or functional derangement and central nervous system (CNS) degeneration. Commencing with the premise of developing some understanding about the brain-nature of ocular structures; we discuss the nature of the cellular and molecular moieties involved in glaucoma and Alzheimer's disease. Substantial deal of literature implies that glaucoma may well be a disease of the brain, nevertheless, manifesting as progressive loss of vision. If that is the case, then targeting brain will be far more imperative in glaucoma therapeutics than any other remedial regimen currently being endorsed.

[Emphasis on promotion of the adaptive technology is the sky point of improving of treatment and prevention level of glaucoma].

PubMed

Wang, Ning-li

2013-11-01

Promoting the control of primary angle-closure glaucoma (PACG) and primary open angle glaucoma (POAG) is most important prevention program of blindness in China. PACG has been incorporated into the prevention program of blindness in China based on the population-based screening studies. However, the clinical screening should be strengthened in POAG. The creation of a series of appropriate technologies suitable for glaucoma prevention and management has been achieved in China, especially for PACG. The technologies have been evaluated in the pilot areas and obtained very good results in China. It is recommended to develop new technology suitable for glaucoma management using the following workflow: research, development, and evaluation by large scale hospitals, and then clinical trial in the pilot areas. After a cost-benefit analysis is made, the new technology can be promoted and applied in clinical practice nationwide. We propose to gradually formed a strategical mode of "screening in township hospitals, intervention in county hospitals, and technical support and tackling in provincial hospitals" in order to improve the level of prevention and treatment of glaucoma and reduce the blindness incidence rate caused by glaucoma.

Nanotechnology Applications for Glaucoma.

PubMed

Cetinel, Sibel; Montemagno, Carlo

2016-01-01

Glaucoma is the second leading cause of blindness worldwide, and the antiglaucoma treatments currently available suffer from various complications. Nanotechnology-based treatments show a great deal of promise in overcoming these complications and form the basis for next-generation glaucoma treatment strategies, with the help of applications such as controlled release, targeted delivery, increased bioavailability, diffusion limitations, and biocompatibility. Significant progress has been made in nanomedicine in the efficiency of antiglaucoma medications, nanofabrication systems such as microelectromechanical systems that remove the limitations of nanodevices, and tissue regeneration vesicles for developing glaucoma treatments not based on intraocular pressure. With the use of these advanced technologies, the prevention of glaucoma-induced blindness will be possible in the near future. Herein, we reviewed the recent advances in nanotechnology-based treatment strategies for glaucoma.

Methods to Induce Chronic Ocular Hypertension

PubMed Central

Dey, Ashim; Manthey, Abby L.; Chiu, Kin; Do, Chi-Wai

2018-01-01

Glaucoma, a form of progressive optic neuropathy, is the second leading cause of blindness worldwide. Being a prominent disease affecting vision, substantial efforts are being made to better understand glaucoma pathogenesis and to develop novel treatment options including neuroprotective and neuroregenerative approaches. Cell transplantation has the potential to play a neuroprotective and/or neuroregenerative role for various ocular cell types (e.g., retinal cells, trabecular meshwork). Notably, glaucoma is often associated with elevated intraocular pressure, and over the past 2 decades, several rodent models of chronic ocular hypertension (COH) have been developed that reflect these changes in pressure. However, the underlying pathophysiology of glaucoma in these models and how they compare to the human condition remains unclear. This limitation is the primary barrier for using rodent models to develop novel therapies to manage glaucoma and glaucoma-related blindness. Here, we review the current techniques used to induce COH-related glaucoma in various rodent models, focusing on the strengths and weaknesses of the each, in order to provide a more complete understanding of how these models can be best utilized. To so do, we have separated them based on the target tissue (pre-trabecular, trabecular, and post-trabecular) in order to provide the reader with an encompassing reference describing the most appropriate rodent COH models for their research. We begin with an initial overview of the current use of these models in the evaluation of cell transplantation therapies. PMID:29637819

Stable aqueous dispersions of functionalized multi-layer graphene by pulsed underwater plasma exfoliation of graphite

NASA Astrophysics Data System (ADS)

Meyer-Plath, Asmus; Beckert, Fabian; Tölle, Folke J.; Sturm, Heinz; Mülhaupt, Rolf

2016-02-01

A process was developed for graphite particle exfoliation in water to stably dispersed multi-layer graphene. It uses electrohydraulic shockwaves and the functionalizing effect of solution plasma discharges in water. The discharges were excited by 100 ns high voltage pulsing of graphite particle chains that bridge an electrode gap. The underwater discharges allow simultaneous exfoliation and chemical functionalization of graphite particles to partially oxidized multi-layer graphene. Exfoliation is caused by shockwaves that result from rapid evaporation of carbon and water to plasma-excited gas species. Depending on discharge energy and locus of ignition, the shockwaves cause stirring, erosion, exfoliation and/or expansion of graphite flakes. The process was optimized to produce long-term stable aqueous dispersions of multi-layer graphene from graphite in a single process step without requiring addition of intercalants, surfactants, binders or special solvents. A setup was developed that allows continuous production of aqueous dispersions of flake size-selected multi-layer graphenes. Due to the well-preserved sp2-carbon structure, thin films made from the dispersed graphene exhibited high electrical conductivity. Underwater plasma discharge processing exhibits high innovation potential for morphological and chemical modifications of carbonaceous materials and surfaces, especially for the generation of stable dispersions of two-dimensional, layered materials.

Investigational and experimental drugs for intraocular pressure reduction in ocular hypertension and glaucoma.

PubMed

Lusthaus, Jed Asher; Goldberg, Ivan

2016-10-01

Intraocular pressure (IOP) is the most significant modifiable risk factor to prevent onset or progression of glaucoma. Glaucoma prevalence continues to increase, emphasizing the need for improved ocular hypotensive treatment options. To try to improve on both tolerance and IOP control of currently available therapies, different receptors or mechanisms are being explored to reduce IOP more effectively and to improve tolerance. We review synthetic topical and oral drugs in early development for the management of ocular hypertension and glaucoma. New therapeutic agents for IOP control have been discovered; some appear to be reasonably tolerated. IOP reduction may be limited with some agents, but other benefits although unproven may compensate for this, such as less ocular surface disease, enhanced neuro-protection or increased ocular blood flow. Further product development promises improved treatment options for ocular hypertensives and glaucoma sufferers.

Exfoliation Propensity of Oxide Scale in Heat Exchangers Used for Supercritical CO2 Power Cycles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabau, Adrian S; Shingledecker, John P.; Kung, Steve

2016-01-01

Supercritical CO2 (sCO2) Brayton cycle systems offer the possibility of improved efficiency in future fossil energy power generation plants operating at temperatures of 650 C and above. As there are few data on the oxidation/corrosion behavior of structural alloys in sCO2 at these temperatures, modeling to predict the propensity for oxide exfoliation is not well developed, thus hindering materials selection for these novel cycles. The ultimate goal of this effort is to provide needed data on scale exfoliation behavior in sCO2 for confident alloy selection. To date, a model developed by ORNL and EPRI for the exfoliation of oxide scalesmore » formed on boiler tubes in high-temperature, high-pressure steam has proven useful for managing exfoliation in conventional steam plants. A major input provided by the model is the ability to predict the likelihood of scale failure and loss based on understanding of the evolution of the oxide morphologies and the conditions that result in susceptibility to exfoliation. This paper describes initial steps taken to extend the existing model for exfoliation of steam-side oxide scales to sCO2 conditions. The main differences between high-temperature, high-pressure steam and sCO2 that impact the model involve (i) significant geometrical differences in the heat exchangers, ranging from standard pressurized tubes seen typically in steam-producing boilers to designs for sCO2 that employ variously-curved thin walls to create shaped flow paths for extended heat transfer area and small channel cross-sections to promote thermal convection and support pressure loads; (ii) changed operating characteristics with sCO2 due to the differences in physical and thermal properties compared to steam; and (iii) possible modification of the scale morphologies, hence properties that influence exfoliation behavior, due to reaction with carbon species from sCO2. The numerical simulations conducted were based on an assumed sCO2 operating schedule and several generic heat exchanger channel shapes and cross-sectional areas. Implications for the evolution of stresses in the oxide scales formed on sCO2 heat exchangers, and ensuing critical oxide thicknesses for exfoliation, were derived and compared with expectations for an equivalent conventional tubular heat exchanger in a steam cycle (for a given alloy).« less

[21st century management of glaucoma].

PubMed

Tsukahara, Shigeo

2003-12-01

According to a recent epidemiological study done in Japan, 2 or 3 million Japanese people are thought to be suffering from glaucoma, and 70-80% of them have not been examined or diagnosed by ophthalmologists. Therefore, the problem is how to find these untreated and undiagnosed people. At present, treatment of glaucoma continues to be directed at lowering intraocular pressure to prevent progression of glaucomatous optic neuropathy. However, theoretically, there are three stages in the prevention of progression of glaucoma. In the first stage, diagnosis of glaucoma can be done by genetic examination, before occurrence of glaucoma. The MYOCILIN/trabecular meshwork-inducible glucocorticoid response gene and the optineurin gene were identified as the genes that cause open angle glaucoma. Although some Japanese patients have sequence changes in the myocilin gene, there are no apparent specific mutations in Japanese glaucoma patients, in the MYOCILIN/TIGR and optineurin genes. Secondary glaucoma such as steroid glaucoma, induced by allergic diseases, and neovascular glaucoma, induced by retinal circulatory insufficiency, are preventable by improving the causal diseases, diabetes and hypertension. The education of doctors and laymen is important to reduce the occurrence of diabetes, and hypertension to prevent diabetic retinopathy, and retinal vessel occlusion. The second stage in preventing progression of glaucoma is to find the disease as early as possible. In Japan, a physical examination system is in place for everybody over 40 years old, in companies and local districts. Therefore, ocular examination, specially non-mydriatic fundus photographs should be taken in these examinations, and the film should be evaluated by an ophthalmologist, to search for retinal and optic disc abnormalities. Primary open angle glaucoma can be detected through this system in early stages. In primary angle closure glaucoma, instruments for estimating anterior chamber rapidly and accurately are necessary for the diagnosis. There is a special machine which can be handled easily, safely, and economically for detecting angle closure glaucoma, has been developed by Yamanashi University. This machine might help to reduce the number of angle closure glaucoma patients in the world. In the near future, a glaucoma network system should be put in place all over Japan. This organization consists of central headquarter and local central office. Most hospitals and private offices will belong to a local central office, and several glaucoma specialists will work in central and local offices. All glaucoma patients will be registered in local glaucoma office. The information on glaucoma patients will be communicated in the system the through light fiber cables or a satellite system. The patients can ask about their own disease through this glaucoma center system. In the third stage of glaucoma prevention, progression of glaucomatous optic neuropathy is retarded by conventional IOP lowering treatment or neuroprotective drugs. This stage compromises rehabilitation of visual function, implant of artificial visual systems, and regeneration of retinal ganglion cells(RGC). The disturbances of axonal flow in guinea pig optic nerve fibers was demonstrated electromicroscopically by quick-freeze, deep-etching method and, the decrease in numbers of motor proteins like "Kinesin" "Dynein" and "MAP-1" was shown in guinea pig eyes with elevated intraocular pressure by immunohistochemistry. Retinal glanglion cells have been isolated and new findings have been reported using this RGC culture system. Therefore, new neuroprotective drugs will be developed through this culture system.

Improving Access to Eye Care among Persons at High-Risk of Glaucoma in Philadelphia — Design and Methodology: The Philadelphia Glaucoma Detection and Treatment Project

PubMed Central

Myers, Jonathan S.; Henderer, Jeffrey; Crews, John E.; Saaddine, Jinan B.; Molineaux, Jeanne; Johnson, Deiana; Sembhi, Harjeet; Stratford, Shayla; Suleiman, Ayman; Pizzi, Laura; Spaeth, George L.; Katz, L. Jay

2016-01-01

Purpose The Wills Eye Glaucoma Research Center initiated a 2-year demonstration project to develop and implement a community-based intervention to improve detection and management of glaucoma in Philadelphia. Methods The glaucoma detection examination consisted of: ocular, medical, and family history; visual acuity testing; corneal pachymetry; biomicroscopy of the anterior segment; intraocular pressure (IOP) measurement; gonioscopy; funduscopy; automated visual field testing; and fundus-color photography. Treatment included laser surgery and/or IOP-lowering medication. A cost analysis was conducted to understand resource requirements. Outcome measures included; prevalence of glaucoma-related pathology and other eye diseases among high-risk populations; the impact of educational workshops on level of knowledge about glaucoma (assessed by pre- and post-test evaluation); and patient satisfaction of the glaucoma detection examinations in the community (assessed by satisfaction survey). Treatment outcome measures were change in IOP at 4–6 weeks and 4–6 months following selective laser trabeculoplasty treatment, deepening of the anterior chamber angle following laser-peripheral iridotomy treatment, and rate of adherence to recommended follow-up examinations. Cost outcomes included total program costs, cost per case of glaucoma detected, and cost per case of ocular disease detected. Results This project enrolled 1649 participants (African Americans aged 50+ years, adults 60+ years and individuals with a family history of glaucoma). A total of 1074 individuals attended a glaucoma educational workshop and 1508 scheduled glaucoma detection examination appointments in the community setting. Conclusions The Philadelphia Glaucoma Detection and Treatment Project aimed to improve access and use of eye care and to provide a model for a targeted community-based glaucoma program. PMID:26950056

Improving Access to Eye Care among Persons at High-Risk of Glaucoma in Philadelphia--Design and Methodology: The Philadelphia Glaucoma Detection and Treatment Project.

PubMed

Hark, Lisa; Waisbourd, Michael; Myers, Jonathan S; Henderer, Jeffrey; Crews, John E; Saaddine, Jinan B; Molineaux, Jeanne; Johnson, Deiana; Sembhi, Harjeet; Stratford, Shayla; Suleiman, Ayman; Pizzi, Laura; Spaeth, George L; Katz, L Jay

2016-01-01

The Wills Eye Glaucoma Research Center initiated a 2-year demonstration project to develop and implement a community-based intervention to improve detection and management of glaucoma in Philadelphia. The glaucoma detection examination consisted of: ocular, medical, and family history; visual acuity testing; corneal pachymetry; biomicroscopy of the anterior segment; intraocular pressure (IOP) measurement; gonioscopy; funduscopy; automated visual field testing; and fundus-color photography. Treatment included laser surgery and/or IOP-lowering medication. A cost analysis was conducted to understand resource requirements. Outcome measures included; prevalence of glaucoma-related pathology and other eye diseases among high-risk populations; the impact of educational workshops on level of knowledge about glaucoma (assessed by pre- and post-test evaluation); and patient satisfaction of the glaucoma detection examinations in the community (assessed by satisfaction survey). Treatment outcome measures were change in IOP at 4-6 weeks and 4-6 months following selective laser trabeculoplasty treatment, deepening of the anterior chamber angle following laser-peripheral iridotomy treatment, and rate of adherence to recommended follow-up examinations. Cost outcomes included total program costs, cost per case of glaucoma detected, and cost per case of ocular disease detected. This project enrolled 1649 participants (African Americans aged 50+ years, adults 60+ years and individuals with a family history of glaucoma). A total of 1074 individuals attended a glaucoma educational workshop and 1508 scheduled glaucoma detection examination appointments in the community setting. The Philadelphia Glaucoma Detection and Treatment Project aimed to improve access and use of eye care and to provide a model for a targeted community-based glaucoma program.

The pattern of glaucoma in Menelik II Hospital Addis Ababa, Ethiopia.

PubMed

Melka, Fikru; Alemu, Bayuh

2006-04-01

To describe the demographic and clinical profiles glaucoma and evaluate the magnitude of blindness among patients with glaucoma. Cases with glaucoma that were seen at Menelik II hospital Addis Ababa between May 10, 1994 and May 9, 1997 were reviewed Data on relevant demographic and clinical variables were collected and analysed. A total of 1,586 glaucoma patients were seen at the glaucoma clinic during the study period. The male to female ratio was 2:1. The mean age is 51.9 (SD 17.9) years. Those patients above the age of 40 years represented 78% of the total glaucoma population. The prevalence of glaucoma was highest (27.1%) in the age group of 51-60 years. It was bilateral in 806 (51%) of the patients. Primary Open Angle Glaucoma (POAG) was the most frequent type documented in 631 (40%) of the patients, followed by Secondary Glaucomas in 605 (38%), Primary Angle Closure Glaucoma (PACG) in 285 (18%), Normal Tension Glaucoma (NTG) in 36 (2%), and Congenital Glaucoma in 33 (2%). Six hundred fifty six patients (41%) were blind either in one or both eyes. PACG was found to be potentially a blinding type of glaucoma, in which 53% of the patients suffered from blindness. In the other types, poor public awareness and lack of treatment services were the most important factors that largely precopitated the occurrence of blindness. We recommend that, in addition to improving the diagnostic and therapeutic facilities, intensive work be done to increase public awareness on the nature of the disease, to expand the infrastructure and to develop and rationally deploy the required human resources.

Role of vacancy sites and UV-ozone treatment on few layered MoS2 nanoflakes for toxic gas detection

NASA Astrophysics Data System (ADS)

Burman, Debasree; Ghosh, Ruma; Santra, Sumita; Ray, Samit Kumar; Guha, Prasanta Kumar

2017-10-01

Various issues like global warming and environmental pollutions have led to the research of toxic gas detection worldwide. In this work, we have tried to develop a molybdenum disulfide (MoS2) based gas sensor to detect toxic gases like ammonia and NO. MoS2, an inorganic analog of graphene, has attracted lots of attention for many different applications recently. This paper reports the use of liquid exfoliated MoS2 nanoflakes as the sensing layer in a handheld, resistive toxic gas sensor. The nanoflakes were exfoliated from MoS2 bulk powder using a sonication based exfoliation technique at room temperature. The successful exfoliation of the nanoflakes was characterized using different techniques e.g., optical microscopy, atomic force microscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy and ultraviolet-visible spectrophotometry. The characterization results showed that few-layered nanoflakes have successfully been exfoliated. The MoS2 nanoflakes showed reasonable sensing towards ammonia and NO. In order to explore the effect of particle size on ammonia sensing, the MoS2 flakes were also exfoliated using different sonication times. We also observed that various factors like presence of vacancy sites, ambient oxygen, humidity, different contact electrodes have significant effect on the sensing characteristics. In fact, the response of the sensing layer against 400 ppm of ammonia increased from 54.1% to ˜80% when it was UV-ozone treated. This work holds promises to developing cost-effective, reliable and highly sensitive MoS2 based ammonia sensors.

Glaucoma and clinical characteristics in Vietnamese Americans.

PubMed

Peng, Pai-Huei; Manivanh, Richard; Nguyen, Ngoc; Weinreb, Robert N; Lin, Shan C

2011-08-01

To assess the proportions of glaucoma types and clinical characteristics in Vietnamese Americans in a single-center, retrospective study. Medical charts of Vietnamese-American patients who visited a single private practice in Northern California from 1998-2007 were reviewed. The main outcome measures included the distribution and characteristics of glaucoma types, and clinical parameters associated with the presence of various glaucomas. Data from 2247 patients aged 18-98 years were reviewed. Glaucoma was determined for 305 patients (13.6%). Among this group, 54.8% had primary open-angle glaucoma (POAG), 26.9% had primary angle-closure glaucoma (PACG), 13.4% had mixed mechanism glaucoma (MMG), and 4.9% had secondary glaucoma. In the MMG group (41 patients), 27 patients who initially had open angles developed narrow angles and underwent laser peripheral iridotomy (LPI) with a mean follow up of 6.4 years from the time of iridotomy. The other 13 patients had glaucoma progression with open angles after LPI. One POAG patient had neovascular glaucoma due to retinal vein occlusion several years later. Compared to the PACG group, the MMG group had significantly lower baseline intraocular pressure (25.0 vs. 20.2 mmHg, p = 0.007) but with no difference in biometry. POAG is the major type of glaucoma in this clinic-based Vietnamese population. However, Vietnamese appear to have a relatively higher proportion of PACG than Caucasians and those of African descent. It is recommended that gonioscopy be part of the regular eye check-up for adult Vietnamese patients.

Creating high yield water soluble luminescent graphene quantum dots via exfoliating and disintegrating carbon nanotubes and graphite flakes.

PubMed

Lin, Liangxu; Zhang, Shaowei

2012-10-21

We have developed an effective method to exfoliate and disintegrate multi-walled carbon nanotubes and graphite flakes. With this technique, high yield production of luminescent graphene quantum dots with high quantum yield and low oxidization can be achieved.

CHALLENGES IN THE MANAGEMENT OF GLAUCOMA IN A DEVELOPING COUNTRY; A QUALITATIVE STUDY OF PROVIDERS' PERSPECTIVES.

PubMed

Adekoya, B J; Adepoju, F G; Moshood, K F; Balarabe, A H

2015-01-01

Glaucoma management is challenging to patients as well as to the eye care providers. The study is aimed at describing the challenges faced by providers using qualitative methods. In-depth interviews were conducted with selected Ophthalmologists and resident doctors in ophthalmology at centres offering medical and surgical glaucoma services in Lagos state, Nigeria, according to established qualitative methods. This was done using semi-structured, open ended questions to explore the providers' perspective on glaucoma burden, challenges in the management, surgery for glaucoma, acceptance of glaucoma surgery by patients, and recommendations for improving glaucoma services. The discussions were recorded with the aid of a micro-cassette recorder. Familiarisation was done to identify key ideas in the data, then, the main themes and sub-themes were identified. Quotes that reflect the themes and sub-themes were then identified in the data. In-depth interviews were conducted with a total of 11 ophthalmologists and resident doctors in training. Majority were of the opinion that glaucoma is a significant burden constituting about 35% of outpatient visits. Identified patient related challenges include; late presentation, lack of glaucoma awareness, delay in referral from optometrists, and poor compliance with medications. Shortages in needed equipment were also identified. Availability, affordability and counterfeiting of drugs were the major challenges related to medical treatment. Majority of the participants agreed that surgery should be offered to the patients as soon as the diagnosis of glaucoma is made. However, continuous monitoring of the patient on medical treatment is another line of option for them in early cases; if they are convinced the patients will be compliant. Some respondents considered the current number of glaucoma surgeries as adequate, while some think otherwise. Reasons put forward for reluctance to offer glaucoma surgery include; late presentation, lack of patient satisfaction, complications of surgery, and negative publicity. Even though the challenges in the management of glaucoma in developing countries are many, they are not insurmountable. There is need for concerted and integrated efforts involving all cadres of eye care practitioners, patients, institutions and governments to address this important eye disease. Improved awareness, provision of adequate equipment, availability and affordability of medications, need for training and retraining of eye care providers are all important measures that can lead to better management of the glaucoma patient.

Comparison of matrix frequency-doubling technology perimetry and standard automated perimetry in monitoring the development of visual field defects for glaucoma suspect eyes.

PubMed

Hu, Rongrong; Wang, Chenkun; Racette, Lyne

2017-01-01

Perimetry is indispensable for the clinical management of glaucoma suspects. Our goal is to compare the performance of standard automated perimetry (SAP) and Matrix frequency-doubling technology (FDT) perimetry in monitoring the development of visual field (VF) defects in glaucoma suspect eyes. Longitudinal data of paired SAP and FDT from 221 eyes of 155 glaucoma suspects enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. All eyes had glaucomatous optic neuropathy or ocular hypertension, but normal SAP and FDT results at baseline. The development of glaucomatous VF defects was defined as the presence of a cluster of ≥ 3 (less conservative) or ≥ 4 (more conservative) locations confirmed on ≥ 2 additional consecutive tests. Risk factors for the development of VF defects were analyzed by COX proportional hazard models. After conversion into common logarithmic units, the rates of change of global VF indices were fitted with linear mixed models. FDT detected more eyes that developed VF defects than SAP using the less conservative criterion, and no significant difference was observed using the more conservative criterion. For those eyes detected by both SAP and FDT, FDT detected the development of VF defects either earlier than SAP or simultaneously in most cases. Baseline structural measurements were not significantly associated with an increased risk for the development of glaucomatous VF defects on either SAP or FDT. Older age was significantly associated with the development of VF defects on FDT but not on SAP. Both SAP and FDT detected a progressing worsening trend of pattern standard deviation over time with a similar rate of change between these test types. Matrix FDT would be useful to monitor the onset of VF defects in glaucoma suspects and may outperform SAP in the early stage of glaucomatous VF damage.

Neurodegeneration and Neuroprotection in Glaucoma

PubMed Central

Gauthier, Angela C.; Liu, Ji

2016-01-01

Glaucoma is the principal cause of irreversible blindness in the world. The disease leads to progressive optic nerve degeneration with a gradual loss of retinal ganglion cells. Neurodegeneration in glaucoma extends beyond the eye into the lateral geniculate nucleus and visual cortex, and the disease even shares some characteristics with other central nervous system degenerative disorders. Glaucoma destroys neurons through oxidative stress, impairment in axonal transport, neuroinflammation, and excitotoxicity. Autophagy may promote or inhibit disease progression. Currently, lowering intraocular pressure is the only way proven to delay glaucoma advancement. However, many new therapies are being developed, including antioxidants, adenosine receptor antagonists, Rho-pathway inhibitors, stem cell therapy, and neurotrophic factors. These therapies focus on neuroprotection, and they may eventually halt glaucoma progression or reverse the process of the disease itself. PMID:27505018

Current perspective of neuroprotection and glaucoma

PubMed Central

Tian, Kailin; Shibata-Germanos, Shannon; Pahlitzsch, Milena; Cordeiro, M Francesca

2015-01-01

Glaucoma is the second leading cause of blindness worldwide and is most notably characterized by progressive optic nerve atrophy and advancing loss of retinal ganglion cells (RGCs). The main concomitant factor is the elevated intraocular pressure (IOP). Existing treatments are focused generally on lowering IOP. However, both RGC loss and optic nerve atrophy can independently occur with IOP at normal levels. In recent years, there has been substantial progress in the development of neuroprotective therapies for glaucoma in order to restore vital visual function. The present review intends to offer a brief insight into conventional glaucoma treatments and discuss exciting current developments of mostly preclinical data in novel neuroprotective strategies for glaucoma that include recent advances in noninvasive diagnostics going beyond IOP maintenance for an enhanced global view. Such strategies now target RGC loss and optic nerve damage, opening a critical therapeutic window for preventative monitoring and treatment. PMID:26635467

Importance of intraocular pressure in glaucoma

NASA Astrophysics Data System (ADS)

Joos, Karen M.

1999-06-01

Glaucoma results in permanent vision loss and affects the peripheral vision initially. It is presented in 22.5 million people worldwide and is the 3rd cause of blindness. Present tonometers are not ideal for intraocular pressure measurements in all eyes. Of concern, PRK and LASIK may result in lower intraocular pressure readings. A challenges now exists for the development of a tonometer which can easily compensate for corneas with many parameters to avoid a future increase in normal-tension glaucoma or glaucoma which is advanced.

Glaucoma-related adverse events in the first five years after unilateral cataract removal in the Infant Aphakia Treatment Study

PubMed Central

Freedman, Sharon F.; Lynn, Michael J.; Beck, Allen D.; Bothun, Erick D.; Orge, Faruk H.; Lambert, Scott R.

2015-01-01

Importance Glaucoma-related adverse events constitute major sight-threatening complications of cataract removal in infancy, yet their relationship to aphakia versus primary intraocular lens (IOL) implantation remains unsettled. Objective To identify and characterize cases of glaucoma and glaucoma-related adverse events (glaucoma+glaucoma suspect) among children in the Infant Aphakia Treatment Study (IATS) by the age of five years. Design, Setting, and Participants A multicenter randomized controlled trial of 114 infants with unilateral congenital cataract who were between age 1–6 months at surgery. Interventions Participants were randomized at cataract surgery to either primary IOL, or no IOL implantation (contact lens [CL]). Standardized definitions of glaucoma and glaucoma suspect were created for IATS and applied for surveillance and diagnosis. Main Outcome Measures Development of glaucoma and glaucoma+glaucoma suspect in operated eyes up to age five years, plus intraocular pressure, visual acuity, and axial length at age five years. Results Product limit estimates of the risk of glaucoma and glaucoma+glaucoma suspect at 4.8 years after surgery were 17% (95%CI=11%–25%) and 31% (95%CI=24%–41%), respectively. The CL and IOL groups were not significantly different for either outcome: glaucoma (hazard ratio(HR)=0.8[95%CI=0.3–2.0],p=0.62); glaucoma+glaucoma suspect: (HR=1.3[95%CI=0.6–2.5],p=0.58). Younger (versus older) age at surgery conferred increased risk of glaucoma (26% versus 9%, respectively at 4.8 years after surgery (HR=3.2[95%CI=1.2–8.3]), and smaller (versus larger) corneal diameter showed increased risk for glaucoma+glaucoma suspect (HR=2.5[95%CI=1.3–5.0]). Age and corneal diameter were significantly positively correlated. Glaucoma was predominantly open angle (19/20 cases, 95%), most eyes received medication (19/20, 95%), and 8/20 (40%) eyes had surgery. Conclusions and Relevance These results suggest that glaucoma-related adverse events are common and increase between one and five years in infants after unilateral cataract removal at 1–6 months of age; primary IOL placement does not mitigate their risk, but surgery at a younger age increases the risk. Longer follow-up of these children may further characterize risk factors, long-term outcomes, potential differences between eyes having primary IOL vs. aphakia, and optimal timing of unilateral congenital cataract removal. PMID:25996491

[Development of a glaucoma microstent with drainage into the suprachoroidal space: fluid mechanical model approach].

PubMed

Guthoff, R F; Schmidt, W; Buss, D; Schultze, C; Ruppin, U; Stachs, O; Sternberg, K; Klee, D; Chichkov, B; Schmitz, K-P

2009-09-01

The purpose of this study was to develop a microstent with valve function, which normalizes the intraocular pressure (IOP) and drains into the suprachoroidal space. In comparison to the subconjunctival space the suprachoroidal space is attributed with less fibroblast colonization and activity. Different glaucoma drainage devices were idealized as tubes and the flow rates were calculated according to Hagen-Poiseuille. The dimensions of the ideal glaucoma implant were modified with respect to an aqueous humor production of 2 microl/min and the different outflow pathways. Specific components of glaucoma drainage devices at the inlet and outlet were not included. The volume flow calculation of the tested glaucoma implants showed that the dimensions of all lumina were too large to prevent postoperative hypotension. A maximum inner tube diameter of 53 microm was calculated for drainage into the suprachoroidal space based on an intra-ocular pressure (IOP) of 20 mmHg. The glaucoma microstent has to guarantee an aqueous humor flow for physiological IOP. An increase of IOP has to be regulated to physiological pressure conditions by the microvalve.

An Automatic Image Processing System for Glaucoma Screening

PubMed Central

Alodhayb, Sami; Lakshminarayanan, Vasudevan

2017-01-01

Horizontal and vertical cup to disc ratios are the most crucial parameters used clinically to detect glaucoma or monitor its progress and are manually evaluated from retinal fundus images of the optic nerve head. Due to the rarity of the glaucoma experts as well as the increasing in glaucoma's population, an automatically calculated horizontal and vertical cup to disc ratios (HCDR and VCDR, resp.) can be useful for glaucoma screening. We report on two algorithms to calculate the HCDR and VCDR. In the algorithms, level set and inpainting techniques were developed for segmenting the disc, while thresholding using Type-II fuzzy approach was developed for segmenting the cup. The results from the algorithms were verified using the manual markings of images from a dataset of glaucomatous images (retinal fundus images for glaucoma analysis (RIGA dataset)) by six ophthalmologists. The algorithm's accuracy for HCDR and VCDR combined was 74.2%. Only the accuracy of manual markings by one ophthalmologist was higher than the algorithm's accuracy. The algorithm's best agreement was with markings by ophthalmologist number 1 in 230 images (41.8%) of the total tested images. PMID:28947898

Challenges in Liquid-Phase Exfoliation, Processing, and Assembly of Pristine Graphene.

PubMed

Parviz, Dorsa; Irin, Fahmida; Shah, Smit A; Das, Sriya; Sweeney, Charles B; Green, Micah J

2016-10-01

Recent developments in the exfoliation, dispersion, and processing of pristine graphene (i.e., non-oxidized graphene) are described. General metrics are outlined that can be used to assess the quality and processability of various "graphene" products, as well as metrics that determine the potential for industrial scale-up. The pristine graphene production process is categorized from a chemical engineering point of view with three key steps: i) pretreatment, ii) exfoliation, and iii) separation. How pristine graphene colloidal stability is distinct from the exfoliation step and is dependent upon graphene interactions with solvents and dispersants are extensively reviewed. Finally, the challenges and opportunities of using pristine graphene as nanofillers in polymer composites, as well as as building blocks for macrostructure assemblies are summarized in the context of large-scale production. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Retinal fundus images for glaucoma analysis: the RIGA dataset

NASA Astrophysics Data System (ADS)

Almazroa, Ahmed; Alodhayb, Sami; Osman, Essameldin; Ramadan, Eslam; Hummadi, Mohammed; Dlaim, Mohammed; Alkatee, Muhannad; Raahemifar, Kaamran; Lakshminarayanan, Vasudevan

2018-03-01

Glaucoma neuropathy is a major cause of irreversible blindness worldwide. Current models of chronic care will not be able to close the gap of growing prevalence of glaucoma and challenges for access to healthcare services. Teleophthalmology is being developed to close this gap. In order to develop automated techniques for glaucoma detection which can be used in tele-ophthalmology we have developed a large retinal fundus dataset. A de-identified dataset of retinal fundus images for glaucoma analysis (RIGA) was derived from three sources for a total of 750 images. The optic cup and disc boundaries for each image was marked and annotated manually by six experienced ophthalmologists and included the cup to disc (CDR) estimates. Six parameters were extracted and assessed (the disc area and centroid, cup area and centroid, horizontal and vertical cup to disc ratios) among the ophthalmologists. The inter-observer annotations were compared by calculating the standard deviation (SD) for every image between the six ophthalmologists in order to determine if the outliers amongst the six and was used to filter the corresponding images. The data set will be made available to the research community in order to crowd source other analysis from other research groups in order to develop, validate and implement analysis algorithms appropriate for tele-glaucoma assessment. The RIGA dataset can be freely accessed online through University of Michigan, Deep Blue website (doi:10.7302/Z23R0R29).

The Evonik-Mainz Eye Care-Study (EMECS): Development of an Expert System for Glaucoma Risk Detection in a Working Population

PubMed Central

Wahl, Jochen; Barleon, Lorenz; Morfeld, Peter; Lichtmeß, Andrea; Haas-Brähler, Sibylle; Pfeiffer, Norbert

2016-01-01

Purpose To develop an expert system for glaucoma screening in a working population based on a human expert procedure using images of optic nerve head (ONH), visual field (frequency doubling technology, FDT) and intraocular pressure (IOP). Methods 4167 of 13037 (32%) employees between 40 and 65 years of Evonik Industries were screened. An experienced glaucoma expert (JW) assessed papilla parameters and evaluated all individual screening results. His classification into “no glaucoma”, “possible glaucoma” and “probable glaucoma” was defined as “gold standard”. A screening model was developed which was tested versus the gold-standard. This model took into account the assessment of the ONH. Values and relationships of CDR and IOP and the FDT were considered additionally and a glaucoma score was generated. The structure of the screening model was specified a priori whereas values of the parameters were chosen post-hoc to optimize sensitivity and specificity of the algorithm. Simple screening models based on IOP and / or FDT were investigated for comparison. Results 111 persons (2.66%) were classified as glaucoma suspects, thereof 13 (0.31%) as probable and 98 (2.35%) as possible glaucoma suspects by the expert. Re-evaluation by the screening model revealed a sensitivity of 83.8% and a specificity of 99.6% for all glaucoma suspects. The positive predictive value of the model was 80.2%, the negative predictive value 99.6%. Simple screening models showed insufficient diagnostic accuracy. Conclusion Adjustment of ONH and symmetry parameters with respect to excavation and IOP in an expert system produced sufficiently satisfying diagnostic accuracy. This screening model seems to be applicable in such a working population with relatively low age and low glaucoma prevalence. Different experts should validate the model in different populations. PMID:27479301

Detecting hidden exfoliation corrosion in aircraft wing skins using thermography

NASA Astrophysics Data System (ADS)

Prati, John

2000-03-01

A thermal wave (pulse) thermography inspection technique demonstrated the ability to detect hidden subsurface exfoliation corrosion adjacent to countersunk fasteners in aircraft wing skins. In the wing skin, exfoliation corrosion is the result of the interaction between the steel fastener and the aluminum skin material in the presence of moisture. This interaction results in corrosion cracks that tend to grow parallel to the skin surface. The inspection technique developed allows rapid detection and evaluation of hidden (not visible on the surface) corrosion, which extends beyond the head of fastener countersinks in the aluminum skins.

Medical Management of Glaucoma in the 21st Century from a Canadian Perspective

PubMed Central

Birt, Catherine; Gooi, Patrick; Heckler, Lisa; Hutnik, Cindy; Jinapriya, Delan; Shuba, Lesya; Yan, David; Day, Radmila

2016-01-01

Glaucoma is a medical term describing a group of progressive optic neuropathies characterized by degeneration of retinal ganglion cells and retinal nerve fibre layer and resulting in changes in the optic nerve head. Glaucoma is a leading cause of irreversible vision loss worldwide. With the aging population it is expected that the prevalence of glaucoma will continue to increase. Despite recent advances in imaging and visual field testing techniques that allow establishment of earlier diagnosis and treatment initiation, significant numbers of glaucoma patients are undiagnosed and present late in the course of their disease. This can lead to irreversible vision loss, reduced quality of life, and a higher socioeconomic burden. Selection of therapeutic approaches for glaucoma should be based on careful ocular examination, patient medical history, presence of comorbidities, and awareness of concomitant systemic therapies. Therapy should also be individualized to patients' needs and preferences. Recent developments in this therapeutic field require revisiting treatment algorithms and integration of traditional and novel approaches in order to ensure optimal visual outcomes. This article provides an overview of recent developments and practice trends in the medical management of glaucoma in Canada. A discussion of the surgical management is beyond the scope of this paper. PMID:27895937

Postoperative Complications in the Ahmed Baerveldt Comparison Study during Five Years of Follow-up

PubMed Central

Budenz, Donald L.; Feuer, William J.; Barton, Keith; Schiffman, Joyce; Costa, Vital P.; Godfrey, David G.; Buys, Yvonne M.

2016-01-01

PURPOSE To compare the late complications in the Ahmed Baerveldt Comparison Study during 5 years of follow-up. DESIGN Multicenter, prospective, randomized clinical trial. METHODS SETTINGS Sixteen international clinical centers. STUDY POPULATION Two hundred seventy six subjects aged 18 to 85 years with previous intraocular surgery or refractory glaucoma with intraocular pressure of > 18 mmHg. INTERVENTIONS Ahmed Glaucoma Valve FP7 or Baerveldt Glaucoma Implant BG 101-350. MAIN OUTCOME MEASURES Late postoperative complications (beyond 3 months), reoperations for complications, and decreased vision from complications. RESULTS Late complications developed in 56 subjects (46.8 ± 4.8 5 year cumulative % ± SE) in the Ahmed Glaucoma Valve group and 67 (56.3 ± 4.7 5 year cumulative % ± SE) in the Baerveldt Glaucoma Implant group (P = 0.082). The cumulative rates of serious complications were 15.9% and 24.7% in the Ahmed Glaucoma Valve and Baerveldt Glaucoma Implant groups respectively (P = 0.034) although this was largely driven by subjects who had tube occlusions in the two groups (0.8% in the Ahmed Glaucoma Valve group and 5.7% in the Baerveldt Glaucoma Implant group, P = 0.037). Both groups had a relatively high incidence of persistent diplopia (12%) and corneal edema (20%), although half of the corneal edema cases were likely due to pre-existing causes other than the aqueous shunt. The incidence of tube erosion was 1% and 3% in the Ahmed Glaucoma Valve and Baerveldt Glaucoma Implant groups, respectively (P = 0.04). CONCLUSIONS Long term rates of vision threatening complications and complications resulting in reoperation were higher in the Baerveldt Glaucoma Implant than the Ahmed Glaucoma Valve group over 5 years of follow-up. PMID:26596400

Inter-eye Asymmetry of Optical Coherence Tomography Angiography Vessel Density in Bilateral Glaucoma, Glaucoma Suspect, and Healthy Eyes.

PubMed

Hou, Huiyuan; Moghimi, Sasan; Zangwill, Linda M; Shoji, Takuhei; Ghahari, Elham; Manalastas, Patricia Isabel C; Penteado, Rafaella C; Weinreb, Robert N

2018-03-23

To investigate inter-eye retinal vessel density asymmetry in healthy, glaucoma suspect, and mild to moderate glaucoma subjects, and its potential utility for early detection of glaucomatous damage. Cross-sectional study. 153 subjects including 55 healthy, 32 glaucoma suspect, and 66 glaucoma subjects enrolled in the Diagnostic Innovations in Glaucoma Study(DIGS). Vessel density was obtained from optical coherence tomography angiography (OCT-A) macular and optic nerve head scans. Thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (mGCC) was measured with spectral-domain optical coherence tomography (SD-OCT) scans. Inter-eye asymmetry was calculated by taking the absolute value of difference in vessel density and thickness between the right and left eyes. Inter-eye retinal vessel density asymmetry parameters were significantly different among the three groups. Glaucoma suspects had significantly higher peripapillary and macular inter-eye vessel density asymmetries compared to healthy groups in univariate (1.1% vs. 2.0%, P=0.014 and 1.2% vs. 2.5%, P=0.027, respectively) and multivariate analyses (P=0.007 and 0.038, respectively). No significant differences in asymmetry of thickness parameters were found between glaucoma suspect and healthy groups (all P> 0.718). However significant differences in asymmetry of thickness parameters between glaucoma suspects and glaucoma patients (P<0.01) were found for all parameters. Inter-eye vessel density asymmetry can be quantified by OCT-A measurement. Glaucoma suspects have significantly greater vessel density asymmetry than healthy eyes. Longitudinal studies are needed to better characterize the relationship of vessel density asymmetry with the development and progression of glaucoma. Copyright © 2018 Elsevier Inc. All rights reserved.

The Wills Eye Glaucoma App: Interest of Patients and Their Caregivers in a Smartphone-based and Tablet-based Glaucoma Application.

PubMed

Waisbourd, Michael; Dhami, Hermandeep; Zhou, Chen; Hsieh, Michael; Abichandani, Pramod; Pro, Michael J; Moster, Marlene R; Katz, L Jay; Hark, Lisa A; Myers, Jonathan S

2016-09-01

To evaluate the interest of glaucoma patients and their caregivers in a smartphone-based and tablet-based glaucoma application (App), developed by the Wills Eye Glaucoma Research Center in collaboration with Drexel University. Cross-sectional survey of patients with glaucoma and their caregivers. Main outcome measures are answers to survey questions regarding how receptive participants are to using the Glaucoma App. Fifty subjects completed the survey. The mean age (SD) was 59.5 (±17.3) years. A total of 88.6% of the participants lived in a household with access to a smartphone or tablet. The majority (72.3%) of participants would consider downloading the Glaucoma App, and younger participants (<65 y) were more likely to do so compared with their older (≥65 y) counterparts, P=0.025. Participants were more likely to download the App if it was free of charge, compared with a version that costs $3, P=0.018. Although only about one third (37.8%) of participants used eye drop reminders, nearly 3 of 4 (72.9%) participants were receptive to using the automated reminder feature of the Glaucoma App. Glaucoma patients and their caregivers were very interested in using a Glaucoma App; however, many were not willing to spend $3 for an App they seem to value. The free Wills Eye Glaucoma App currently available on the Apple store, includes educational videos, eye drop and appointment reminders, medical and ocular data storage, visual field tutorial, and intraocular pressure tracker. These features aim to increase patients' level of knowledge about glaucoma and improve their adherence to medication and follow-up appointment recommendations.

Relationship Between Anterior Lamina Cribrosa Surface Tilt and Glaucoma Development in Myopic Eyes.

PubMed

Lee, Eun Jung; Han, Jong Chul; Kee, Changwon

2017-05-01

To evaluate the anterior lamina cribrosa (LC) surface tilt angle in myopic eyes and associate it with glaucoma development. In this retrospective study, medical records of myopic patients referred for glaucoma examination from July 1, 2012 to March 30, 2016 were reviewed. Comprehensive ophthalmic examination including spectral-domain optical coherence tomography were performed. We measured the angle of anterior LC surface tilt against Bruch's membrane opening from optical coherence tomography images at the center of the clinical optic disc margin. In horizontal and vertical sections, the angles were defined as α and β, respectively. Patients were grouped according to the presence of glaucomatous damage and factors including optic nerve head morphologic parameters and LC tilt angles were compared between the 2 groups. Among 138 patients originally enrolled, 102 patients were finally analyzed. One eye from 1 patient was randomly chosen. Fifty-five eyes had glaucoma and 47 were normal. The degree of myopia and all optic nerve head morphologic parameters were not significantly different between the 2 groups. However, |α| and |β| were significantly larger in the glaucoma group (all P<0.001), and significances were maintained in multivariate analysis (P<0.001). Larger anterior LC surface tilt angles were related to the presence of glaucoma in normal-pressure myopic eyes. Angulation of the LC against Bruch's membrane opening plane might be associated with increased glaucoma susceptibility in myopic eyes. Further investigations are warranted before clinical utilization of LC tilt as glaucoma susceptibility biomarker.

THE AFRICAN DESCENT AND GLAUCOMA EVALUATION STUDY (ADAGES): PREDICTORS OF VISUAL FIELD DAMAGE IN GLAUCOMA SUSPECTS

PubMed Central

Khachatryan, Naira; Medeiros, Felipe A.; Sharpsten, Lucie; Bowd, Christopher; Sample, Pamela A.; Liebmann, Jeffrey M.; Girkin, Christopher A.; Weinreb, Robert N.; Miki, Atsuya; Hammel, Na’ama; Zangwill, Linda M.

2015-01-01

Purpose To evaluate racial differences in the development of visual field (VF) damage in glaucoma suspects. Design Prospective, observational cohort study. Methods Six hundred thirty six eyes from 357 glaucoma suspects with normal VF at baseline were included from the multicenter African Descent and Glaucoma Evaluation Study (ADAGES). Racial differences in the development of VF damage were examined using multivariable Cox Proportional Hazard models. Results Thirty one (25.4%) of 122 African descent participants and 47 (20.0%) of 235 European descent participants developed VF damage (p=0.078). In multivariable analysis, worse baseline VF mean deviation, higher mean arterial pressure during follow up, and a race *mean intraocular pressure (IOP) interaction term were significantly associated with the development of VF damage suggesting that racial differences in the risk of VF damage varied by IOP. At higher mean IOP levels, race was predictive of the development of VF damage even after adjusting for potentially confounding factors. At mean IOPs during follow-up of 22, 24 and 26 mmHg, multivariable hazard ratios (95%CI) for the development of VF damage in African descent compared to European descent subjects were 2.03 (1.15–3.57), 2.71 (1.39–5.29), and 3.61 (1.61–8.08), respectively. However, at lower mean IOP levels (below 22 mmHg) during follow-up, African descent was not predictive of the development of VF damage. Conclusion In this cohort of glaucoma suspects with similar access to treatment, multivariate analysis revealed that at higher mean IOP during follow-up, individuals of African descent were more likely to develop VF damage than individuals of European descent. PMID:25597839

Late-onset endophthalmitis secondary to exposed glaucoma tube implant in a rare case of paediatric glaucoma.

PubMed

Ranganath, Akshatha; Hashim, Adnan

2011-01-01

Glaucoma drainage implants (GDIs) are used to treat paediatric glaucoma resistant to conventional medical and surgical treatment, achieving good intraocular pressure (IOP) control and long-term success. Late endophthalmitis is a rare complication that may develop following GDI surgery. A 17-year-old male presented with acute endophthalmitis 2 years after Ahmed glaucoma valve implantation with pericardial patch graft for management of refractory glaucoma secondary to congenital ectropion uveae. The glaucoma tube was exposed due to erosion of the overlying conjunctiva with no visible pericardial graft. After control of active infection, he underwent tube revision surgery whereby the exposed tube was retained and repatched with a double-thickness pericardial patch graft. He did well following surgery with good control of IOP and restoration of vision. Conjunctival dehiscence with graft melting over the GDI tube presented a major risk factor for endophthalmitis. Prompt surgical revision of an exposed tube is highly recommended to avoid ocular morbidity.

Incidence of secondary glaucoma in behcet disease.

PubMed

Elgin, Ufuk; Berker, Nilufer; Batman, Aygen

2004-12-01

To determine the incidence of secondary glaucoma in Behcet disease. A total of 230 eyes of 129 patients with Behcet disease, were examined in uveitis and glaucoma clinics of Ankara Social Security Eye Hospital between January 1997 and September 2002. The data from all patients were investigated both retrospectively and prospectively. The mean age of 129 patients was 34.2 +/- 7.4 years (range, 18 to 55 years). In 22 patients (17%), the disease was diagnosed on the basis of the ocular findings, while in the remaining 107 patients (83%), the period between the diagnosis of Behcet disease and the onset of the ocular symptoms was 23.3 +/- 17 months (range, 1 month to 5.3 years); 122 eyes (53%) had the episodes of acute recurrent iridocyclitis, while 108 eyes (47%) developed chronic posterior uveitis, including vitreitis, retinitis, vasculitis, or optic nerve involvement. Secondary glaucoma was diagnosed in 25 eyes (10.9%); 11 eyes (44%) with steroid or inflammation induced open angle glaucoma, 6 eyes (24%) with partial angle-closure glaucoma and peripheral anterior synechiae, 5 eyes (20%) with angle closure glaucoma, peripheral anterior synechiae, and pupil block and 3 eyes (12%) with neovascular glaucoma. The treatments included YAG-laser iridotomy in 5 eyes, diode-laser cyclodestruction in 3 eyes, primary trabeculectomies with mitomycin-c in 4 eyes, secondary trabeculectomies with mitomycin-c in 2 eyes, Ahmed valve implantations in 2 eyes, and cyclocryotherapy in 3 eyes. We suggest that secondary glaucoma is a common and serious complication of Behcet disease. It develops as a result of multiple factors, generally triggered by recurrent intraocular inflammation. Early recognition and treatment of these factors have vital importance to avoid the visual morbidity.

Juxtacanalicular tissue in pigmentary and primary open angle glaucoma. The hydrodynamic role of pigment and other constituents.

PubMed

Murphy, C G; Johnson, M; Alvarado, J A

1992-12-01

We tested the hypothesis that obstruction of the juxtacanalicular tissues, by melanin granules in pigmentary glaucoma and by other impermeable material in primary open angle glaucoma, leads to the development of a chronic glaucomatous condition. The distribution and concentration of melanin and other impermeable materials in the juxtacanalicular tissues and elsewhere in the trabecular meshwork was determined in 13 specimens. Six specimens were from patients with pigmentary glaucoma, two from patients with pigment dispersion syndrome, and three from patients with primary open angle glaucoma, as well as two from normal subjects. The effect of these materials on flow resistance was estimated using two hydrodynamic models. In model A, the electron-lucent spaces of the juxtacanalicular tissue were assumed to be open spaces, while in model B, these spaces and spaces filled with ground substance were assumed to be gel filled. In pigmentary glaucoma, 3.5% of the pigment was found in the juxtacanalicular tissue, while 96.5% was found in the corneoscleral and uveoscleral tissues. Permeabilities calculated according to model A were much higher than those expected from estimates of outflow facility in all groups, in agreement with the previous report of Ethier et al. The gel-filled spaces available for fluid flow, as determined by model B, showed no statistically demonstrable differences (pigmentary glaucoma, 32.9%; primary open angle glaucoma, 36.6%; pigment dispersion syndrome, 43.4%; normal, 44.1%). Furthermore, the amount of pigment present in the juxtacanalicular tissue was determined to have a negligible influence on permeability. Thus, the development of the chronic glaucomatous condition cannot be directly attributed to pigment accumulation in the juxtacanalicular tissue in pigmentary glaucoma.

On the exfoliating polymeric cellular dosage forms for immediate drug release.

PubMed

Blaesi, Aron H; Saka, Nannaji

2016-06-01

The most prevalent pharmaceutical dosage forms at present-the oral immediate-release tablets and capsules-are granular solids. Though effective in releasing drug rapidly, development and manufacture of such dosage forms are fraught with difficulties inherent to particulate processing. Predictable dosage form manufacture could be achieved by liquid-based processing, but cast solid dosage forms are not suitable for immediate drug release due to their resistance to fluid percolation. To overcome this limitation, we have recently introduced cellular dosage forms that can be readily prepared from polymeric melts. It has been shown that open-cell structures comprising polyethylene glycol 8000 (PEG 8k) excipient and a drug exfoliate upon immersion in a dissolution medium. The drug is then released rapidly due to the large specific surface area of the exfoliations. In this work, we vary the molecular weight of the PEG excipient and investigate its effect on the drug release kinetics of structures with predominantly open-cell topology. We demonstrate that the exfoliation rate decreases substantially if the excipient molecular weight is increased from 12 to 100kg/mol, which causes the drug dissolution time to increase by more than a factor of ten. A model is then developed to elucidate the exfoliation behavior of cellular structures. Diverse transport processes are considered: percolation due to capillarity, diffusion of dissolution medium through the cell walls, and viscous flow of the saturated excipient. It is found that the lower exfoliation rate and the longer dissolution time of the dosage forms with higher excipient molecular weight are primarily due to the greater viscosity of the cell walls after fluid penetration. Copyright © 2016 Elsevier B.V. All rights reserved.

Glaucoma as a Metabolic Optic Neuropathy: Making the Case for Nicotinamide Treatment in Glaucoma.

PubMed

Williams, Pete A; Harder, Jeffrey M; John, Simon W M

2017-12-01

Mitochondrial dysfunction may be an important, if not essential, component of human glaucoma. Using transcriptomics followed by molecular and neurobiological techniques, we have recently demonstrated that mitochondrial dysfunction within retinal ganglion cells is an early feature in the DBA/2J mouse model of inherited glaucoma. Guided by these findings, we discovered that the retinal level of nicotinamide adenine dinucleotide (NAD, a key molecule for mitochondrial health) declines in an age-dependent manner. We hypothesized that this decline in NAD renders retinal ganglion cells susceptible to damage during periods of elevated intraocular pressure. To replete NAD levels in this glaucoma, we administered nicotinamide (the amide of vitamin B3). At the lowest dose tested, nicotinamide robustly protected from glaucoma (~70% of eyes had no detectable glaucomatous neurodegeneration). At this dose, nicotinamide had no influence on intraocular pressure and so its effect was neuroprotective. At the highest dose tested, 93% of eyes had no detectable glaucoma. This represents a ~10-fold decrease in the risk of developing glaucoma. At this dose, intraocular pressure still became elevated but there was a reduction in the degree of elevation showing an additional benefit. Thus, nicotinamide is unexpectedly potent at preventing this glaucoma and is an attractive option for glaucoma therapeutics. Our findings demonstrate the promise for both preventing and treating glaucoma by interventions that bolster metabolism during increasing age and during periods of elevated intraocular pressure. Nicotinamide prevents age-related declines in NAD (a decline that occurs in different genetic contexts and species). NAD precursors are reported to protect from a variety of neurodegenerative conditions. Thus, nicotinamide may provide a much needed neuroprotective treatment against human glaucoma. This manuscript summarizes human data implicating mitochondria in glaucoma, and argues for studies to further assess the safety and efficacy of nicotinamide in human glaucoma care.

[Glaucoma and retinal surgery].

PubMed

Müller, M; Geerling, G; Zierhut, M; Klink, T

2010-05-01

In the therapeutic approach to complex glaucomas different initial situations were considered: pre-existing glaucoma, induction of glaucoma after vitreoretinal surgery and antiglaucomatous procedures. In pre-existing glaucoma and after filtering surgery maintenance of the filtering bleb requires a vitreoretinal approach for conjunctiva preservation with techniques such as pneumatic retinopexy or small gauge vitrectomy. After vitreoretinal surgery an increase in intraocular pressure (IOP) is common. Secondary glaucoma may occur after scleral buckling and after vitrectomy with or without gas or silicone oil tamponade as well as after application of steroids. Angle closure glaucoma after scleral buckling develops because of congestion and anterior rotation of the ciliary body. Vitreous tamponades with expansive or saturated gases may cause angle-closure glaucoma with or without pupillary blockage and may critically shorten ocular perfusion. Postoperative checks, immediate action and a ban on boarding aircraft over the period of intraocular gas tamponade prevent permanent damage to the eye. The majority of secondary glaucomas can effectively be controlled by topical medication and adequate postoperative posture of the patient. Besides the temporary use of systemic antiglaucomatous medication or laser therapy, very rarely in cases of massive swelling or overfill, a direct intervention, such as partial gas or silicone oil removal is required. A prophylactic inferior peripheral iridectomy prevents pupillary blockage in aphakic eyes with intraocular tamponade. In cases of heavy silicone oil use, the peripheral iridectomy is placed in the superior position. Nd:YAG laser application will regulate IOP in cases of occlusion. Secondary glaucoma due to silicone oil emulsification overload is treated by trabecular meshwork aspiration and lavage. In refractory glaucoma repetitive cyclophotocoagulation and drainage implants represent an approved method for long-term IOP regulation. The underlying cause of secondary glaucoma after vitreoretinal surgery is often multifactorial in nature and may benefit from an exact analysis for an adequate and successful treatment regimen.

Outcome of primary trabeculotomy ab interno (Trabectome) surgery in patients with steroid-induced glaucoma

PubMed Central

Ngai, Philip; Kim, Grace; Chak, Garrick; Lin, Ken; Maeda, Masahiro; Mosaed, Sameh

2016-01-01

Abstract To determine the efficacy and safety of Trabectome surgery on patients with steroid response, ranging from ocular hypertension refractory to maximal medical therapy to the development of steroid-induced glaucoma. A nonrandomized, nonblinded, retrospective study of 20 subjects with steroid response was conducted. All 20 eyes underwent Trabectome surgery alone. Nine subjects had steroid response with unremarkable visual field, 3 had mild steroid-induced glaucoma, and 8 had advanced steroid-induced glaucoma. Outcome measures included intraocular pressure (IOP), number of glaucoma medications, need for secondary glaucoma surgery, and steroid regimen. Mann–Whitney U test was used to compare postoperative IOP and number of medications to preoperative IOP and number of medications. Kaplan–Meier was used for survival analysis, and success was defined as: IOP reduced by 20% or more on any 2 consecutive visits after 3 months; IOP ≤21 mm Hg on any 2 consecutive visits after 3 months; and no secondary glaucoma surgery. The average preoperative IOP was 33.8 ± 6.9 mm Hg and average preoperative glaucoma medication usage was 3.85 ± 0.75 medications. At 12 months, the IOP was reduced to 15.00 ± 3.46 mm Hg (P = 0.03) and glaucoma medication was reduced to 2.3 ± 1.4 (P < 0.01). The survival rate at 12 months was 93%. At 12 months, 10 patients were continued on their preoperative steroid treatments, 5 were on tapered steroid treatments, and 5 had ceased steroid treatments entirely. One patient required secondary glaucoma surgery (glaucoma drainage device). No other complications were noted. The Trabectome procedure is safe and highly effective for steroid-response glaucoma, even in the context of continued steroid treatment. PMID:27977576

[CANNABIS AND GLAUCOMA: AN ANCIENT LEGEND OR A NOVEL THERAPEUTIC HORIZON?].

PubMed

Mathalone, Nurit; Wolf, Alvit; Geyer, Orna

2015-06-01

Glaucoma causes damage to the optic nerve and compromises the visual field. The main risk factor of the disease is the level of the intra-ocular pressure. Therapeutic options include medical and surgical treatment, aimed to lower the intra-ocular pressure. Consumption of the cannabis plant (Cannabis Satival has been known since ancient times. It can be consumed orally, topically, intra-venous or by inhalation. The main active ingredient of cannabis is THC (Tetra-Hydro-Cannabinol). One of THC's reported effects is the reduction of intra-ocular pressure. Several studies have demonstrated temporary intra-ocular pressure decrease in both healthy subjects and glaucoma patients following topical application or systemic consumption. The effect was a short term one. It was followed by the development of resistance to the drug after prolonged intake and it was also accompanied by topical and systemic side effects. Cannabis may be considered as a therapeutic option in glaucoma. Its limited effect, development of resistance, acquired side effects and the accompanying psycho-active influence limit its advantage and cause its efficacy to be dubious. Therefore, cannabis treatment for glaucoma currently seems impractical and is not recommended by either the Israeli or the American glaucoma societies.

XEN glaucoma treatment system in the management of refractory glaucomas: a short review on trial data and potential role in clinical practice.

PubMed

De Gregorio, A; Pedrotti, E; Stevan, G; Bertoncello, A; Morselli, S

2018-01-01

The recent development of new devices that are significantly less invasive, collectively termed minimally invasive glaucoma surgery, offers new perspective of intraocular pressure reduction with less risk, short operating times, and rapid recovery. The aim of this work is to provide a panoramic review of the currently published clinical data to assess the potential role of XEN gel stent (Allergan PLC, Irvine, CA, USA) in the management of glaucoma, which is the only filtering minimally invasive glaucoma surgery device that allows the subconjunctival filtration. The ab interno placement of the XEN gel stent offers an alternative for lowering intraocular pressure in refractory glaucoma as a final step, and in patients intolerant to medical therapy as an early surgical approach with minimum conjunctival tissue disruption, restricted flow to avoid hypotony, and long-term safety.

EX-PRESS Glaucoma Filtration Device: efficacy, safety, and predictability

PubMed Central

Chan, Jessica E; Netland, Peter A

2015-01-01

Trabeculectomy has been the traditional primary surgical therapy for open-angle glaucoma. While trabeculectomy is effective in lowering intraocular pressure, complications associated with the procedure have motivated the development of alternative techniques and devices, including the EX-PRESS Glaucoma Filtration Device. This review describes the efficacy, safety, complication rates, and potential advantages and disadvantages of the EX-PRESS Glaucoma Filtration Device. EX-PRESS implantation is technically simpler compared with that of trabeculectomy, with fewer surgical steps. Vision recovery has been more rapid after EX-PRESS implantation compared with trabeculectomy. Intraocular pressure variation is lower during the early postoperative period, indicating a more predictable procedure. While efficacy of the EX-PRESS implant has been comparable to trabeculectomy, postoperative complications appear less common after EX-PRESS implantation compared with trabeculectomy. The EX-PRESS Glaucoma Filtration Device appears to be safe and effective in the surgical management of open-angle glaucoma. PMID:26366105

XEN glaucoma treatment system in the management of refractory glaucomas: a short review on trial data and potential role in clinical practice

PubMed Central

De Gregorio, A; Pedrotti, E; Stevan, G; Bertoncello, A; Morselli, S

2018-01-01

The recent development of new devices that are significantly less invasive, collectively termed minimally invasive glaucoma surgery, offers new perspective of intraocular pressure reduction with less risk, short operating times, and rapid recovery. The aim of this work is to provide a panoramic review of the currently published clinical data to assess the potential role of XEN gel stent (Allergan PLC, Irvine, CA, USA) in the management of glaucoma, which is the only filtering minimally invasive glaucoma surgery device that allows the subconjunctival filtration. The ab interno placement of the XEN gel stent offers an alternative for lowering intraocular pressure in refractory glaucoma as a final step, and in patients intolerant to medical therapy as an early surgical approach with minimum conjunctival tissue disruption, restricted flow to avoid hypotony, and long-term safety. PMID:29750009

[Aiming for zero blindness].

PubMed

Nakazawa, Toru

2015-03-01

Glaucoma is the leading cause of acquired blindness in Japan. One reason that it often leads to blindness is that it can continue to worsen even after effective medical reduction of intraocular pressure (IOP), the only evidence-based treatment. The limitations of current treatments make it critical to identify IOP-independent factors that can cause glaucoma and develop new drugs to target these factors. This is a challenging task, as the pathology of glaucoma is thought to be very complex, with different combinations of factors underlying its development and progression in different patients. Additionally, there is a deficiency in methods to efficiently perform clinical evaluations and reliably probe the state of the disease over relatively short periods. In addition, newly developed drugs need to be evaluated with clinical trials, for which human and financial resources are limited, before they can be widely used for treatment. Taking all these issues into consideration, it is evident that there are two urgent issues to consider: the development of methods to classify glaucoma in detail based on its pathology, and the improvement of clinical evaluation methods. In this review, we discuss some of our efforts to develop new neuroprotective agents for glaucoma, with a focus on the following three areas: 1. Clinical research and development of methods to classify glaucoma in detail based on IOP-independent factors, and the exploration of possibilities for the improvement of clinical evaluation of glaucoma. 2. Pathology-based research and development of new drugs for glaucoma, focusing on comprehensive gene expression analysis and the development of molecule-targeting drugs, using murine optic nerve crush as a disease model. 3. Development of next generation in vivo imaging modalities and the establishment of infrastructure enabling "big-data" analysis. First, we discuss our clinical research and the development of methods to classify glaucoma in detail based on IOP-independent factors, as well as our investigation of ways to improve the clinical evaluation of the disease. Our research was prompted by the multifactorial nature of glaucoma. There is a high degree of variability in the pattern and speed of the progression of visual field defects in individual patients, presenting a major obstacle for successful clinical trials. To overcome this, we classified the eyes of glaucoma patients into 4 types, corresponding to the 4 patterns of glaucomatous optic nerve head morphology described: by Nicolela et al. and then tested the validity of this method by assessing the uniformity of clinical features in each group. We found that in normal tension glaucoma (NTG) eyes, each disc morphology group had a characteristic location in which the loss of circumpapillary retinal nerve fiber layer thickness (cpRNFLT; measured with optical coherence tomography: OCT) was most likely to occur. Furthermore, the incidence of reductions in visual acuity differed between the groups, as did the speed of visual field loss, the distribution of defective visual field test points, and the location of test points that were most susceptible to progressive damage, measured by Humphrey static perimetry. These results indicate that Nicolela's method of classifying eyes with glaucoma was able to overcome the difficulties caused by the diverse nature of the disease, at least to a certain extent. Building on these findings, we then set out to identify sectors of the visual field that correspond to the distribution of retinal nerve fibers, with the aim of detecting glaucoma progression with improved sensitivity. We first mapped the statistical correlation between visual field test points and cpRNFLT in each temporal clock-hour sector (from 6 to 12 o'clock), using OCT data from NTG patients. The resulting series of maps allowed us to identify areas containing visual field test points that were prone to be affected together as a group. We also used a similar method to identify visual field sectors within a 10 x 10 grid displayed by an OCT map of the macula. By analyzing both the visual field and the macular map sectors, we anticipate that a more accurate and sensitive detection of glaucoma progression can become possible. We also used laser speckle flowgraphy (LSFG) to assess optic nerve blood flow. We found that compared to healthy eyes, eyes with early-stage NTG had decreased blood flow, and the peak of the blood flow wave form of each heartbeat was delayed. Finally, we used a method combining swept source OCT (SS-OCT) and newly developed analysis software to reconstruct the entire lamina cribrosa, a structure situated deep in the optic nerve head. This morphological analysis returned preliminary data suggesting that alterations in the morphology of the lamina cribrosa are already present in the early stages of glaucoma. This result indicates that axonal injury, mediated by morphological abnormalities of the lamina cribrosa, is involved in the pathogenesis of glaucoma. The next topic discussed is the pathology-based drug research and development, focusing on the use of comprehensive gene expression analysis and the development of molecule-targeting drugs in a murine model of optic nerve injury. Learning from clinical data on glaucoma and the lamina cribrosa, we carried out basic research to first determine what factors regulate axonal injury, and then develop drugs targeting these factors. Specifically, we performed a comprehensive gene expression analysis, using a next generation sequencer, and pathway analysis of retinal samples obtained from a murine model of axonal injury. This analysis revealed a characteristic upregulation of genes (such as Chop) that belongs to the endoplasmic reticulum stress pathway. An immunohistological analysis revealed that these changes in gene expression took place in the retinal ganglion cells, suggesting that endoplasmic reticulum stress molecules may be suitable therapeutic targets. Among these molecules, we chose CHOP as our primary target for drug development. Currently, we are in the process of screening a library of 1274 drugs, all of which are already used in human subjects, for CHOP inhibitors. The last topic of our discussion is future possibilities for glaucoma management. First, we discuss the development of next generation in vivo imaging modalities that allow detailed description of pathomechanisms of this multifactorial disease, glaucoma. The purpose of this research was to improve the efficacy of glaucoma diagnosis and to visualize its pathology at a cellular/molecular level and develop molecule-specific therapies. Currently available visual field tests are subjective, since they rely on a determination of the threshold of light perception, and are affected by poor reproducibility. The current dependence on visual field tests to ascertain the progression of glaucoma is thus a serious limitation on an important task of ophthalmologists. We, therefore, turned our focus to the establishment of an in vivo imaging method to detect dying retinal ganglion cells, which would highlight the pathologic state of glaucoma with high sensitivity. To this end, we used confocal scanning ophthalmoscopy to assess the usefulness of SYTOX Orange as a cell death probe. Our results showed that this probe could reveal dying retinal ganglion cells clearly, quickly and with high sensitivity. We, therefore, believe that the clinical application of probes that can sensitively detect dying retinal ganglion cells is a highly promising approach. This also applies to the use of molecular tools that can provide information on the molecular pathology of glaucoma. Finally, we would like to introduce our national collaborative work on the analysis of "big-data". The project aims to collect as wide a range of data as possible at an unprecedented scale. The data to be registered ranges from basic glaucoma data, such as IOP and visual field test results, to data from the most sophisticated comprehensive expression analyses or imaging data. This is an important area of research, since it promises to enable the exploration of targets for drug discovery and the identification of new biomarkers to efficiently detect glaucoma progression by applying new analysis strategies to the complex mass data. The project not only depends on the collaborative efforts of various types of clinical settings including private practices, medical centers and university hospitals, but also contributions of the pharmaceutical and the medical device industries. Thus, uniting a wide range of Japanese interests and resources is the key for success. In summary, in order to aim for ZERO BLINDNESS, a drastic improvement in the quality of our patient care, drug development research for unmet medical demands, and a strategic collaboration of various professionals in the ophthalmic industry are essential. With the deep appreciation we fell towards the selfless support extended during the earthquake disaster, we wish to translate our "gratitude" into "power" from Tohoku. In doing so, we as academicians are determined to keep on contributing to the society by making progress in the medicine.

Applications of the oral scraped (exfoliative) cytology in oral cancer and precancer.

PubMed

Acha, Amelia; Ruesga, María T; Rodríguez, María J; Martínez de Pancorbo, María A; Aguirre, José M

2005-01-01

Scraped (exfoliative) cytology is a simple and harmless procedure, which has been a controversial technique according to its real validity in oral pathology. Lately it has re-emerged due to its application in oral precancer and cancer as a diagnostic and predictive method as well as for monitoring patients. New diagnostic techniques have been developed, such as "brush biopsy" and multiple molecular studies using the cells collected. In this review we are going to analyse the more novel aspects related with the applications of the scraped or exfoliative cytology in oral precancerous and cancerous pathology, specially focusing on molecular studies and their diagnostic and prognostic implications.

Predicting progression of glaucoma from rates of frequency doubling technology perimetry change.

PubMed

Meira-Freitas, Daniel; Tatham, Andrew J; Lisboa, Renato; Kuang, Tung-Mei; Zangwill, Linda M; Weinreb, Robert N; Girkin, Christopher A; Liebmann, Jeffrey M; Medeiros, Felipe A

2014-02-01

To evaluate the ability of longitudinal frequency doubling technology (FDT) to predict the development of glaucomatous visual field loss on standard automated perimetry (SAP) in glaucoma suspects. Prospective, observational cohort study. The study included 587 eyes of 367 patients with suspected glaucoma at baseline selected from the Diagnostic Innovations in Glaucoma Study (DIGS) and the African Descent and Glaucoma Evaluation Study (ADAGES). These eyes had an average of 6.7 ± 1.9 FDT tests during a mean follow-up time of 73.1 ± 28.0 months. Glaucoma suspects had intraocular pressure (IOP) >21 mmHg or an optic disc appearance suspicious of glaucoma. All patients had normal or nonrepeatable abnormal SAP at baseline. Humphrey Matrix FDT (Carl Zeiss Meditec, Inc, Dublin, CA) testing was performed within 6 months of SAP testing. The study end point was the development of 3 consecutive abnormal SAP test results. Joint longitudinal survival models were used to evaluate the ability of rates of FDT pattern standard deviation (PSD) change to predict the development of visual field loss on SAP, adjusting for confounding variables (baseline age, mean IOP, corneal thickness, and follow-up measurements of SAP PSD). The R(2) index was used to evaluate and compare the predictive abilities of the model containing longitudinal FDT PSD data with the model containing only baseline data. Sixty-three of 587 eyes (11%) developed SAP visual field loss during follow-up. The mean rate of FDT PSD change in eyes that developed SAP visual field loss was 0.07 dB/year versus 0.02 dB/year in those that did not (P < 0.001). Baseline FDT PSD and slopes of FDT PSD change were significantly predictive of progression, with hazard ratios of 1.11 per 0.1 dB higher (95% confidence interval [CI], 1.04-1.18; P = 0.002) and 4.40 per 0.1 dB/year faster (95% CI, 1.08-17.96; P = 0.04), respectively. The longitudinal model performed significantly better than the baseline model with an R(2) of 82% (95% CI, 74-89) versus 11% (95% CI, 2-24), respectively. Rates of FDT PSD change were highly predictive of the development of SAP visual field loss in glaucoma suspects. This finding suggests that longitudinal FDT evaluation may be useful for risk stratification of patients with suspected glaucoma. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

The glaucoma research foundation patient survey: patient understanding of glaucoma and its treatment.

PubMed

Herndon, Leon W; Brunner, Thomas M; Rollins, Jane Neff

2006-01-01

Determine patients' understanding of glaucoma and its treatment, their sources of information about glaucoma, their preferences for treatment, their experience with medication side effects, and their reasons for changing eye doctors. Prospective, nonrandomized patient survey study. A questionnaire was developed and sent to the 22,000 subscribers of the Gleams newsletter who have glaucoma. Questionnaires were returned by 4310 glaucoma patients. Most respondents received glaucoma information from their eye doctor. Only 28% of respondents reported having changed eye doctors for reasons related to their glaucoma. Of those who had, 60% cited poor communication as the reason. When queried about specific side effects associated with their medication, over 85% of responding patients were never or rarely bothered by headaches and eyelid darkening. Most respondents (67% and 55%, respectively) were rarely or never disturbed by red eye or burning and stinging. Most respondents understood the importance of intraocular pressure (IOP) lowering in glaucoma, and of those patients who expressed a preference, 92% reported that they would prefer the medication that lowers IOP the most, even if it caused red eye for a few weeks, over a medication that caused no red eye but did not get IOP as low. Patients who subscribe to Gleams and responded to the survey rely most on their doctors for information about glaucoma and its treatment. Most understand the importance of maintaining low IOP to decrease the risk of vision loss, and most will tolerate temporary ocular side effects to achieve low IOP.

Ethnic differences in primary angle-closure glaucoma.

PubMed

Yip, Jennifer L Y; Foster, Paul J

2006-04-01

Observational studies from different countries have shown that populations of East Asian origin have a higher frequency of primary angle-closure glaucoma compared with those of European or African descent. As half of all cases of glaucoma reside in Asia, and with primary angle-closure glaucoma carrying a higher rate of visual morbidity, primary angle-closure glaucoma poses an important public health problem; however, the inconsistent use of techniques and definitions to detect and diagnose primary angle-closure glaucoma has resulted in difficulties in interpreting the accuracy and comparability of such data. Therefore it is important to review these studies in the light of a consistent classification system. There are increasing reports that support previous findings on the incidence and prevalence of primary angle-closure glaucoma in different ethnic groups. There have also been further investigations into the mechanism and natural history of primary angle-closure glaucoma in Asian populations. International investigations into primary angle-closure glaucoma have demonstrated reproducible evidence that ethnic variations do exist. Cross-sectional studies in this area have also suggested that differences in anterior chamber depth, together with its association with peripheral anterior synechiae, may be part of the underlying mechanism behind these differences. The ideas generated need to be further explored with longitudinal data of changes in anterior chamber depth and peripheral anterior synechiae in different populations. The detailed mechanisms behind the development of angle-closure and primary angle-closure glaucoma should also be investigated.

Glaucoma

MedlinePlus

Open-angle glaucoma; Chronic glaucoma; Chronic open-angle glaucoma; Primary open-angle glaucoma; Closed-angle glaucoma; Narrow-angle glaucoma; Angle-closure glaucoma; Acute glaucoma; Secondary glaucoma; Congenital glaucoma; Vision ...

Effective NaBH4-exfoliated ultrathin multilayer Co(OH)2 nanosheets arrays and sulfidation for energy storage

NASA Astrophysics Data System (ADS)

Yang, Wanjun; Qu, Gan; Chen, Mingyue; Ma, Wenhao; Li, Wenhui; Tang, Yiwen

2018-07-01

Facile engineering ultrathin nano structural materials is still a huge challenge for material science. Thereinto, the strategy of exfoliating shows great advantages. In this work, we develop a convenient approach to exfoliate Co(OH)2 nanosheets into ultrathin Co(OH)2 nanoflakes through NaBH4-exfoliation method. Moreover, the microstructures of the Co(OH)2 nanosheets are conveniently controlled by varying the exfoliation time. As a result, the obtained ultrathin Co(OH)2-72 h nanosheets deliver the excellent electrochemical performance. In order to improve the energy storage properties, the obtained ultrathin Co(OH)2 nanosheets are further modified to enhance the conductivity via sulfidation. Consequently, the synthesized Co(OH)2-72 h/CoS2 composites exhibit a specific capacitance of 2536 F g‑1 at 1 A g‑1, which is more outstanding than that of Co(OH)2-72 h. What’s more, the Co(OH)2-72 h/CoS2 composites show a capacitance retention of 83.3% after 10 000 cycles. Besides, the assembled asymmetric supercapacitor displays a power density of 482 W kg‑1 at an energy density of 36 Wh kg‑1, demonstrating a large potential for application.

Effective NaBH4-exfoliated ultrathin multilayer Co(OH)2 nanosheets arrays and sulfidation for energy storage.

PubMed

Yang, Wanjun; Qu, Gan; Chen, Mingyue; Ma, Wenhao; Li, Wenhui; Tang, Yiwen

2018-07-20

Facile engineering ultrathin nano structural materials is still a huge challenge for material science. Thereinto, the strategy of exfoliating shows great advantages. In this work, we develop a convenient approach to exfoliate Co(OH) 2 nanosheets into ultrathin Co(OH) 2 nanoflakes through NaBH 4 -exfoliation method. Moreover, the microstructures of the Co(OH) 2 nanosheets are conveniently controlled by varying the exfoliation time. As a result, the obtained ultrathin Co(OH) 2 -72 h nanosheets deliver the excellent electrochemical performance. In order to improve the energy storage properties, the obtained ultrathin Co(OH) 2 nanosheets are further modified to enhance the conductivity via sulfidation. Consequently, the synthesized Co(OH) 2 -72 h/CoS 2 composites exhibit a specific capacitance of 2536 F g -1 at 1 A g -1 , which is more outstanding than that of Co(OH) 2 -72 h. What's more, the Co(OH) 2 -72 h/CoS 2 composites show a capacitance retention of 83.3% after 10 000 cycles. Besides, the assembled asymmetric supercapacitor displays a power density of 482 W kg -1 at an energy density of 36 Wh kg -1 , demonstrating a large potential for application.

Maximizing cost-effectiveness by adjusting treatment strategy according to glaucoma severity

PubMed Central

Guedes, Ricardo Augusto Paletta; Guedes, Vanessa Maria Paletta; Gomes, Carlos Eduardo de Mello; Chaoubah, Alfredo

2016-01-01

Abstract Background: The aim of this study is to determine the most cost-effective strategy for the treatment of primary open-angle glaucoma (POAG) in Brazil, from the payer's perspective (Brazilian Public Health System) in the setting of the Glaucoma Referral Centers. Methods: Study design was a cost-effectiveness analysis of different treatment strategies for POAG. We developed 3 Markov models (one for each glaucoma stage: early, moderate and advanced), using a hypothetical cohort of POAG patients, from the perspective of the Brazilian Public Health System (SUS) and a horizon of the average life expectancy of the Brazilian population. Different strategies were tested according to disease severity. For early glaucoma, we compared observation, laser and medications. For moderate glaucoma, medications, laser and surgery. For advanced glaucoma, medications and surgery. Main outcome measures were ICER (incremental cost-effectiveness ratio), medical direct costs and QALY (quality-adjusted life year). Results: In early glaucoma, both laser and medical treatment were cost-effective (ICERs of initial laser and initial medical treatment over observation only, were R$ 2,811.39/QALY and R$ 3,450.47/QALY). Compared to observation strategy, the two alternatives have provided significant gains in quality of life. In moderate glaucoma population, medical treatment presented the highest costs among treatment strategies. Both laser and surgery were highly cost-effective in this group. For advanced glaucoma, both tested strategies were cost-effective. Starting age had a great impact on results in all studied groups. Initiating glaucoma therapy using laser or surgery were more cost-effective, the younger the patient. Conclusion: All tested treatment strategies for glaucoma provided real gains in quality of life and were cost-effective. However, according to the disease severity, not all strategies provided the same cost-effectiveness profile. Based on our findings, there should be a preferred strategy for each glaucoma stage, according to a cost-effectiveness ratio ranking. PMID:28033286

Cost of glaucoma treatment in a developing country over a 5-year period

PubMed Central

Lazcano-Gomez, Gabriel; Ramos-Cadena, María de los Angeles; Torres-Tamayo, Margarita; Hernandez de Oteyza, Alejandra; Turati-Acosta, Mauricio; Jimenez-Román, Jesús

2016-01-01

Abstract The aim of the study was to disclose a realistic estimate of primary open-angle glaucoma treatment, follow-up costs, and patients’ monthly glaucoma-economic burden in an ophthalmology hospital in Mexico City. Prospective survey of 462 primary open-angle glaucoma patients from 2007 to 2012 was carried out. Costs from visits, glaucoma follow-up studies, laser, and glaucoma surgical procedures were obtained from hospital pricings. Education, employment, and monthly income were interrogated. Total cost was divided into hypotensive treatment cost, nonpharmacologic treatment cost (laser and surgeries), and follow-up studies and consults. Average wholesale price for drugs analyzed was obtained from IMS Health data; monthly cost was calculated using: Monthly cost  = ([average wholesale price/number of drops per eye dropper] × number of daily applications) × 30 days. Patients were classified according to their glaucoma severity, and data were analyzed based on monthly income (average annual exchange rate: 12.85 Mexican pesos = 1 USD). The mean age was 70 ± 10 years, women = 81%, elementary school = 39%, and unemployed = 53%. Low-income group = 266 patients (57%), 146 with mild glaucoma; moderate-income group = 176 patients (38%), 81 with mild glaucoma; high-income group = 20 patients (4.3%), 10 with mild glaucoma. Patients’ monthly average economic burden in glaucoma treatment: low-income patients = 61.5%, moderate-income patients = 19.5%, and high-income patients = 7.9%. Glaucoma-economic burden is substantial not only for health systems, but for the family and the patient. Therefore, screening plans for earlier diagnosis, and health policies that lessen the cost of disease management and increase adherence to treatment, and reduce the prevalence of blindness attributed to glaucoma are essential. These would improve quality of life, reduce personal and national expenditure, and help increase national economy. PMID:27893669

Cost of glaucoma treatment in a developing country over a 5-year period.

PubMed

Lazcano-Gomez, Gabriel; Ramos-Cadena, María de Los Angeles; Torres-Tamayo, Margarita; Hernandez de Oteyza, Alejandra; Turati-Acosta, Mauricio; Jimenez-Román, Jesús

2016-11-01

The aim of the study was to disclose a realistic estimate of primary open-angle glaucoma treatment, follow-up costs, and patients' monthly glaucoma-economic burden in an ophthalmology hospital in Mexico City.Prospective survey of 462 primary open-angle glaucoma patients from 2007 to 2012 was carried out. Costs from visits, glaucoma follow-up studies, laser, and glaucoma surgical procedures were obtained from hospital pricings. Education, employment, and monthly income were interrogated. Total cost was divided into hypotensive treatment cost, nonpharmacologic treatment cost (laser and surgeries), and follow-up studies and consults. Average wholesale price for drugs analyzed was obtained from IMS Health data; monthly cost was calculated using: Monthly cost  = ([average wholesale price/number of drops per eye dropper] × number of daily applications) × 30 days.Patients were classified according to their glaucoma severity, and data were analyzed based on monthly income (average annual exchange rate: 12.85 Mexican pesos = 1 USD).The mean age was 70 ± 10 years, women = 81%, elementary school = 39%, and unemployed = 53%. Low-income group = 266 patients (57%), 146 with mild glaucoma; moderate-income group = 176 patients (38%), 81 with mild glaucoma; high-income group = 20 patients (4.3%), 10 with mild glaucoma. Patients' monthly average economic burden in glaucoma treatment: low-income patients = 61.5%, moderate-income patients = 19.5%, and high-income patients = 7.9%.Glaucoma-economic burden is substantial not only for health systems, but for the family and the patient. Therefore, screening plans for earlier diagnosis, and health policies that lessen the cost of disease management and increase adherence to treatment, and reduce the prevalence of blindness attributed to glaucoma are essential. These would improve quality of life, reduce personal and national expenditure, and help increase national economy.

[Visual development and amblyopia prophylaxis in pediatric glaucoma].

PubMed

Steffen, H

2011-07-01

In children with congenital glaucoma the functional long-term result is often disappointing even if the intraocular pressure is well controlled. The reason for this discrepancy is attributed to amblyogenic factors responsible for interfering with normal visual development. These amblyogenic factors are corneal edema, irregular astigmatism and non-corrected ametropia as monocular causes. Binocular causes are anisometropia-induced suppression and strabismus. Full ametropic correction and a very early prophylaxis and treatment of amblyopia with a close follow-up are mandatory to reduce amblyogenic visual impairment in children with congenital glaucoma.

Neovascular glaucoma after helium ion irradiation for uveal melanoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, M.K.; Char, D.H.; Castro, J.L.

1986-02-01

Neovascular glaucoma developed in 22 of 169 uveal melanoma patients treated with helium ion irradiation. Most patients had large melanomas; no eyes containing small melanomas developed anterior segment neovascularization. The mean onset of glaucoma was 14.1 months (range, 7-31 months). The incidence of anterior segment neovascularization increased with radiation dosage; there was an approximately three-fold increase at 80 GyE versus 60 GyE of helium ion radiation (23% vs. 8.5%) (P less than 0.05). Neovascular glaucoma occurred more commonly in larger tumors; the incidence was not affected by tumor location, presence of subretinal fluid, nor rate of tumor regression. Fifty-three percentmore » of patients had some response with intraocular pressures of 21 mmHg or less to a combination of antiglaucoma treatments.« less

Glaucoma management in patients with osteo-odonto-keratoprosthesis (OOKP): the Singapore OOKP Study.

PubMed

Kumar, Rajesh S; Tan, Donald T H; Por, Yong-Ming; Oen, Francis T; Hoh, Sek-Tien; Parthasarathy, Anand; Aung, Tin

2009-01-01

To report diagnostic modalities and treatment options for glaucoma in eyes with osteo-odonto keratoprosthesis (OOKP). Eyes that underwent OOKP were evaluated for glaucoma at the time of the first postoperative visit, then at 1 and 3 months after the procedure, and thereafter every 6 months. All eyes underwent stereo-biomicroscopic optic nerve head (ONH) assessment, kinetic (Goldmann perimetry) and automated static visual field testing, ONH photography, Heidelberg retina tomograph, scanning laser polarimetery (GDx), and optical coherence tomography. Treatment of glaucoma was also reviewed. Average follow-up period was 19.1 (range: 5 to 31) months. Of the 15 eyes that underwent OOKP, 5 eyes had preexisting glaucoma. None of the other 10 eyes developed glaucoma after OOKP. ONH photography and visual field testing were the most reliable methods to assess status of the disease, whereas Heidelberg retina tomograph and optical coherence tomography could be performed with reasonable reproducibility and quality; GDx imaging was poor. All patients with glaucoma were treated with oral acetazolamide 500 mg twice a day. Transscleral cyclophotocoagulation was performed in 3 eyes at stage 2 of OOKP surgery. Progression of glaucoma was noted in 2 eyes on the basis of optic disc photographs and automated perimetry. Visual field testing and optic disc assessment with optic disc photographs seem to be effective methods to monitor eyes with OOKP for glaucoma. Treatment strategies include oral medications to lower intraocular pressure and cyclophotocoagulation.

Determination Of Association Of Pigmentary Glaucoma With Pigment Dispersion Syndrome.

PubMed

Shah, Imtiaz Ali; Shah, Shujaat Ali; Nagdev, Partab Rai; Abbasi, Safdar Ali; Abbasi, Naeem Ali; Katpar, Safdar Akhtar

2017-01-01

Pigment Dispersion Syndrome (PDS) is an autosomal dominant disorder of white males between 20 to 40 years of age characterized by deposition of pigment on the lens, zonules of lens, trabecular meshwork and corneal endothelium (Krukenberg's spindle) in addition to radial, spoke like transillumination defects in the mid peripheral iris. This study was conducted to determine the frequency of occurrence of Pigmentary Glaucoma in patients with Pigment Dispersion Syndrome (PDS). This longitudinal follow up study included patients presenting with Krukenberg's spindle on the endothelial side of cornea and pigmentation of angle of anterior chamber seen on slit lamp examination and gonioscopy. Seventy-two cases of PDS were included in the study, amongst them 63 (87.50%) were males. Mean age was 35.00±6.54 years (range 24-46 years). Forty-seven (65.28%) patients had an IOP in the range of 10-14 mmHg, 22 (30.56%) patients had an IOP in the range of 15-18 mmHg and 3 (4.17%) patients developed an IOP of greater than 19 mmHg. Fundoscopy showed myopic degeneration in 49 (68.06%) patients and optic disc cupping in 3 (4.17%) patients. Four (5.56%) patients had refractive error between +1D to +3D, 9 (12.50%) patients had refractive error between -1D to -4D, 21 (29.17%) patients had refractive error between -5 D to -8 D and 38 (52.78%) patients had refractive error between -9 D to -12 D. Our study showed that one patient having PDS developed glaucoma at 5 years of follow up and three patients developed glaucoma at 14 years of follow up. On the basis of this study we conclude that early onset primary open angle glaucoma associated with PDS or Juvenile glaucoma associated with PDS might have been mistaken as Pigmentary Glaucoma in Pakistani patients and a distinct entity in the form of Pigmentary Glaucoma may be non-existent.

Toward Single Atom Chains with Exfoliated Tellurium.

PubMed

Churchill, Hugh O H; Salamo, Gregory J; Yu, Shui-Qing; Hironaka, Takayuki; Hu, Xian; Stacy, Jeb; Shih, Ishiang

2017-08-10

We demonstrate that the atom chain structure of Te allows it to be exfoliated as ultra-thin flakes and nanowires. Atomic force microscopy of exfoliated Te shows that thicknesses of 1-2 nm and widths below 100 nm can be exfoliated with this method. The Raman modes of exfoliated Te match those of bulk Te, with a slight shift (4 cm -1 ) due to a hardening of the A 1 and E modes. Polarized Raman spectroscopy is used to determine the crystal orientation of exfoliated Te flakes. These experiments establish exfoliation as a route to achieve nanoscale trigonal Te while also demonstrating the potential for fabrication of single atom chains of Te.

A New Glaucoma Severity Score Combining Structural and Functional Defects.

PubMed

Wachtl, J; Töteberg-Harms, M; Frimmel, S; Kniestedt, C

2017-04-01

Background In order to assess glaucoma severity and to compare the success of surgical and medical therapy and study outcomes, an objective and independent staging tool is necessary. A combination of information from both structural and functional testing is probably the best approach to stage glaucomatous damage. There has been no universally accepted standard for glaucoma staging. The aim of this study was to develop a Glaucoma Severity Score (GSS) for objective assessment of a patient's glaucoma severity, combining both functional and structural information. Materials and methods The Glaucoma Severity Score includes the following 3 criteria: superior and inferior Retinal Nerve Fibre Layer (RNFL) thickness, perimetric mean defect (MD), and agreement of anatomical and perimetric defects, as assessed by two glaucoma specialists. The specialists defined a staging tool for each of the 3 criteria in a consensus process, assigning specific characteristics to a scale value between 0 and 2 or 0 and 3, respectively. The GSS ranges between 0 and 10 points. In a prospective observational study, the data of 112 glaucoma patients were assessed independently by the two specialists according to this staging tool. Results The GSS was applied to 112 eyes and patients (59.8 % female) with a mean age of 66.3 ± 13.1 years. Mean GSS was 4.73 points. Cohen's kappa coefficient was determined to measure inter-rater agreement between glaucoma specialists for the third criterion. With κ = 0.83, the agreement was very good. Thus, all 3 criteria of the GSS may be regarded as objective. Conclusions The Glaucoma Severity Score is an objective tool, combining both structural and functional characteristics, and permitting comparison of different patients, populations and studies. The Glaucoma Severity Score has proven effective in the objective assessment of 112 glaucoma patients and is relatively user-friendly in clinical practice. A comparative study of the GSS with the results of the FORUM® Glaucoma Workplace (Carl Zeiss Meditec AG, Jena, Germany) will be the next step. If outcomes match, the Glaucoma Severity Score can be accepted as a promising tool to stage glaucoma and monitor changes objectively in patients when comparing glaucoma progression in study analyses. Georg Thieme Verlag KG Stuttgart · New York.

Edge orientations of mechanically exfoliated anisotropic two-dimensional materials

NASA Astrophysics Data System (ADS)

Yang, Juntan; Wang, Yi; Li, Yinfeng; Gao, Huajian; Chai, Yang; Yao, Haimin

2018-03-01

Mechanical exfoliation is an approach widely applied to prepare high-quality two-dimensional (2D) materials for investigating their intrinsic physical properties. During mechanical exfoliation, in-plane cleavage results in new edges whose orientations play an important role in determining the properties of the as-exfoliated 2D materials especially those with high anisotropy. Here, we systematically investigate the factors affecting the edge orientation of 2D materials obtained by mechanical exfoliation. Our theoretical study manifests that the fractured direction during mechanical exfoliation is determined synergistically by the tearing direction and material anisotropy of fracture energy. For a specific 2D material, our theory enables us to predict the possible edge orientations of the exfoliated flakes as well as their occurring probabilities. The theoretical prediction is experimentally verified by examining the inter-edge angles of the exfoliated flakes of four typical 2D materials including graphene, MoS2, PtS2, and black phosphorus. This work not only sheds light on the mechanics of exfoliation of the 2D materials but also provides a new approach to deriving information of edge orientations of mechanically exfoliated 2D materials by data mining of their macroscopic geometric features.

Glaucoma-related Changes in the Mechanical Properties and Collagen Micro-architecture of the Human Sclera

PubMed Central

Coudrillier, Baptiste; Pijanka, Jacek K.; Jefferys, Joan L.; Goel, Adhiraj; Quigley, Harry A.; Boote, Craig; Nguyen, Thao D.

2015-01-01

Objective The biomechanical behavior of the sclera determines the level of mechanical insult from intraocular pressure to the axons and tissues of the optic nerve head, as is of interest in glaucoma. In this study, we measure the collagen fiber structure and the strain response, and estimate the material properties of glaucomatous and normal human donor scleras. Methods Twenty-two posterior scleras from normal and diagnosed glaucoma donors were obtained from an eyebank. Optic nerve cross-sections were graded to determine the presence of axon loss. The specimens were subjected to pressure-controlled inflation testing. Full-field displacement maps were measured by digital image correlation (DIC) and spatially differentiated to compute surface strains. Maps of the collagen fiber structure across the posterior sclera of each inflated specimen were obtained using synchrotron wide-angle X-ray scattering (WAXS). Finite element (FE) models of the posterior scleras, incorporating a specimen-specific representation of the collagen structure, were constructed from the DIC-measured geometry. An inverse finite element analysis was developed to estimate the stiffness of the collagen fiber and inter-fiber matrix. Results The differences between glaucoma and non-glaucoma eyes were small in magnitude. Sectorial variations of degree of fiber alignment and peripapillary scleral strain significantly differed between normal and diagnosed glaucoma specimens. Meridional strains were on average larger in diagnosed glaucoma eyes compared with normal specimens. Non-glaucoma specimens had on average the lowest matrix and fiber stiffness, followed by undamaged glaucoma eyes, and damaged glaucoma eyes but the differences in stiffness were not significant. Conclusion The observed biomechanical and microstructural changes could be the result of tissue remodeling occuring in glaucoma and are likely to alter the mechanical environment of the optic nerve head and contribute to axonal damage. PMID:26161963

Measurement of Optic Disc Cup Surface Depth Using Cirrus HD-OCT.

PubMed

Kim, Young Kook; Ha, Ahnul; Lee, Won June; Jeoung, Jin Wook; Park, Ki Ho

2017-12-01

To introduce the measurement method of optic disc cup surface depth using spectral-domain optical coherence tomography (SD-OCT) and then evaluate the rates of cup surface depression at 3 different stages of glaucoma. We retrospectively identified 52 eyes with preperimetric glaucoma, 56 with mild-or-moderate glaucoma and 50 with severe glaucoma and followed them for at least 48 months. Eyes were imaged using SD-OCT (Cirrus HD-OCT) at 12-month intervals. The mean cup surface depth was calculated using the following formula: Cup volume/(disc area×average cup-to-disc ratio)-200 μm. The rates of mean cup surface depression (μm/y) were significantly greater in mild-or-moderate glaucoma (-7.96±1.03) than in preperimetric (-3.11±0.61) and severe glaucoma (-0.70±0.12; all P<0.001). The percentile rates of mean cup surface depression (%/y) were significantly greater than those of average of retinal nerve fiber layer (RNFL) thinning (%/y) in preperimetric glaucoma (-1.64±0.12 vs. -1.11±0.07; P<0.001) and mild-or-moderate glaucoma (-4.20±0.33 vs. -3.14±0.19; P<0.001); and conversely, in severe glaucoma, mean cup surface depth changed slower than did average RNFL thickness (-0.64±0.06 vs. -0.75±0.08%/y; P<0.001). In early-to-moderate glaucoma, the cup surface depth changed faster than did the RNFL thickness. These results signify the possibility that SD-OCT-based estimation of cup surface depth might be useful for monitoring of glaucoma development and progression.

Association between body levels of trace metals and glaucoma prevalence.

PubMed

Lin, Shuai-Chun; Singh, Kuldev; Lin, Shan C

2015-10-01

Abnormal body levels of essential elements and exposure to toxic trace metals have been postulated to contribute to the pathogenesis of diseases affecting many organ systems, including the eye. To investigate associations between body levels of trace metals and the prevalence of glaucoma in a cross-sectional population-based study. Blood or urine metallic element levels and information pertaining to ocular disease were available for 2680 individuals 19 years and older participating in the fourth Korea National Health and Nutrition Examination Survey between January 1, 2008, and December 31, 2009, the second and the third years of the survey (2007-2009). Glaucoma diagnosis was based on criteria established by the International Society of Geographic and Epidemiologic Ophthalmology. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine associations between blood and urine trace element levels and the odds of glaucoma diagnosis. All analyses were performed between September 2014 and December 2014. The presence or absence of glaucoma. After adjustment for potential confounders, blood manganese level was negatively associated with the odds of glaucoma diagnosis (odds ratio [OR], 0.44; 95% CI, 0.21-0.92). Blood mercury level was positively associated with glaucoma prevalence (OR, 1.01; 95% CI, 1.00-1.03). No definitive association was identified between blood cadmium or lead levels or urine arsenic level and a diagnosis of glaucoma. These findings in a cross-sectional study of the South Korean population suggest that a lower blood manganese level and a higher blood mercury level are associated with greater odds of glaucoma. For more confidence that trace metals may have a role in the pathogenesis of glaucoma, prospective studies would need to confirm that the presence of such trace metals increases the chance of developing glaucoma.

Prediction of functional loss in glaucoma from progressive optic disc damage.

PubMed

Medeiros, Felipe A; Alencar, Luciana M; Zangwill, Linda M; Bowd, Christopher; Sample, Pamela A; Weinreb, Robert N

2009-10-01

To evaluate the ability of progressive optic disc damage detected by assessment of longitudinal stereophotographs to predict future development of functional loss in those with suspected glaucoma. The study included 639 eyes of 407 patients with suspected glaucoma followed up for an average of 8.0 years with annual standard automated perimetry visual field and optic disc stereophotographs. All patients had normal and reliable standard automated perimetry results at baseline. Conversion to glaucoma was defined as development of 3 consecutive abnormal visual fields during follow-up. Presence of progressive optic disc damage was evaluated by grading longitudinally acquired simultaneous stereophotographs. Other predictive factors included age, intraocular pressure, central corneal thickness, pattern standard deviation, and baseline stereophotograph grading. Hazard ratios for predicting visual field loss were obtained by extended Cox models, with optic disc progression as a time-dependent covariate. Predictive accuracy was evaluated using a modified R(2) index. Progressive optic disc damage had a hazard ratio of 25.8 (95% confidence interval, 16.0-41.7) and was the most important risk factor for development of visual field loss with an R(2) of 79%. The R(2)s for other predictive factors ranged from 6% to 26%. Presence of progressive optic disc damage on stereophotographs was a highly predictive factor for future development of functional loss in glaucoma. These findings suggest the importance of careful monitoring of the optic disc appearance and a potential role for longitudinal assessment of the optic disc as an end point in clinical trials and as a reference for evaluation of diagnostic tests in glaucoma.

The Potential of Human Stem Cells for the Study and Treatment of Glaucoma

PubMed Central

Chamling, Xitiz; Sluch, Valentin M.; Zack, Donald J.

2016-01-01

Purpose Currently, the only available and approved treatments for glaucoma are various pharmacologic, laser-based, and surgical procedures that lower IOP. Although these treatments can be effective, they are not always sufficient, and they cannot restore vision that has already been lost. The goal of this review is to briefly assess current developments in the application of stem cell biology to the study and treatment of glaucoma and other forms of optic neuropathy. Methods A combined literature review and summary of the glaucoma-related discussion at the 2015 “Sight Restoration Through Stem Cell Therapy” meeting that was sponsored by the Ocular Research Symposia Foundation (ORSF). Results Ongoing advancements in basic and eye-related developmental biology have enabled researchers to direct murine and human stem cells along specific developmental paths and to differentiate them into a variety of ocular cell types of interest. The most advanced of these efforts involve the differentiation of stem cells into retinal pigment epithelial cells, work that has led to the initiation of several human trials. More related to the glaucoma field, there have been recent advances in developing protocols for differentiation of stem cells into trabecular meshwork and retinal ganglion cells. Additionally, efforts are being made to generate stem cell–derived cells that can be used to secrete neuroprotective factors. Conclusions Advancing stem cell technology provides opportunities to improve our understanding of glaucoma-related biology and develop models for drug development, and offers the possibility of cell-based therapies to restore sight to patients who have already lost vision. PMID:27116666

Thermal influences on spontaneous rock dome exfoliation

USGS Publications Warehouse

Collins, Brian D.; Stock, Greg M.; Eppes, Martha C.; Lewis, Scott W.; Corbett, Skye C.; Smith, Joel B.

2018-01-01

Rock domes, with their onion-skin layers of exfoliation sheets, are among the most captivating landforms on Earth. Long recognized as integral in shaping domes, the exact mechanism(s) by which exfoliation occurs remains enigmatic, mainly due to the lack of direct observations of natural events. In August 2014, during the hottest days of summer, a granitic dome in California, USA, spontaneously exfoliated; witnesses observed extensive cracking, including a ~8000 kg sheet popping into the air. Subsequent exfoliation episodes during the following two summers were recorded by instrumentation that captured—for the first time—exfoliation deformation and stress conditions. Here we show that thermal cycling and cumulative dome surface heating can induce subcritical cracking that culminates in seemingly spontaneous exfoliation. Our results indicate that thermal stresses—largely discounted in dome formation literature—can play a key role in triggering exfoliation and therefore may be an important control for shaping domes worldwide.

Exfoliation of the epidermal cells and defecation by amphibian larvae in response to coelomic fluid and lysenin from the earthworm Eisenia foetida.

PubMed

Kobayashi, Hideshi; Suzuki, Hirohumi; Ohta, Naoshi

2006-08-01

Coelomic fluid (CF) and lysenin from the earthworm Eisenia foetida induced heavy epidermal exfoliation in the larvae of Bufo japonicus formosus at developmental stages from hatching (stage 22) to operculum completion (stage 34). In experiments with Xenopus laevis, we observed that exfoliated cells were not stained by trypan blue. Thus, it appeared that these cells were still alive. It is likely, therefore, that both CF and lysenin might disrupt the adhesion between epidermal cells of larvae prior to stage 34. Since it is known that lysenin exerts its toxic effects through its specific binding to sphingomyelin (SM), SM might be involved in such adhesion. This hypothesis was supported by the observations that CF and lysenin which had been incubated with SM-liposomes lost their exfoliative activity. In larvae after stage 34, the mechanism of adhesion between epidermal cells seemed to change and the adhesion was no longer disrupted by CF and lysenin. In larvae at around stage 34, a collagen layer started to form beneath the basement membrane of the epidermis. Furthermore, larvae at around this stage started to eat solid food. The developing collagen layer and food intake might be related indirectly to the chemical change in epidermal adhesion. The induction of exfoliation by CF and lysenin was also observed in other amphibian species. In Bufo larvae, defecation was induced both by CF and by lysenin but this effect was independent of exfoliation.

Screening of Glaucoma or Cataract Prevalence in Vitiligo Patients and Its Relationship With Periorbital Steroid Use.

PubMed

Khurrum, Huma; AlGhamdi, Khalid M; Osman, Essam

2016-01-01

There is scarce literature connecting vitiligo and primary open angle glaucoma (POAG). Most literature reports that secondary complications are a direct consequence of corticosteroid treatment of vitiligo. In this study, we aimed to investigate the prevalence of ocular problems in patients with vitiligo and to determine its association with periorbital topical corticosteroid use. A cross-sectional study was carried out on 90 patients with vitiligo. The Vitiligo European Task Force questionnaire was completed for each patient. A control group comprising 90 healthy individuals who did not have vitiligo and who were matched on age and gender was used for comparison. A complete ophthalmologic examination was performed. A family history of glaucoma and the use of topical steroids were recorded. Two (2/90, 2.2%) of the patients with vitiligo had glaucoma compared with none of the individuals in the control group (P = .25). Nineteen of the 90 patients with vitiligo used periorbital steroids, and of these patients, 10.5% (2/19) developed glaucoma. The duration of periorbital corticosteroid use was 4.50 ± 2.1 years. Eighty-nine percent (17/19) of the vitiligo patients who applied the potent topical corticosteroid (class I) clobetasol propionate to the periorbital area did not develop glaucoma. In contrast, glaucoma was not observed in 79% (71/90) of the vitiligo patients who did not use steroids. Cataract, uveitis, or fundus problems were not observed in either group. The study suggests that patients who have vitiligo and use topical steroids periorbitally do not have an increased risk of glaucoma or cataracts. Future studies that have a larger sample size and use a detailed steroid use protocol are needed. © The Author(s) 2015.

Comparison of glaucoma knowledge and referral practices among family physicians with ophthalmologists' expectations.

PubMed

Basilious, Alfred; Cheng, Jason; Buys, Yvonne M

2015-06-01

To compare family physicians' glaucoma knowledge and clinical skills with ophthalmologists' expectations. An electronic cross-sectional survey of family physicians and ophthalmologists. Participants included members of the Canadian Ophthalmological Society, Canadian Glaucoma Society, and the American Glaucoma Society, as well as family physicians in the Canadian Medical Directory and the Society of Rural Physicians of Canada listserv. Two complementary surveys were developed to evaluate family physicians' glaucoma knowledge and basic examination skills, and ophthalmologists' expected level of family physician clinical knowledge and skills. χ(2) tests identified differences between family physician and ophthalmologist responses. Differences in family physician knowledge based on practice location and frequency of patient visits with a diagnosis of glaucoma were also evaluated. A total of 142 ophthalmologists and 110 family physicians completed the survey. The majority (82%) of family physicians reported seeing patients with diagnosed glaucoma weekly, monthly, or semiannually. Significantly fewer family physicians than expected (p < 0.001) identified African descent (46%) and corticosteroid use (84%) as glaucoma risk factors. Family physicians were significantly less likely to refer based on risk factors (72%) than expected by ophthalmologists (91%; p < 0.001). Only 28% of family physicians were comfortable performing direct ophthalmoscopy, and 37% were comfortable checking for a relative afferent pupillary defect. A significant percentage of family physicians lacked knowledge of glaucoma medications (30%) and side effects (57%). This study revealed significant disparities in family physician glaucoma knowledge, clinical examination skills, and referral practices. Educational materials should target these knowledge gaps. Copyright © 2015 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Lifetime risk of blindness in open-angle glaucoma.

PubMed

Peters, Dorothea; Bengtsson, Boel; Heijl, Anders

2013-10-01

To determine the lifetime risk and duration of blindness in patients with manifest open-angle glaucoma (OAG). Retrospective chart review. We studied glaucoma patients who died between January 2006 and June 2010. Most glaucoma patients living in the catchment area (city of Malmö; n = 305 000) are managed at the Department of Ophthalmology at Skåne University Hospital in Malmö. From the patient records we extracted visual field status, visual acuity, and low vision or blindness as defined by the World Health Organization (WHO) criteria and caused by glaucoma at the time of diagnosis and during follow-up. We also noted age at diagnosis and death and when low vision or blindness occurred. Five hundred and ninety-two patients were included. At the time of the last visit 250 patients (42.2%) had at least 1 blind eye because of glaucoma, while 97 patients (16.4%) were bilaterally blind, and 12 patients (0.5%) had low vision. Median time with a glaucoma diagnosis was 12 years (<1-29), median age when developing bilateral blindness was 86 years, and median duration of bilateral blindness was 2 years (<1-13). The cumulative incidences of blindness in at least 1 eye and bilateral blindness from glaucoma were 26.5% and 5.5%, respectively, after 10 years, and 38.1% and 13.5% at 20 years. Approximately 1 out of 6 glaucoma patients was bilaterally blind from glaucoma at the last visit. Median duration of bilateral blindness was 2 years. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Glaucoma –state of the art and perspectives on treatment

PubMed Central

Wójcik-Gryciuk, Anna; Skup, Małgorzata; Waleszczyk, Wioletta J.

2015-01-01

Glaucoma is a chronic optic neuropathy characterized by progressive damage to the optic nerve, death of retinal ganglion cells and ultimately visual field loss. It is one of the leading causes of irreversible loss of vision worldwide. The most important trigger of glaucomatous damage is elevated eye pressure, and the current standard approach in glaucoma therapy is reduction of intraocular pressure (IOP). However, despite the use of effective medications or surgical treatment leading to lowering of IOP, progression of glaucomatous changes and loss of vision among patients with glaucoma is common. Therefore, it is critical to prevent vision loss through additional treatment. To implement such treatment(s), it is imperative to identify pathophysiological changes in glaucoma and develop therapeutic methods taking into account neuroprotection. Currently, there is no method of neuroprotection with long-term proven effectiveness in the treatment of glaucoma. Among the most promising molecules shown to protect the retina and optic nerve are neurotrophic factors. Thus, the current focus is on the development of safe and non-invasive methods for the long-term elevation of the intraocular level of neurotrophins through advanced gene therapy and topical eye treatment and on the search for selective agonists of neurotrophin receptors affording more efficient neuroprotection. PMID:26684267

Micro-invasive glaucoma surgery (MIGS): a review of surgical procedures using stents

PubMed Central

Pillunat, Lutz E; Erb, Carl; Jünemann, Anselm GM; Kimmich, Friedemann

2017-01-01

Over the last decade several novel surgical treatment options and devices for glaucoma have been developed. All these developments aim to cause as little trauma as possible to the eye, to safely, effectively, and sustainably reduce intraocular pressure (IOP), to produce reproducible results, and to be easy to adopt. The term “micro-invasive glaucoma surgery (MIGS)” was used for summarizing all these procedures. Currently MIGS is gaining more and more interest and popularity. The possible reduction of the number of glaucoma medications, the ab interno approach without damaging the conjunctival tissue, and the probably safer procedures compared to incisional surgical methods may explain the increased interest in MIGS. The use of glaucoma drainage implants for lowering IOP in difficult-to-treat patients has been established for a long time, however, a variety of new glaucoma micro-stents are being manufactured by using various materials and are available to increase aqueous outflow via different pathways. This review summarizes published results of randomized clinical studies and extensive case report series on these devices, including Schlemm’s canal stents (iStent®, iStent® inject, Hydrus), suprachoroidal stents (CyPass®, iStent® Supra), and subconjunctival stents (XEN). The article summarizes the findings of published material on efficacy and safety for each of these approaches. PMID:28919702

Wound Dehiscence and Device Migration after Subconjunctival Bevacizumab Injection with Ahmed Glaucoma Valve Implantation.

PubMed

Miraftabi, Arezoo; Nilforushan, Naveed

2016-01-01

To report a complication pertaining to subconjunctival bevacizumab injection as an adjunct to Ahmed Glaucoma Valve (AGV) implantation. A 54-year-old woman with history of complicated cataract surgery was referred for advanced intractable glaucoma. AGV implantation with adjunctive subconjunctival bevacizumab (1.25 mg) was performed with satisfactory results during the first postoperative week. However, 10 days after surgery, she developed wound dehiscence and tube exposure. The second case was a 33-year-old man with history of congenital glaucoma and uncontrolled IOP who developed AGV exposure and wound dehiscence after surgery. In both cases, for prevention of endophthalmitis and corneal damage by the unstable tube, the shunt was removed and the conjunctiva was re-sutured. The potential adverse effect of subconjunctival bevacizumab injection on wound healing should be considered in AGV surgery.

Glaucoma filtration surgery following sustained elevation of intraocular pressure secondary to intravitreal anti-VEGF injections.

PubMed

Skalicky, Simon E; Ho, Ivan; Agar, Ashish; Bank, Allan

2012-07-01

To document cases of sustained elevation of intraocular pressure (IOP) while receiving intravitreal anti-vascular endothelial growth factor (VEGF) agents and subsequent management. A retrospective series of all cases managed by the authors and colleagues was performed. Six patients developed sustained elevated IOP; five received ranibizumab and one bevacizumab. Four received unilateral and two received bilateral injections. Two had preexisting primary open-angle glaucoma and one had pseudoexfoliative glaucoma, all with stable IOP prior to anti-VEGF treatment. Angles were open in all cases. Peak IOP averaged 43 mm Hg (range: 34 to 60 mm Hg). The mean number of injections preceding the IOP increase was 10 (range: 1 to 20). Four patients required trabeculectomy, one selective laser trabeculoplasty, and one multiple topical medications. A sustained increase in IOP requiring glaucoma filtering surgery is a rare but important treatment complication for patients receiving intravitreal anti-VEGF therapy, especially those with preexisting glaucoma or glaucoma risk factors. Copyright 2012, SLACK Incorporated.

Secondary pigmentary glaucoma in patients with underlying primary pigment dispersion syndrome.

PubMed

Sivaraman, Kavitha R; Patel, Chirag G; Vajaranant, Thasarat S; Aref, Ahmad A

2013-01-01

Primary pigment dispersion syndrome (PPDS) is a bilateral condition that occurs in anatomically predisposed individuals. PPDS may evolve into pigmentary glaucoma, but it is difficult to predict which patients will progress. Secondary pigment dispersion is more often unilateral and acquired as a result of surgery, trauma, or intraocular tumor, but can likewise lead to pigmentary glaucoma. We report two cases of patients with bilateral PPDS who developed secondary pigment dispersion and pigmentary glaucoma in one eye. Patients with PPDS who acquire a secondary mechanism of pigment dispersion may be at an increased risk of progression to pigmentary glaucoma, presumably due to an increased burden of liberated pigment. In addition to regular surveillance for progression to glaucoma from PPDS, secondary causes of pigmentary dispersion in these eyes should be considered when patients present with grossly asymmetric findings. When secondary pigment dispersion is identified in eyes with PPDS, we recommend prompt intervention to alleviate the cause of secondary pigment dispersion and/or aggressive control of intraocular pressure to limit glaucomatous damage.

Secondary pigmentary glaucoma in patients with underlying primary pigment dispersion syndrome

PubMed Central

Sivaraman, Kavitha R; Patel, Chirag G; Vajaranant, Thasarat S; Aref, Ahmad A

2013-01-01

Primary pigment dispersion syndrome (PPDS) is a bilateral condition that occurs in anatomically predisposed individuals. PPDS may evolve into pigmentary glaucoma, but it is difficult to predict which patients will progress. Secondary pigment dispersion is more often unilateral and acquired as a result of surgery, trauma, or intraocular tumor, but can likewise lead to pigmentary glaucoma. We report two cases of patients with bilateral PPDS who developed secondary pigment dispersion and pigmentary glaucoma in one eye. Patients with PPDS who acquire a secondary mechanism of pigment dispersion may be at an increased risk of progression to pigmentary glaucoma, presumably due to an increased burden of liberated pigment. In addition to regular surveillance for progression to glaucoma from PPDS, secondary causes of pigmentary dispersion in these eyes should be considered when patients present with grossly asymmetric findings. When secondary pigment dispersion is identified in eyes with PPDS, we recommend prompt intervention to alleviate the cause of secondary pigment dispersion and/or aggressive control of intraocular pressure to limit glaucomatous damage. PMID:23569351

Ultrahigh-throughput exfoliation of graphite into pristine 'single-layer' graphene using microwaves and molecularly engineered ionic liquids.

PubMed

Matsumoto, Michio; Saito, Yusuke; Park, Chiyoung; Fukushima, Takanori; Aida, Takuzo

2015-09-01

Graphene has shown much promise as an organic electronic material but, despite recent achievements in the production of few-layer graphene, the quantitative exfoliation of graphite into pristine single-layer graphene has remained one of the main challenges in developing practical devices. Recently, reduced graphene oxide has been recognized as a non-feasible alternative to graphene owing to variable defect types and levels, and attention is turning towards reliable methods for the high-throughput exfoliation of graphite. Here we report that microwave irradiation of graphite suspended in molecularly engineered oligomeric ionic liquids allows for ultrahigh-efficiency exfoliation (93% yield) with a high selectivity (95%) towards 'single-layer' graphene (that is, with thicknesses <1 nm) in a short processing time (30 minutes). The isolated graphene sheets show negligible structural deterioration. They are also readily redispersible in oligomeric ionic liquids up to ~100 mg ml(-1), and form physical gels in which an anisotropic orientation of graphene sheets, once induced by a magnetic field, is maintained.

Supercritical fluid extraction of bi & multi-layer graphene sheets from graphite by using exfoliation technique

NASA Astrophysics Data System (ADS)

Xavier, Gauravi; Dave, Bhoomi; Khanna, Sakshum

2018-05-01

In recent times, researchers have turned to explore the possibility of using Supercritical Fluid (SCFs) system to penetrate into the inert-gaping of graphite and exfoliate it into a number of layer graphene sheets. The supercritical fluid holds excellent wetting surfaces with low interfacial tension and high diffusion coefficients. Although SCFs exfoliation approach looks promising to developed large scale & low-cost graphene sheet but has not received much attention. To arouse interest and reflection on this approach, this review is organized to summarize the recent progress in graphene production by SCF technology. Here we present the simplest route to obtained layers of graphene sheets by intercalating and exfoliating graphite using supercritical CO2 processing. The layers graphene nano-sheets were collected in dichloromethane (DCM) solution which prevents the restocking of sheets. The obtained graphene sheets show the desired characteristics and thus can be used in physical, chemical and biological sciences. Thus this method provides an effortless and eco-friendly approach for the synthesis of layers of graphene sheets.

Estimation of melanin content in iris of human eye: prognosis for glaucoma diagnostics

NASA Astrophysics Data System (ADS)

Bashkatov, Alexey N.; Koblova, Ekaterina V.; Genina, Elina A.; Kamenskikh, Tatyana G.; Dolotov, Leonid E.; Sinichkin, Yury P.; Tuchin, Valery V.

2007-02-01

Based on the experimental data obtained in vivo from digital analysis of color images of human irises, the mean melanin content in human eye irises has been estimated. For registration of the color images a digital camera Olympus C-5060 has been used. The images have been obtained from irises of healthy volunteers as well as from irises of patients with open-angle glaucoma. The computer program has been developed for digital analysis of the images. The result has been useful for development of novel and optimization of already existing methods of non-invasive glaucoma diagnostics.

[Application value of corneal hysteresis in diagnosis and treatment of glaucoma].

PubMed

He, L Y; Liang, L; Zhu, M N

2017-02-11

Glaucoma is the first leading cause of irreversible blindness world widely, but the pathogenesis was still unclear. The collagen fibers from cornea and sclera connect to each other and both of them have similar extracellular matrix components. The biomechanical characteristics of optic nerve lamina cribrosa may associated with the biomechanical properties of the cornea. Therefore, the study of corneal physiological can indirectly reflex the compression and damage in optic nerve lamina cribrosa. The technical developments in corneal hysteresis examination had been updated these years constantly. Many researches implicated that low corneal hysteresis involved in pathogenesis and progression of glaucoma which refresh our recognition of the relationship between cornea and glaucoma. This review summarized the characteristics of corneal hysteresis, the examination and the connection with glaucoma to provide the reference for clinical work. (Chin J Ophthalmol, 2017, 53: 140-143) .

Racial Influences of Uveitic Glaucoma: Consolidation of Current Knowledge of Diagnosis and Treatment.

PubMed

Gregory, Anthony C; Zhang, Matthew M; Rapoport, Yuna; Ling, Jeanie D; Kuchtey, Rachel W

2016-01-01

The etiology, frequency, manifestation, and treatment of uveitis and uveitic glaucoma are commonly influenced by race. This study aims to review the effect of race on the diagnosis and treatment of patients with common diseases of uveitis that may develop into glaucoma. Race affects the presentation and prevalence of uveitis. Sarcoidosis, for example, is more common in Blacks than in Whites in the United States. Furthermore, Blacks more commonly have anterior segment involvement, while Whites more commonly have posterior segment involvement. In addition, treatments-such as steroid implants and trabeculectomy-in the setting of uveitis and uveitic glaucoma may have higher risk of failure in Black patients. Over the last half-century, we have increased our understanding of the role of race in uveitis and uveitic glaucoma. Major gaps remain and further study is needed.

Pharmaceutical management of the childhood glaucomas.

PubMed

Talbot, A W; Russell-Eggitt, I

2000-05-01

Glaucoma in childhood is a diverse, blinding group of conditions, which presents a major therapeutic challenge. Treatment is primarily surgical with medical treatments used as an adjunct. None of these drugs has been granted approval by the regulatory agencies for use in children, but they are used on a compassionate basis. Issues of efficacy and safety of these medications in children are discussed. beta-adrenoceptor blockers have been employed as first line pharmaceutical therapy for many years. Recently three new classes of drugs have been developed for use in glaucoma in adults. beta-blockers remain first line therapy if there are no contraindications such as asthma. Topical carbonic anhydrase inhibitors (CAI) appear to be less effective than beta-blockers, but seem safe systemically, although associated with local irritation. They are useful as an adjunct to beta-blockers or as first line therapy when beta-blockers are contraindicated. Prostaglandins have not proved as effective in childhood glaucoma as in adult glaucoma, although it works well in some patients with juvenile open angle glaucoma (JOAG) and others with aphakic glaucoma. alpha-adrenergic agonists, although effective at least in the short-term, have serious, potential systemic side effects, which demand close observation when used in neonates and young infants.

Challenges in the management of glaucoma in developing countries.

PubMed

Butt, Nadeem Hafeez; Ayub, Muhammad Hammad; Ali, Muhammad Hassaan

2016-01-01

Glaucoma is the most common optic neuropathy characterized by normal to raised intraocular pressure (IOP), visual field defects, loss of retinal nerve fiber layer, thinning of the neuroretinal rim, and cupping of the optic disc. IOP reduction by medical, laser, or surgical therapies remains the only clinically proven treatment of glaucoma. The challenges in glaucoma management are diverse. They include early detection and diagnosis, setting of appropriate target IOP, choice of treatment, monitoring of quality of life and sight, and compliance with the treatment. Early diagnosis can be made by assessing optic nerve structure using imaging devices and optic nerve function through perimetry. Reducing IOP and controlling its fluctuations are considered to be the most important factors in limiting progression of glaucoma. Selection of the best suitable therapy out of medical, surgical, or laser treatment options is yet another management challenge. Patients suffering from glaucoma experience poor quality of life owing to the diagnosis itself, functional visual loss, inconvenience and cost of treatment, and side effects of treatment. All these factors lead to poor compliance, adherence, and persistence to treatment, and further progression of the disease. It is, therefore, important that ophthalmologists keep all the aforementioned factors in mind when managing patients with glaucoma.

Development and characterization of nano-fiber patch for the treatment of glaucoma.

PubMed

Gagandeep; Garg, Tarun; Malik, Basant; Rath, Goutam; Goyal, Amit K

2014-03-12

In the present work polymeric nano-fiber patches was developed for the effective treatment of glaucoma using timolol maleate and dorzolamide hydrochloride as model drugs. The nano-fibers were prepared by electrospinning technique and were characterized on the basis of fiber diameter, morphology, entrapment efficiency, mucoadhesive strength, and drug release behavior, etc. Final formulations were inserted in the cul-de-sac of glaucoma induced rabbits and the efficacy of the formulation was evaluated. The results clearly indicated the potential of the developed formulation for occur drug delivery. There was a significant fall in the intraocular pressure compared to commercial eye drops. Copyright © 2013 Elsevier B.V. All rights reserved.

High-Yield Preparation and Electrochemical Properties of Few-Layer MoS2 Nanosheets by Exfoliating Natural Molybdenite Powders Directly via a Coupled Ultrasonication-Milling Process

NASA Astrophysics Data System (ADS)

Dong, Huina; Chen, Deliang; Wang, Kai; Zhang, Rui

2016-09-01

Cost-effective and scalable preparation of two-dimensional (2D) molybdenum disulfide (MoS2) has been the bottleneck that limits their applications. This paper reports a novel coupled ultrasonication-milling (CUM) process to exfoliate natural molybdenite powders to achieve few-layer MoS2 (FL-MoS2) nanosheets in the solvent of N-methyl-2-pyrrolidone (NMP) with polyvinylpyrrolidone (PVP) molecules. The synergistic effect of ultrasonication and sand milling highly enhanced the exfoliation efficiency, and the precursor of natural molybdenite powders minimizes the synthetic cost of FL-MoS2 nanosheets. The exfoliation of natural molybdenite powders was conducted in a home-made CUM system, mainly consisting of an ultrasonic cell disruptor and a ceramic sand mill. The samples were characterized by X-ray diffraction, UV-vis spectra, Raman spectra, FT-IR, SEM, TEM, AFM, and N2 adsorption-desorption. The factors that influence the exfoliation in the CUM process, including the initial concentration of natural molybdenite powders ( C in, 15-55 g L-1), ultrasonic power ( P u, 200-350 W), rotation speed of sand mill ( ω s, 1500-2250 r.p.m), exfoliation time ( t ex, 0.5-6 h), and the molar ratio of PVP unit to MoS2 ( R pm, 0-1), were systematically investigated. Under the optimal CUM conditions (i.e., C in = 45 g L-1, P u = 280 W, ω s = 2250 r.p.m and R pm = 0.5), the yield at t ex = 6 h reaches 21.6 %, and the corresponding exfoliation rate is as high as 1.42 g L-1 h-1. The exfoliation efficiency of the CUM mode is much higher than that of either the ultrasonication (U) mode or the milling (M) mode. The synergistic mechanism and influencing rules of the CUM process in exfoliating natural molybdenite powders were elaborated. The as-obtained FL-MoS2 nanosheets have a high specific surface area of 924 m2 g-1 and show highly enhanced electrocatalytic performance in hydrogen evolution reaction and good electrochemical sensing property in detecting ascorbic acid. The CUM process developed has paved a low-cost, green, and highly efficient way towards FL-MoS2 nanosheets from natural molybdenite powders.

Further evidence for a locus for autosomal dominant juvenile glaucoma on chromosome 1q and evidence for genetic heterogeneity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiggs, J.; Paglinauan, C.; Stawski, S.

1994-09-01

Glaucoma is a term used to describe a group of disorders which have in common a characteristic degeneration of the optic nerve associated with typical visual field defects and usually associated with elevated intraocular pressure. Two percent of white Americans and 6-10% of black Americans are affected by the disease. Compelling data indicate that susceptibility to many types of glaucoma is inherited. Hereditary juvenile glaucoma is one form of glaucoma that develops in children and is inherited as an autosomal dominant trait with high penetrance. Using a single large Caucasian pedigree affected with autosomal dominant juvenile glaucoma, Sheffield discovered positivemore » linkage to a group of markers that map to a 30 cM region on the long arm of chromosome 1 (1q21-q31). We have subsequently identified three unrelated Caucasian pedigrees affected with autosomal dominant juvenile glaucoma that also demonstrate linkage to this region on chromosome 1, with the highest combined lod score of 5.12 at theta = .05 for marker D1S218. The identification of critical recombinant individuals in our three pedigrees has allowed us to further localize the disease gene to a 12 cM region between markers D1S242 and D1S431. In addition, we have identified several pedigrees which do not demonstrate linkage to chromosome 1q, including a black family affected with autosomal dominant juvenile glaucoma that is indistinguishable clinically from the disorder affecting the caucasian pedigrees and three pedigrees affected with pigmentary dispersion syndrome, a form of glaucoma that also affects the juvenile population and is also inherited as an autosomal dominant trait. These findings provide evidence for genetic heterogeneity in juvenile glaucoma.« less

Glaucoma evolution in patients with diabetes.

PubMed

Apreutesei, Nicoleta Anton; Chiselita, D; Motas, O I

2014-01-01

Glaucoma and diabetes are two chronic diseases with a long suspected pathogenic relationship. Screening for glaucoma in patients with diabetes. A retrospective study on 92 eyes from 46 patients with primitive open angle glaucoma (POAG) (normal and hypertensive) and intraocular hypertension (OHT) receiving medication and/or surgery associated with diabetes mellitus (DM) (type I, type II, mixed) is presented. Participants were divided into two groups as following: 16 eyes with glaucoma and diabetic retinopathy changes (group 1) and 76 eyes with glaucoma and without diabetic retinopathy changes (group 2). The following parameters were analysed: ocular pressure (Goldmann aplanotonometry), perimeter development (computerized perimetry) and fundus condition (absence, presence or progression of diabetic retinopathy). In patients with glaucoma and diabetic retinopathy (8 patients) we found a mean difference between treated intraocular pressure (IOP) and IOP last untreated control of 4.95 mmHg; a depreciation of the MD by 4.18 dB and an average number of glaucoma medications used of 0.889 +/- 1.054. Predominant changes in proliferative diabetic retinopathy were mild. In patients with glaucoma in the absence of diabetic retinopathy, the average difference between untreated IOP and IOP under treatment at the last check-up was 1.63 mmHg, the MD depreciation was by 0.65 dB and the average number of glaucoma medications used was 0.795 +/- 0.978. No statistically significant differences in terms of initial and final pressure were found. No statistically significant differences in the evolution of changes in perimeter between the two groups were observed. The presence of non-proliferating diabetic retinopathy influenced (only marginally statistically) the glaucomatous disease progression. Large comparative prospective studies are needed for the long-term follow up.

Ahmed Glaucoma Valve Implantation for Uveitic Glaucoma Secondary to Behçet Disease.

PubMed

Satana, Banu; Yalvac, Ilgaz S; Sungur, Gulten; Eksioglu, Umit; Basarir, Berna; Altan, Cigdem; Duman, Sunay

2015-01-01

To evaluate outcomes of patients with uveitic glaucoma secondary to Behçet disease (BD) who underwent Ahmed glaucoma valve (AGV) implantation. A retrospective chart review of 14 eyes of 10 patients with uveitic glaucoma associated with BD who underwent AGV implantation at a tertiary referral center. Treatment success was defined as intraocular pressure (IOP) between 6 and 21 mm Hg with or without antiglaucoma medication, without further additional glaucoma surgery or loss of light perception. The main outcome measures were IOP, best-corrected visual acuity measured with Snellen charts, and number of glaucoma medications. Mean duration of postoperative follow-up was 18.2±6.6 months (range, 6 to 31 mo). Of the 14 eyes, 10 (71.4%) were pseudophakic and 5 (35.7%) had primary AGV implantation without a history of previous glaucoma surgery. At the most recent follow-up visit, 13 of the 14 eyes had an IOP between 6 and 21 mm Hg. Mean IOP was significantly reduced during follow-up, as compared with preoperative values (P≤0.005). The cumulative probability of surgical success rate was 90.9% at 18 months based on Kaplan-Meier survival analysis. The mean number of antiglaucoma medications required to achieve the desired IOP decreased from 3.4±0.5 preoperatively to 1.0±1.1 postoperatively (P≤0.05). Visual acuity loss of >2 lines occurred in 4 eyes (28.5%) due to optic atrophy associated with retinal vasculitis. Temporary hypotony developed during follow-up in 4 eyes (28.5%) at first postoperative week. For the management of uveitic glaucoma associated with BD, AGV implantation is a successful method for glaucoma control but requires additional surgical interventions for high early hypotony rates.

Molecular characterisation of congenital glaucoma in a consanguineous Canadian community: a step towards preventing glaucoma related blindness

PubMed Central

Martin, S; Sutherland, J.; Levin, A.; Klose, R.; Priston, M.; Heon, E.

2000-01-01

Glaucoma is a leading cause of irreversible blindness in Canada. Congenital glaucoma usually manifests during the first years of life and is characterised by severe visual loss and autosomal recessive inheritance. Two disease loci, on chromosomes 1p36 and 2p21, have been associated with various forms of congenital glaucoma. A branch of a large six generation family from a consanguineous Amish community in south western Ontario was affected with congenital glaucoma and was studied by linkage and mutational analysis to identify the glaucoma related genetic defects. Linkage analysis using the MLINK component of the LINKAGE package (v 5.1) showed evidence of linkage to the 2p21 region (Zmax=3.34, θ=0, D2S1348 and D2S1346). Mutational analysis of the primary candidate gene, CYP1B1, was done by direct cycle sequencing, dideoxy fingerprinting analysis, and fragment analysis. Two different disease causing mutations in exon 3, 1410del13 and 1505G→A, both segregated with the disease phenotype. The two different combinations of these alleles appeared to result in a variable expressivity of the phenotype. The compound heterozygote appeared to have a milder phenotype when compared to the homozygotes for the 13 bp deletion. The congenital glaucoma phenotype for this large inbred Amish family is the result of mutations in CYP1B1 (2p21). The molecular information derived from this study will be used to help identify carriers of the CYP1B1 mutation in this community and optimise the management of those at risk of developing glaucoma.


Keywords: congenital glaucoma; CYP1B1; gene; genetic counselling PMID:10851252

Exfoliation of gastric pit-parietal cells into the gastric lumen associated with a stimulation of isolated rat gastric mucosa in vitro: a morphological study by the application of cryotechniques.

PubMed

Aoyama, Fumiyo; Sawaguchi, Akira; Ide, Soyuki; Kitamura, Kazuo; Suganuma, Tatsuo

2008-06-01

It is clinicopathologically important to elucidate the cell kinetics for the maintenance of normal gastric epithelium. In a rat gastric mucosa isolated after stimulation, a number of cells were exfoliated into the gastric lumen of the pit region. The present study was undertaken to clarify the origin of exfoliated cells and their histochemical profiles by taking the advantages of cryotechniques. As results, most of the exfoliated cells were identified as pit-parietal cells labeled with both peanut-lectin and anti-H+/K+-ATPase antibody. Quantitative analysis verified a time-dependent increase in the number of exfoliated cells in the gastric mucosa isolated after stimulation. The exfoliated cells exhibited a diffuse intracellular staining for E-cadherin, suggesting a dissociation of the adhesion molecule prior to the cell exfoliation. It should be noted that most of the exfoliated cells were negative to the apoptotic markers (TUNEL staining and caspase-3). Ultrastructurally, autophagosome-like structures consisting of H+/K+-ATPase positive membranes were frequently seen in the exfoliated pit-parietal cells. In addition, the pit-parietal cell exfoliation was accompanied by sealing of their basal portion with the cytoplasmic processes of adjacent surface mucous cells. The present morphological findings provide a new insight into the cell kinetics in the gastric epithelium in vitro.

Research progress on human genes involved in the pathogenesis of glaucoma (Review).

PubMed

Wang, Hong-Wei; Sun, Peng; Chen, Yao; Jiang, Li-Ping; Wu, Hui-Ping; Zhang, Wen; Gao, Feng

2018-05-23

Glaucoma is the leading cause of irreversible blindness globally. It is known that the incidence of glaucoma is closely associated with inheritance. A large number of studies have suggested that genetic factors are involved in the occurrence and development of glaucoma, and even affect the drug sensitivity and prognosis of glaucoma. In the present review, 22 loci of glaucoma are presented, including the relevant genes (myocilin, interleukin 20 receptor subunit B, optineurin, ankyrin repeat‑ and SOCS box‑containing protein 10, WD repeat‑containing protein 36, EGF‑containing fibulin‑like extracellular matrix protein 1, neurotrophin 4, TANK‑binding kinase 1, cytochrome P450 subfamily I polypeptide 1, latent transforming growth factor β binding protein 2 and TEK tyrosine kinase endothelial) and 74 other genes (including toll‑like receptor 4, sine oculis homeobox Drosophila homolog of 1, doublecortin‑like kinase 1, RE repeats‑encoding gene, retinitis pigmentosa GTPase regulator‑interacting protein, lysyl oxidase‑like protein 1, heat‑shock 70‑kDa protein 1A, baculoviral IAP repeat‑containing protein 6, 5,10‑methylenetetrahydrofolate reductase and nitric oxide synthase 3 and nanophthalmos 1) that are more closely associated with glaucoma. The pathogenesis of these glaucoma‑associated genes, glaucomatous genetics and genetic approaches, as well as glaucomatous risk factors, including increasing age, glaucoma family history, high myopia, diabetes, ocular trauma, smoking, intraocular pressure increase and/or fluctuation were also discussed.

Frequency-doubling technology perimetry and multifocal visual evoked potential in glaucoma, suspected glaucoma, and control patients

PubMed Central

Kanadani, Fabio N; Mello, Paulo AA; Dorairaj, Syril K; Kanadani, Tereza CM

2014-01-01

Introduction The gold standard in functional glaucoma evaluation is standard automated perimetry (SAP). However, SAP depends on the reliability of the patients’ responses and other external factors; therefore, other technologies have been developed for earlier detection of visual field changes in glaucoma patients. The frequency-doubling perimetry (FDT) is believed to detect glaucoma earlier than SAP. The multifocal visual evoked potential (mfVEP) is an objective test for functional evaluation. Objective To evaluate the sensitivity and specificity of FDT and mfVEP tests in normal, suspect, and glaucomatous eyes and compare the monocular and interocular mfVEP. Methods Ninety-five eyes from 95 individuals (23 controls, 33 glaucoma suspects, 39 glaucomatous) were enrolled. All participants underwent a full ophthalmic examination, followed by SAP, FDT, and mfVEP tests. Results The area under the curve for mean deviation and pattern standard deviation were 0.756 and 0.761, respectively, for FDT, 0.564 and 0.512 for signal and alpha for interocular mfVEP, and 0.568 and 0.538 for signal and alpha for monocular mfVEP. This difference between monocular and interocular mfVEP was not significant. Conclusion The FDT Matrix was superior to mfVEP in glaucoma detection. The difference between monocular and interocular mfVEP in the diagnosis of glaucoma was not significant. PMID:25075173

Wound Dehiscence and Device Migration after Subconjunctival Bevacizumab Injection with Ahmed Glaucoma Valve Implantation

PubMed Central

Miraftabi, Arezoo; Nilforushan, Naveed

2016-01-01

Purpose: To report a complication pertaining to subconjunctival bevacizumab injection as an adjunct to Ahmed Glaucoma Valve (AGV) implantation. Case Report: A 54-year-old woman with history of complicated cataract surgery was referred for advanced intractable glaucoma. AGV implantation with adjunctive subconjunctival bevacizumab (1.25 mg) was performed with satisfactory results during the first postoperative week. However, 10 days after surgery, she developed wound dehiscence and tube exposure. The second case was a 33-year-old man with history of congenital glaucoma and uncontrolled IOP who developed AGV exposure and wound dehiscence after surgery. In both cases, for prevention of endophthalmitis and corneal damage by the unstable tube, the shunt was removed and the conjunctiva was re-sutured. Conclusion: The potential adverse effect of subconjunctival bevacizumab injection on wound healing should be considered in AGV surgery. PMID:27195095

An ultrahigh pressure homogenization technique for easily exfoliating few-layer phosphorene from bulk black phosphorus

NASA Astrophysics Data System (ADS)

Guan, Qing-Qing; Zhou, Hua-Jing; Ning, Ping; Lian, Pei-Chao; Wang, Bo; He, Liang; Chai, Xin-Sheng

2018-05-01

We have developed an easy and efficient method for exfoliating few-layer sheets of black phosphorus (BP) in N-methyl-2-pyrrolidone, using ultra-high pressure homogenization (UPH). The BP was first exfoliated into sheets that were a few atomic layers thick, using a homogenizer for only 30 min. Next, a double centrifugation procedure was used to separate the material into few-layer nanosheets that were examined by X-ray diffraction, atomic force microscopy (AFM), transmission electron microscopy (TEM), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), and energy-dispersive X-ray (EDX) spectroscopy. The results show that the products are specimens of phosphorene that are only a few-layer thick.

Immunogold localisation of laminin in normal and exfoliative iris.

PubMed Central

Konstas, A. G.; Marshall, G. E.; Lee, W. R.

1990-01-01

Immunoelectron microscopic studies of exfoliative iris tissue (seven specimens) revealed the presence of laminin in the fibrillar component of exfoliation material. The immunogold label was uniformly distributed on the exfoliation fibres. Deposition of laminin labelled exfoliation material in the dilator muscle was a noteworthy feature, as was an apparent depletion of laminin in the basement membranes of ostensibly unaffected vessels. In control iris tissue (five enucleated eyes) laminin was identified in the basement membrane round vascular contractile cells, but not beneath the endothelium. Images PMID:2390517

The Role of Minimally Invasive Glaucoma Surgery Devices in the Management of Glaucoma

PubMed Central

Fingeret, Murray; Dickerson, Jaime E.

2018-01-01

SIGNIFICANCE Noncompliance is a problem affecting glaucoma patients. Approaches to improve adherence include the use of drug-delivery systems and safer forms of surgery. Minimally invasive glaucoma surgery (MIGS) has reduced complications, particularly in combination with cataract surgery, and with its good intraocular pressure (IOP) reduction may reduce or eliminate glaucoma medications. Glaucoma is a progressive disease and a leading cause of irreversible blindness. Elevated IOP is the most important risk factor, but effective medical management is dependent on patient adherence. This review summarizes the adherence problem in glaucoma and the efforts, including MIGS, to provide effective IOP control that is not dependent on patient compliance. The current understanding of patient adherence to pharmacological treatment of glaucoma is discussed including the challenges facing glaucoma patients. Historical approaches to providing IOP control in a sustained and reliable way are presented culminating in a review of the burgeoning use of MIGS devices. It is estimated that, in the United States, 27% of prescriptions written, across all medications, are not filled or are filled but not taken. For ocular hypotensive medications, even when filled, a large percentage (which varies widely by study) are not instilled as prescribed. To address this problem, methods for sustained drug delivery have been and continue to be developed, as well as surgical and laser approaches. Most recently, MIGS devices have gained popularity because of the ease of implantation during cataract surgery, favorable safety profile, and the possibility for effective and long-lasting IOP lowering, as well as the reduction or elimination of need for IOP-lowering medication. Poor adherence to treatment is relatively common among glaucoma patients and is associated with progression of disease. Recommending MIGS implantation during cataract surgery may offer optometrists a valuable treatment option in managing glaucoma patients, particularly where good adherence is in doubt. PMID:29370021

Scanning laser polarimetry in glaucoma

PubMed Central

Dada, Tanuj; Sharma, Reetika; Angmo, Dewang; Sinha, Gautam; Bhartiya, Shibal; Mishra, Sanjay K; Panda, Anita; Sihota, Ramanjit

2014-01-01

Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White-on-white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far. PMID:25494244

Scanning laser polarimetry in glaucoma.

PubMed

Dada, Tanuj; Sharma, Reetika; Angmo, Dewang; Sinha, Gautam; Bhartiya, Shibal; Mishra, Sanjay K; Panda, Anita; Sihota, Ramanjit

2014-11-01

Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White-on-white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far.

Unilateral glaucoma in Sotos syndrome (cerebral gigantism).

PubMed

Yen, M T; Gedde, S J; Flynn, J T

2000-12-01

To report a patient with unilateral glaucoma associated with Sotos syndrome. Sotos syndrome (cerebral gigantism) is a disorder of growth and development with characteristic facial changes and normal endocrine function. Ocular manifestations may also include megalocornea, iris hypoplasia, cataracts, megalophthalmos, strabismus, nystagmus, and retinal dystrophy. Case report. A 50 year-old man with the clinical features of Sotos syndrome presented with complaints of decreased vision in the left eye. Ophthalmologic examination revealed bilateral megalocornea, megalophthalmos, iris hypoplasia and transillumination defects, cataracts, and unilateral glaucoma. Intraocular pressure was lowered, and visual field loss was stabilized with topical medications. Sotos syndrome patients should be examined routinely to allow for early detection and treatment of potential ocular problems, including glaucoma.

Glaucoma history and risk factors.

PubMed

McMonnies, Charles W

Apart from the risk of developing glaucoma there is also the risk that it is not detected and irreversible loss of vision ensues. Some studies of methods of glaucoma diagnosis have examined the results of instrument-based examinations with great if not complete reliance on objective findings in arriving at a diagnosis. The very valuable advances in glaucoma detection instrument technologies, and apparent increasing dependence on them, may have led to reduced consideration of information available from a patient history in those studies. Dependence on objective evidence of glaucomatous pathology may reduce the possibility of detecting glaucoma suspects or patients at risk for becoming glaucoma suspects. A valid positive family history of glaucoma is very valuable information. However, negative family histories can often be unreliable due to large numbers of glaucoma cases being undiagnosed. No evidence of family history is appropriate rather than no family history. In addition the unreliability of a negative family history is increased when patients with glaucoma fail to inform their family members. A finding of no family history can only be stated as no known family history. In examining the potential diagnostic contribution from a patient history, this review considers, age, frailty, race, type and degree of refractive error, systemic hyper- and hypotension, vasospasm, migraine, pigmentary dispersion syndrome, pseudoexfoliation syndrome, obstructive sleep apnea syndrome, diabetes, medication interactions and side effects, the degree of exposure to intraocular and intracranial pressure elevations and fluctuations, smoking, and symptoms in addition to genetics and family history of the disease. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma.

PubMed

Gangeddula, Viswa; Ranchet, Maud; Akinwuntan, Abiodun E; Bollinger, Kathryn; Devos, Hannes

2017-01-01

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma. Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal-Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions. Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups ( p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1-Q3) 3 (2-6.50) vs. 2 (0.50-2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2-6) vs. 1 (0.50-2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls ( p = 0.02). Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma.

[Uveitic Secondary Glaucoma].

PubMed

Lommatzsch, Claudia; Heinz, Carsten

2018-05-01

An intraocular pressure increase with development of glaucomatous damage is a common complication of uveitis. The prevalence has a wide range depending on various factors such as the underlying uveitis type and the duration of the disease. Pathogenetically, a distinction must be made between a secondary angle closure component and the more frequently occurring open-angle glaucoma. In diagnostics, in addition to the clinical optic nerve head assessment, perimetry and tonometry, the use of imaging examination equipment, such as OCT and HRT, are recommended. In the context of uveitic glaucoma, it must be considered in the evaluation, because the glaucoma-typical changes are generally less pronounced or can be concealed by retinal swelling in comparison with other forms of glaucoma. Therapeutically, drug therapy in the form of eye drops continues to be a first-line recommendation, with the use of topical carbonic anhydrase inhibitors or beta-blockers primarily preferred, depending on the contraindications. An operative therapy follows after unsuccessful or inadequate conservative therapy: the adequate surgical technique depends on the respective finding and includes actually techniques such as filtering procedures and glaucoma drainage devices. Georg Thieme Verlag KG Stuttgart · New York.

Surgical management of glaucoma: An Indian perspective

PubMed Central

Ramakrishnan, R; Khurana, Mona

2011-01-01

Glaucoma is a serious sight-threatening disorder aptly named the Silent thief of sight. India, being the second most populous country in the world, has about 20% of the world glaucoma population. The complex geographical and socioeconomic architecture and the economic extremes have a profound effect on its health system. The present times are abundant with fresh developments in the field of glaucoma. Though newer modalities are present in India, they are not ample and are unequally distributed. Adherence and persistence with medical therapy is an issue owing to a multitude of factors. In such a setting, most of the ophthalmologists find themselves performing glaucoma surgeries quite often. In the present era, there are a number of new surgeries to choose from, especially procedures which are nonpenetrating and blebless. Faced with a spectrum of surgeries from shunts to canal surgeries and trabecular bypass devices, the surgeon is often in a dilemma. Still, trabeculectomy remains the gold standard with an increasing trend toward glaucoma drainage devices. The new procedures and devices are worth exploring but await long-term results, good training of surgeons and cost effectiveness. PMID:21150023

Nanotechnology and glaucoma: a review of the potential implications of glaucoma nanomedicine.

PubMed

Kim, Nathaniel J; Harris, Alon; Gerber, Austin; Tobe, Leslie Abrams; Amireskandari, Annahita; Huck, Andrew; Siesky, Brent

2014-04-01

The purpose of this review is to discuss the evolution of nanotechnology and its potential diagnostic and therapeutic applications in the field of ophthalmology, particularly as it pertains to glaucoma. We reviewed literature using MEDLINE and PubMed databases with the following search terms: glaucoma, nanotechnology, nanomedicine, nanoparticles, ophthalmology and liposomes. We also reviewed pertinent references from articles found in this search. A brief history of nanotechnology and nanomedicine will be covered, followed by a discussion of the advantages and concerns of using this technology in the field of glaucoma. We will look at various studies concerning the development of nanomedicine, its potential applications in ocular drug delivery, diagnostic and imaging modalities and, surgical techniques. In particular, the challenges of assuring safety and efficacy of nanomedicine will be examined. We conclude that nanotechnology offers a novel approach to expanding diagnostic, imaging and surgical modalities in glaucoma and may contribute to the knowledge of disease pathogenesis at a molecular level. However, more research is needed to better elucidate the mechanism of cellular entry, the potential for nanoparticle cytotoxicity and the assurance of clinical efficacy.

[New concepts for pressure-controlled glaucoma implants].

PubMed

Allemann, R; Stachs, O; Falke, K; Schmidt, W; Siewert, S; Sternberg, K; Chichkov, B; Wree, A; Schmitz, K-P; Guthoff, R F

2013-08-01

In industrialized countries glaucoma is one of the most common causes that leads to blindness. It is also the most common cause of irreversible blindness worldwide. In addition to local treatment of intraocular pressure and filtering glaucoma surgery, alloplastic implants are increasingly being used in glaucoma therapy. As long-term results published in the literature of commonly used implants are unsatisfactory, it seems useful to search for new concepts. In order to avoid the well-known short-term and long-term postoperative complications a pressure-controlled microstent with antiproliferative surface modifications was developed. Additionally, the functionality of such a microstent should be investigated using an animal glaucoma model. This paper describes the concept of a microstent which drains aquous humour from the anterior chamber into the suprachoroidal space. In addition, the glaucoma models described in the literature are discussed. Unfortunately, none of the methods could be reproduced permanently. First results show a correct implantation of a coated microstent with valve where the anti-proliferative effect could be demonstrated histologically. The promising results should lead to further investigations and the final goal will be the testing of the stent in the human eye.

Chemically exfoliating large sheets of phosphorene via choline chloride urea viscosity-tuning

NASA Astrophysics Data System (ADS)

Ng, A.; Sutto, T. E.; Matis, B. R.; Deng, Y.; Ye, P. D.; Stroud, R. M.; Brintlinger, T. H.; Bassim, N. D.

2017-04-01

Exfoliation of two-dimensional phosphorene from bulk black phosphorous through chemical means is demonstrated where the solvent system of choice (choline chloride urea diluted with ethanol) has the ability to successfully exfoliate large-area multi-layer phosphorene sheets and further protect the flakes from ambient degradation. The intercalant solvent molecules, aided by low-powered sonication, diffuse between the layers of the bulk black phosphorus, allowing for the exfoliation of the multi-layer phosphorene through breaking of the interlayer van der Waals bonds. Through viscosity tuning, the optimal parameters (1:1 ratio between the intercalant and the diluting solvent) at which the exfoliation takes place is determined. Our exfoliation technique is shown to produce multi-layer phosphorene flakes with surface areas greater than 3 μm2 (a factor of three larger than what has previously been reported for a similar exfoliation method) while limiting exposure to the ambient environment, thereby protecting the flakes from degradation. Characterization techniques such as optical microscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, and (scanning) transmission electron microscopy are used to investigate the quality, quantity, and thickness of the exfoliated flakes.

Minimally-invasive glaucoma surgeries (MIGS) for open angle glaucoma: A systematic review and meta-analysis

PubMed Central

Maule, Milena; Ceccarelli, Manuela; Fea, Antonio Maria

2017-01-01

Background MIGS have been developed as a surgical alternative for glaucomatous patients. Purpose To analyze the change in intraocular pressure (IOP) and glaucoma medications using different MIGS devices (Trabectome, iStent, Excimer Laser Trabeculotomy (ELT), iStent Supra, CyPass, XEN, Hydrus, Fugo Blade, Ab interno canaloplasty, Goniscopy-assisted transluminal trabeculotomy) as a solo procedure or in association with phacoemulsification. Methods Randomized control trials (RCT) and non-RCT (non randomized comparative studies, NRS, and before-after studies) were included. Studies with at least one year of follow-up in patients affected by primary open angle glaucoma, pseudoexfoliative glaucoma or pigmentary glaucoma were considered. Risk of Bias assessment was performed using the Cochrane Risk of Bias and the ROBINS-I tools. The main outcome was the effect of MIGS devices compared to medical therapy, cataract surgery, other glaucoma surgeries and other MIGS on both IOP and use of glaucoma medications 12 months after surgery. Outcomes measures were the mean difference in the change of IOP and glaucoma medication compared to baseline at one and two years and all ocular adverse events. The current meta-analysis is registered on PROSPERO (reference n° CRD42016037280). Results Over a total of 3,069 studies, nine RCT and 21 case series with a total of 2.928 eyes were included. Main concerns about risk of bias in RCTs were lack of blinding, allocation concealment and attrition bias while in non-RCTs they were represented by patients’ selection, masking of participants and co-intervention management. Limited evidence was found based on both RCTs and non RCTs that compared MIGS surgery with medical therapy or other MIGS. In before-after series, MIGS surgery seemed effective in lowering both IOP and glaucoma drug use. MIGS showed a good safety profile: IOP spikes were the most frequent complications and no cases of infection or BCVA loss due to glaucoma were reported. Conclusions Although MIGS seem efficient in the reduction of the IOP and glaucoma medication and show good safety profile, this evidence is mainly derived from non-comparative studies and further, good quality RCTs are warranted. PMID:28850575

Building a glaucoma interaction network using a text mining approach.

PubMed

Soliman, Maha; Nasraoui, Olfa; Cooper, Nigel G F

2016-01-01

The volume of biomedical literature and its underlying knowledge base is rapidly expanding, making it beyond the ability of a single human being to read through all the literature. Several automated methods have been developed to help make sense of this dilemma. The present study reports on the results of a text mining approach to extract gene interactions from the data warehouse of published experimental results which are then used to benchmark an interaction network associated with glaucoma. To the best of our knowledge, there is, as yet, no glaucoma interaction network derived solely from text mining approaches. The presence of such a network could provide a useful summative knowledge base to complement other forms of clinical information related to this disease. A glaucoma corpus was constructed from PubMed Central and a text mining approach was applied to extract genes and their relations from this corpus. The extracted relations between genes were checked using reference interaction databases and classified generally as known or new relations. The extracted genes and relations were then used to construct a glaucoma interaction network. Analysis of the resulting network indicated that it bears the characteristics of a small world interaction network. Our analysis showed the presence of seven glaucoma linked genes that defined the network modularity. A web-based system for browsing and visualizing the extracted glaucoma related interaction networks is made available at http://neurogene.spd.louisville.edu/GlaucomaINViewer/Form1.aspx. This study has reported the first version of a glaucoma interaction network using a text mining approach. The power of such an approach is in its ability to cover a wide range of glaucoma related studies published over many years. Hence, a bigger picture of the disease can be established. To the best of our knowledge, this is the first glaucoma interaction network to summarize the known literature. The major findings were a set of relations that could not be found in existing interaction databases and that were found to be new, in addition to a smaller subnetwork consisting of interconnected clusters of seven glaucoma genes. Future improvements can be applied towards obtaining a better version of this network.

The clinical characteristics of patients with glaucoma presenting to Botswana healthcare facilities: an observational study

PubMed Central

Jackson, Daniel J; Razai, Mohammad S; Falama, Rosemary; Mongwa, Matlhogonolo; Mutapanduwa, Mishell; Baemisi, Chao; Josiah, Engelinah; Nkomazana, Oathokwa; Lehasa, Alice; Brealey, Evelyn; White, Andrew J; Jankowski, Deborah; Kerr-Muir, Malcolm G; Martin, Keith R; Ngondi, Jeremiah M

2014-01-01

Objective This study aimed to establish the clinical characteristics of patients with glaucoma attending eye care facilities in Botswana, and management of glaucoma among patients who received care in these facilities. The study also aimed to calculate the number of new diagnoses of glaucoma within the glaucoma service. Design A prospective, hospital-based, observational study. Setting A multicentre study was undertaken in government-run eye departments in Botswana from June to August 2012. Participants All patients with a diagnosis of glaucoma attending clinics at seven study sites were invited to participate. Outcome measures Examination findings, diagnosis and management were extracted from individual patient-held medical charts. Sociodemographic characteristics, patient knowledge and understanding of glaucoma were assessed through face-to-face interviews. In addition, details of outpatient attendances for 2011 were collected from 21 government-run hospitals. Results The majority of the 366 patients interviewed had a diagnosis of primary glaucoma (86.6%). The diagnoses were mainly made by ophthalmologists (48.6%) and ophthalmic nurses (44.0%). Many patients (38.5%) had been symptomatic for over 6 months before visiting an eye clinic. The mean presenting intraocular pressure was 28.2 mm Hg (SD 11.9 mm Hg). Most follow-up patients (79.2%) had not received surgery, however, many (89.5%) would accept surgery. Only 11.5% of participants had heard of glaucoma prior to diagnosis. Many participants (35.9%) did not understand glaucoma after being diagnosed. The majority (94.9%) of living first-degree relatives had never been examined. The number of newly diagnosed glaucoma cases for 2011 in the south of the country was 14.1/100 000; 95% CI (12.0 to 16.5), in the north it was 16.2/100 000; 95% CI (13.8 to 19.0). Conclusions Glaucoma is a significant burden that presents challenges to ophthalmic services in Botswana. Many patients have limited understanding of the condition and poor access to services. There is a need to develop a treatment infrastructure to include safe surgery and a reliable supply of effective medication. PMID:25472657

Minimally-invasive glaucoma surgeries (MIGS) for open angle glaucoma: A systematic review and meta-analysis.

PubMed

Lavia, Carlo; Dallorto, Laura; Maule, Milena; Ceccarelli, Manuela; Fea, Antonio Maria

2017-01-01

MIGS have been developed as a surgical alternative for glaucomatous patients. To analyze the change in intraocular pressure (IOP) and glaucoma medications using different MIGS devices (Trabectome, iStent, Excimer Laser Trabeculotomy (ELT), iStent Supra, CyPass, XEN, Hydrus, Fugo Blade, Ab interno canaloplasty, Goniscopy-assisted transluminal trabeculotomy) as a solo procedure or in association with phacoemulsification. Randomized control trials (RCT) and non-RCT (non randomized comparative studies, NRS, and before-after studies) were included. Studies with at least one year of follow-up in patients affected by primary open angle glaucoma, pseudoexfoliative glaucoma or pigmentary glaucoma were considered. Risk of Bias assessment was performed using the Cochrane Risk of Bias and the ROBINS-I tools. The main outcome was the effect of MIGS devices compared to medical therapy, cataract surgery, other glaucoma surgeries and other MIGS on both IOP and use of glaucoma medications 12 months after surgery. Outcomes measures were the mean difference in the change of IOP and glaucoma medication compared to baseline at one and two years and all ocular adverse events. The current meta-analysis is registered on PROSPERO (reference n° CRD42016037280). Over a total of 3,069 studies, nine RCT and 21 case series with a total of 2.928 eyes were included. Main concerns about risk of bias in RCTs were lack of blinding, allocation concealment and attrition bias while in non-RCTs they were represented by patients' selection, masking of participants and co-intervention management. Limited evidence was found based on both RCTs and non RCTs that compared MIGS surgery with medical therapy or other MIGS. In before-after series, MIGS surgery seemed effective in lowering both IOP and glaucoma drug use. MIGS showed a good safety profile: IOP spikes were the most frequent complications and no cases of infection or BCVA loss due to glaucoma were reported. Although MIGS seem efficient in the reduction of the IOP and glaucoma medication and show good safety profile, this evidence is mainly derived from non-comparative studies and further, good quality RCTs are warranted.

Programs to optimize adherence in glaucoma.

PubMed

Kowing, Dianne; Messer, Dawn; Slagle, Scott; Wasik, Alyon

2010-07-01

This study was designed to raise awareness of the materials, devices, and Internet resources available to improve adherence to use of medications for the treatment of glaucoma and to review new devices under development. A review of current indexed literature and Internet resources was conducted. A variety of educational brochures, pamphlets, and fact sheets promoting adherence to ocular hypotensive medications are available through multiple organizations and are easily accessed and ordered on the Internet. Video and Web-based patient educational tools have been designed to support patient adherence to glaucoma management plans and promote open dialogue between patients and providers. Reminder and recall systems that integrate with office software can be sent to cell phones as well as e-mails and personal digital assistant (PDAs), alerting patients to upcoming appointments and reminding them to instill their drops. Bottle devices with dosing support (timers with audible and visual signals and dispensing aids) and electronic monitoring have been shown to promote adherence. New products currently under development to improve the delivery of medications include nanoparticles, punctal plugs, and contact lenses that release glaucoma medications. Many educational materials, services, Internet resources, and devices are available to optometrists to encourage patient adherence to glaucoma treatment and management. Published by Elsevier Inc.

Gene Therapy Targeting Glaucoma: Where Are We?

PubMed Central

Liu, Xuyang; Rasmussen, Carol A.; Gabelt, B’Ann T.; Brandt, Curtis R.; Kaufman, Paul L.

2010-01-01

In a chronic disease such as glaucoma, a therapy that provides a long lasting local effect, with minimal systemic side effects, while circumventing the issue of patient compliance, is very attractive. The field of gene therapy is growing rapidly and ocular applications are expanding. Our understanding of the molecular pathogenesis of glaucoma is leading to greater specificity in ocular tissue targeting. Improvements in gene delivery techniques, refinement of vector construction methods, and development of better animal models combine to bring this potential therapy closer to reality. PMID:19539835

Rates of retinal nerve fiber layer thinning in glaucoma suspect eyes

PubMed Central

Miki, Atsuya; Medeiros, Felipe A.; Weinreb, Robert N.; Jain, Sonia; He, Feng; Sharpsten, Lucie; Khachatryan, Naira; Hammel, Na’ama; Liebmann, Jeffrey M.; Girkin, Christopher A.; Sample, Pamela A.; Zangwill, Linda M.

2015-01-01

Purpose To compare the rates of retinal nerve fiber layer (RNFL) loss in patients suspect of having glaucoma who developed visual field damage (VFD) to those who did not develop VFD, and to determine whether the rate of RNFL loss can be used to predict who will develop VFD.. Design Prospective observational cohort study Participants Glaucoma suspects, defined as having glaucomatous optic neuropathy or ocular hypertension (Intraocular pressure (IOP)>21 mmHg) without repeatable VFD at baseline from the Diagnostic Innovations in Glaucoma Study, and the African Descent and Glaucoma Evaluation Study. Methods Global and quadrant RNFL thickness (RNFLT) were measured with the Spectralis spectral-domain optical coherence tomography (SD-OCT). VFD was defined as having 3 consecutive abnormal visual fields. The rate of RNFL loss in eyes developing VFD was compared with eyes not developing VFD using multivariable linear mixed-effects models. A joint longitudinal survival model utilized the estimated RNFLT slope to predict the risk of developing VFD, while adjusting for potential confounding variables. Main Outcome Measures The rate of RNFL thinning and the probability of developing VFD. Results Four hundred and fifty-four eyes of 294 glaucoma suspects were included. The average number of SD-OCT examinations was 4.6 (range, 2–9) with median follow-up time of 2.2 (0.4–4.1) years. Forty eyes (8.8%) developed VFD. The estimated mean rate of global RNFL loss was significantly faster in eyes developing VFD compared with eyes that did not (−2.02μm/year vs. −0.82μm/year, P<0.001). The joint longitudinal survival model showed that each 1μm/year faster rate of global RNFL loss corresponded to a 2.05 times higher risk of developing VFD (Hazards Ratio (HR)=2.05, 95% Confidence Interval (CI): 1.14–3.71; p=0.017). Conclusions The rate of global RNFL loss was more than twice as fast in eyes developing VFD compared with eyes that did not develop them. Joint longitudinal survival model showed that a 1μm/year faster rate of RNFLT loss corresponded to a 2.05 times higher risk of developing VFD. These results suggest that measuring the rate of SD-OCT RNFL loss may be a useful tool to help identify patients who are at a high risk of developing visual field loss. PMID:24629619

Ultrahigh-throughput exfoliation of graphite into pristine ‘single-layer’ graphene using microwaves and molecularly engineered ionic liquids

NASA Astrophysics Data System (ADS)

Matsumoto, Michio; Saito, Yusuke; Park, Chiyoung; Fukushima, Takanori; Aida, Takuzo

2015-09-01

Graphene has shown much promise as an organic electronic material but, despite recent achievements in the production of few-layer graphene, the quantitative exfoliation of graphite into pristine single-layer graphene has remained one of the main challenges in developing practical devices. Recently, reduced graphene oxide has been recognized as a non-feasible alternative to graphene owing to variable defect types and levels, and attention is turning towards reliable methods for the high-throughput exfoliation of graphite. Here we report that microwave irradiation of graphite suspended in molecularly engineered oligomeric ionic liquids allows for ultrahigh-efficiency exfoliation (93% yield) with a high selectivity (95%) towards ‘single-layer’ graphene (that is, with thicknesses <1 nm) in a short processing time (30 minutes). The isolated graphene sheets show negligible structural deterioration. They are also readily redispersible in oligomeric ionic liquids up to ~100 mg ml-1, and form physical gels in which an anisotropic orientation of graphene sheets, once induced by a magnetic field, is maintained.

Black tea assisted exfoliation using a kitchen mixer allowing one-step production of graphene

NASA Astrophysics Data System (ADS)

Ismail, Zulhelmi; Farhana Abu Kassim, Nurul; Hannifa Abdullah, Abu; Sakinah Zainal Abidin, Anis; Sameha Ismail, Fadwa; Yusoh, Kamal

2017-07-01

A kitchen mixer is one of the possible tools for the exfoliation of graphene. While organic solvents such as NMP or DMF are suitable for the exfoliation of graphite, the majority are toxic and dangerously harmful when exposed to humans and the environment. Therefore, an alternative solvent must be proposed for green and sustainable production of graphene. In this initial work, we have developed a new synthesis method for graphene through the direct exfoliation of graphite in commercial black tea. We found that our maximum yield concentration of graphene is Y  =  0.032 mg ml-l after 15 min of mixing. From the data of Raman, the level of defects in our produced graphene is suggested as being very minor (I D/I G  =  0.17), despite possible graphene functionalization by oxygen groups in tea. Incorporation of our graphene into PMMA results in shifting the onset temperature from 300 °C to 326 °C, which impressively validates the potential of the produced graphene as a thermal reinforcement material for polymer composites.

The development of a micro‐shunt made from poly(styrene‐block‐isobutylene‐block‐styrene) to treat glaucoma

PubMed Central

Riss, Isabelle; Batlle, Juan F.; Kato, Yasushi P.; Martin, John B.; Arrieta, Esdras; Palmberg, Paul; Parrish, Richard K.; Weber, Bruce A.; Kwon, Yongmoon; Parel, Jean‐Marie

2015-01-01

Abstract Glaucoma is the second leading cause of blindness with ∼70 million people worldwide who are blind from this disease. The currently practiced trabeculectomy surgery, the gold standard treatment used to stop the progression of vision loss, is rather draconian, traumatic to the patient and requires much surgical skill to perform. This article summarizes the more than 10‐year development path of a novel device called the InnFocus MicroShunt®, which is a minimally invasive glaucoma drainage micro‐tube used to shunt aqueous humor from the anterior chamber of the eye to a flap formed under the conjunctiva and Tenon's Capsule. The safety and clinical performance of this device approaches that of trabeculectomy. The impetus to develop this device stemmed from the invention of a new biomaterial called poly(styrene‐block‐isobutylene‐block‐styrene), or “SIBS.” SIBS is ultra‐stable with virtually no foreign body reaction in the body, which manifests in the eye as clinically insignificant inflammation and capsule formation. The quest for an easier, safer, and more effective method of treating glaucoma led to the marriage of SIBS with this glaucoma drainage micro‐tube. This article summarizes the development of SIBS and the subsequent three iterations of design and four clinical trials that drove the one‐year qualified success rate of the device from 43% to 100%. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 211–221, 2017. PMID:26380916

Willingness to Use Mobile Health in Glaucoma Patients.

PubMed

Dai, Miaomiao; Xu, Jianan; Lin, Jialiu; Wang, Zhonghao; Huang, Wenmin; Huang, Jingjing

2017-10-01

Development of mobile health (m-health) in China carries tremendous potential, especially for glaucoma, one of the major chronic ophthalmic diseases afflicting millions of people. However, little research has been undertaken to investigate the willingness of glaucoma patients to use m-health and the factors influencing their decisions. This was a cross-sectional study. A self-administered or face-to-face interview survey was performed on 1,487 patients with glaucoma at the outpatient glaucoma service, Zhongshan Ophthalmic Center, Sun Yat-sen University. Questionnaires captured patients' demographic data, WeChat access, and willingness to receive m-health. The data were analyzed by single factor chi-square test. Multiple logistic regression revealed the motivators and barriers to accept m-health adoption. One thousand ninety-seven valid questionnaires were obtained. Seven hundred twenty-five respondents (66.1%) were willing to participate in m-health programs. 65.4% were younger than 60 years old. 40.9% had travel time from home to hospital of >3 h. 63.6% had more than four follow-up visits for glaucoma. 86.5% experienced trouble events during clinic visits. The overall WeChat usage rate was 61.7%. Age, travel time, number of visits, trouble events in clinic, and WeChat access in patients with glaucoma were related to the willingness to use m-health (p < 0.05). Most patients with glaucoma were willing to participate in m-health programs, which are essential to increasing and improving access to care.

The East London glaucoma prediction score: web-based validation of glaucoma risk screening tool

PubMed Central

Stephen, Cook; Benjamin, Longo-Mbenza

2013-01-01

AIM It is difficult for Optometrists and General Practitioners to know which patients are at risk. The East London glaucoma prediction score (ELGPS) is a web based risk calculator that has been developed to determine Glaucoma risk at the time of screening. Multiple risk factors that are available in a low tech environment are assessed to provide a risk assessment. This is extremely useful in settings where access to specialist care is difficult. Use of the calculator is educational. It is a free web based service. Data capture is user specific. METHOD The scoring system is a web based questionnaire that captures and subsequently calculates the relative risk for the presence of Glaucoma at the time of screening. Three categories of patient are described: Unlikely to have Glaucoma; Glaucoma Suspect and Glaucoma. A case review methodology of patients with known diagnosis is employed to validate the calculator risk assessment. RESULTS Data from the patient records of 400 patients with an established diagnosis has been captured and used to validate the screening tool. The website reports that the calculated diagnosis correlates with the actual diagnosis 82% of the time. Biostatistics analysis showed: Sensitivity = 88%; Positive predictive value = 97%; Specificity = 75%. CONCLUSION Analysis of the first 400 patients validates the web based screening tool as being a good method of screening for the at risk population. The validation is ongoing. The web based format will allow a more widespread recruitment for different geographic, population and personnel variables. PMID:23550097

Developing an Item Bank to Measure Quality of Life in Individuals With Glaucoma, and the Results of the Interview With Patients: The Effect of Visual Function, Visual Field Progression Rate, Medical, and Surgical Treatments on Quality of Life.

PubMed

Matsuura, Masato; Hirasawa, Kazunori; Hirasawa, Hiroyo; Yanagisawa, Mieko; Murata, Hiroshi; Mayama, Chihiro; Asaoka, Ryo

2017-02-01

To construct a new item bank to measure quality of life (QOL) in glaucoma patients and to evaluate glaucoma patients' QOL using the item bank. An item bank of questions was generated through a literature review of QOL instruments useful for glaucoma patients. Using this item bank, a cognitive survey was performed on 203 patients with glaucoma (112 males and 91 females, 61.9±11.9 y old; mean±SD). The results were then analyzed using the Rasch analysis, and the Rasch-derived disability scores were predicted using linear modelling and the following clinical parameters: age, mean total deviation (mTD) in superior and inferior visual field (mTDsup/mTDinf), mTD progression rate, better visual acuity, worse visual acuity, number of eye drops administered per day, number of trabeculectomy procedures experienced in both eyes. A total of 23 questionnaires of QOL in glaucoma patients were identified resulting in an item bank of 187 questions related to the following tasks: reading/writing, walking, going out, eating and driving (direct disability) as well as questions concerned with worry/anxiety, social participation, and physical symptoms (indirect disability). In the optimal model for direct disability, age and mTDinf were identified as significant predictors, whereas number of eye drops administered per day and number of trabeculectomy experienced were included in the optimal model for indirect disability. A new item bank to measure QOL in glaucoma patients was developed and evaluated. Age and mTDinf were found to be related to direct disability while medical and surgical treatments were related to indirect disability.

A "Tandem" Strategy to Fabricate Flexible Graphene/Polypyrrole Nanofiber Film Using the Surfactant-Exfoliated Graphene for Supercapacitors.

PubMed

Shu, Kewei; Chao, Yunfeng; Chou, Shulei; Wang, Caiyun; Zheng, Tian; Gambhir, Sanjeev; Wallace, Gordon G

2018-06-19

The surfactant-assisted liquid-phase exfoliation of expanded graphite can produce graphene sheets in large quantities with minimal defects. However, it is difficult to completely remove the surfactant from the final product, thus affecting the electrochemical properties of the produced graphene. In this article, a novel approach to fabricate flexible graphene/polypyrrole film was developed: using surfactant cetyltrimethylammonium bromide as a template for growth of polypyrrole nanofibers (PPyNFs) instead of removal after the exfoliation process; followed by a simple filtration method. The introduction of PPyNF not only increases the electrochemical performance, but also ensures flexibility. This composite film electrode offers a capacitance up to 161 F g -1 along with a capacitance retention rate of over 80% after 5000 cycles.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma

PubMed Central

Gangeddula, Viswa; Ranchet, Maud; Akinwuntan, Abiodun E.; Bollinger, Kathryn; Devos, Hannes

2017-01-01

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma. Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal–Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions. Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups (p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1–Q3) 3 (2–6.50) vs. controls: 2 (0.50–2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2–6) vs. controls: 1 (0.50–2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls (p = 0.02). Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma. PMID:28912712

Sturge-Weber Syndrome: A Review.

PubMed

Higueros, E; Roe, E; Granell, E; Baselga, E

2017-06-01

Sturge-Weber syndrome is a sporadic congenital neurocutaneous disorder caused by a somatic activating mutation in GNAQ; it affects 1 in every 20,000 to 50,000 newborns. It is characterized by a facial Port-wine stain, leptomeningeal angiomatosis, and glaucoma. Seizures are the most common neurological manifestation and typically present in the first months of life. Glaucoma may be present at birth or develop later. Neuroimaging studies show leptomeningeal angiomatosis, supporting diagnosis. Standard treatment for Sturge-Weber syndrome includes laser treatment for the Port-wine stain, anticonvulsants, and medical or surgical treatment for the glaucoma. Prognosis depends on the extent of leptomeningeal involvement and the severity of the glaucoma. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

High-Yield Preparation and Electrochemical Properties of Few-Layer MoS2 Nanosheets by Exfoliating Natural Molybdenite Powders Directly via a Coupled Ultrasonication-Milling Process.

PubMed

Dong, Huina; Chen, Deliang; Wang, Kai; Zhang, Rui

2016-12-01

Cost-effective and scalable preparation of two-dimensional (2D) molybdenum disulfide (MoS2) has been the bottleneck that limits their applications. This paper reports a novel coupled ultrasonication-milling (CUM) process to exfoliate natural molybdenite powders to achieve few-layer MoS2 (FL-MoS2) nanosheets in the solvent of N-methyl-2-pyrrolidone (NMP) with polyvinylpyrrolidone (PVP) molecules. The synergistic effect of ultrasonication and sand milling highly enhanced the exfoliation efficiency, and the precursor of natural molybdenite powders minimizes the synthetic cost of FL-MoS2 nanosheets. The exfoliation of natural molybdenite powders was conducted in a home-made CUM system, mainly consisting of an ultrasonic cell disruptor and a ceramic sand mill. The samples were characterized by X-ray diffraction, UV-vis spectra, Raman spectra, FT-IR, SEM, TEM, AFM, and N2 adsorption-desorption. The factors that influence the exfoliation in the CUM process, including the initial concentration of natural molybdenite powders (C in, 15-55 g L(-1)), ultrasonic power (P u, 200-350 W), rotation speed of sand mill (ω s, 1500-2250 r.p.m), exfoliation time (t ex, 0.5-6 h), and the molar ratio of PVP unit to MoS2 (R pm, 0-1), were systematically investigated. Under the optimal CUM conditions (i.e., C in = 45 g L(-1), P u = 280 W, ω s = 2250 r.p.m and R pm = 0.5), the yield at t ex = 6 h reaches 21.6 %, and the corresponding exfoliation rate is as high as 1.42 g L(-1) h(-1). The exfoliation efficiency of the CUM mode is much higher than that of either the ultrasonication (U) mode or the milling (M) mode. The synergistic mechanism and influencing rules of the CUM process in exfoliating natural molybdenite powders were elaborated. The as-obtained FL-MoS2 nanosheets have a high specific surface area of 924 m(2) g(-1) and show highly enhanced electrocatalytic performance in hydrogen evolution reaction and good electrochemical sensing property in detecting ascorbic acid. The CUM process developed has paved a low-cost, green, and highly efficient way towards FL-MoS2 nanosheets from natural molybdenite powders.

Decolorizing of azo dye Reactive red 24 aqueous solution using exfoliated graphite and H2O2 under ultrasound irradiation.

PubMed

Li, Mei; Li, Ji-Tai; Sun, Han-Wen

2008-07-01

At its natural pH (6.95), the decolorization of Reactive red 24 in ultrasound, ultrasound/H2O2, exfoliated graphite, ultrasound/exfoliated graphite, exfoliated graphite/H2O2 and ultrasound/exfoliated graphite/H2O2 systems were compared. An enhancement was observed for the decolorization in ultrasound/exfoliated graphite/H2O2 system. The effect of solution pH, H2O2 and exfoliated graphite dosages, and temperature on the decolorization of Reactive red 24 was investigated. The sonochemical treatment in combination with exfoliated graphite/H2O2 showed a synergistic effect for the decolorization of Reactive red 24. The results indicated that under proper conditions, there was a possibility to remove Reactive red 24 very efficient from aqueous solution. The decolorization of other azo dyes (Reactive red 2, Methyl orange, Acid red 1, Acid red 73, Acid red 249, Acid orange 7, Acid blue 113, Acid brown 75, Acid green 20, Acid yellow 42, Acid mordant brown 33, Acid mordant yellow 10 and Direct green 1) was also investigated, at their natural pH.

Oral Microbiome Link to Neurodegeneration in Glaucoma

PubMed Central

Astafurov, Konstantin; Elhawy, Eman; Ren, Lizhen; Dong, Cecilia Q.; Igboin, Christina; Hyman, Leslie; Griffen, Ann; Mittag, Thomas; Danias, John

2014-01-01

Background Glaucoma is a progressive optic nerve degenerative disease that often leads to blindness. Local inflammatory responses are implicated in the pathology of glaucoma. Although inflammatory episodes outside the CNS, such as those due to acute systemic infections, have been linked to central neurodegeneration, they do not appear to be relevant to glaucoma. Based on clinical observations, we hypothesized that chronic subclinical peripheral inflammation contributes to neurodegeneration in glaucoma. Methods Mouthwash specimens from patients with glaucoma and control subjects were analyzed for the amount of bacteria. To determine a possible pathogenic mechanism, low-dose subcutaneous lipopolysaccharide (LPS) was administered in two separate animal models of glaucoma. Glaucomatous neurodegeneration was assessed in the retina and optic nerve two months later. Changes in gene expression of toll-like receptor 4 (TLR4) signaling pathway and complement as well as changes in microglial numbers and morphology were analyzed in the retina and optic nerve. The effect of pharmacologic blockade of TLR4 with naloxone was determined. Findings Patients with glaucoma had higher bacterial oral counts compared to control subjects (p<0.017). Low-dose LPS administration in glaucoma animal models resulted in enhancement of axonal degeneration and neuronal loss. Microglial activation in the optic nerve and retina as well as upregulation of TLR4 signaling and complement system were observed. Pharmacologic blockade of TLR4 partially ameliorated the enhanced damage. Conclusions The above findings suggest that the oral microbiome contributes to glaucoma pathophysiology. A plausible mechanism by which increased bacterial loads can lead to neurodegeneration is provided by experiments in animal models of the disease and involves activation of microglia in the retina and optic nerve, mediated through TLR4 signaling and complement upregulation. The finding that commensal bacteria may play a role in the development and/or progression of glaucomatous pathology may also be relevant to other chronic neurodegenerative disorders. PMID:25180891

Comparative proteomic study in serum of patients with primary open-angle glaucoma and pseudoexfoliation glaucoma.

PubMed

González-Iglesias, Héctor; Álvarez, Lydia; García, Montserrat; Escribano, Julio; Rodríguez-Calvo, Pedro Pablo; Fernández-Vega, Luis; Coca-Prados, Miguel

2014-02-26

Alterations in the sera proteins between patients with Primary Open-Angle Glaucoma (POAG), Pseudoexfoliation Glaucoma (PEXG), and healthy controls were identified through a proven approach utilizing equalization of high-abundance serum proteins with ProteoMiner™, two-dimensional fluorescent difference gel electrophoresis (2D-DIGE), MALDI-TOF/TOF, and nanoLC-MS-MS. Quantitative immunoassays of the 17 most-differentially-altered proteins identified in this analysis confirmed that they were also over expressed in the intact serum of newly recruited glaucoma patients. Overall, this report identifies a panel of candidates for glaucoma biomarkers and supports their further validation in large population studies. Additionally, functional pathway analysis of these candidate proteins suggested that they are part of a network linked to regulating immune and inflammatory-related processes. The data have been deposited to the ProteomeXchange with identifier PXD000198. POAG and PEXG are major causes of age-related blindness in the world; however, treatment can be very effective if they are identified early on in the progression. Genetic linkage studies can only explain a limited number of cases, suggesting that these forms of glaucoma are multigenic in nature. Other important factors, such as modifier genes, epigenetic influences, environmental and dietary agents, and inflammatory and oxidative effects are also believed to affect the development of these diseases. The characterization of metabolic and/or proteins changes, for example in bodily fluids, before the clinical manifestation of glaucoma is of considerable relevance for its early diagnosis. In the present work, identification of over-expressed proteins in serum of glaucoma patients (POAG and PEXG) linked to immune and inflammatory processes supports the finding that changes in these pathways also manifest systemically in patients with these pathologies. This study provides a new basis to validate the identified proteins as biomarkers of glaucoma in a large-scale-multiplexed screening in sera. Copyright © 2013 Elsevier B.V. All rights reserved.

An introduction to DARC technology.

PubMed

Ahmad, Syed Shoeb

2017-01-01

Glaucoma is a multi-factorial neurodegenerative disorder. The common denominator in all types of glaucomas is retinal ganglion cell death through apoptosis. However, this cellular demise in glaucoma is detected late by structural or functional analyses. There can be a 10-year delay prior to the appearance of visual field defects and pre-perimetric glaucoma is an issue still being addressed. However, a new cutting-edge technology called detection of apoptosing retinal cells (DARC) is being developed. This technique is capable of non-invasive, real-time visualization of apoptotic changes at the cellular level. It can detect glaucomatous cell damage at a very early stage, at the moment apoptosis starts, and thus management can be initiated even prior to development of visual field changes. In future, this technique will also be able to provide conclusive evidence of the effectiveness of treatment protocol and the need for any modifications which may be required. This article aims to provide a concise review of DARC technology.

NDI method to locate intergranular corrosion around fastener holes in aluminum wing skins

NASA Astrophysics Data System (ADS)

Rutherford, Paul S.

1998-03-01

Contact between galvanically dissimilar metals, such as cadmium plated steel fasteners and aluminum wing skins are known to be a source of corrosion. There is a design requirement to fill the void between the contacting surfaces of steel fasteners with a wet sealant. However, if the contacting surface is damaged or a void exists between the fastener head and the aluminum skin, moisture can collect and intergranular corrosion may occur along aluminum grain boundaries, which run parallel to the surface of the wing skin. If intergranular corrosion is allowed to propagate, delamination of the thin layers of aluminum, known as exfoliation corrosion will occur. When this intergranular corrosion reaches an exfoliated state, extensive rework is involved in removing the corrosion. This paper discusses the results of a USAF E-3A Engineering Service Task 89-E3B3-16 to develop a nondestructive inspection procedure to detect intergranular corrosion in an incipient state before it reaches exfoliation. Eddy current and ultrasonic inspection techniques were evaluated. A novel ultrasonic pulse echo technique was developed which utilizes a focus transducer with a hand held fixture. Inspections were performed on test parts which were removed from the upper wing skin of a retired 707 which had varying degrees of intergranular and exfoliation corrosion. Inspection results are compared to the results from the mechanical rework of the wing skin and dissection of a wing skin fastener hole.

Granite Exfoliation, Cosumnes River Watershed, Somerset, California

NASA Astrophysics Data System (ADS)

Crockett, I. Q.; Neiss-Cortez, M.

2015-12-01

In the Sierra Nevada foothills of California there are many exposed granite plutons within the greater Sierra Nevada batholith. As with most exposed parts of the batholith, these granite slabs exfoliate. It is important to understand exfoliation for issues of public safety as it can cause rock slides near homes, roads, and recreation areas. Through observation, measuring, and mapping we characterize exfoliation in our Cosumnes River watershed community.

Prevalence of comorbid retinal disease in patients with glaucoma at an academic medical center.

PubMed

Griffith, Joseph F; Goldberg, Jeffrey L

2015-01-01

Patients with various retinal diseases and patients who have undergone retinal procedures and surgeries have an increased risk of developing ocular hypertension and glaucoma. Little is known about the epidemiology of comorbid retinal diseases in glaucoma patients. This study evaluated the prevalence of retinal comorbidities in a population of patients with five types of glaucoma. A longitudinal, retrospective study was conducted using International Classification of Disease (ICD-9) billing records from 2003 to 2010 at an academic medical center. Patients were classified as having primary open-angle glaucoma (POAG), low tension open-angle glaucoma (NTG), pigmentary open-angle glaucoma, chronic-angle closure glaucoma (CACG), or pseudoexfoliation glaucoma (PXG) if they had at least three clinic visits with the same ICD-9 code. Patients were classified as having a retinal comorbidity if they had two visits with the same code. Variables were analyzed with the independent t-test, χ (2) test, analysis of variance, or Fisher's exact test. A total of 5,154 patients had glaucoma, and 14.8% of these had a retinal comorbidity. The prevalence of comorbid retinal disease was higher in patients with POAG (15.7%) than in those with NTG (10.7%), PXG (10.1%), or pigmentary open-angle glaucoma (3.7%; P<0.05). Two hundred and two patients had diabetic retinopathy, with POAG patients (4.5%) having a higher prevalence than those with CACG (1.4%) or PXG (0.6%; P<0.001). There were 297 patients who had macular degeneration and both POAG (2.0%) and PXG patients (2.9%) had a higher prevalence of nonexudative macular degeneration than those with CACG (0%; P<0.01). Patients with comorbid retinal disease had a higher prevalence of blindness and low vision than those without comorbid retinal disease (1.97% versus 1.02%, P=0.02). The high prevalence of comorbid retinal disease and the nearly twofold increase in blindness and low vision in this population demonstrate the need for ophthalmologists to determine if patients have multiple etiologies for their vision loss. The higher prevalence of certain retinal diseases in POAG patients may reflect common pathophysiological processes that warrant further investigation.

Minimally invasive glaucoma surgery as primary stand-alone surgery for glaucoma.

PubMed

Kerr, Nathan M; Wang, Jing; Barton, Keith

2017-05-01

Recently, many new devices and procedures have been developed to lower intraocular pressure in a less invasive and purportedly safer manner than traditional glaucoma surgery. These new devices might encourage an earlier transition to surgery and reduce the long-term commitment to topical glaucoma medications with their associated compliance and intolerance issues. Although often seen as an adjunct to cataract surgery, a growing body of evidence suggests that primary minimally invasive glaucoma surgery may be a viable initial treatment option. New studies have shown that primary ab interno trabeculectomy (Trabectome, NeoMedix Inc., Tustin, CA, USA), trabecular micro-bypass stent insertion (iStent and iStent Inject, Glaukos Corporation, Laguna Hills, CA, USA), canalicular scaffolding (Hydrus, Invantis Inc., Irvine CA, USA), the ab interno gel Implant (XEN, Allergan, Dublin, Ireland) or supraciliary stenting (CyPass Micro-Stent, Alcon, Fort Worth, TX, USA) may lower the lowering intraocular pressure and/or topical medication burden in phakic or pseudophakic patients with glaucoma. This effect seems to last at least 12 months but reliable cost-effectiveness and quality of life indicators have not yet been established by investigator-initiated randomized trials of sufficient size and duration. © 2016 Royal Australian and New Zealand College of Ophthalmologists.

Developmental approach towards high resolution optical coherence tomography for glaucoma diagnostics

NASA Astrophysics Data System (ADS)

Kemper, Björn; Ketelhut, Steffi; Heiduschka, Peter; Thorn, Marie; Larsen, Michael; Schnekenburger, Jürgen

2018-02-01

Glaucoma is caused by a pathological rise in the intraocular pressure, which results in a progressive loss of vision by a damage to retinal cells and the optical nerve head. Early detection of pressure-induced damage is thus essential for the reduction of eye pressure and to prevent severe incapacity or blindness. Within the new European Project GALAHAD (Glaucoma Advanced, Label free High Resolution Automated OCT Diagnostics), we will develop a new low-cost and high-resolution OCT system for the early detection of glaucoma. The device is designed to improve diagnosis based on a new system of optical coherence tomography. Although OCT systems are at present available in ophthalmology centres, high-resolution devices are extremely expensive. The novelty of the new Galahad system is its super wideband light source to achieve high image resolution at a reasonable cost. Proof of concept experiments with cell and tissue Glaucoma test standards and animal models are planned for the test of the new optical components and new algorithms performance for the identification of Glaucoma associated cell and tissue structures. The intense training of the software systems with various samples should result in a increased sensitivity and specificity of the OCT software system.

What was Glaucoma Called Before the 20th Century?

PubMed Central

Leffler, Christopher T.; Schwartz, Stephen G.; Giliberti, Francesca M.; Young, Matthew T.; Bermudez, Dennis

2015-01-01

Glaucoma involves a characteristic optic neuropathy, often with elevated intraocular pressure. Before 1850, poor vision with a normal eye appearance, as occurs in primary open-angle glaucoma, was termed amaurosis, gutta serena, or black cataract. Few observers noted palpable hardness of the eye in amaurosis. On the other hand, angle-closure glaucoma can produce a green or gray pupil, and therefore was called, variously, glaucoma (derived from the Greek for glaucous, a nonspecific term connoting blue, green, or light gray) and viriditate oculi. Angle closure, with palpable hardness of the eye, mydriasis, and anterior prominence of the lens, was described in greater detail in the 18th and 19th centuries. The introduction of the ophthalmoscope in 1850 permitted the visualization of the excavated optic neuropathy in eyes with a normal or with a dilated greenish-gray pupil. Physicians developed a better appreciation of the role of intraocular pressure in both conditions, which became subsumed under the rubric “glaucoma”. PMID:26483611

Refractory open-angle glaucoma after neodymium-yttrium-aluminum-garnet laser lysis of vitreous floaters.

PubMed

Cowan, Lisa A; Khine, Kay T; Chopra, Vikas; Fazio, Doreen T; Francis, Brian A

2015-01-01

To illustrate 3 cases of chronic open-angle glaucoma secondary to the neodymium-yttrium-aluminum-garnet (Nd:YAG) laser vitreolysis procedure for symptomatic vitreous floaters. Observational case series. Location of the study was the Doheny Eye Institute. Three eyes of 2 patients who developed chronic open-angle glaucoma after Nd:YAG vitreolysis for symptomatic floaters presenting with very high intraocular pressure (IOP >40 mm Hg) were selected. The time from the laser treatment to the onset of elevated pressure ranges from 1 week to 8 months. There was no associated inflammation, steroid use, or other identifiable cause of chronic IOP elevation. All eyes were treated initially with glaucoma medication, followed by selective laser trabeculoplasty (SLT) and eventually glaucoma surgery (Trabectome) in 2 eyes for disease management. In all eyes, intraocular pressures were eventually stabilized within a normal pressure range from 18 to 38 months following Nd:YAG vitreolysis. At the latest follow-up post surgery, all eyes had intraocular pressures of 22 mm Hg or less with or without medications. Secondary open-angle glaucoma is a complication of Nd:YAG vitreolysis for symptomatic floaters that may present with an increase in intraocular pressure immediately, or many months after the surgery. Furthermore this complication may be permanent and require chronic medical therapy or glaucoma surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

Are we ready for genetic testing for primary open-angle glaucoma?

PubMed

Khawaja, Anthony P; Viswanathan, Ananth C

2018-05-01

Following a dramatic reduction in the cost of genotyping technology in recent years, there have been significant advances in the understanding of the genetic basis of glaucoma. Glaucoma patients represent around a quarter of all outpatient activity in the UK hospital eye service and are a huge burden for the National Health Service. A potential benefit of genetic testing is personalised glaucoma management, allowing direction of our limited healthcare resources to the glaucoma patients who most need it. Our review aims to summarise recent discoveries in the field of glaucoma genetics and to discuss their potential clinical utility. While genome-wide association studies have now identified over ten genes associated with primary open-angle glaucoma (POAG), individually, variants in these genes are not predictive of POAG in populations. There are data suggesting some of these POAG variants are associated with conversion from ocular hypertension to POAG and visual field progression among POAG patients. However, these studies have not been replicated yet and such genetic testing is not currently justified in clinical care. In contrast, genetic testing for inherited early-onset disease in relatives of POAG patients with a known genetic mutation is of clear benefit; this can support either regular review to commence early treatment when the disease develops, or discharge from ophthalmology services of relatives who do not carry the mutation. Genetic testing for POAG at a population level is not currently justified.

Spontaneous dislocation of a crystalline lens to the anterior chamber with pupillary block glaucoma in Noonan Syndrome: a case report.

PubMed

Mukhopadhyaya, Udayaditya; Chakraborti, Chandana; Mondal, Anindita; Pattyanayak, Ujjal; Agarwal, Rajesh Kumar; Tripathi, Partha

2014-01-01

We report a 13-year-old child with Noonan Syndrome who developed spontaneous dislocation of the crystalline lens in anterior chamber leading to pupillary block glaucoma in the left eye and subluxation of lens in right eye. Intracapsular extraction of the dislocated lens was done in the left eye. Prompt diagnosis and management is needed in such cases to avoid glaucoma and corneal endothelial cell damage. We could not find any such case after thorough Medline search.

Unilateral angle-closure glaucoma with ciliochoroidal effusion after the consumption of cannabis: a case report.

PubMed

Hanna, Rana; Tiosano, Beatrice; Dbayat, Noora; Gaton, Dan

2014-01-01

A 35-year-old male patient, diagnosed with acute angle-closure glaucoma, did not improve despite intensive treatment with antiglaucoma medications. Ultrasound biomicroscopy revealed a ciliochoroidal effusion. Due to his past history of drug abuse, a urine test was analyzed and found to be positive for cannabis. After topical cycloplegia and oral steroid therapy, his symptoms improved substantially. The present case highlights the role of ultrasound biomicroscopy in evaluating patients with acute angle-closure glaucoma and the role of cannabis abuse in the development of ciliochoroidal effusion.

Ophthalmologist-patient communication, self-efficacy, and glaucoma medication adherence

PubMed Central

Sleath, Betsy; Blalock, Susan J.; Carpenter, Delesha M.; Sayner, Robyn; Muir, Kelly W.; Slota, Catherine; Lawrence, Scott D.; Giangiacomo, Annette L.; Hartnett, Mary Elizabeth; Tudor, Gail; Goldsmith, Jason A.; Robin, Alan L.

2015-01-01

Objective The objective of the study was to examine the association between provider-patient communication, glaucoma medication adherence self-efficacy, outcome expectations, and glaucoma medication adherence. Design Prospective observational cohort study. Participants 279 patients with glaucoma who were newly prescribed or on glaucoma medications were recruited at six ophthalmology clinics. Methods Patients’ visits were video-tape recorded and communication variables were coded using a detailed coding tool developed by the authors. Adherence was measured using Medication Event Monitoring Systems for 60 days after their visits. Main outcome measures The following adherence variables were measured for the 60 day period after their visits: whether the patient took 80% or more of the prescribed doses, percent correct number of prescribed doses taken each day, and percent prescribed doses taken on time. Results Higher glaucoma medication adherence self-efficacy was positively associated with better adherence with all three measures. African American race was negatively associated with percent correct number of doses taken each day (beta= −0.16, p<0.05) and whether the patient took 80% or more of the prescribed doses (odds ratio=0.37, 95% confidence interval 0.16, 0.86). Physician education about how to administer drops was positively associated with percent correct number of doses taken each day (beta= 0.18, p<0.01) and percent prescribed doses taken on time (beta=0.15, p<0.05). Conclusions These findings indicate that provider education about how to administer glaucoma drops and patient glaucoma medication adherence self-efficacy are positively associated with adherence. PMID:25542521

Simplifying "target" intraocular pressure for different stages of primary open-angle glaucoma and primary angle-closure glaucoma.

PubMed

Sihota, Ramanjit; Angmo, Dewang; Ramaswamy, Deepa; Dada, Tanuj

2018-04-01

Lowering of intraocular pressure is currently the only therapeutic measure for Glaucoma management. Many longterm, randomized trials have shown the efficacy of lowering IOP, either by a percentage of baseline, or to a specified level. This has lead to the concept of 'Target" IOP, a range of IOP on therapy, that would stabilize the Glaucoma/prevent further visual field loss, without significantly affecting a patient's quality of life. A clinical staging of Glaucoma by optic nerve head evaluation and perimetric parameters, allows a patient's eye to be categorized as having - mild, moderate or severe Glaucomatous damage. An initial attempt should be made to achieve the following IOP range for both POAG or PACG after an iridotomy. In mild glaucoma the initial target IOP range could be kept as 15-17 mmHg, for moderate glaucoma 12-15 mmHg and in the severe stage of glaucomatous damage 10-12 mmHg. Factoring in baseline IOP, age, vascular perfusion parameters, and change on perimetry or imaging during follow up, this range may be reassessed over 6 months to a year. "Target" IOP requires further lowering when the patient continues to progress or develops a systemic disease such as a TIA. Conversely, in the event of a very elderly or sick patient with stable nerve and visual field over time, the target IOP could be raised and medications reduced. An appropriate use of medications/laser/surgery to achieve such a "Target" IOP range in POAG or PACG can maintain visual fields and quality of life, preventing Glaucoma blindness.

Port-wine vascular malformations and glaucoma risk in Sturge-Weber syndrome.

PubMed

Sharan, Sapna; Swamy, Brighu; Taranath, Deepa Ajay; Jamieson, Robyn; Yu, Tao; Wargon, Orli; Grigg, John R

2009-08-01

Treatment of the capillary vascular malformation (port-wine stain) in Sturge-Weber syndrome with the use of a laser is helpful cosmetically. However, concerns have been raised that laser obliteration of port-wine stains may result in ocular hypertension. The aim of this study was to review clinical features and management of ocular complications of SWS and assess the effects of dermatological laser treatment on the incidence of glaucoma or ocular hypertension. This retrospective cohort study was conducted in an institutional setting. All patients had involvement of the face. Patients who underwent skin laser to the port-wine vascular malformation were analyzed further. Ocular involvement, glaucoma, and skin laser treatment and the relationship to ocular hypertension/glaucoma were observed. Forty-one Sturge-Weber syndrome patients with port-wine vascular malformation were analyzed. Glaucoma was observed in 24 patients (58.5%) at mean age of 2.9 years (range, 0.0-16.5). Of these, 18 (75.0%) were treated with medical therapy, and 10 (41.7%) required trabeculectomy, with 2 of these requiring Seton implant. Of the 41 patients, 28 (68.3%) underwent laser to face/forehead. Mean age of laser commencement was 5 years (range, 0.4-16.5). Thirteen did not undergo laser treatment. Fourteen of the 28 and 10 of the 13 developed ocular hypertension/glaucoma. This retrospective review did not find evidence to suggest that laser treatment of port-wine vascular malformations causes glaucoma or that it can worsen a preexisting ocular hypertension or glaucoma. Statistical analysis was inconclusive.

The clinical characteristics of patients with glaucoma presenting to Botswana healthcare facilities: an observational study.

PubMed

Jackson, Daniel J; Razai, Mohammad S; Falama, Rosemary; Mongwa, Matlhogonolo; Mutapanduwa, Mishell; Baemisi, Chao; Josiah, Engelinah; Nkomazana, Oathokwa; Lehasa, Alice; Brealey, Evelyn; White, Andrew J; Jankowski, Deborah; Kerr-Muir, Malcolm G; Martin, Keith R; Ngondi, Jeremiah M

2014-12-03

This study aimed to establish the clinical characteristics of patients with glaucoma attending eye care facilities in Botswana, and management of glaucoma among patients who received care in these facilities. The study also aimed to calculate the number of new diagnoses of glaucoma within the glaucoma service. A prospective, hospital-based, observational study. A multicentre study was undertaken in government-run eye departments in Botswana from June to August 2012. All patients with a diagnosis of glaucoma attending clinics at seven study sites were invited to participate. Examination findings, diagnosis and management were extracted from individual patient-held medical charts. Sociodemographic characteristics, patient knowledge and understanding of glaucoma were assessed through face-to-face interviews. In addition, details of outpatient attendances for 2011 were collected from 21 government-run hospitals. The majority of the 366 patients interviewed had a diagnosis of primary glaucoma (86.6%). The diagnoses were mainly made by ophthalmologists (48.6%) and ophthalmic nurses (44.0%). Many patients (38.5%) had been symptomatic for over 6 months before visiting an eye clinic. The mean presenting intraocular pressure was 28.2 mm Hg (SD 11.9 mm Hg). Most follow-up patients (79.2%) had not received surgery, however, many (89.5%) would accept surgery. Only 11.5% of participants had heard of glaucoma prior to diagnosis. Many participants (35.9%) did not understand glaucoma after being diagnosed. The majority (94.9%) of living first-degree relatives had never been examined. The number of newly diagnosed glaucoma cases for 2011 in the south of the country was 14.1/100,000; 95% CI (12.0 to 16.5), in the north it was 16.2/100,000; 95% CI (13.8 to 19.0). Glaucoma is a significant burden that presents challenges to ophthalmic services in Botswana. Many patients have limited understanding of the condition and poor access to services. There is a need to develop a treatment infrastructure to include safe surgery and a reliable supply of effective medication. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Eye-Tracking as a Tool to Evaluate Functional Ability in Everyday Tasks in Glaucoma.

PubMed

Kasneci, Enkelejda; Black, Alex A; Wood, Joanne M

2017-01-01

To date, few studies have investigated the eye movement patterns of individuals with glaucoma while they undertake everyday tasks in real-world settings. While some of these studies have reported possible compensatory gaze patterns in those with glaucoma who demonstrated good task performance despite their visual field loss, little is known about the complex interaction between field loss and visual scanning strategies and the impact on task performance and, consequently, on quality of life. We review existing approaches that have quantified the effect of glaucomatous visual field defects on the ability to undertake everyday activities through the use of eye movement analysis. Furthermore, we discuss current developments in eye-tracking technology and the potential for combining eye-tracking with virtual reality and advanced analytical approaches. Recent technological developments suggest that systems based on eye-tracking have the potential to assist individuals with glaucomatous loss to maintain or even improve their performance on everyday tasks and hence enhance their long-term quality of life. We discuss novel approaches for studying the visual search behavior of individuals with glaucoma that have the potential to assist individuals with glaucoma, through the use of personalized programs that take into consideration the individual characteristics of their remaining visual field and visual search behavior.

Eye-Tracking as a Tool to Evaluate Functional Ability in Everyday Tasks in Glaucoma

PubMed Central

Black, Alex A.

2017-01-01

To date, few studies have investigated the eye movement patterns of individuals with glaucoma while they undertake everyday tasks in real-world settings. While some of these studies have reported possible compensatory gaze patterns in those with glaucoma who demonstrated good task performance despite their visual field loss, little is known about the complex interaction between field loss and visual scanning strategies and the impact on task performance and, consequently, on quality of life. We review existing approaches that have quantified the effect of glaucomatous visual field defects on the ability to undertake everyday activities through the use of eye movement analysis. Furthermore, we discuss current developments in eye-tracking technology and the potential for combining eye-tracking with virtual reality and advanced analytical approaches. Recent technological developments suggest that systems based on eye-tracking have the potential to assist individuals with glaucomatous loss to maintain or even improve their performance on everyday tasks and hence enhance their long-term quality of life. We discuss novel approaches for studying the visual search behavior of individuals with glaucoma that have the potential to assist individuals with glaucoma, through the use of personalized programs that take into consideration the individual characteristics of their remaining visual field and visual search behavior. PMID:28293433

The development of a micro-shunt made from poly(styrene-block-isobutylene-block-styrene) to treat glaucoma.

PubMed

Pinchuk, Leonard; Riss, Isabelle; Batlle, Juan F; Kato, Yasushi P; Martin, John B; Arrieta, Esdras; Palmberg, Paul; Parrish, Richard K; Weber, Bruce A; Kwon, Yongmoon; Parel, Jean-Marie

2017-01-01

Glaucoma is the second leading cause of blindness with ∼70 million people worldwide who are blind from this disease. The currently practiced trabeculectomy surgery, the gold standard treatment used to stop the progression of vision loss, is rather draconian, traumatic to the patient and requires much surgical skill to perform. This article summarizes the more than 10-year development path of a novel device called the InnFocus MicroShunt®, which is a minimally invasive glaucoma drainage micro-tube used to shunt aqueous humor from the anterior chamber of the eye to a flap formed under the conjunctiva and Tenon's Capsule. The safety and clinical performance of this device approaches that of trabeculectomy. The impetus to develop this device stemmed from the invention of a new biomaterial called poly(styrene-block-isobutylene-block-styrene), or "SIBS." SIBS is ultra-stable with virtually no foreign body reaction in the body, which manifests in the eye as clinically insignificant inflammation and capsule formation. The quest for an easier, safer, and more effective method of treating glaucoma led to the marriage of SIBS with this glaucoma drainage micro-tube. This article summarizes the development of SIBS and the subsequent three iterations of design and four clinical trials that drove the one-year qualified success rate of the device from 43% to 100%. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 211-221, 2017. © 2015 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc.

Development of machine learning models for diagnosis of glaucoma.

PubMed

Kim, Seong Jae; Cho, Kyong Jin; Oh, Sejong

2017-01-01

The study aimed to develop machine learning models that have strong prediction power and interpretability for diagnosis of glaucoma based on retinal nerve fiber layer (RNFL) thickness and visual field (VF). We collected various candidate features from the examination of retinal nerve fiber layer (RNFL) thickness and visual field (VF). We also developed synthesized features from original features. We then selected the best features proper for classification (diagnosis) through feature evaluation. We used 100 cases of data as a test dataset and 399 cases of data as a training and validation dataset. To develop the glaucoma prediction model, we considered four machine learning algorithms: C5.0, random forest (RF), support vector machine (SVM), and k-nearest neighbor (KNN). We repeatedly composed a learning model using the training dataset and evaluated it by using the validation dataset. Finally, we got the best learning model that produces the highest validation accuracy. We analyzed quality of the models using several measures. The random forest model shows best performance and C5.0, SVM, and KNN models show similar accuracy. In the random forest model, the classification accuracy is 0.98, sensitivity is 0.983, specificity is 0.975, and AUC is 0.979. The developed prediction models show high accuracy, sensitivity, specificity, and AUC in classifying among glaucoma and healthy eyes. It will be used for predicting glaucoma against unknown examination records. Clinicians may reference the prediction results and be able to make better decisions. We may combine multiple learning models to increase prediction accuracy. The C5.0 model includes decision rules for prediction. It can be used to explain the reasons for specific predictions.

Experiences with developing and implementing a virtual clinic for glaucoma care in an NHS setting.

PubMed

Kotecha, Aachal; Baldwin, Alex; Brookes, John; Foster, Paul J

2015-01-01

This article describes the development of a virtual glaucoma clinic, whereby technicians collect information for remote review by a consultant specialist. This was a hospital-based service evaluation study. Patients suitable for the stable monitoring service (SMS) were low-risk patients with "suspect", "early"-to-"moderate" glaucoma who were deemed stable by their consultant care team. Three technicians and one health care assistant ran the service. Patients underwent tests in a streamlined manner in a dedicated clinical facility, with virtual review of data by a consultant specialist through an electronic patient record. Feasibility of developing a novel service within a UK National Health Service setting and improvement of patient journey time within the service were studied. Challenges to implementation of virtual clinic include staffing issues and use of information technology. Patient journey time within the SMS averaged 51 minutes, compared with 92 minutes in the glaucoma outpatient department. Patient satisfaction with the new service was high. Implementing innovation into existing services of the National Health Service is challenging. However, the virtual clinic showed an improved patient journey time compared with that experienced within the general glaucoma outpatient department. There exists a discrepancy between patient management decisions of reviewers, suggesting that some may be more risk averse than others when managing patients seen within this model. Future work will assess the ability to detect progression of disease in this model compared with the general outpatient model of care.

Effect of Cu content on exfoliation corrosion and electrochemical corrosion of A7N01 aluminum alloy in EXCO solution

NASA Astrophysics Data System (ADS)

He, Yaling; Wang, Xiaomin; Hu, Jie; Zhou, Qiang; Chen, Hui

2017-07-01

The exfoliation corrosion (EXCO) sensitivities and electrochemical corrosions of A7N01 aluminum (Al) alloys with 0.074% and 0.136% Cu contents were investigated in EXCO solution. The exfoliation corrosion developed more rapidly for the alloy with 0.136% Cu by expressing higher exfoliation rate and deeper corrosion pits as observed by SEM and laser confocal scanning microscopy (LCSM). In EXCO solution, the alloy with 0.136% Cu content showed lower open-circuit potential (OCP) than the alloy with 0.074% Cu content. The alloy with 0.136% Cu content had bigger “hysteresis loop” in cyclic polarization curve which meant lower self-passivation ability. In electrochemical impedance spectroscopy plot, its curvature radius and capacitance index were lower. The electrochemical test results revealed that the alloy with 0.136% Cu content showed more severe electrochemical corrosion than the alloy with 0.074% Cu content, consistent with the exfoliation corrosion results. The microstructures of two alloys were observed through optical microscopy (OM) and transmission electron microscopy (TEM). The continuous distribution of the equilibrium precipitate η-MgZn2 on grain boundaries, the decreasing of the width of precipitate-free zone (PFZ) and the coarse Cu-Fe-Si-rich phase were responsible for the higher corrosion sensitivity of the Al alloy with 0.136% Cu than that of Al alloy with 0.074% Cu content in EXCO solution.

Assessment of contrast gain signature in inferred magnocellular and parvocellular pathways in patients with glaucoma

PubMed Central

Sun, Hao; Swanson, William H.; Arvidson, Brian; Dul, Mitchell W.

2010-01-01

PURPOSE Contrast gain signatures of inferred magnocellular and parvocellular postreceptoral pathways were assessed for patients with glaucoma using a contrast discrimination paradigm developed by Pokorny and Smith. The potential causes for changes in contrast gain signature were investigated using model simulations of ganglion cell contrast responses. METHODS Foveal contrast discrimination thresholds were measured with a pedestal-Δ-pedestal paradigm developed by Pokorny and Smith (1997). Stimuli were 27 msec luminance increments superimposed on 227 msec pulsed Δ-pedestals. Contrast thresholds and contrast gain signatures mediated by the inferred magnocellular (MC) and parvocellular (PC) pathways were assessed using linear fits to contrast discrimination thresholds at either lower or higher Δ-pedestal contrasts, respectively. Twenty-seven patients with glaucoma were tested, as well as 16 age-similar control subjects free of eye disease. RESULTS Contrast sensitivity and contrast gain signature mediated by the inferred MC pathway were lower for the glaucoma group, and reduced contrast gain signature was correlated with reduced contrast sensitivity (r2=45%, p<0.0005). These two parameters mediated by the inferred PC pathway were little affected for the glaucoma group. Model simulations suggest that the reduced contrast sensitivity and contrast gain signature were consistent with the hypothesis that reduced MC ganglion cell dendritic complexity can lead to reduced effective retinal illuminance, and hence increased semi-saturation contrast of the ganglion cell contrast response functions. CONCLUSIONS The contrast sensitivity and contrast gain signature of the inferred MC pathway were reduced in patients with glaucoma. The results were consistent with a model of ganglion cell dysfunction due to reduced synaptic density. PMID:18501947

Considerations for spectroscopy of liquid-exfoliated 2D materials: emerging photoluminescence of N-methyl-2-pyrrolidone.

PubMed

Ogilvie, Sean P; Large, Matthew J; Fratta, Giuseppe; Meloni, Manuela; Canton-Vitoria, Ruben; Tagmatarchis, Nikos; Massuyeau, Florian; Ewels, Christopher P; King, Alice A K; Dalton, Alan B

2017-12-01

N-methyl-2-pyrrolidone (NMP) has been shown to be the most effective solvent for liquid phase exfoliation and dispersion of a range of 2D materials including graphene, molybdenum disulphide (MoS 2 ) and black phosphorus. However, NMP is also known to be susceptible to sonochemical degradation during exfoliation. We report that this degradation gives rise to strong visible photoluminescence of NMP. Sonochemical modification is shown to influence exfoliation of layered materials in NMP and the optical absorbance of the solvent in the dispersion. The emerging optical properties of the degraded solvent present challenges for spectroscopy of nanomaterial dispersions; most notably the possibility of observing solvent photoluminescence in the spectra of 2D materials such as MoS 2 , highlighting the need for stable solvents and exfoliation processes to minimise the influence of solvent degradation on the properties of liquid-exfoliated 2D materials.

Multiplex Cytokine Analysis of Aqueous Humor in Juvenile Idiopathic Arthritis-Associated Anterior Uveitis With or Without Secondary Glaucoma.

PubMed

Bauer, Dirk; Kasper, Maren; Walscheid, Karoline; Koch, Jörg M; Müther, Philipp S; Kirchhof, Bernd; Heiligenhaus, Arnd; Heinz, Carsten

2018-01-01

Patients with juvenile idiopathic arthritis often develop chronic anterior uveitis (JIAU). JIAU patients possess a particularly high risk for developing secondary glaucoma when inflammatory inactivity has been achieved. By using multiplex bead assay analysis, we assessed levels of pro- and anti-inflammatory cytokines, chemokines, or metalloproteinases in the aqueous humor (AH) of patients with clinically inactive JIAU with (JIAUwG) or without secondary glaucoma (JIAUwoG), or from patients with senile cataract as controls. Laser-flare photometry analysis prior to surgery showed no significant differences between JIAUwG or JIAUwoG. Compared with the control group, levels of interleukin-8, matrix metalloproteinase-2, -3, -9, serum amyloid A (SAA), transforming growth factor beta-1, -2, -3 (TGFβ-1, -2, -3), and tumor necrosis factor-alpha in the AH were significantly higher in patients with clinically inactive JIAUwG or JIAUwoG. Samples from JIAwoG patients displayed significantly higher levels of SAA ( P  < 0.0116) than JIAUwG patients. JIAUwG patients showed an increased level of TGFβ-2 in AH samples compared with JIAUwoG ( P  < 0.0009). These molecules may contribute to the clinical development of glaucoma in patients with JIAU.

Using optical coherence tomography to evaluate glaucoma implant healing response in rabbit eyes

NASA Astrophysics Data System (ADS)

Gossage, Kirk W.; Tkaczyk, Tomasz S.; Barton, Jennifer K.

2002-06-01

Glaucoma is a set of diseases that cause optic nerve damage and visual field loss. The most important risk factor for the development of glaucoma is elevated intraocular pressure. One approach used to alleviate the pressure increase is to surgically install glaucoma implants. Two standard Ahmed and ten experimental ePTFE implants were evaluated in this study in rabbit eyes. The implants were imaged with optical coherence tomography (OCT) at 0, 7, 15, 30, and 90 days after implantation. Histology was collected at days 7, 15, 30, and 90 and compared to the OCT images. Preliminary analysis of images indicates that OCT can visualize the development of fibrous encapsulation of the implant, tissue erosion, fibrin accumulation in the implant tube, and tube position in the anterior chamber. A new OCT handheld probe was developed to facilitate in vivo imaging in rabbit eye studies. The OCT probe consists of a mechanical scaffold designed to allow the imaging fiber to be held in a fixed position with respect to the rabbit eye, with minimal anesthesia. A piezo electric lateral scanning device allows the imaging fiber to be scanned across the tissue so that 2D images may be acquired.

Reliable Exfoliation of Large-Area High-Quality Flakes of Graphene and Other Two-Dimensional Materials.

PubMed

Huang, Yuan; Sutter, Eli; Shi, Norman N; Zheng, Jiabao; Yang, Tianzhong; Englund, Dirk; Gao, Hong-Jun; Sutter, Peter

2015-11-24

Mechanical exfoliation has been a key enabler of the exploration of the properties of two-dimensional materials, such as graphene, by providing routine access to high-quality material. The original exfoliation method, which remained largely unchanged during the past decade, provides relatively small flakes with moderate yield. Here, we report a modified approach for exfoliating thin monolayer and few-layer flakes from layered crystals. Our method introduces two process steps that enhance and homogenize the adhesion force between the outermost sheet in contact with a substrate: Prior to exfoliation, ambient adsorbates are effectively removed from the substrate by oxygen plasma cleaning, and an additional heat treatment maximizes the uniform contact area at the interface between the source crystal and the substrate. For graphene exfoliation, these simple process steps increased the yield and the area of the transferred flakes by more than 50 times compared to the established exfoliation methods. Raman and AFM characterization shows that the graphene flakes are of similar high quality as those obtained in previous reports. Graphene field-effect devices were fabricated and measured with back-gating and solution top-gating, yielding mobilities of ∼4000 and 12,000 cm(2)/(V s), respectively, and thus demonstrating excellent electrical properties. Experiments with other layered crystals, e.g., a bismuth strontium calcium copper oxide (BSCCO) superconductor, show enhancements in exfoliation yield and flake area similar to those for graphene, suggesting that our modified exfoliation method provides an effective way for producing large area, high-quality flakes of a wide range of 2D materials.

Solar Exposure and Residential Geographic History in Relation to Exfoliation Syndrome in the United States and Israel

PubMed Central

Pasquale, Louis R.; Jiwani, Aliya Z.; Zehavi-Dorin, Tzukit; Majd, Arow; Rhee, Douglas J.; Chen, Teresa; Turalba, Angela; Shen, Lucy; Brauner, Stacey; Grosskreutz, Cynthia; Gardiner, Matthew; Chen, Sherleen; Borboli-Gerogiannis, Sheila; Greenstein, Scott H.; Chang, Kenneth; Ritch, Robert; Loomis, Stephanie; Kang, Jae H.; Wiggs, Janey L.; Levkovitch-Verbin, Hani

2014-01-01

Importance Residential (geographic) history and extent of solar exposure may be important risk factors for exfoliation syndrome, but detailed lifetime solar exposure has not been previously evaluated in exfoliation syndrome. Objective To assess the relation between residential history, solar exposure and exfoliation syndrome. Design Clinic-based, case control studies. Setting A clinical center in the United States and in Israel. Participants Exfoliation syndrome cases and controls (all 60+ years old Caucasians) enrolled from 2010 to 2012 (United States: 118 cases and 106 controls; Israel: 67 cases and 72 controls). Main Outcomes and Measures Weighted lifetime average latitude of residence and average number of hours per week spent outdoors as determined by validated questionnaires. Results In multivariable analyses, each degree of weighted lifetime average residential latitude away from the equator was associated with an 11% increased odds of exfoliation syndrome (pooled odds ratio = 1.11; 95% CI: 1.05-1.17; p < .001). Furthermore, every hour per week spent outdoors during the summer, averaged over a lifetime, was associated with a 4% increased odds of exfoliation syndrome (pooled odds ratio = 1.04; 95% CI: 1.00-1.07; p = .03). For every 1% of average lifetime summer time between 10 a.m. and 4 p.m. that sunglasses were worn, the odds of exfoliation syndrome decreased by 2% (odds ratio = 0.98; 95% CI: 0.97-0.99; p < .001) in the United States, but not in Israel (odds ratio = 1.00; 95% CI: 0.99-1.01; p = .92; p for heterogeneity = .005). In the United States, after controlling for important environmental covariates, history of work over water or snow was associated with increased odds of exfoliation syndrome (odds ratio = 3.86; 95% CI: 1.36-10.9); in Israel, there were too few people with such history for analysis. We did not identify an association between brimmed hat wear and exfoliation syndrome (p>.57). Conclusion and Relevance Lifetime outdoor activities may contribute to exfoliation syndrome. The association with work over snow or water and the lack of association with brimmed hat wear suggests that ocular exposure to light from reflective surfaces may be an important type of exposure in exfoliation syndrome etiology. PMID:25188364

Retinal Adaptation Abnormalities in Primary Open-Angle Glaucoma

PubMed Central

Dul, Mitchell; Ennis, Robert; Radner, Shira; Lee, Barry; Zaidi, Qasim

2015-01-01

Purpose. Dynamic color and brightness adaptation are crucial for visual functioning. The effects of glaucoma on retinal ganglion cells (RGCs) could compromise these functions. We have previously used slow dynamic changes of light at moderate intensities to measure the speed and magnitude of subtractive adaptation in RGCs. We used the same procedure to test if RGC abnormalities cause slower and weaker adaptation for patients with glaucoma when compared to age-similar controls. We assessed adaptation deficits in specific classes of RGCs by testing along the three cardinal color axes that isolate konio, parvo, and magno RGCs. Methods. For one eye each of 10 primary open-angle glaucoma patients and their age-similar controls, we measured the speed and magnitude of adapting to 1/32 Hz color modulations along the three cardinal axes, at central fixation and 8° superior, inferior, nasal, and temporal to fixation. Results. In all 15 comparisons (5 locations × 3 color axes), average adaptation was slower and weaker for glaucoma patients than for controls. Adaptation developed slower at central targets than at 8° eccentricities for controls, but not for patients. Adaptation speed and magnitude differed between affected and control eyes even at retinal locations showing no visual field loss with clinical perimetry. Conclusions. Neural adaptation is weaker in glaucoma patients for all three classes of RGCs. Since adaptation abnormalities are manifested even at retinal locations not exhibiting a visual field loss, this novel form of assessment may offer a functional insight into glaucoma and an early diagnosis tool. PMID:25613950

The prevalence of glaucoma in patients undergoing surgery for eyelid entropion or ectropion

PubMed Central

Golan, Shani; Rabina, Gilad; Kurtz, Shimon; Leibovitch, Igal

2016-01-01

Purpose and design The aim of this study was to establish the prevalence of known glaucoma in patients undergoing ectropion or entropion surgical repair. In this study, retrospective review of case series was performed. Participants All patients who underwent ectropion or entropion surgery in a tertiary medical center between 2007 and 2014 were included. The etiology of eyelid malpositioning was involutional or cicatricial. Methods The medical files of the study participants were reviewed for the presence and type of glaucoma, medical treatment, duration of treatment, and the amount of drops per day. These data were compared to a matched control group of 101 patients who underwent blepharoplasty for dermatochalasis in the same department during the same period. Main outcome measure In this study, the prevalence of glaucoma in individuals with ectropion or entropion was the main outcome measure. Results A total of 227 patients (57% men, mean age: 79.2 years) who underwent ectropion or entropion surgery comprised the study group and 101 patients who underwent upper blepharoplasty for dermatochalasis comprised the control group. Compared to four patients in the control group (4%, P=0.01), 30 of the study patients (13.2%) had coexisting glaucoma. Of 30 glaucomatous patients, 25 had primary open-angle glaucoma for a mean duration of 10.3 years. The glaucomatous patients were treated with an average of 2.7 antiglaucoma medications. Conclusion An increased prevalence of known glaucoma in patients undergoing ectropion or entropion repair surgery was found. This observation may indicate that the chronic usage of topical anti-glaucoma eyedrops may lead to an increased risk of developing eyelid malpositions, especially in elderly patients. PMID:27785003

A Diagnostic Calculator for Detecting Glaucoma on the Basis of Retinal Nerve Fiber Layer, Optic Disc, and Retinal Ganglion Cell Analysis by Optical Coherence Tomography.

PubMed

Larrosa, José Manuel; Moreno-Montañés, Javier; Martinez-de-la-Casa, José María; Polo, Vicente; Velázquez-Villoria, Álvaro; Berrozpe, Clara; García-Granero, Marta

2015-10-01

The purpose of this study was to develop and validate a multivariate predictive model to detect glaucoma by using a combination of retinal nerve fiber layer (RNFL), retinal ganglion cell-inner plexiform (GCIPL), and optic disc parameters measured using spectral-domain optical coherence tomography (OCT). Five hundred eyes from 500 participants and 187 eyes of another 187 participants were included in the study and validation groups, respectively. Patients with glaucoma were classified in five groups based on visual field damage. Sensitivity and specificity of all glaucoma OCT parameters were analyzed. Receiver operating characteristic curves (ROC) and areas under the ROC (AUC) were compared. Three predictive multivariate models (quantitative, qualitative, and combined) that used a combination of the best OCT parameters were constructed. A diagnostic calculator was created using the combined multivariate model. The best AUC parameters were: inferior RNFL, average RNFL, vertical cup/disc ratio, minimal GCIPL, and inferior-temporal GCIPL. Comparisons among the parameters did not show that the GCIPL parameters were better than those of the RNFL in early and advanced glaucoma. The highest AUC was in the combined predictive model (0.937; 95% confidence interval, 0.911-0.957) and was significantly (P = 0.0001) higher than the other isolated parameters considered in early and advanced glaucoma. The validation group displayed similar results to those of the study group. Best GCIPL, RNFL, and optic disc parameters showed a similar ability to detect glaucoma. The combined predictive formula improved the glaucoma detection compared to the best isolated parameters evaluated. The diagnostic calculator obtained good classification from participants in both the study and validation groups.

Population and High-Risk Group Screening for Glaucoma: The Los Angeles Latino Eye Study

PubMed Central

Francis, Brian A.; Vigen, Cheryl; Lai, Mei-Ying; Winarko, Jonathan; Nguyen, Betsy; Azen, Stanley

2011-01-01

Purpose. To evaluate the ability of various screening tests, both individually and in combination, to detect glaucoma in the general Latino population and high-risk subgroups. Methods. The Los Angeles Latino Eye Study is a population-based study of eye disease in Latinos 40 years of age and older. Participants (n = 6082) underwent Humphrey visual field testing (HVF), frequency doubling technology (FDT) perimetry, measurement of intraocular pressure (IOP) and central corneal thickness (CCT), and independent assessment of optic nerve vertical cup disc (C/D) ratio. Screening parameters were evaluated for three definitions of glaucoma based on optic disc, visual field, and a combination of both. Analyses were also conducted for high-risk subgroups (family history of glaucoma, diabetes mellitus, and age ≥65 years). Sensitivity, specificity, and receiver operating characteristic curves were calculated for those continuous parameters independently associated with glaucoma. Classification and regression tree (CART) analysis was used to develop a multivariate algorithm for glaucoma screening. Results. Preset cutoffs for screening parameters yielded a generally poor balance of sensitivity and specificity (sensitivity/specificity for IOP ≥21 mm Hg and C/D ≥0.8 was 0.24/0.97 and 0.60/0.98, respectively). Assessment of high-risk subgroups did not improve the sensitivity/specificity of individual screening parameters. A CART analysis using multiple screening parameters—C/D, HVF, and IOP—substantially improved the balance of sensitivity and specificity (sensitivity/specificity 0.92/0.92). Conclusions. No single screening parameter is useful for glaucoma screening. However, a combination of vertical C/D ratio, HVF, and IOP provides the best balance of sensitivity/specificity and is likely to provide the highest yield in glaucoma screening programs. PMID:21245400

Graft failure: III. Glaucoma escalation after penetrating keratoplasty.

PubMed

Greenlee, Emily C; Kwon, Young H

2008-06-01

Glaucoma after penetrating keratoplasty is a frequently observed post-operative complication and is a risk factor for graft failure. Penetrating keratoplasty performed for aphakic and pseudophakic bullous keratopathy and inflammatory conditions are more likely to cause postoperative glaucoma compared with keratoconus and Fuchs' endothelial dystrophy. The intraocular pressure elevation may occur immediately after surgery or in the early to late postoperative period. Early postoperative causes of glaucoma include pre-existing glaucoma, retained viscoelastic, hyphema, inflammation, pupillary block, aqueous misdirection, or suprachoroidal hemorrhage. Late causes include pre-existing glaucoma, angle-closure glaucoma, ghost cell glaucoma, suprachoroidal hemorrhage, and steroid-induced glaucoma. Determining the cause of IOP elevation can help guide therapeutic intervention. Treatments for refractory glaucoma include topical anti-glaucoma medications such as beta-adrenergic blockers. Topical carbonic anhydrase inhibitors, miotic agents, adrenergic agonists, and prostaglandin analogs should be used with caution in the post-keratoplasty patient, because of the possibility of corneal decompensation, cystoid macular edema, or persistent inflammation. Various glaucoma surgical treatments have reported success in post-keratoplasty glaucoma. Trabeculectomy with mitomycin C can be successful in controlling IOP without the corneal toxicity noted with 5-fluorouracil. Glaucoma drainage devices have successfully controlled intraocular pressure in postkeratoplasty glaucoma; this is, however, associated with increased risk of graft failure. Placement of the tube through the pars plana may improve graft success compared with implantation within the anterior chamber. In addition, cyclophotocoagulation remains a useful procedure for eyes that have refractory glaucoma despite multiple surgical interventions.

Glaucoma incidence in an unselected cohort of diabetic patients: is diabetes mellitus a risk factor for glaucoma? DARTS/MEMO collaboration. Diabetes Audit and Research in Tayside Study. Medicines Monitoring Unit.

PubMed

Ellis, J D; Evans, J M; Ruta, D A; Baines, P S; Leese, G; MacDonald, T M; Morris, A D

2000-11-01

To evaluate whether diabetes mellitus is a risk factor for the development of primary open angle glaucoma or ocular hypertension (OHT). A historical cohort study of an unselected population comprising all residents of the Tayside region of Scotland was performed using record linkage techniques followed by case note review. Ascertainment of prevalent diabetes was achieved using the Diabetes Audit and Research in Tayside Study (DARTS) validated regional diabetes register. Glaucoma and treated OHT were defined by encashment of community prescriptions and the statutory surgical procedure coding database. The study population comprised 6631 diabetic subjects and 166 144 non-diabetic subjects aged >40 years without glaucoma or OHT at study entry. 65 patients with diabetes and 958 without diabetes were identified as new cases of glaucoma or treated OHT during the 24 month study period, yielding a standardised morbidity ratio of 127 (95% CI, 96-158). Case note review demonstrated non-differential misclassification of prevalent glaucoma and OHT as incident disease (diabetic cohort 20%, non-diabetic cohort 24%; p=0.56) primarily as a result of non-compliance in medically treated disease. Removing misclassified cases and adjusting for age yielded an incidence of primary open angle glaucoma in diabetes of 1.1/1000 patient years (95% CI, 0.89-1. 31) compared to 0.7/1000 patient years (95% CI, 0.54-0.86) in the non-diabetic cohort; RR 1.57 (95% CI, 0.99-2.48). This study failed to confirm an association between diabetes mellitus and primary open angle glaucoma and ocular hypertension. A non-significant increase in diagnosed and treated disease in the diabetic population was observed, but evidence was also found that detection bias contributes to this association.

Biomarkers in primary open angle glaucoma.

PubMed

Kokotas, Haris; Kroupis, Christos; Chiras, Dimitrios; Grigoriadou, Maria; Lamnissou, Klea; Petersen, Michael B; Kitsos, George

2012-12-01

Glaucoma, a leading cause of blindness worldwide, is currently defined as a disturbance of the structural or functional integrity of the optic nerve that causes characteristic atrophic changes in the optic nerve, which may lead to specific visual field defects over time. This disturbance usually can be arrested or diminished by adequate lowering of intraocular pressure (IOP). Glaucoma can be divided roughly into two main categories, ‘ open angle ’ and ‘ closed angle ’ glaucoma.Open angle, chronic glaucoma tends to progress at a slower rate and patients may not notice loss of vision until the disease has progressed significantly. Primary open angle glaucoma(POAG) is described distinctly as a multifactorial optic neuropathy that is chronic and progressive with a characteristic acquired loss of optic nerve fibers. Such loss develops in the presence of open anterior chamber angles, characteristic visual field abnormalities, and IOP that is too high for the healthy eye. It manifests by cupping and atrophy of the optic disc, in the absence of other known causes of glaucomatous disease. Several biological markers have been implicated with the disease. The purpose of this study was to summarize the current knowledge regarding the non-genetic molecular markers which have been predicted to have an association with POAG but have not yet been validated.

Hybrid dendrimer hydrogel/poly(lactic-co-glycolic acid) nanoparticle platform: an advanced vehicle for topical delivery of antiglaucoma drugs and a likely solution to improving compliance and adherence in glaucoma management.

PubMed

Yang, Hu; Leffler, Christopher T

2013-03-01

Glaucoma therapy typically begins with topical medications, of which there are 4 major classes in common use in the United States: beta-adrenergic antagonists, alpha-agonists, carbonic anhydrase inhibitors, and prostaglandin analogs. Unfortunately, all 4 classes require at least daily dosing, and 3 of the 4 classes are approved to be administered 2 or 3 times daily. This need for frequent dosing with multiple medications makes compliance difficult. Longer-acting formulations and combinations that require less frequent administration might improve compliance and therefore medication effectiveness. Recently, we developed an ocular drug delivery system, a hybrid dendrimer hydrogel/poly(lactic-co-glycolic acid) nanoparticle platform for delivering glaucoma therapeutics topically. This platform is designed to deliver glaucoma drugs to the eye efficiently and release the drug in a slow fashion. Furthermore, this delivery platform is designed to be compatible with many of the glaucoma drugs that are currently approved for use. In this article, we review this new delivery system with in-depth discussion of its structural features, properties, and preclinical application in glaucoma treatment. In addition, future directions and translational efforts for marketing this technology are elaborated.

Acetazolamide-related life-threatening hypophosphatemia in a glaucoma patient.

PubMed

Hu, Ching-Yun; Lee, Bor-Jen; Cheng, Hsiang-Fan; Wang, Chen-Yu

2015-01-01

Acetazolamide-related hypophosphatemia leading to cardiac arrest is extremely rare. Herein we report a 78-year-old female glaucoma patient who developed general weakness and acute respiratory failure, followed by cardiac arrest 1 day after taking acetazolamide. The patient was successfully weaned from the ventilator after correction of hypophosphatemia and fully recovered. As acetazolamide was shown to have the potential to cause a lethal side effect in stable glaucoma, the risk of hypophosphatemia should be kept in mind by ophthalmologists. An examination of serum metabolic panels may be indicated in patients at risk of hypophosphatemia.

Unilateral Angle-Closure Glaucoma with Ciliochoroidal Effusion after the Consumption of Cannabis: A Case Report

PubMed Central

Hanna, Rana; Tiosano, Beatrice; Dbayat, Noora; Gaton, Dan

2014-01-01

A 35-year-old male patient, diagnosed with acute angle-closure glaucoma, did not improve despite intensive treatment with antiglaucoma medications. Ultrasound biomicroscopy revealed a ciliochoroidal effusion. Due to his past history of drug abuse, a urine test was analyzed and found to be positive for cannabis. After topical cycloplegia and oral steroid therapy, his symptoms improved substantially. The present case highlights the role of ultrasound biomicroscopy in evaluating patients with acute angle-closure glaucoma and the role of cannabis abuse in the development of ciliochoroidal effusion. PMID:25606036

Barriers to glaucoma case finding as perceived by optometrists in Ireland.

PubMed

Barrett, Catriona; O'Brien, Colm; Butler, John S; Loughman, James

2018-01-01

This research was designed to provide an in-depth exploration of the perceptions of optometrists relating to the challenges of glaucoma case finding in the Irish health-care system. A survey was developed, piloted and distributed for anonymous completion by optometrists registered to practise in Ireland. The survey included 10 five-level Likert items exploring potential barriers to glaucoma detection and a free-text box for participants to comment more broadly. One hundred and ninety-nine optometrists (27 per cent of registrants) responded to the survey. Among the barriers identified, there was notable agreement (71 per cent) with the need for extra training on glaucoma detection. Logistic regression showed that optometrists without postgraduate qualifications were more likely to agree with the need for extra training (OR 3.2, 95 per cent CI 1.3-8.1). Respondents largely agreed (61 per cent) that patient unwillingness to pay additional fees for supplementary glaucoma-specific tests was also a barrier. Appointment times of less than 30 minutes were significantly associated with six of the 10 proposed barriers to glaucoma detection. A logistic regression analysis (n = 179) confirmed that the time allotted per appointment was a significant predictor of the agreement time of optometrists as a barrier (χ 2 [1] = 13.52, p < 0.001). Multiple linear regression showed that optometrists with less experience, charging lower fees, and working in large multiples or franchised practices have the shortest appointment times. The strong link found between postgraduate education and the confidence of optometrists in detecting glaucoma indicates that optometrists wishing to increase their scope of practice in the new legislative environment in Ireland may more actively seek training in areas of interest. The responses also indicate a lack of funding for the level of diagnostic testing required for accurate glaucoma diagnosis. Recent increases in the state's eye examination fees look likely to address the identified time and financial barriers to glaucoma detection in Ireland. Future work should look to analyse the effects of increased funding on optometric case finding for glaucoma. © 2017 Optometry Australia.

Detection of early changes in lung-cell cytology by flow-systems analysis techniques. Progress report, January 1--June 30, 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinkamp, J. A.; Hansen, K. M.; Wilson, J. S.

1976-08-01

This report summarizes results of preliminary experiments to develop cytological and biochemical indicators for estimating damage to respiratory epithelium exposed to toxic agents associated with the by-products of nonnuclear energy production using advanced flow-systems cell-analysis technologies. Since initiation of the program one year ago, progress has been made in obtaining adequate numbers of exfoliated lung cells from the Syrian hamster for flow analysis; cytological techniques developed on human exfoliated gynecological samples have been adapted to hamster lung epithelium for obtaining single-cell suspensions; and lung-cell samples have been initially characterized based on DNA content, total protein, nuclear and cytoplasmic size, andmore » multiangle light-scatter measurements. Preliminary results from measurements of the above parameters which recently became available are described in this report. As the flow-systems technology is adapted further to analysis of exfoliated lung cells, measurements of changes in physical and biochemical cellular properties as a function of exposure to toxic agents will be performed.« less

Characterization of the deformation and thermal behavior of granitic exfoliation sheets with LiDAR and infrared thermography (Yosemite Valley, USA)

NASA Astrophysics Data System (ADS)

Guerin, Antoine; Derron, Marc-Henri; Jaboyedoff, Michel; Collins, Brian D.; Stock, Greg M.

2017-04-01

Yosemite Valley is a long (11 km) and deep ( 1 km) glacier-carved valley, bounded by steep granitic cliffs cutting the western slope of the central Sierra Nevada mountain range (California, USA). These cliffs produce numerous rockfalls every year (925 events reported between 1857 and 2011) and this rockfall activity is often linked to the presence of sheeting joints (Stock et al., 2013), also called exfoliation joints, formed in response to stress changes associated with changes in the topography (Martel, 2011). Furthermore, the historical rockfall inventory indicates that many events occurred without recognized triggers (Austin et al., 2014), in summer time, and on sunny days in particular. This suggests that thermal stress changes are involved in triggering of rockfalls (Collins and Stock, 2016). To further characterize the relationship between thermal stresses and rock face deformation, we carried out three experiments in Yosemite Valley during October 2015: (i) monitoring of a sub-vertical granodiorite exfoliation sheet on the Rhombus Wall for 24 consecutive hours (from 8:00 p.m. to 8:00 p.m.) using terrestrial LiDAR, crackmeters and infrared thermal sensors; (ii) monitoring the El Capitan rockwall composed of tens of exfoliation sheets for 8 consecutive hours (from 5:30 p.m. to 1:30 a.m.) with terrestrial LiDAR and thermal imaging; (iii) collecting several sequences of thermal GigaPan panoramas during periods of rock cooling on both cliffs (Rhombus Wall and El Capitan). In parallel to these experiments, we also developed a method for calibrating and correcting the raw apparent temperature measured by our thermal imager (a FLIR T660 infrared camera) from thermoresistances, reflective and black papers and by using some information given by the LiDAR point clouds (range, dip and dip direction). LiDAR monitoring of experiments (i) and (ii) allowed us to detect millimetric deformations for the exfoliations sheets whose crack aperture is persistent, deep and greater than 9 cm, confirming the results of Collins and Stock (2016). Then, the LiDAR - infrared thermography coupling allowed us to establish a link between the contraction - expansion cycles observed and daily thermal variations: the cycles of contraction (crack closure) occur between 3:00 p.m. and 8:00 a.m. and are associated with cooling, whereas the opposite is true for the expansion cycles (crack opening). In addition, in the case of experiment (i), we observe a delay of about 40 minutes between the time when surface temperatures are minimum and the maximum closure of the crack (-5.33 +/- 0.01 mm), which occurs a little before 8:00 a.m. Concerning the thermal behavior of the exfoliation sheets, the experiments (i) and (ii) show that the exfoliation sheets are almost always colder than surrounding stable areas, except during the hottest hours of the day when the temperatures are similar. At the end of the night, the temperature deviation between an exfoliation sheet and a stable part can reach 5 to 6 Celsius degrees (values valid for October) and this thermal contrast makes it possible to remotely detect the presence of exfoliation sheets in a rockwall. This result was then confirmed by the experiment (iii) which shows that a whole series of exfoliation sheets could be detected at a distance of 1 km, by means of thermal comparisons. Coupled to the LiDAR, infrared thermography can thus be useful for drawing a 3D map of exfoliation sheets in a cliff of several hundred meters high.

Glaucoma diagnostics.

PubMed

Geimer, Sabina Andersson

2013-02-01

This thesis addresses several aspects of glaucoma diagnostics from both a clinical and a screening perspective. New instruments for diagnosing glaucoma have been developed over the past years, but little information is available regarding their performance as screening methods and their usefulness in ordinary clinical practice. PURPOSE OF THE RESEARCH UNDERLYING THIS THESIS:  The objectives of this research were as follows: to compare the accuracy of results of analysis of the optic nerve head (ONH) achieved by computerized imaging using the Heidelberg Retina Tomograph (HRT) and by subjective assessment performed by physicians with different degrees of experience of glaucoma (paper III); to evaluate the effect of a continuous medical education (CME) lecture on subjective assessment of the ONH for diagnosis of glaucoma (paper II); to investigate subjective assessment of perimetric test results by physicians with varying knowledge of glaucoma with a trained artificial neural network (ANN) and to compare the certainty of the classifications (paper IV); and to compare the diagnostic performance of time-domain Stratus optical coherence tomography (OCT) with that of spectral-domain Cirrus OCT (paper I), frequency doubling technology (FDT) screening perimetry and scanning laser polarimetry with the GDx variable corneal compensator (VCC) in a random population-based sample and in patients with glaucoma of varying disease severity.   In evaluation of the ONH, use of the HRT statistical tools, Moorfields regression analysis (MRA) and the Glaucoma Probability Score (GPS) was compared with subjective assessment performed by 45 physicians. Optic nerve head images and photographs from 138 healthy and 97 glaucoma subjects were included. The sensitivity of MRA was higher (87-94%) than that of the average physician (62-82%), considerably greater than that of ophthalmologists with subspecialties other than glaucoma (53-77%) and non-significantly better than that of glaucoma experts (72-88%). Sensitivity achieved by GPS (79-93%) was also greater than that of the average physician. MRA correctly classified all eyes with advanced glaucomatous visual field defects, a result that was not achieved by GPS or even by the glaucoma experts. In eyes with small discs, MRA sensitivity (88%) was comparable with that of glaucoma experts (85%) and much better than that of GPS (50%). Also, the group comprising all physicians provided specificity (75-92%) similar to that of both MRA (69 - 86%) and GPS (72-94%) (Andersson et al. 2011a). A 1-hr CME lecture on ONH assessment led to a significant improvement in sensitivity (from 70% to 80%) and a significant decrease in uncertain assessments (from 22% to 13%), whereas specificity remained unchanged (68%) (Andersson et al. 2011b). A rise in sensitivity was seen in all subgroups of physicians, including glaucoma experts. Thirty physicians assessing standard automated perimetry (SAP) test results as Humphrey Field Analyzer single-field analysis printouts with full StatPac information from 99 patients with glaucoma and 66 healthy subjects were compared with a trained ANN regarding diagnostic performance. ANN reached significantly higher sensitivity (93%) than the average physician (83%), whereas specificity was similar for these two groups (91% and 90%, respectively). Diagnostic accuracy was similar among the different groups of physicians and seemingly rather independent of experience. Sensitivity ranged from 82% in the subgroup of other subspecialists to 87% in the glaucoma expert group, and specificity ranged from 88% among general ophthalmologists to 91% for glaucoma experts. The ANN attained certainty of classification that was in parity with that provided by the glaucoma experts and did not make any completely incorrect classifications of the visual fields (i.e. erroneous classifications were in the borderline zone) (Andersson et al. 2012). From a population-based randomly selected sample (n=308) of older subjects (aged ≥ 50 years) living in southern Sweden, 170 subjects underwent a comprehensive examination that included Stratus OCT, Cirrus OCT, an FDT screening programme and the GDx VCC. The same test protocol was applied to 138 randomized clinical patients with different stages of glaucoma. In the population-based sample, both Stratus and Cirrus OCT showed high diagnostic accuracy with area under the receiver-operating curve (aROC) values close to 1.0 (Bengtsson et al. 2012). Both OCT instruments correctly classified all of the clinical glaucoma patients with advanced disease. FDT screening showed high sensitivity (91%) but erroneously gave normal test results for some eyes with advanced disease. GDx VCC had lower sensitivity (73-92%) and also led to a large proportion of examinations with an atypical retardation pattern that is known to affect the diagnostic efficiency of this instrument.   The HRT MRA performed better than most physicians and was consistent with the glaucoma experts. These results suggest that MRA can be a valuable tool for diagnosing glaucoma in ordinary practice, particularly when only a few glaucoma experts are available. Even though MRA provided 100% sensitivity in eyes with advanced glaucoma, it probably does not offer sufficient specificity to make it suitable as a screening method. Continuing medical education on ONH analysis had a small, but positive effect on diagnostic accuracy for glaucoma. An ANN trained to classify visual fields seemed to perform at least as well as most of the participating physicians, whose performances were remarkably similar regardless of their level of experience. This indicates that available tools for interpreting SAP findings are helpful in assessments of visual field test results. However, SAP is associated with learning effects (Heijl et al. 1989) that may entail low specificity for untrained subjects, and hence, it is not an ideal screening method for glaucoma. By comparison, the screening test of FDT is rapid and easy, but it is probably less suitable for screening purpose, because some eyes with advanced glaucoma were missed in this investigation. GDx VCC images for a relatively large number of eyes could not be analysed and is thus not appropriate for screening. The OCT instruments offer both high sensitivity and high specificity, and all eyes with advanced disease were correctly classified as glaucomatous in this evaluation. However, these instruments are still expensive and require special operator skills. Additional development to obtain OCT instrument that is more compact, easier to use and less expensive might render such tomography suitable as a screening tool for glaucoma. © 2013 The Author. Acta Ophthalmologica © 2013 Acta Ophthalmologica Scandinavica Foundation.

The Health Of Patients' Eyes (HOPE) Glaucoma study. The effectiveness of a 'glaucoma personal record' for newly diagnosed glaucoma patients: study protocol for a randomised controlled trial.

PubMed

Forbes, Marina; Fairlamb, Helen; Jonker, Leon

2015-08-07

Glaucoma involves progressive optic nerve fibre loss, subsequently leading to irreversible and disabling visual field defects. In Europe, the prevalence of glaucoma is approximately 2.2 % of all people aged over 40 years; this equates to 12 million people. Glaucoma patients require regular lifelong follow-up, contributing to a large financial and resource burden for the National Health Service (NHS) in the UK. This study aims to determine whether providing newly diagnosed glaucoma patients with a personalised client-held eye health summary ('glaucoma personal record'), improves patients' knowledge of their glaucoma condition. A potential long-term benefit could be improved self-management and henceforth a slower rate of deterioration. HOPE Glaucoma is a 3-year, prospective, parallel-group, pragmatic, single-centred, randomised controlled trial. An anticipated 122 adults, newly diagnosed with glaucoma (including ocular hypertension, suspected glaucoma and/or chronic open-angle glaucoma) will be recruited from a nurse-led ophthalmology outpatient clinic at a medium-sized NHS Trust. Participants will be randomly allocated to receive standard clinical care (control arm) or standard care plus a glaucoma personal record, detailing the current state of their condition (interventional arm). Participant assessments are designed to test whether provision of a glaucoma personal record 1) improves patient knowledge of glaucoma and 2) contributes to improvements in clinical outcomes, i.e. delay of visual field loss. The primary outcome measure is better client knowledge of glaucoma at the 9-12 month follow-up visit. Secondary outcome measures include the rate of visual field loss and patient-reported outcome measures on visual function (National Eye Institute VFQ - 25) measured at baseline, 9-12 months, 24 months and 36 months. Estimating a 20 % drop-out rate, the study will have 90 % power to detect a mean two-point difference in glaucoma knowledge score between groups at 5 % significance - based on two-sided Mann-Whitney U test. If a glaucoma personal record is found to significantly improve glaucoma patients' knowledge of their condition, this intervention could potentially provide a low-cost, straightforward tool to educate and engage glaucoma patients. Subsequently, this could have the potential to increase patient self-management and therefore allow glaucoma patients to prolong their sight functionality for longer. ISRCTN41306818 , registered on 22 August 2013.

Quantitative prediction of oral cancer risk in patients with oral leukoplakia.

PubMed

Liu, Yao; Li, Yicheng; Fu, Yue; Liu, Tong; Liu, Xiaoyong; Zhang, Xinyan; Fu, Jie; Guan, Xiaobing; Chen, Tong; Chen, Xiaoxin; Sun, Zheng

2017-07-11

Exfoliative cytology has been widely used for early diagnosis of oral squamous cell carcinoma. We have developed an oral cancer risk index using DNA index value to quantitatively assess cancer risk in patients with oral leukoplakia, but with limited success. In order to improve the performance of the risk index, we collected exfoliative cytology, histopathology, and clinical follow-up data from two independent cohorts of normal, leukoplakia and cancer subjects (training set and validation set). Peaks were defined on the basis of first derivatives with positives, and modern machine learning techniques were utilized to build statistical prediction models on the reconstructed data. Random forest was found to be the best model with high sensitivity (100%) and specificity (99.2%). Using the Peaks-Random Forest model, we constructed an index (OCRI2) as a quantitative measurement of cancer risk. Among 11 leukoplakia patients with an OCRI2 over 0.5, 4 (36.4%) developed cancer during follow-up (23 ± 20 months), whereas 3 (5.3%) of 57 leukoplakia patients with an OCRI2 less than 0.5 developed cancer (32 ± 31 months). OCRI2 is better than other methods in predicting oral squamous cell carcinoma during follow-up. In conclusion, we have developed an exfoliative cytology-based method for quantitative prediction of cancer risk in patients with oral leukoplakia.

Genome-wide analysis of multiethnic cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma

PubMed Central

Vitart, Veronique; Nag, Abhishek; Hewitt, Alex W; Höhn, René; Venturini, Cristina; Mirshahi, Alireza; Ramdas, Wishal D.; Thorleifsson, Gudmar; Vithana, Eranga; Khor, Chiea-Chuen; Stefansson, Arni B; Liao, Jiemin; Haines, Jonathan L; Amin, Najaf; Wang, Ya Xing; Wild, Philipp S; Ozel, Ayse B; Li, Jun Z; Fleck, Brian W; Zeller, Tanja; Staffieri, Sandra E; Teo, Yik-Ying; Cuellar-Partida, Gabriel; Luo, Xiaoyan; Allingham, R Rand; Richards, Julia E; Senft, Andrea; Karssen, Lennart C; Zheng, Yingfeng; Bellenguez, Céline; Xu, Liang; Iglesias, Adriana I; Wilson, James F; Kang, Jae H; van Leeuwen, Elisabeth M; Jonsson, Vesteinn; Thorsteinsdottir, Unnur; Despriet, Dominiek D.G.; Ennis, Sarah; Moroi, Sayoko E; Martin, Nicholas G; Jansonius, Nomdo M; Yazar, Seyhan; Tai, E-Shyong; Amouyel, Philippe; Kirwan, James; van Koolwijk, Leonieke M.E.; Hauser, Michael A; Jonasson, Fridbert; Leo, Paul; Loomis, Stephanie J; Fogarty, Rhys; Rivadeneira, Fernando; Kearns, Lisa; Lackner, Karl J; de Jong, Paulus T.V.M.; Simpson, Claire L; Pennell, Craig E; Oostra, Ben A; Uitterlinden, André G; Saw, Seang-Mei; Lotery, Andrew J; Bailey-Wilson, Joan E; Hofman, Albert; Vingerling, Johannes R; Maubaret, Cécilia; Pfeiffer, Norbert; Wolfs, Roger C.W.; Lemij, Hans G; Young, Terri L; Pasquale, Louis R; Delcourt, Cécile; Spector, Timothy D; Klaver, Caroline C.W.; Small, Kerrin S; Burdon, Kathryn P; Stefansson, Kari; Wong, Tien-Yin; Viswanathan, Ananth; Mackey, David A; Craig, Jamie E; Wiggs, Janey L; van Duijn, Cornelia M; Hammond, Christopher J; Aung, Tin

2014-01-01

Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma and IOP variability may herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multiethnic participants for IOP. We confirm genetic association of known loci for IOP and primary open angle glaucoma (POAG) and identify four new IOP loci located on chromosome 3q25.31 within the FNDC3B gene (p=4.19×10−08 for rs6445055), two on chromosome 9 (p=2.80×10−11 for rs2472493 near ABCA1 and p=6.39×10−11 for rs8176693 within ABO) and one on chromosome 11p11.2 (best p=1.04×10−11 for rs747782). Separate meta-analyses of four independent POAG cohorts, totaling 4,284 cases and 95,560 controls, show that three of these IOP loci are also associated with POAG. PMID:25173106

How to get between the sheets: a review of recent works on the electrochemical exfoliation of graphene materials from bulk graphite

NASA Astrophysics Data System (ADS)

Abdelkader, A. M.; Cooper, A. J.; Dryfe, R. A. W.; Kinloch, I. A.

2015-04-01

Since the beginning of the `graphene era' post-2004, there has been significant interest in developing a high purity, high yield, and scalable fabrication route toward graphene materials for both primary research purposes and industrial production. One suitable approach to graphene production lies in the realm of electrochemical exfoliation, in which a potential difference is applied between a graphite anode/cathode in the presence of an electrolyte-containing medium. Herein we review various works on the electrochemical fabrication of graphene materials specifically through the use of electrochemical intercalation and exfoliation of a graphite source electrode, focusing on the quality and purity of products formed. We categorise the most significant works in terms of anodic and cathodic control, highlighting the merits of the respective approaches, as well as indicating the challenges associated with both procedures.

Overview of the [corrected] travoprost /timolol BAK-free fixed combination.

PubMed

Konstas, Anastasios G P; Quaranta, Luciano; Realini, Tony

2012-04-01

Glaucoma is the second leading cause of blindness globally, representing a significant public health concern. More than 60 million people are affected by glaucoma worldwide; as this population ages, the number is expected to increase. Glaucoma is a collection of heterogeneous diseases sharing common clinical characteristics. The goal of treatment is to prevent significant visual dysfunction through reduction of intraocular pressure (IOP). This is a review of the current literature about combination therapeutic regimens for the reduction of IOP, focusing on the risk : benefit profile of a fixed-combination therapy using travoprost and timolol. Since the debut of prostaglandin analogues in the 1990s, only modest innovation has occurred in glaucoma pharmacology. A growing body of research has established that the preservative benzalkonium chloride (BAK) might not be the benign contributor expected of excipient ingredients. Thus, BAK-free treatments were developed, with the goal of IOP reduction without furthering ocular surface disease symptoms. The BAK-free travoprost/timolol combination represents an important addition to glaucoma medication options and may fill an unmet need in this therapeutic arena.

Palladium-103 plaque radiation therapy for ciliary body melanoma through a functioning glaucoma filtering bleb.

PubMed

Pathan, Arif H K; Barash, Alexander; Tena, Lawrence B; Finger, Paul T

2018-01-01

To provide a clinical description of the long-term outcome of a 103 Pd plaque-irradiated ciliary body melanoma with extrascleral extension while attempting to preserve a subadjacent glaucoma filtering bleb. A 75-year-old woman with pseudoexfoliative glaucoma for 17 years, 16 years status post argon laser trabeculoplasty, and 15 years status post trabeculectomy in the left eye, was diagnosed with an ipsilateral ciliary body melanoma with visible extrascleral extension. Treatment involved insertion of a 103 Pd radioactive plaque over the functioning trabeculectomy, with removal 7 days later. At plaque insertion, amniotic membrane grafts were used to cover the plaque and protect the filtering site. The tumor was successfully treated without clinical evidence of harm to the filtering bleb, with resultant stable intraocular pressure. However, the patient developed blebitis 1.5 years later. Though it resolved with topical antibiotic therapy, the bleb became less succulent. Two years postoperatively, she developed a spontaneous hyphema that resolved after one injection of transscleral bevacizumab 1.25 mg. Her tumor continually regressed in thickness. Without additional glaucoma surgery, her intraocular pressure remained well-controlled on topical medications for 6 years. Ciliary body melanoma with minimal extrascleral extension beneath a functioning filtering bleb can be treated using radioactive plaque therapy. In this case, we were able to achieve both tumor regression and glaucoma control by covering the plaque with an amniotic membrane graft.

Levels of Antibodies against Human Heat Shock Protein (HSP) 60 in Patients with Glaucoma in Poland

PubMed Central

Grabska-Liberek, Iwona; Skonieczna, Katarzyna; Olesińska, Marzena; Terelak-Borys, Barbara; Kocięcki, Jarosandlstrokaw; Sikora, Mariusz; Jamrozy-Witkowska, Agnieszka; Tesla, Piotr; Czarnocka, Barbara

2015-01-01

Background Although elevated intraocular pressure is a major risk factor for the development of glaucoma, there is increasing evidence that the immune system may be involved in the development of normal-tension glaucoma (NTG). The aim of this study was to determine if NTG is associated with elevated levels of antibodies against human heat shock protein (HSP) 60. Material/Methods The study was conducted in 139 subjects (35 subjects with NTG [Group 1], 34 subjects with primary open-angle glaucoma/POAG/[Group 2], 24 subjects with autoimmune rheumatic diseases [Group 3], and 36 healthy controls [Group 4]). All subjects had complete ophthalmologic examination (visual acuity, slit-lamp examination, tonometry, gonioscopy; visual-field examination, and optical coherence tomography/OCT/of the optic nerve head and the macula). Blood samples were collected for the measurements of serum levels of antibodies against human HSP60. Results The subjects with rheumatic diseases had the highest median serum level of antibodies against HSP60 – 20.49 ng/mL. The values in the subjects with NTG, POAG, and in controls were 18.79 ng/mL, 18.61 ng/mL and 17.61 ng/mL, respectively (p=0.96). Conclusions This study does not confirm the hypothesis that normal-tension glaucoma is associated with elevated blood levels of antibodies against human heat shock protein (HSP) 60. PMID:25786333

A new glaucoma hypothesis: a role of glymphatic system dysfunction.

PubMed

Wostyn, Peter; Van Dam, Debby; Audenaert, Kurt; Killer, Hanspeter Esriel; De Deyn, Peter Paul; De Groot, Veva

2015-06-29

In a recent review article titled "A new look at cerebrospinal fluid circulation", Brinker et al. comprehensively described novel insights from molecular and cellular biology as well as neuroimaging research, which indicate that cerebrospinal fluid (CSF) physiology is much more complex than previously believed. The glymphatic system is a recently defined brain-wide paravascular pathway for CSF and interstitial fluid exchange that facilitates efficient clearance of interstitial solutes, including amyloid-β, from the brain. Although further studies are needed to substantiate the functional significance of the glymphatic concept, one implication is that glymphatic pathway dysfunction may contribute to the deficient amyloid-β clearance in Alzheimer's disease. In this paper, we review several lines of evidence suggesting that the glymphatic system may also have potential clinical relevance for the understanding of glaucoma. As a clinically acceptable MRI-based approach to evaluate glymphatic pathway function in humans has recently been developed, a unique opportunity now exists to investigate whether suppression of the glymphatic system contributes to the development of glaucoma. The observation of a dysfunctional glymphatic system in patients with glaucoma would provide support for the hypothesis recently proposed by our group that CSF circulatory dysfunction may play a contributory role in the pathogenesis of glaucomatous damage. This would suggest a new hypothesis for glaucoma, which, just like Alzheimer's disease, might be considered then as an imbalance between production and clearance of neurotoxins, including amyloid-β.

Development of photopolymerizable clay nanocomposites utilizing reactive dispersants

NASA Astrophysics Data System (ADS)

Owusu-Adom, Kwame

Nanocomposites hold tremendous promise for expanding the utility of polymeric materials. However, accessing particulate sizes in the nanoscale domain continues to be a scientific challenge, especially in highly cross-linked photopolymerizable systems. In this study, photopolymerizable nanocomposites utilizing clay nanoparticles and reactive dispersants have been developed. The influence of particle size, dispersant-clay interactions, and surfactant concentration on photopolymerization behavior and nanoparticle dispersion has been elucidated. Clay particles serve as templates upon which surfactants aggregate during photopolymerization. This results in higher photopolymerization rates with addition of increasing concentrations of polymerizable surfactants. Furthermore, polymerizable surfactants induce faster photopolymerization rates compared to non-polymerizable analogues in systems that have ionically-bound dispersants on the particle surface. Utilizing reactive organoclays induces significant changes to the photopolymerization behavior depending on the choice of reactive functionality employed. Faster acrylate photopolymerization rates occur in photopolymer systems containing thiol-modified clays, while much slower rates occur for nonpolymerizable organoclay systems. In addition, chemical compatibility between monomer and clay dispersant (based on chemical similarity or polarity) allows enhancement of exfoliation in photopolymerizable formulations. With polymerizable dispersants, exfoliation is readily achieved in various multifunctional acrylate systems. The degree of exfoliation depends on the position of the reactive group relative to the surfactant's cationic site and the type of functionality. Thiolated organoclays exfoliate during polymerization, while methacrylated clays show substantially less dependence on polymerization behavior. Interestingly, changes in the physical properties of the resulting nanocomposite are independent of the degree of exfoliation in polymerizable organoclay systems. The polymer cross-link density dictates the magnitude of change in both modulus and glass transition temperature of the nanocomposite. Substantial increases in modulus and Tg occur in elastomeric and low cross-link density polymers, while decreases occur in the modulus and Tg of highly cross-linked polymer networks. Finally, these parameters have formed a basis for developing nanocomposites with higher moduli and lower volumetric shrinkage. The photopolymerization rates of these systems are controllable and increase substantially with addition of polymerizable organoclays. Such properties occur in traditional multifunctional acrylate photopolymer systems as well as new binary thiol-(meth)acrylate and ternary thiol-ene-(meth)acrylate photopolymers.

Apparently spontaneous fracture of a granitic exfoliation dome: observations and monitoring

NASA Astrophysics Data System (ADS)

Collins, B. D.; Stock, G. M.; Eppes, M. C.; Lewis, S. W.; Corbett, S.; Smith, J. B.

2016-12-01

Exfoliation sheet formation has attracted scientific attention for more than two centuries. Although a number of theories have been proposed, firm understanding of the cause of exfoliation has proved elusive, partly because observations of their formation are scarce. The 2014-2016 spontaneous exfoliation of Twain Harte Dome, located in the western foothills of California's Sierra Nevada Mesozoic granitic batholith, provides an unprecedented opportunity to study this phenomenon. Understanding such events can offer direct insight into similar exfoliating environments where spontaneous rock fracturing generates related geohazards such as rock falls. Twain Harte Dome fractured energetically on at least 5 occasions in August and September 2014, with slabs of rock thrust into the air 40 cm in a few seconds time and surficial fracture of rock occurring over a total area of 2,800 m2. Several of these events were witnessed first-hand and recorded by video. Additional (but non-energetic) cracking occurred during August 2015, followed by another energetic fracturing event in June 2016 over a much smaller (16 m2) area that again sent granite slabs airborne. No previous spontaneous exfoliation had been recorded here over the past 90 years and no obvious trigger (e.g., earthquake) occurred prior to the recent events. Using high-resolution topographic and fracture mapping, acoustic emission monitoring, and environmental monitoring, we show that these fracture events are correlated with hot summer periods - an indication that thermal stresses likely have an important role in causing exfoliation. Surface crackmeter, and subsurface borehole extensometer and rock bolt force measurements strengthen this relationship, with stresses and deformations spiking during hot summer afternoons. Our instrumentation data captured one of the exfoliation events and show that cumulative stress and deformation increases may have acted as precursor signals to the apparently spontaneous rock exfoliation.

Glaucoma: Screening Can Save Your Sight!

MedlinePlus

... of this page please turn Javascript on. Feature: Glaucoma Glaucoma: Screening Can Save Your Sight! Past Issues / Fall 2009 Table of Contents People with glaucoma see the world through a tunnel. Glaucoma is ...

Pigment dispersion syndrome: a clinical study.

PubMed Central

Scheie, H G; Cameron, J D

1981-01-01

This study involved a group of 407 patients (799 eyes) with pigment dispersion syndrome gathered from a glaucoma population of 9200 patients. The sex distribution was equal. The majority (65%) of patients were myopic. The incidence of retinal detachment was 6.4%. No patients were black, but 5 were mulatto. Approximately one-quarter of the patients wih pigment dispersion syndrome (31% of the men, 19% of the women) had glaucoma. The average age of onset of glaucoma was 15 years less than in control patients with chronic simple glaucoma. When both eyes were affected by glaucoma, the glaucoma was consistently more severe in the eye with the more heavily pigmented angle. The degree of iris transillumination was found to be of no importance in predicting the presence of glaucoma or the severity of trabecular pigmentation. The pressure in 66% of the eyes with pigmentary glaucoma was controlled medically. A higher percentage of patients with pigmentary glaucoma required surgery than patients in the control group with chronic simple glaucoma. Men with pigmentary glaucoma required surgery at a much earlier age than women with pigmentary glaucoma. PMID:7236571

Glaucoma correlates with increased risk of Parkinson's disease in the elderly: a national-based cohort study in Taiwan.

PubMed

Lai, Shih-Wei; Lin, Cheng-Li; Liao, Kuan-Fu

2017-08-01

Very little is known about the association between glaucoma and Parkinson's disease in the elderly. The objective of this study was to determine whether glaucoma is associated with Parkinson's disease in older people in Taiwan. A retrospective cohort study was conducted to analyze the Taiwan National Health Insurance Program database from 2000 to 2010. We included 4330 subjects aged 65 years or older with newly diagnosed glaucoma as the glaucoma group, and 17,000 randomly selected subjects without a glaucoma diagnosis as the non-glaucoma group. Both groups were matched for sex, age, other comorbidities, and index year of glaucoma diagnosis. The incidence of Parkinson's disease at the end of 2011 was measured. A multivariable Cox proportional hazard regression model was used to measure the hazard ratio and 95% confidence intervals for Parkinson's disease associated with glaucoma. The overall incidence of Parkinson's disease was 1.28-fold higher in the glaucoma group than that in the non-glaucoma group (7.73 vs. 6.02 per 1000 person-years; 95% confidence interval 1.18, 1.40). After controlling for potential confounding factors, the adjusted hazard ratio of Parkinson's disease was 1.23 for the glaucoma group (95% confidence interval 1.05, 1.46), compared with the non-glaucoma group. Older people with glaucoma correlate with a small but statistically significant increase in the risk for Parkinson's disease. Whether glaucoma may be a non-motor feature of Parkinson's disease in older people requires further research to confirm.

Mechanism - based translational pharmacokinetic - pharmacodynamic model to predict intraocular pressure lowering effect of drugs in patients with glaucoma or ocular hypertension.

PubMed

Durairaj, Chandrasekar; Shen, Jie; Cherukury, Madhu

2014-08-01

To develop a mechanism based translational pharmacokinetic-pharmacodynamic (PKPD) model in preclinical species and to predict the intraocular pressure (IOP) following drug treatment in patients with glaucoma or ocular hypertension (OHT). Baseline diurnal IOP of normotensive albino rabbits, beagle dogs and patients with glaucoma or OHT was collected from literature. In addition, diurnal IOP of patients treated with brimonidine or Xalatan® were also obtained from literature. Healthy normotensive New Zealand rabbits were topically treated with a single drop of 0.15% brimonidine tartrate and normotensive beagle dogs were treated with a single drop of Xalatan®. At pre-determined time intervals, IOP was measured and aqueous humor samples were obtained from a satellite group of animals. Population based PKPD modeling was performed to describe the IOP data and the chosen model was extended to predict the IOP in patients. Baseline IOP clearly depicts a distinctive circadian rhythm in rabbits versus human. An aqueous humor dynamics based physiological model was developed to describe the baseline diurnal IOP across species. Model was extended to incorporate the effect of drug administration on baseline IOP in rabbits and dogs. The translational model with substituted human aqueous humor dynamic parameters predicted IOP in patients following drug treatment. A physiology based mechanistic PKPD model was developed to describe the baseline and post-treatment IOP in animals. The preclinical PKPD model was successfully translated to predict IOP in patients with glaucoma or OHT and can be applied in assisting dose and treatment selection and predicting outcome of glaucoma clinical trials.

Experiences with developing and implementing a virtual clinic for glaucoma care in an NHS setting

PubMed Central

Kotecha, Aachal; Baldwin, Alex; Brookes, John; Foster, Paul J

2015-01-01

Background This article describes the development of a virtual glaucoma clinic, whereby technicians collect information for remote review by a consultant specialist. Design and Methods This was a hospital-based service evaluation study. Patients suitable for the stable monitoring service (SMS) were low-risk patients with “suspect”, “early”-to-“moderate” glaucoma who were deemed stable by their consultant care team. Three technicians and one health care assistant ran the service. Patients underwent tests in a streamlined manner in a dedicated clinical facility, with virtual review of data by a consultant specialist through an electronic patient record. Main outcome measure Feasibility of developing a novel service within a UK National Health Service setting and improvement of patient journey time within the service were studied. Results Challenges to implementation of virtual clinic include staffing issues and use of information technology. Patient journey time within the SMS averaged 51 minutes, compared with 92 minutes in the glaucoma outpatient department. Patient satisfaction with the new service was high. Conclusion Implementing innovation into existing services of the National Health Service is challenging. However, the virtual clinic showed an improved patient journey time compared with that experienced within the general glaucoma outpatient department. There exists a discrepancy between patient management decisions of reviewers, suggesting that some may be more risk averse than others when managing patients seen within this model. Future work will assess the ability to detect progression of disease in this model compared with the general outpatient model of care. PMID:26508830

Proposing new indicators for glaucoma healthcare service.

PubMed

Liang, Yuan Bo; Zhang, Ye; Musch, David C; Congdon, Nathan

2017-01-01

Glaucoma is the first leading cause of irreversible blindness worldwide with increasing importance in public health. Indicators of glaucoma care quality as well as efficiency would benefit public health assessments, but are lacking. We propose three such indicators. First, the glaucoma coverage rate (GCR), which is the number of people known to have glaucoma divided by the total number of people with glaucoma as estimated from population-based studies multiplied by 100%. Second, the glaucoma detection rate (GDR), which is number of newly diagnosed glaucoma patients in one year divided by the population in a defined area in millions. Third, the glaucoma follow-up adherence rate (GFAR), calculated as the number of patients with glaucoma who visit eye care provider(s) at least once a year over the total number of patients with glaucoma in given eye care provider(s) in a specific period. Regularly tracking and reporting these three indicators may help to improve the healthcare system performance at national or regional levels.

Assessment of contrast gain signature in inferred magnocellular and parvocellular pathways in patients with glaucoma.

PubMed

Sun, Hao; Swanson, William H; Arvidson, Brian; Dul, Mitchell W

2008-11-01

Contrast gain signatures of inferred magnocellular and parvocellular postreceptoral pathways were assessed for patients with glaucoma using a contrast discrimination paradigm developed by Pokorny and Smith. The potential causes for changes in contrast gain signature were investigated using model simulations of ganglion cell contrast responses. Foveal contrast discrimination thresholds were measured with a pedestal-Delta-pedestal paradigm developed by Pokorny and Smith [Pokorny, J., & Smith, V. C. (1997). Psychophysical signatures associated with magnocellular and parvocellular pathway contrast gain. Journal of the Optical Society of America A, 14(9), 2477-2486]. Stimuli were 27 ms luminance increments superimposed on 227 ms pulsed Delta-pedestals. Contrast thresholds and contrast gain signatures mediated by the inferred magnocellular (MC) and parvocellular (PC) pathways were assessed using linear fits to contrast discrimination thresholds at either lower or higher Delta-pedestal contrasts, respectively. Twenty-seven patients with glaucoma were tested, as well as 16 age-similar control subjects free of eye disease. Contrast sensitivity and contrast gain signature mediated by the inferred MC pathway were lower for the glaucoma group, and reduced contrast gain signature was correlated with reduced contrast sensitivity (r(2)=45%, p<.0005). These two parameters mediated by the inferred PC pathway were little affected for the glaucoma group. Model simulations suggest that the reduced contrast sensitivity and contrast gain signature were consistent with the hypothesis that reduced MC ganglion cell dendritic complexity can lead to reduced effective retinal illuminance, and hence increased semi-saturation contrast of the ganglion cell contrast response functions. The contrast sensitivity and contrast gain signature of the inferred MC pathway were reduced in patients with glaucoma. The results were consistent with a model of ganglion cell dysfunction due to reduced synaptic density.

Acetone improves the topographical homogeneity of liquid phase exfoliated few-layer black phosphorus flakes.

PubMed

Gomez Perez, Juan; Konya, Zoltan; Kukovecz, Akos

2018-06-12

Liquid phase exfoliation of 2D materials has issues related to the sorption of the solvent, the oxidation of the sample during storage, and the topographical inhomogeneity of the exfoliated material. N-methyl-2-pyrrolidone (NMP), a common solvent for black phosphorus (BP) exfoliation, has additional drawbacks like the formation of by-products during sonication and poor solvent volatility. Here we demonstrate an improvement in the topographical homogeneity (i.e. thickness and lateral dimensions) of NMP-exfoliated BP flakes after resuspension in acetone. The typical size of monolayers and bilayers stabilised in acetone was 99.8±27.4 nm and 159.1±57 nm, respectively. These standard deviations represent a threefold improvement over those of the NMP-exfoliated originals. Phosphorene can also be exfoliated directly in acetone by very long ultrasonication. The product suspension enjoys the same dimensional homogeneity benefits, which confirms that this effect is an intrinsic property of the acetone-BP system. The quality and stability of the exfoliated flakes was checked by XRD, TEM, electron diffraction and Raman spectroscopy. Thermal expansion coefficients of the A1g, B2g and A2g Raman modes were calculated for drop-casted samples as -0.01828 cm-1/K, -0.03056 cm-1/K and -0.03219 cm-1/K, respectively. The flakes withstand 20 minutes in O2 flow at 373 K without lattice distortion. . © 2018 IOP Publishing Ltd.

Comparison of Promoter Hypermethylation Pattern in Salivary Rinses Collected with and without an Exfoliating Brush from Patients with HNSCC

PubMed Central

Sun, Wenyue; Zaboli, David; Liu, Yan; Arnaoutakis, Demetri; Khan, Tanbir; Wang, Hao; Koch, Wayne; Khan, Zubair; Califano, Joseph A.

2012-01-01

Background Salivary rinses have been recently proposed as a valuable resource for the development of epigenetic biomarkers for detection and monitoring of head and neck squamous cell carcinoma (HNSCC). Both salivary rinses collected with and without an exfoliating brush from patients with HNSCC are used in detection of promoter hypermethylation, yet their correlation of promoter hypermethylation has not been evaluated. This study was to evaluate the concordance of promoter hypermethylation between salivary rinses collected with and without an exfoliating brush from patients with HNSCC. Methodolgy 57 paired salivary rinses collected with or without an exfoliating brush from identical HNSCC patients were evaluated for promoter hypermethylation status using Quantitative Methylation-Specific PCR. Target tumor suppressor gene promoter regions were selected based on our previous studies describing a panel for HNSCC screening and surveillance, including P16, CCNA1, DCC, TIMP3, MGMT, DAPK and MINT31. Principal Findings In salivary rinses collected with and without brush, frequent methylation was detected in P16 (8.8% vs. 5.2%), CCNA1 (26.3% vs. 22.8%), DCC (33.3% vs. 29.8%), TIMP3 (31.6% vs. 36.8%), MGMT (29.8% vs. 38.6%), DAPK (14.0% vs. 19.2%), and MINT31 (10.5% vs. 8.8%). Spearman's rank correlation coefficient showed a positive correlation between salivary rinses collected with and without brush for P16 (ρ = 0.79), CCNA1 (ρ = 0.61), DCC (ρ = 0.58), TIMP3 (ρ = 0.10), MGMT (ρ = 0.70), DAPK (ρ = 0.51) and MINT31 (ρ = 0.72) (P<0.01). The percent agreement of promoter methylation between salivary rinses with brush and without brush were 96.5% for P16, 82.5% for CCNA1, 78.9% for DCC, 59.7% for TIMP3, 84.2% for MGMT, 84.2% for DAPK, and 94.7% for MINT31. Conclusions Our study demonstrated strong correlations of gene promoter hypermethylation between salivary rinses collected with and without an exfoliating brush. Salivary rinse collection without using an exfoliating brush may offer a cost effective, rapid, non-invasive, and reliable means for development of epigenetic salivary rinse biomarkers. PMID:22438973

A Population-based survey of the prevalence and types of glaucoma in Nigeria: results from the Nigeria National Blindness and Visual Impairment Survey.

PubMed

Kyari, Fatima; Entekume, Gabriel; Rabiu, Mansur; Spry, Paul; Wormald, Richard; Nolan, Winifred; Murthy, Gudlavalleti V S; Gilbert, Clare E

2015-12-12

Glaucoma is the leading cause of irreversible blindness worldwide. There tends to be a lower reporting of glaucoma in Africa compared to other blinding conditions in global burden data. Research findings of glaucoma in Nigeria will significantly increase our understanding of glaucoma in Nigeria, in people of the West African diaspora and similar population groups. We determined the prevalence and types of glaucoma in Nigeria from the Nigeria National Blindness and Visual Impairment cross-sectional Survey of adults aged ≥40 years. Multistage stratified cluster random sampling with probability-proportional-to-size procedures were used to select a nationally representative sample of 15,027 persons aged ≥40 years. Participants had logMAR visual acuity measurement, FDT visual function testing, autorefraction, A-scan biometry and optic disc assessment. Participants with visual acuity of worse than 6/12 or suspicious optic discs had detailed examination including Goldmann applanation tonometry, gonioscopy and fundus photography. Disc images were graded by Moorfields Eye Hospital Reading Centre. Glaucoma was defined using International Society of Geographical and Epidemiological Ophthalmology criteria; and classified into primary open-angle or primary angle-closure or secondary glaucoma. Diagnosis of glaucoma was based on ISGEO classification. The type of glaucoma was determined by gonioscopy. A total of 13,591 participants in 305 clusters were examined (response rate 90.4 %). Optic disc grading was available for 25,289 (93 %) eyes of 13,081 (96 %) participants. There were 682 participants with glaucoma; a prevalence of 5.02 % (95 % CI 4.60-5.47). Among those with definite primary glaucoma that had gonioscopy (n = 243), open-angle glaucoma was more common (86 %) than angle-closure glaucoma (14 %). 8 % of glaucoma was secondary with the commonest causes being couching (38 %), trauma (21 %) and uveitis (19 %). Only 5.6 % (38/682) of participants with glaucoma knew they had the condition. One in every 5 persons with glaucoma (136;20 %) was blind i.e., visual acuity worse than 3/60. Nigeria has a high prevalence of glaucoma which is largely open-angle glaucoma. A high proportion of those affected are blind. Secondary glaucoma was mostly as a consequence of procedures for cataract. Public health control strategies and high quality glaucoma care service will be required to reduce morbidity and blindness from glaucoma.

The association between socioeconomic status and visual impairments among primary glaucoma: the results from Nationwide Korean National Health Insurance Cohort from 2004 to 2013.

PubMed

Sung, Haejune; Shin, Hyun Ho; Baek, Yunseng; Kim, Gyu Ah; Koh, Jae Sang; Park, Eun-Cheol; Shin, Jaeyong

2017-08-23

Glaucoma is one of the most leading causes of permanent visual impairments in Korea, and social expenses spent for the glaucoma are increasing. This study is to identify association between socioeconomic status and the visual impairments caused by primary glaucoma in Korea. This study is based on a cohort study using stratified representative samples in the National Health Insurance claim data from 2002 to 2013 with 1,025,340 representative subjects. Target subjects were patients who are newly diagnosed with primary glaucoma from 2004 to 2013. We conducted a multiple logistic regression analysis depending on the occurrence of visual impairment and its temporal order compared to the glaucoma diagnosis. Among 1728 patients with primary glaucoma, those with low and middle income shows higher odds ratio (OR) of the visual impairments than those with high income group (low income; OR = 3.42, 95% Confidential Interval (CI):2.06-5.66, middle income; OR = 2.13, 95% CI: 1.28-3.55), in case of the occurrence of the visual impairments preceded the diagnosis of glaucoma. Glaucoma patients without pre-existing glaucoma history before visual impairment have higher association between socioeconomic status and the occurrence of visual impairments by primary glaucoma. Since glaucoma had not been diagnosed and recognized yet, the differences may have been derived from the disparities of the awareness of the glaucoma. These findings call attention to the correlation between socioeconomic factors and the visual impairments by glaucoma, and raise public health needs over the importance of glaucoma awareness and eye screening for glaucoma, especially for low socioeconomic status.

The Frequency of Optical Coherence Tomography Testing in Glaucoma at a Single Academic Medical Center.

PubMed

Griffith, Joseph F; Goldberg, Jeffrey L

2016-03-01

To determine the frequency of optical coherence tomography (OCT) examinations compared with clinical examinations and visual field (VF) tests in patients with 5 types of glaucoma. A retrospective, longitudinal cohort study was conducted of 5154 patients treated between 2003 and 2010 at a single academic medical center. Patients were classified using billing records as having primary open-angle glaucoma, low-tension open-angle glaucoma (NTG), pigmentary open-angle glaucoma, chronic angle-closure glaucoma, or pseudoexfoliation glaucoma. Analysis of variance, χ test, and exact χ test were performed to identify associations between glaucoma type and test frequency. Pigmentary open-angle glaucoma and NTG patients had a higher rate of undergoing at least 2 VFs (94.4%, 94.9%), and chronic angle-closure glaucoma patients had a lower rate of undergoing at least 2 OCTs (25.3%) than all other glaucoma types. NTG patients also had the highest rate of undergoing at least 2 OCTs and at least 2 VFs (36.6%). Overall, the rate of clinical examinations (2.68 examinations/y) exceeded the rates of OCTs (1.39 examinations/y), which exceeded the rate of VF tests (1.24 tests/y). There were no differences in OCT frequency between glaucoma types (0.91 to 1.63 OCTs/y). Within each glaucoma diagnosis, patients had clinical examinations more frequently than OCTs and clinical examinations more frequently than VFs. Primary open-angle glaucoma and pseudoexfoliation glaucoma patients also had OCTs more frequently than VFs. More patients had at least 2 VF tests than at least 2 OCTs (4481 vs. 1679). The relative use of clinical examinations, VF testing, and OCT imaging varies among glaucoma diagnoses.

Prevalence and Determinants of Glaucoma in Citizens of Qatar Aged 40 Years or Older: A Community-Based Survey

PubMed Central

Al-Mansouri, Fatma A.; Kanaan, Aida; Gamra, Hamad; Khandekar, Rajiv; Hashim, Shakeel P.; Al Qahtani, Omar; Ahmed, Mohd. Farouk

2011-01-01

Background: We present the prevalence and determinants of glaucoma among subjects 40 years of age and older in Qatar. Materials and Methods: This community-based survey was held in 2009 at 49 randomly selected clusters. Demographic details and history of glaucoma was collected by the nurses. Ophthalmologists evaluated the optic disc and retina using a digital camera housed in a mobile van. Visual field was tested with an automated perimeter, the intraocular pressure with an applanation tonometer and the angle of the anterior chamber by gonioscopy. A panel of glaucoma experts diagnosed subjects with glaucoma. Results: This survey enrolled 3,149 (97.3%) participants. The age- and sex-adjusted prevalence of glaucoma in the population aged 40 years and older was 1.73% (95% confidence intervals [CI] 1.69-1.77). Accordingly, 5,641 individuals in this age group in Qatar would have glaucoma. Chronological age of 60 years and older (Odds ratio [OR] 11.1) and the presence of myopia (OR 1.78) were predictors of glaucoma. Open-angle glaucoma was diagnosed in 44 (65.7%) individuals with glaucoma. In nine (13.4%) and 15 (20.9%) subjects, angle closure glaucoma and other (post-traumatic, pseudoexfoliation) glaucoma were present. Bilateral blindness (vision <3/60) and severe visual impairment (<6/60) were found in four (6%) and three (4.5%) subjects with glaucoma, respectively. Glaucoma was treated in 36 (54%) subjects. Conclusions: The prevalence of glaucoma among citizens of Qatar aged 40 years and older was 1.71%. Glaucoma was associated with the age of 60 years and older and the presence of myopia. PMID:21731325

Thermally exfoliated graphite oxide

NASA Technical Reports Server (NTRS)

Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Abdala, Ahmed (Inventor)

2011-01-01

A modified graphite oxide material contains a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g, wherein the thermally exfoliated graphite oxide displays no signature of the original graphite and/or graphite oxide, as determined by X-ray diffraction.

One Year of Glaucoma Research in Review: 2013 to 2014

PubMed Central

Van Tassel, Sarah H.; Radcliffe, Nathan M.; Demetriades, Anna M.

2015-01-01

Purpose The purpose of this study was to provide the practicing clinical ophthalmologist with an update of relevant glaucoma literature published from 2013 to 2014. Design Literature review. Methods The authors conducted a 1-year (October 1, 2013, to September 30, 2014) English-language glaucoma literature search on PubMed of articles containing “glaucoma” or “glaucomatous” with title/abstract as a filter. Medical Subject Headings (MeSH) filtered searching was not performed because of the newness of the reviewed material. Results Literature review yielded 2,314 articles, after which we excluded reviews and letters to the editor. We highlighted articles featuring new or updated approaches to the pathophysiology, diagnosis, or treatment of glaucoma and gave preference to human research. Conclusions This review features literature that is of interest to ophthalmologists in practice and also highlights studies that may provide insight to future developments applicable to clinical ophthalmology. PMID:26197218

Low-Cost Rapid Prototyping of Liquid Crystal Polymer Based Magnetic Microactuators for Glaucoma Drainage Devices

PubMed Central

Park, Hyunsu; John, Simon; Lee, Hyowon

2017-01-01

Glaucoma is one of the leading causes of blindness in the world. Although there is no cure for glaucoma, pharmaceutical or surgical interventions are known to delay the progression of this debilitating disease. In recent years, implantation of glaucoma drainage devices (GDD) have increased due to their ability to manage IOP better than other therapeutic approaches. However, only 50% of the implanted devices remain functional after 5 years often due to biofouling. Here, we report our latest progress towards developing self-clearing GDDs using integrated magnetic microactuators. Our hypothesis is that these magnetic microdevices can provide local mechanical perturbations to prophylactically remove biological accumulation. To reduce the cost and increase the throughput of fabrication, we utilize a maskless photolithography setup and commercially available liquid crystal polymer foils to create prototype devices. The mechanical response of the devices is reported and compared with the theoretical values. PMID:28269212

Low-cost rapid prototyping of liquid crystal polymer based magnetic microactuators for glaucoma drainage devices.

PubMed

Hyunsu Park; John, Simon; Hyowon Lee

2016-08-01

Glaucoma is one of the leading causes of blindness in the world. Although there is no cure for glaucoma, pharmaceutical or surgical interventions are known to delay the progression of this debilitating disease. In recent years, implantation of glaucoma drainage devices (GDD) have increased due to their ability to manage IOP better than other therapeutic approaches. However, only 50% of the implanted devices remain functional after 5 years often due to biofouling. Here, we report our latest progress towards developing self-clearing GDDs using integrated magnetic microactuators. Our hypothesis is that these magnetic microdevices can provide local mechanical perturbations to prophylactically remove biological accumulation. To reduce the cost and increase the throughput of fabrication, we utilize a maskless photolithography setup and commercially available liquid crystal polymer foils to create prototype devices. The mechanical response of the devices is reported and compared with the theoretical values.

Copy Number Variations of TBK1 in Australian Patients With Primary Open-Angle Glaucoma

PubMed Central

AWADALLA, MONA S.; FINGERT, JOHN H.; ROOS, BENJAMIN E.; CHEN, SIMON; HOLMES, RICHARD; GRAHAM, STUART L.; CHEHADE, MARK; GALANOPOLOUS, ANNA; RIDGE, BRONWYN; SOUZEAU, EMMANUELLE; ZHOU, TIGER; SIGGS, OWEN M.; HEWITT, ALEX W.; MACKEY, DAVID A.; BURDON, KATHRYN P.; CRAIG, JAMIE E.

2015-01-01

PURPOSE To investigate the presence of TBK1 copy number variations in a large, well-characterized Australian cohort of patients with glaucoma comprising both normal-tension glaucoma and high-tension glaucoma cases. DESIGN A retrospective cohort study. METHODS DNA samples from patients with normal-tension glaucoma and high-tension glaucoma and unaffected controls were screened for TBK1 copy number variations using real-time quantitative polymerase chain reaction. Samples with additional copies of the TBK1 gene were further tested using custom comparative genomic hybridization arrays. RESULTS Four out of 334 normal-tension glaucoma cases (1.2%) were found to carry TBK1 copy number variations using quantitative polymerase chain reaction. One extra dose of the TBK1 gene (duplication) was detected in 3 normal-tension glaucoma patients, while 2 extra doses of the gene (triplication) were detected in a fourth normal-tension glaucoma patient. The results were further confirmed by custom comparative genomic hybridization arrays. Further, the TBK1 copy number variation segregated with normal-tension glaucoma in the family members of the probands, showing an autosomal dominant pattern of inheritance. No TBK1 copy number variations were detected in 1045 Australian patients with high-tension glaucoma or in 254 unaffected controls. CONCLUSION We report the presence of TBK1 copy number variations in our Australian normal-tension glaucoma cohort, including the first example of more than 1 extra copy of this gene in glaucoma patients (gene triplication). These results confirm TBK1 to be an important cause of normal-tension glaucoma, but do not suggest common involvement in high-tension glaucoma. PMID:25284765

A Mixed-Methods Evaluation of a Community-Based Glaucoma Check Service in Hackney, London, UK.

PubMed

Holdsworth, Elizabeth; Datta, Jessica; Marks, Dalya; Kuper, Hannah; Lee, Helen; Leamon, Shaun; Lindfield, Robert; Wormald, Richard; Clarke, Jonathan; Elkarmouty, Ahmed; Macdowall, Wendy

2017-08-01

To evaluate the uptake, feasibility and acceptability of a general practice-based optometrist-led glaucoma check service. The service targeted people of black Caribbean and black African descent aged 40-65 years, resident in Hackney, London, United Kingdom. The study used a mixed-method design, including analysis of service data, prospective audit of secondary care referrals patient survey, cost-consequence analysis, and interviews with staff involved in developing and implementing the service. A total of 3040 patients were invited to undergo the free check; 595 (19.6%) booked an appointment and 461 (15.2%) attended. Overall, 31 patients (6.8%) were referred to secondary care, of whom 22 attended and were assessed for glaucoma. Four were diagnosed with glaucoma and eight with suspected glaucoma, i.e. 2.6% of patients who underwent the check. The cost per patient identified with suspected or confirmed glaucoma was £9,013. Staff who were interviewed suggested that patients who attended might be those who routinely attended optometrist appointments, however only 62.4% of survey respondents reported having had an eye examination in the previous two years, and 11.4% of women and 16.0% of men reported never having had an eye examination. This study represents one possible configuration for a glaucoma case-finding service, and it contributes to a wider debate about whether screening, targeted or otherwise, should be offered in the UK. Our findings suggest that general practice is an acceptable setting and that such a service may reach some people not previously engaged with primary eye care services.

Associations between matrix metalloproteinase gene polymorphisms and glaucoma susceptibility: a meta-analysis.

PubMed

Wu, Ming-Yue; Wu, Yang; Zhang, Yong; Liu, Cai-Yun; Deng, Chun-Yan; Peng, Le; Zhou, Lan

2017-04-21

Matrix metalloproteinases (MMPs) polymorphisms have been implicated in the pathogenesis of glaucoma risk. However, the results were controversial. We performed a meta-analysis to evaluate the precise associations between MMPs polymorphisms and glaucoma risk. Related studies were reviewed by searching electronic databases within four databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the association between the most common polymorphisms of MMPs and glaucoma risk. Heterogeneity, publication bias and sensitivity analysis were conducted to guarantee the statistical power. Overall, 11 selected articles involving 2,388 cases and 2,319 controls were included in this meta-analysis. Significant associations were only found between MMP-9 rs17576 G > A polymorphism (GA vs. GG: OR = 0.80, 95%CI = 0.67-0.97, P = 0.02, I 2  = 0%), MMP-9 rs3918249 C > T polymorphism (TT vs. CC + CT: OR = 0.71, 95%CI = 0.51-0.98, P = 0.04, I 2  = 0%) and glaucoma risk in the general population. Subgroup analysis also suggested that MMP-9 rs17576 G > A was related to glaucoma in the Caucasian population (GA vs. GG: OR = 0.67, 95%CI = 0.45-1.00, P = 0.05; GA + AA vs. GG: OR = 0.66, 95%CI = 0.45-0.97, P = 0.03, I 2  = 0%). Our meta-analysis demonstrates that MMP-9 rs17576 G > A polymorphism might be a protective factor against the development of glaucoma in Caucasian population.

Retinal adaptation abnormalities in primary open-angle glaucoma.

PubMed

Dul, Mitchell; Ennis, Robert; Radner, Shira; Lee, Barry; Zaidi, Qasim

2015-01-22

Dynamic color and brightness adaptation are crucial for visual functioning. The effects of glaucoma on retinal ganglion cells (RGCs) could compromise these functions. We have previously used slow dynamic changes of light at moderate intensities to measure the speed and magnitude of subtractive adaptation in RGCs. We used the same procedure to test if RGC abnormalities cause slower and weaker adaptation for patients with glaucoma when compared to age-similar controls. We assessed adaptation deficits in specific classes of RGCs by testing along the three cardinal color axes that isolate konio, parvo, and magno RGCs. For one eye each of 10 primary open-angle glaucoma patients and their age-similar controls, we measured the speed and magnitude of adapting to 1/32 Hz color modulations along the three cardinal axes, at central fixation and 8° superior, inferior, nasal, and temporal to fixation. In all 15 comparisons (5 locations × 3 color axes), average adaptation was slower and weaker for glaucoma patients than for controls. Adaptation developed slower at central targets than at 8° eccentricities for controls, but not for patients. Adaptation speed and magnitude differed between affected and control eyes even at retinal locations showing no visual field loss with clinical perimetry. Neural adaptation is weaker in glaucoma patients for all three classes of RGCs. Since adaptation abnormalities are manifested even at retinal locations not exhibiting a visual field loss, this novel form of assessment may offer a functional insight into glaucoma and an early diagnosis tool. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Pathophysiology, diagnosis, and management of glaucoma associated with Sturge-Weber syndrome.

PubMed

Javaid, Usman; Ali, Muhammad Hassaan; Jamal, Samreen; Butt, Nadeem Hafeez

2018-02-01

Sturge-Weber syndrome (SWS), also known as encephalotrigeminal angiomatosis, is a condition which includes leptomeningeal hemangioma, facial angiomatosis or nevus flammeus, and ocular changes. SWS can lead to severe complications of anterior segment involving conjunctiva and eyelids, whereas posterior segment of the eye may also be affected by diffuse choroidal hemorrhages. This article was written with the objectives to determine the pathophysiology, diagnosis, and treatment of glaucoma associated with this rare and challenging disorder. A detailed literature search was conducted on PubMed, EMBASE, Cochrane Library, and Google Scholar using the key words. Forty-five articles matched our inclusion criteria that were included in this systematic review. Glaucoma is the one of the commonest ocular manifestations of SWS. It is caused by anterior chamber malformations, increased pressure in the episcleral veins, and changes in ocular hemodynamics. Glaucoma associated with SWS is usually congenital but can develop adults as well. The treatment of glaucoma associated with SWS is quite challenging because of early-onset, severe visual field impairment at the time of diagnosis, and unresponsiveness to standard medical treatment. Several surgical procedures have been devised but the long-term control of the intraocular pressure and visual function remain unsatisfactory. Modifications in the filtration surgery techniques and use of newer anti-fibrotic agents have produced good control of intraocular pressure. Management of glaucoma associated with SWS is multi-dimensional and needs both medical and surgical interventions for better control. The treatment should be devised on case to case basis depending upon the intraocular pressure, stage of the disease, and type of glaucoma.

Rare Diseases Leading to Childhood Glaucoma: Epidemiology, Pathophysiogenesis, and Management.

PubMed

Abdolrahimzadeh, Solmaz; Fameli, Valeria; Mollo, Roberto; Contestabile, Maria Teresa; Perdicchi, Andrea; Recupero, Santi Maria

2015-01-01

Noteworthy heterogeneity exists in the rare diseases associated with childhood glaucoma. Primary congenital glaucoma is mostly sporadic; however, 10% to 40% of cases are familial. CYP1B1 gene mutations seem to account for 87% of familial cases and 27% of sporadic cases. Childhood glaucoma is classified in primary and secondary congenital glaucoma, further divided as glaucoma arising in dysgenesis associated with neural crest anomalies, phakomatoses, metabolic disorders, mitotic diseases, congenital disorders, and acquired conditions. Neural crest alterations lead to the wide spectrum of iridocorneal trabeculodysgenesis. Systemic diseases associated with childhood glaucoma include the heterogenous group of phakomatoses where glaucoma is frequently encountered in the Sturge-Weber syndrome and its variants, in phakomatosis pigmentovascularis associated with oculodermal melanocytosis, and more rarely in neurofibromatosis type 1. Childhood glaucoma is also described in systemic disorders of mitotic and metabolic activity. Acquired secondary glaucoma has been associated with uveitis, trauma, drugs, and neoplastic diseases. A database research revealed reports of childhood glaucoma in rare diseases, which do not include glaucoma in their manifestation. These are otopalatodigital syndrome, complete androgen insensitivity, pseudotrisomy 13, Brachmann-de Lange syndrome, acrofrontofacionasal dysostosis, caudal regression syndrome, and Wolf-Hirschhorn syndrome.

Evaluation of Nanoclay Exfoliation Strategies for Thermoset Polyimide Nanocomposite Systems

NASA Technical Reports Server (NTRS)

Ginter, Michael J.; Jana, Sadhan C.; Miller, Sandi G.

2007-01-01

Prior works show exfoliated layered silicate reinforcement improves polymer composite properties. However, achieving full clay exfoliation in high performance thermoset polyimides remains a challenge. This study explores a new method of clay exfoliation, which includes clay intercalation by lower molecular weight PMR monomer under conditions of low and high shear and sonication, clay treatments by aliphatic and aromatic surfactants, and clay dispersion in primary, higher molecular weight PMR resin. Clay spacing, thermal, and mechanical properties were evaluated and compared with the best results available in literature for PMR polyimide systems.

Development of a competency framework for optometrists with a specialist interest in glaucoma.

PubMed

Myint, J; Edgar, D F; Kotecha, A; Crabb, D P; Lawrenson, J G

2010-09-01

To develop a competency framework, using a modified Delphi methodology, for optometrists with a specialist interest in glaucoma, which would provide a basis for training and accreditation. A modified iterative Delphi technique was used using a 16-member panel consisting almost exclusively of sub-specialist optometrists and ophthalmologists. The first round involved scoring the relevance of a draft series of competencies using a 9-point Likert scale with a free-text option to modify any competency or suggest additional competencies. The revised framework was subjected to a second round of scoring and free-text comment. The Delphi process was followed by a face-to-face structured workshop to debate and agree the final framework. The version of the framework agreed at the workshop was sent out for a 4-month period of external stakeholder validation. There was a 100% response to round 1 and an 94% response to round 2. All panel members attended the workshop. The final version of the competency framework was validated by a subsequent stakeholder consultation and contained 19 competencies for the diagnosis of glaucoma and 7 further competencies for monitoring and treatment. Application of a consensus methodology consisting of a modified Delphi technique allowed the development of a competency framework for glaucoma specialisation by optometrists. This will help to shape the development of a speciality curriculum and potentially could be adapted for other healthcare professionals.

Boron Nitride Nanoribbons from Exfoliation of Boron Nitride Nanotubes

NASA Technical Reports Server (NTRS)

Hung, Ching-Cheh; Hurst, Janet; Santiago, Diana

2017-01-01

Two types of boron nitride nanotubes (BNNTs) were exfoliated into boron nitride nanoribbons (BNNR), which were identified using transmission electron microscopy: (1) commercial BNNTs with thin tube walls and small diameters. Tube unzipping was indicated by a large decrease of the sample's surface area and volume for pores less than 2 nm in diameter. (2) BNNTs with large diameters and thick walls synthesized at NASA Glenn Research Center. Here, tube unraveling was indicated by a large increase in external surface area and pore volume. For both, the exfoliation process was similar to the previous reported method to exfoliate commercial hexagonal boron nitride (hBN): Mixtures of BNNT, FeCl3, and NaF (or KF) were sequentially treated in 250 to 350 C nitrogen for intercalation, 500 to 750 C air for exfoliation, and finally HCl for purification. Property changes of the nanosized boron nitride throughout this process were also similar to the previously observed changes of commercial hBN during the exfoliation process: Both crystal structure (x-ray diffraction data) and chemical properties (Fourier-transform infrared spectroscopy data) of the original reactant changed after intercalation and exfoliation, but most (not all) of these changes revert back to those of the reactant once the final, purified products are obtained.

Service innovation in glaucoma management: using a Web-based electronic patient record to facilitate virtual specialist supervision of a shared care glaucoma programme.

PubMed

Wright, Heathcote R; Diamond, Jeremy P

2015-03-01

To assess the importance of specialist supervision in a new model of glaucoma service delivery. An optometrist supported by three technicians managed each glaucoma clinic. Patients underwent testing and clinical examination before the optometrist triaged them into one of five groups: 'normal', 'stable', 'low risk', 'unstable' and 'high risk'. Patient data were uploaded to an electronic medical record to facilitate virtual review by a glaucoma specialist. 24 257 glaucoma reviews at three glaucoma clinics during a 31-month period were analysed. The clinic optometrists and glaucoma specialists had substantial agreement (κ 0.69). 13 patients were identified to be high risk by the glaucoma specialist that had not been identified as such by the optometrist. Glaucoma specialists amended 13% of the optometrists' interim decisions resulting in an overall reduction in review appointments by 2.4%. Employing technicians and optometrists to triage glaucoma patients into groups defined by risk of blindness allows higher risk patients to be directed to a glaucoma specialist. Virtual review allows the glaucoma specialist to remain in overall control while reducing the risk that patients are treated or followed-up unnecessarily. Demand for glaucoma appointments can be reduced allowing scarce medical resources to be directed to patients most in need. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Watch Out for Glaucoma | NIH MedlinePlus the Magazine

MedlinePlus

... of this page please turn JavaScript on. Feature: Glaucoma Watch Out for Glaucoma Past Issues / Spring 2015 Table of Contents A ... used to check eye pressure for signs of glaucoma. Photo courtesy of NEI Glaucoma is a group ...

Update on pigment dispersion syndrome and pigmentary glaucoma.

PubMed

Okafor, Kingsley; Vinod, Kateki; Gedde, Steven J

2017-03-01

The present article reviews the clinical features and pathogenesis of pigment dispersion syndrome and pigmentary glaucoma and provides an update regarding their diagnosis and management. Newer imaging modalities including ultrasound biomicroscopy and anterior segment optical coherence tomography facilitate visualization of the iris concavity characteristic of eyes with pigment dispersion syndrome and pigmentary glaucoma. Patients with pigmentary glaucoma may be distinguished from those with other glaucoma types by the presence of typical symptoms, personality type, and patterns of diurnal intraocular pressure fluctuation. Although laser iridotomy has been shown to alter iris anatomy in pigmentary glaucoma, it is not proven to slow visual field progression. Multiple trials have validated the safety and efficacy of filtering surgery in treating pigmentary glaucoma, with fewer studies published on the role of micro-invasive glaucoma surgery. Literature from the review period has further defined the unique clinical characteristics of pigment dispersion syndrome and pigmentary glaucoma. Laser surgery has a limited role in the management of these entities, whereas trabeculectomy remains an acceptable first-line surgical treatment. Further studies are needed to define the potential application of the newer micro-invasive glaucoma procedures in pigmentary glaucoma.

Optic Disc Drusen and Family History of Glaucoma-Results of a Patient-directed Survey.

PubMed

Gramer, Gwendolyn; Gramer, Eugen; Weisschuh, Nicole

2017-10-01

Prospective evaluation of family history (FH) of glaucoma and FH of optic disc drusen (ODD) in patients with sonographically confirmed ODD. A total of 87 patients with ODD interviewed all their first-degree and second-degree relatives using a detailed questionnaire on whether an ophthalmologist had diagnosed or excluded glaucoma or ocular hypertension (OH). Using a second questionnaire, 62 of these patients also provided information about ODD in their FH. Control groups for FH of glaucoma consisted of 2170 patients with glaucoma or OH evaluated with the same methods and identical questions for FH of glaucoma in a previous study, and of 176 healthy individuals without glaucoma or ODD who were interviewed on family history of glaucoma. Glaucoma in FH was significantly more frequent in patients with ODD with an incidence of 20.7% compared with healthy controls with an incidence of 2.8%, and half as frequent as in glaucoma patients with an incidence of 40%. ODD in FH were found in 9.7% of patients with ODD. As there is a high frequency of family history of glaucoma in patients with ODD, evaluation of FH of ODD and FH of glaucoma is essential in patients with ODD. Glaucoma in FH of ODD patients requires intraocular pressure monitoring and whenever deemed beneficial timely initiation of intraocular pressure-lowering therapy.

Stage of visual field loss and age at diagnosis in 1988 patients with different glaucomas: implications for glaucoma screening and driving ability.

PubMed

Gramer, Gwendolyn; Gramer, Eugen

2018-04-01

To compare stage of visual field loss (VFL) and age at diagnosis between patients with different types of glaucoma with regard to glaucoma screening and driving ability. In a cross-sectional study of 1988 consecutive patients with different types of glaucoma VFL at diagnosis and age at diagnosis were assessed. Patients with binocular advanced or severe VFL were classified unable, patients with no VFL in one eye and VFL I-V (Aulhorn classification) in the other eye able, all other constellations questionably able to drive. There were significant differences in age at diagnosis between different glaucomas and between patients with different stages of VFL at diagnosis. Age-related assessment of VFL at diagnosis in normal tension glaucoma (NTG) compared to primary open-angle glaucoma (POAG) showed that NTG is not a disease of the elderly but a disease with late diagnosis at severe VFL. In POAG a solely age-related glaucoma screening, e.g. from the age of 50 years, does not sufficiently lead to diagnosis at an early stage of the disease. In POAG solely based on binocular VFL 11.5% of patients were judged unable, 29.2% questionably able to drive, in NTG 19.6%/43.1%, pigmentary glaucoma 16%/22%, pseudoexfoliation glaucoma 9.1%/16.7%, and in primary angle-closure glaucoma 14.6%/30%. Depending on type of glaucoma more than 50% of patients require counselling regarding safe driving as part of clinical care. A disease-specific, age-related perimetric examination considering additional risk factors like family history of glaucoma is essential for early detection of glaucoma and road safety.

Diagnostic ability of macular ganglion cell asymmetry for glaucoma.

PubMed

Hwang, Young Hoon; Ahn, Sang Il; Ko, Sung Ju

2015-11-01

Using spectral-domain optical coherence tomography (OCT), this study aims to investigate the glaucoma diagnostic ability of macular ganglion cell asymmetry analysis. A cross-sectional study was conducted. This study was performed to investigate glaucoma diagnostic ability of macular ganglion cell asymmetry analysis in eyes with various degrees of glaucoma. We enrolled 181 healthy eyes and 265 glaucomatous eyes. Glaucomatous eyes were subdivided into pre-perimetric, early, moderate and advanced-to-severe glaucoma based on visual field test results. For each eye, macular ganglion cell-inner plexiform layer (GCIPL) thickness was measured using OCT. Average GCIPL thickness, GCIPL thicknesses in superior and inferior hemispheres, absolute difference in GCIPL thickness between superior and inferior hemispheres and GCIPL asymmetry index calculated as the absolute value of log10 (inferior hemisphere thickness/superior hemisphere thickness) were analysed. Areas under the receiver operating characteristics curves (AUCs) of GCIPL parameter were calculated and compared. All of the GCIPL parameters showed good glaucoma diagnostic ability (AUCs ≥ 0.817, P < 0.01). AUCs of average, superior and inferior GCIPL thickness increased as the severity of glaucoma increased. GCIPL thickness difference and asymmetry index showed the highest AUCs in early and moderate glaucoma and lower AUCs in pre-perimetric and advanced-to-severe glaucoma. GCIPL thickness difference and asymmetry index showed better glaucoma diagnostic ability than other GCIPL parameters only in early stage of glaucoma (P < 0.05); in other stages, these parameters had similar to or worse glaucoma diagnostic ability than other GCIPL parameters. Macular ganglion cell asymmetry analysis showed good glaucoma diagnostic ability, especially in early-stage glaucoma. However, it has limited usefulness in other stages of glaucoma. © 2015 Royal Australian and New Zealand College of Ophthalmologists.

The effect of an Ahmed glaucoma valve implant on corneal endothelial cell density in children with glaucoma secondary to uveitis.

PubMed

Kalinina Ayuso, Viera; Scheerlinck, Laura M; de Boer, Joke H

2013-03-01

To assess the effect of Ahmed glaucoma valve implants on corneal endothelial cell density (ECD) in children with uveitic glaucoma. Cross-sectional study. setting: Institutional. patientpopulation: Eighty eyes from 42 patients diagnosed with uveitis before the age of 16. Twenty-eight eyes had an Ahmed glaucoma valve implant because of secondary glaucoma. Fifty-two eyes without an implant served as controls. intervention orobservationprocedure(s): Corneal ECD was examined cross-sectionally using a noncontact specular microscope. Univariate and multivariate generalized estimating equations analyses with correction for paired eyes were performed. mainoutcomemeasure(s): Correlation of ECD with the presence of an Ahmed glaucoma valve implant and with the time following implantation. ECD was significantly lower in the Ahmed glaucoma valve group than in controls (2359 and 3088 cells/mm(2), respectively; P < .001) following an average of 3.5 years after Ahmed glaucoma valve implantation. Presence of an Ahmed glaucoma valve implant, previous intraocular surgery, age, duration of uveitis, and history of corneal touch by the implant tube were all significantly associated with decreased ECD. Following a multivariate analysis, presence of an Ahmed glaucoma valve implant (B = -340; adjusted P < .011) and older age (B = -58; adjusted P = .005) remained independently associated with decreased ECD. Within the implant group, the age-adjusted time interval following Ahmed glaucoma valve implantation was highly correlated with decreased ECD (B = -558, P < .001). Ahmed glaucoma valve implants in children with uveitic glaucoma are independently associated with decreased ECD, and this effect is associated with the time interval following Ahmed glaucoma valve implantation. Copyright © 2013 Elsevier Inc. All rights reserved.

A Review of the Ahmed Glaucoma Valve Implant and Comparison with Other Surgical Operations.

PubMed

Riva, Ivano; Roberti, Gloria; Katsanos, Andreas; Oddone, Francesco; Quaranta, Luciano

2017-04-01

The Ahmed glaucoma valve (AGV) is a popular glaucoma drainage implant used for the control of intraocular pressure in patients with glaucoma. While in the past AGV implantation was reserved for glaucoma patients poorly controlled after one or more filtration procedures, mounting evidence has recently encouraged its use as a primary surgery in selected cases. AGV has been demonstrated to be safe and effective in reducing intraocular pressure in patients with primary or secondary refractory glaucoma. Compared to other glaucoma surgeries, AGV implantation has shown favorable efficacy and safety. The aim of this article is to review the results of studies directly comparing AGV with other surgical procedures in patients with glaucoma.

Does Your Child Have Glaucoma?

MedlinePlus

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Glaucoma and disability: which tasks are affected, and at what stage of disease?

PubMed

Ramulu, Pradeep

2009-03-01

To summarize recent work from clinical and epidemiological studies that describe how, and at what stage, glaucoma affects the performance of important vision-related activities. Difficulties with the extremes of lighting are the most frequent complaint in glaucoma. Individuals with bilateral glaucoma also self-report difficulty with a broad array of tasks, including reading, walking, and driving. Bilateral glaucoma is associated with driving cessation and limitation, bumping into objects, slower walking, and falls. Some, but not all, studies also demonstrate higher accident rates in glaucoma. Measurable effects on reading speed have only been observed with field damage severe enough to affect binocular central acuity. Glaucoma with bilateral visual field loss is associated with increased symptoms and a measurable decline in mobility and driving. Further work is necessary to establish whether unilateral glaucoma has a significant impact on patients, to determine whether reading difficulty is common in patients with bilateral glaucoma, and to establish the effects of lighting conditions on task performance in glaucoma.

New solvent-stabilized few-layer black phosphorus for antibacterial applications.

PubMed

Sun, Zhenyu; Zhang, Yuqin; Yu, Hao; Yan, Chao; Liu, Yongchao; Hong, Song; Tao, Hengcong; Robertson, Alex W; Wang, Zhuo; Pádua, Agílio A H

2018-06-22

Discovering highly efficient, environmentally friendly, and low-cost exfoliating media that can both disperse and protect black phosphorus (BP) remains a challenge. Herein, we demonstrate such a new molecule, N,N'-dimethylpropyleneurea (DMPU), for effective exfoliation and dispersion of two-dimensional BP nanosheets. A very high exfoliation efficiency of up to 16% was achieved in DMPU, significantly surpassing other good solvents. Exfoliated flakes are free from structural disorder or oxidation. Nanosheets retain high stability in DMPU even after addition of 25 vol% of common solvents. The solvation shell appears to protect the nanosheets from reacting with water and air, more remarkably than the best solvent N-cyclohexyl-2-pyrrolidone reported so far. Molecular dynamics simulations of the exfoliation process show that DMPU is among the effective solvents, although energetically it does not appear as favorable as some other amides. We also demonstrate that our exfoliated BP nanosheets exhibit excellent antimicrobial activities against both Escherichia coli and Staphylococcus aureus, outperforming other common two-dimensional materials of graphene and MoS2, suggesting promise in biomedical applications.

Exfoliated YBCO filaments for second-generation superconducting cable

NASA Astrophysics Data System (ADS)

Solovyov, Vyacheslav; Farrell, Paul

2017-01-01

The second-generation high temperature superconductor (2G HTS) wire is the most promising conductor for high-field magnets such as accelerator dipoles and compact fusion devices. The key element of the wire is a thin Y1Ba2Cu3O7 (YBCO) layer deposited on a flexible metal substrate. The substrate, which becomes incorporated in the 2G conductor, reduces the electrical and mechanical performance of the wire. This is a process that exfoliates the YBCO layer from the substrate while retaining the critical current density of the superconductor. Ten-centimeter long coupons of exfoliated YBCO layers were manufactured, and detailed structural, electrical, and mechanical characterization were reported. After exfoliation, the YBCO layer was supported by a 75 μm thick stainless steel foil, which makes for a compact, mechanically stronger, and inexpensive conductor. The critical current density of the filaments was measured at both 77 K and 4.2 K. The exfoliated YBCO retained 90% of the original critical current. Similarly, tests in an external magnetic field at 4.2 K confirmed that the pinning strength of the YBCO layer was also retained following exfoliation.

Imaging patients with glaucoma using spectral-domain optical coherence tomography and optical microangiography

NASA Astrophysics Data System (ADS)

Auyeung, Kris; Auyeung, Kelsey; Kono, Rei; Chen, Chieh-Li; Zhang, Qinqin; Wang, Ruikang K.

2015-03-01

In ophthalmology, a reliable means of diagnosing glaucoma in its early stages is still an open issue. Past efforts, including forays into fluorescent angiography (FA) and early optical coherence tomography (OCT) systems, to develop a potential biomarker for the disease have been explored. However, this development has been hindered by the inability of the current techniques to provide useful depth and microvasculature information of the optic nerve head (ONH), which have been debated as possible hallmarks of glaucoma progression. We reasoned that a system incorporating a spectral-domain OCT (SD-OCT) based Optical Microangiography (OMAG) system, could allow an effective, non-invasive methodology to evaluate effects on microvasculature by glaucoma. SD-OCT follows the principle of light reflection and interference to produce detailed cross-sectional and 3D images of the eye. OMAG produces imaging contrasts via endogenous light scattering from moving particles, allowing for 3D image productions of dynamic blood perfusion at capillary-level resolution. The purpose of this study was to investigate the optic cup perfusion (flow) differences in glaucomatous and normal eyes. Images from three normal and five glaucomatous subjects were analyzed our OCT based OMAG system for blood perfusion and structural images, allowing for comparisons. Preliminary results from blood flow analysis revealed reduced blood perfusion within the whole-depth region encompassing the Lamina Cribrosa in glaucomatous cases as compared to normal ones. We conclude that our OCT-OMAG system may provide promise and viability for glaucoma screening.

[Management of corneal endothelial decompensation with Descemet's membrane endothelial keratoplasty in a patient with Ahmed glaucoma valve implant].

PubMed

Röck, T; Bartz-Schmidt, K-U; Röck, D; Yoeruek, E

2014-05-01

Currently, the main causes for developing bullous keratopathy are from problems related to intraocular surgery, trauma, infection, Fuchs' endothelial dystrophy and chronically elevated intraocular pressure. In the 1990s penetrating keratoplasty was once considered the therapy of choice for treatment of bullous keratopathy but in recent years it has been replaced by posterior lamellar keratoplasty. The Descemet membrane endothelial keratoplasty (DMEK) procedure represents the final development of posterior lamellar keratoplasty. The question now arises whether DMEK can be used in patients with bullous keratopathy and Ahmed glaucoma valve implant. A 72-year-old man was referred to our hospital for further evaluation with the diagnosis of bullous keratopathy and pseudoexfoliative glaucoma. The bullous keratopathy was caused by a variety of previous operations as well as decompensation of intraocular pressure. This article describes the therapy of bullous keratopathy by DMEK with existing Ahmed glaucoma valve implant. After surgery the cornea became clear and the best-corrected visual acuity improved from hand movement to 0.2. The intraocular pressure remained normal (10-14 mmHg) without antiglaucoma medication and the endothelial cell count decreased only slightly over a follow-up of 13 months. No complications were encountered. The DMEK surgical procedure seems to be possible in patients with Ahmed glaucoma valve implant and endothelial decompensation. However, further studies with a larger number of patients should follow to validate the replacement of penetrating keratoplasty and other posterior lamellar procedures by DMEK.

Blindness following bleb-related infection in open angle glaucoma.

PubMed

Yamada, Hiroki; Sawada, Akira; Kuwayama, Yasuaki; Yamamoto, Tetsuya

2014-11-01

To estimate the risk of blindness following bleb-related infection after trabeculectomy with mitomycin C in open angle glaucoma, utilizing data obtained from two prospective multicenter studies. The incidence of bleb-related infection in open angle glaucoma after the first or second glaucoma surgery was calculated using a Kaplan-Meier analysis and data from the Collaborative Bleb-related Infection Incidence and Treatment Study (CBIITS). The rate of blindness following bleb-related infection was calculated using data from the Japan Glaucoma Society Survey of Bleb-related Infection (JGSSBI). Finally, the rate of blindness following bleb-related infection after filtering surgery was estimated based on the above two data sets. Blindness was defined as an eye with a visual acuity of 0.04 or less. The incidences of development of bleb-related infection at 5 years were 2.6 ± 0.7 % (calculated cumulative incidence ± standard error) for all infections and 0.9 ± 0.4 % for endophthalmitis in all cases in the CBIITS data. The rates of blindness in the JGSSBI data were 14 % for the total cases with bleb-related infection and 30 % for the endophthalmitis subgroup. The rate of blindness developing within 5 years following trabeculectomy was estimated to be approximately 0.24-0.36 %. The rate of blindness following bleb-related infection within 5 years after trabeculectomy is considerable and thus careful consideration must be given to the indication for trabeculectomy and the selection of surgical techniques.

Marijuana Use Among Patients With Glaucoma in a City With Legalized Medical Marijuana Use.

PubMed

Belyea, David A; Alhabshan, Rashed; Del Rio-Gonzalez, Ana Maria; Chadha, Nisha; Lamba, Tania; Golshani, Cyrus; Merchant, Kunal; Passi, Neena; Dan, Jacob A

2016-03-01

Previous research has shown several limitations associated with the use of marijuana as a treatment for glaucoma. However, little is known regarding patients' perceptions toward using marijuana for glaucoma and their intentions to use this therapeutic alternative. To identify factors among patients with glaucoma that could lead to intentions to use marijuana for treatment. This cross-sectional survey study of 204 patients with glaucoma or suspected to have glaucoma was conducted at an academic-based glaucoma clinic in Washington, DC, between February 1 and July 31, 2013. Patients completed a self-administered survey assessing demographics, perceived severity of glaucoma, prior knowledge about marijuana use in glaucoma, past marijuana use, perceptions toward marijuana use (legality, systemic adverse effects, safety and effectiveness, and false beliefs), satisfaction with current glaucoma management, relevance of treatment costs, and intentions to use marijuana for glaucoma. Medical records were reviewed for disease severity. Data analysis was conducted from September 1, 2013, to September 30, 2015. The main outcome was patients' intentions to use marijuana for glaucoma. Multiple linear regression analysis was conducted to identify factors associated with patients' intentions to use marijuana for glaucoma. Of the 334 patients who were invited to participate in the study, 204 (61.1%) completed the survey. About half the participants were women (104 [51.0]%), and 82 (40.2%) were white. Regression analysis of 204 respondents indicated that perceptions of legality of marijuana use (β, 0.378; 95% CI, 0.205 to 0.444; P < .001), false beliefs regarding marijuana (β, 0.323; 95% CI, 0.236 to 0.504; P < .001), satisfaction with current glaucoma care (β, -0.222; 95% CI, -0.362 to -0.128; P < .001), and relevance of marijuana and glaucoma treatment costs (β, 0.127; 95% CI, 0.008 to 0.210; P = .04) were significantly associated with intentions to use marijuana for glaucoma treatment after controlling for demographic variables, disease severity, and previous marijuana use. This study's findings suggest a need for more education on this topic for ophthalmologists to be able to protect patients with glaucoma against the increased acceptability among the public of using marijuana based on false perceptions of its therapeutic value in glaucoma therapy. Considering the strong influence of perceptions of the legality of marijuana use on intentions to use this substance as a treatment for glaucoma, patient education might be particularly relevant in states in which marijuana use for glaucoma is legal, as in the case of the current study's setting.

Green synthesis route for WS2 nanosheets using water intercalation

NASA Astrophysics Data System (ADS)

Jha, Ravindra; Santra, Sumita; Guha, Prasanta Kumar

2016-09-01

The exfoliation of layered materials has attracted a lot of attention in recent times. In this report, we have exfoliated WS2 in deionized water (without using any chemical solvents, surfactants, etc) using the thermal coefficient mismatch between WS2 and H2O along with other anomalous properties of water, such as the formation of five-, six- and seven-ring structures while freezing. Two different green synthesis routes have been proposed for WS2 exfoliation. We call them the ‘hard’ and ‘soft’ quenching methods. The nanosheets were investigated using different characterization tools and we found the exfoliation of the bulk into <4 layers with an average lateral dimension of 200 nm. The exfoliation method is unique in the sense of producing pristine nanosheets due to the absence of any organic solvents, which are difficult to remove.

New approach to elaborate exfoliated starch-based nanobiocomposites.

PubMed

Chivrac, Frédéric; Pollet, Eric; Schmutz, Marc; Avérous, Luc

2008-03-01

The present paper reports the successful elaboration of exfoliated plasticized starch-based nanobiocomposites. This was made possible by using cationic starch as a new clay organomodifier to better match the polarity of the matrix and thus to facilitate the clay exfoliation process. To demonstrate the efficiency of this new approach, either natural (MMT-Na) or organomodified (OMMT-CS) montmorillonite were incorporated into the starch nanobiocomposites by a melt blending process. The morphological analyses (SAXD and TEM) showed that MMT-Na leads to the formation of intercalated nanobiocomposites. On the contrary, OMMT-CS allowed the elaboration of well-exfoliated nanobiocomposites. Tensile tests performed on the obtained nanobiocomposites showed that exfoliated nanobiocomposites display enhanced mechanical properties compared to those of the intercalated nanobiocomposites and neat matrix. These results clearly highlight the great interest in using OMMT-CS to obtain starch-based nanobiocomposites with improved properties.

Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry.

PubMed

Ryder, Christopher R; Wood, Joshua D; Wells, Spencer A; Yang, Yang; Jariwala, Deep; Marks, Tobin J; Schatz, George C; Hersam, Mark C

2016-06-01

Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical and electronic properties. Exfoliated black phosphorus (BP)-a layered two-dimensional semiconductor-exhibits favourable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chemically reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.

Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry

NASA Astrophysics Data System (ADS)

Ryder, Christopher R.; Wood, Joshua D.; Wells, Spencer A.; Yang, Yang; Jariwala, Deep; Marks, Tobin J.; Schatz, George C.; Hersam, Mark C.

2016-06-01

Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical and electronic properties. Exfoliated black phosphorus (BP)—a layered two-dimensional semiconductor—exhibits favourable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chemically reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.

XEN Gel Implant: a new surgical approach in glaucoma.

PubMed

Chaudhary, Ankita; Salinas, Lauriane; Guidotti, Jacopo; Mermoud, André; Mansouri, Kaweh

2018-01-01

Glaucoma is a leading cause of blindness worldwide. Intraocular pressure (IOP) lowering is the only effective treatment strategy. Traditional glaucoma surgeries are generally considered to be unpredictable and associated with a high rate of complications. This has led to the development of a novel XEN Gel Implant, a type of minimally invasive glaucoma surgery (MIGS), lowering the IOP without extensive surgical dissection. Areas covered: A literature search was undertaken on PubMed using the terms XEN glaucoma, gelatin microstent, and MIGS. All the articles and case reports on XEN Gel Implant and selected articles on MIGS were studied and reviewed. We have discussed the results of most studies on XEN Gel Implant related to its efficacy, safety and success. Expert commentary: The XEN Gel Implant effectively lowers IOP and medication use, with a favorable safety profile. Long-term data on its success and cost-effectiveness are lacking. The studies have shown it to be without any serious adverse events and to have good safety profile encouraging future research on this novel implant. There is a need to correctly identify selection criteria for patients, who would benefit the most from the XEN Gel Implant.

Glaucoma and quality of life: fall and driving risk.

PubMed

Montana, Cynthia L; Bhorade, Anjali M

2018-03-01

Numerous population-based studies suggest that glaucoma is an independent risk factor for falling and motor vehicle collisions, particularly for older adults. These adverse events lead to increased healthcare expenditures and decreased quality of life. Current research priorities, therefore, include identifying factors that predispose glaucoma patients to falling and unsafe driving, and developing screening strategies and targeted rehabilitation. The purpose of this article is to review recent studies that address these priorities. Studies continue to support that glaucoma patients, particularly those with advanced disease, have an increased risk of falling or unsafe driving. Risk factors, however, remain variable and include severity and location of visual field defects, contrast sensitivity, and performance on divided attention tasks. Such variability is likely because of the multifactorial nature of ambulating and driving and compensatory strategies used by patients. Falls and unsafe driving remain a serious public health issue for older adults with glaucoma. Ambulation and driving are complex tasks and there is no consensus yet, regarding the best methods for risk stratification and targeted interventions to increase safety. Therefore, comprehensive and individualized assessments are recommended to most effectively evaluate a patient's risk for falling or unsafe driving.

Characterizing the “POAGome”: A bioinformatics-driven approach to primary open-angle glaucoma

PubMed Central

Danford, Ian D.; Verkuil, Lana D.; Choi, Daniel J.; Collins, David W.; Gudiseva, Harini V.; Uyhazi, Katherine E.; Lau, Marisa K.; Kanu, Levi N.; Grant, Gregory R.; Chavali, Venkata R.M.; O’Brien, Joan M.

2017-01-01

Primary open-angle glaucoma (POAG) is a genetically, physiologically, and phenotypically complex neurodegenerative disorder. This study addressed the expanding collection of genes associated with POAG, referred to as the “POAGome.” We used bioinformatics tools to perform an extensive, systematic literature search and compiled 542 genes with confirmed associations with POAG and its related phenotypes (normal tension glaucoma, ocular hypertension, juvenile open-angle glaucoma, and primary congenital glaucoma). The genes were classified according to their associated ocular tissues and phenotypes, and functional annotation and pathway analyses were subsequently performed. Our study reveals that no single molecular pathway can encompass the pathophysiology of POAG. The analyses suggested that inflammation and senescence may play pivotal roles in both the development and perpetuation of the retinal ganglion cell degeneration seen in POAG. The TGF-β signaling pathway was repeatedly implicated in our analyses, suggesting that it may be an important contributor to the manifestation of POAG in the anterior and posterior segments of the globe. We propose a molecular model of POAG revolving around TGF-β signaling, which incorporates the roles of inflammation and senescence in this disease. Finally, we highlight emerging molecular therapies that show promise for treating POAG. PMID:28223208

ReGAE 5: Can we improve the surgical journey for African-Caribbean patients undergoing glaucoma filtration surgery? Some preliminary findings

PubMed Central

Cross, Vinette; Shah, Peter; Glynn, Martin; Chidrawar, Shivani

2009-01-01

Aim: To explore the experiences of African-Caribbean patients who had undergone filtration surgery for advanced glaucoma. Methods: Semi-structured qualitative interviews were used to collect the data and an interview guide was developed. Participants recounted when they first became aware of a problem with their eyes and their feelings at the time. Subsequently they were probed about their subjective experiences of becoming a glaucoma patient, receiving treatment, the decision to undergo surgery, and its aftermath. The perceptions of three participants from three different generations of African-Caribbean men were selected from the larger study for presentation in this paper. Interview transcripts were subjected to narrative analysis. Results: The concept of patient-partnership was re-framed in terms of mentorship. Surgeon–patient relationships are central to developing effective coping strategies. Support to face the ordeals ahead, challenge to take on new responsibilities, and help to envision a meaningful life with glaucoma are fundamental to fostering trust and maintaining motivation to continue. Conclusions: The use of patient narratives provides a valuable a resource for enhancing communication skills and patient-centered care in the hospital eye service. PMID:19668538

Development of a Web-based Glaucoma Registry at King Khaled Eye Specialist Hospital, Saudi Arabia: A Cost-Effective Methodology

PubMed Central

Zaman, Babar; Khandekar, Rajiv; Al Shahwan, Sami; Song, Jonathan; Al Jadaan, Ibrahim; Al Jiasim, Leyla; Owaydha, Ohood; Asghar, Nasira; Hijazi, Amar; Edward, Deepak P.

2014-01-01

In this brief communication, we present the steps used to establish a web-based congenital glaucoma registry at our institution. The contents of a case report form (CRF) were developed by a group of glaucoma subspecialists. Information Technology (IT) specialists used Lime Survey softwareTM to create an electronic CRF. A MY Structured Query Language (MySQL) server was used as a database with a virtual machine operating system. Two ophthalmologists and 2 IT specialists worked for 7 hours, and a biostatistician and a data registrar worked for 24 hours each to establish the electronic CRF. Using the CRF which was transferred to the Lime survey tool, and the MYSQL server application, data could be directly stored in spreadsheet programs that included Microsoft Excel, SPSS, and R-Language and queried in real-time. In a pilot test, clinical data from 80 patients with congenital glaucoma were entered into the registry and successful descriptive analysis and data entry validation was performed. A web-based disease registry was established in a short period of time in a cost-efficient manner using available resources and a team-based approach. PMID:24791112

Development of a web-based glaucoma registry at King Khaled Eye Specialist Hospital, Saudi Arabia: a cost-effective methodology.

PubMed

Zaman, Babar; Khandekar, Rajiv; Al Shahwan, Sami; Song, Jonathan; Al Jadaan, Ibrahim; Al Jiasim, Leyla; Owaydha, Ohood; Asghar, Nasira; Hijazi, Amar; Edward, Deepak P

2014-01-01

In this brief communication, we present the steps used to establish a web-based congenital glaucoma registry at our institution. The contents of a case report form (CRF) were developed by a group of glaucoma subspecialists. Information Technology (IT) specialists used Lime Survey softwareTM to create an electronic CRF. A MY Structured Query Language (MySQL) server was used as a database with a virtual machine operating system. Two ophthalmologists and 2 IT specialists worked for 7 hours, and a biostatistician and a data registrar worked for 24 hours each to establish the electronic CRF. Using the CRF which was transferred to the Lime survey tool, and the MYSQL server application, data could be directly stored in spreadsheet programs that included Microsoft Excel, SPSS, and R-Language and queried in real-time. In a pilot test, clinical data from 80 patients with congenital glaucoma were entered into the registry and successful descriptive analysis and data entry validation was performed. A web-based disease registry was established in a short period of time in a cost-efficient manner using available resources and a team-based approach.

Glaucoma: Biological Trabecular and Neuroretinal Pathology with Perspectives of Therapy Innovation and Preventive Diagnosis

PubMed Central

Nuzzi, Raffaele; Tridico, Federico

2017-01-01

Glaucoma is a common degenerative disease affecting retinal ganglion cells (RGC) and optic nerve axons, with progressive and chronic course. It is one of the most important reasons of social blindness in industrialized countries. Glaucoma can lead to the development of irreversible visual field loss, if not treated. Diagnosis may be difficult due to lack of symptoms in early stages of disease. In many cases, when patients arrive at clinical evaluation, a severe neuronal damage may have already occurred. In recent years, newer perspective in glaucoma treatment have emerged. The current research is focusing on finding newer drugs and associations or better delivery systems in order to improve the pharmacological treatment and patient compliance. Moreover, the application of various stem cell types with restorative and neuroprotective intent may be found appealing (intravitreal autologous cellular therapy). Advances are made also in terms of parasurgical treatment, characterized by various laser types and techniques. Moreover, recent research has led to the development of central and peripheral retinal rehabilitation (featuring residing cells reactivation and replacement of defective elements), as well as innovations in diagnosis through more specific and refined methods and inexpensive tests. PMID:28928631

Optical coherence tomography angiography in glaucoma care.

PubMed

Chansangpetch, Sunee; Lin, Shan C

2018-05-14

Rapid improvements in optical coherence tomography (OCT) technology have allowed for enhancement of both image resolution and scanning speed, and the development of vascular assessment modality. Optical coherence tomography angiography (OCTA) is the non-invasive in vivo imaging of the vasculature located within the retina and optic nerve head area. The principle of OCTA is to use the variations in OCT signals caused by moving particles as the contrast mechanism for imaging of flow. Several algorithms which aim to maximize the contrast signal and minimize the noise have been developed including the phase-based techniques, intensity-based techniques (e.g., split-spectrum amplitude decorrelation angiography (SSADA)), and complex-based techniques (e.g., optical microangiography (OMAG)). With its reliable technique, high image resolution, and current availability, OCTA has been widely used in the assessment of posterior segment diseases including glaucoma in which ocular perfusion dysfunction has been proposed as a pathophysiological mechanism. This review will provide the reader with information on the principle techniques of OCTA; the current literature on OCTA reproducibility; its applications to glaucoma detection and monitoring of progression; and the role of OCTA in the assessment of the vascular component in glaucoma pathogenesis.

Variability of vertical cup to disc ratio measurement and the effects of glaucoma 5-year risk estimation in untreated ocular hypertensive eyes.

PubMed

Chan, Poemen Pui Man; Chiu, Vivian S M; Wong, Mandy O I

2018-06-01

To compare the vertical cup to disc ratio (VCDR) measurements obtained with optical coherence tomography (OCT), Heidelberg retina tomography (HRT) and stereophotography of the optic nerve head (ONH) in patients with ocular hypertension (OHT), and their corresponding estimated 5-year risk for development of glaucoma. ONH images of patients with OHT were taken by fundus camera (stereoscopic images), OCT and HRT. Optic disc stereophotographs were evaluated with a stereo-viewer by two glaucoma specialists (SP1 and SP2) and the VCDR was measured with the ImageJ software. VCDR measurements obtained with stereophotography, OCT and HRT were used to calculate the estimated 5-year risk. One hundred and forty eyes of 75 patients with OHT were included. The VCDR values measured by OCT, HRT, SP1 and SP2 were 0.60±0.14, 0.53±0.23, 0.44±0.13 and 0.49±0.10, respectively. The corresponding 5-year risk for development of glaucoma was 19.54%±16.60%, 18.13%±16.96%, 15.64%±14.35% and 16.70%±14.49%, respectively. Different degrees of proportional biases were observed in VCDR measurements obtained with stereophotography, OCT and HRT. The maximum difference of VCDR measurement was 0.64, while the maximum difference of the corresponding 5-year risk was 24.02%. The disagreement in VCDR measured by OCT, HRT and stereophotography in untreated OHT eyes extends to their 5-year risk estimation of glaucoma development. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Conjunctival inclusion cyst following repair of tube erosion in a child with aphakic glaucoma, leading to endophthalmitis.

PubMed

Roy, Avik Kumar; Senthil, Sirisha

2015-01-01

Glaucoma in aphakia is a major long term complication following congenital cataract surgery. Implantation of glaucoma drainage device provides an effective approach to manage refractory paediatric glaucoma. However implant surgery in young individuals is not free of complications. The prompt detection and management of tube erosion is of utmost importance to prevent devastating sequel of endophthalmitis. Implantation cyst following repair of tube erosion has not been reported so far. This case illustrates the rare occurrence of inclusion cyst following repair of tube erosion, the possible causes and its consequences. A 2-year-old child with aphakia developed intractable glaucoma. Following a failed glaucoma filtering surgery he underwent sequential Ahmed Glaucoma Valve implantation in both the eyes. Six weeks following right eye surgery, the child presented with conjunctival erosion overlying the tube, which was treated with scleral patch graft and conjunctival advancement. One month after the repair of tube erosion, the child presented with implantation cyst under the scleral patch graft, which was treated by drainage with a 29G needle. The child presented with endophthalmitis of his right eye following an episode of bilateral conjunctivitis. This was managed by an emergency pars plana vitrectomy, intraocular antibiotics and tube excision. At the last follow up visit, the IOP was 20 mmHg with 2 topical antiglaucoma medications in the right eye following a trans scleral photocoagulation. Lifelong careful follow-up of paediatric eyes with implant surgery is mandatory to look for complication such as tube erosion. It is important to place additional sutures to secure the patch graft during implantation of glaucoma drainage devices in children to prevent graft displacement and consequent tube erosion. During repair of tube erosion, it is crucial to remove all the conjunctival epithelium around the tube, thus not to incorporate epithelial tissue within the surgical wound.

The Cost-Effectiveness Analysis of Teleglaucoma Screening Device

PubMed Central

Thomas, Sera

2015-01-01

Glaucoma is the leading cause of irreversible vision loss and costs the American economy $2.9 billion. Teleglaucoma remotely detects glaucoma improving access to ophthalmic care in rural areas. It helps manage glaucoma more efficiently to preserve vision and reduce healthcare costs. A cost-effectiveness analysis was conducted using healthcare provider or third-party payer perspective within rural Canada. The study population were patients at-risk of glaucoma which includes those with diabetes and/or hypertension, family history of glaucoma, adults older than 50 years, and concurrent ocular conditions in rural Alberta. Markov modelling was used to model glaucoma health states. Effectiveness was measured in Quality-Adjusted Life Years (QALYs) and costs were used in Canadian dollars. Using TreeAge Pro 2009, incremental cost-effectiveness ratios (ICER) were developed in dollars per QALYs. Deterministic and probabilistic sensitivity analyses were performed to assess the factors affecting cost-effectiveness. Teleglaucoma had a 20% increase in ophthalmologist-referral rate; it reduced patient travel times by 61 hours and physician wait times by 30% in comparison to in-person examination (standard of care). Teleglaucoma costs $872 per patient screened which was 80% less than in-person examination. Teleglaucoma had a greater incremental effectiveness providing an additional 0.12 QALY per patient examination. It was more sensitive (86.5%) and less specific (78.6%) than in-person examination. Teleglaucoma was more cost-effective than in-person examination with an ICER of-$27,460/QALY. This indicated that teleglaucoma will save $27, 460 for each additional QALY gained. Long term benefits showed teleglaucoma prevents 24% cases of glaucoma blindness after 30 years. Teleglaucoma demonstrated improved health outcomes, as well as, cost benefits. It increases access to ophthalmic care and improves healthcare service efficiency, specifically in rural areas. Teleglaucoma is more cost-effective than current in-person examination and can improve the quality of life in glaucoma patients. PMID:26382956

The Cost-Effectiveness Analysis of Teleglaucoma Screening Device.

PubMed

Thomas, Sera; Hodge, William; Malvankar-Mehta, Monali

2015-01-01

Glaucoma is the leading cause of irreversible vision loss and costs the American economy $2.9 billion. Teleglaucoma remotely detects glaucoma improving access to ophthalmic care in rural areas. It helps manage glaucoma more efficiently to preserve vision and reduce healthcare costs. A cost-effectiveness analysis was conducted using healthcare provider or third-party payer perspective within rural Canada. The study population were patients at-risk of glaucoma which includes those with diabetes and/or hypertension, family history of glaucoma, adults older than 50 years, and concurrent ocular conditions in rural Alberta. Markov modelling was used to model glaucoma health states. Effectiveness was measured in Quality-Adjusted Life Years (QALYs) and costs were used in Canadian dollars. Using TreeAge Pro 2009, incremental cost-effectiveness ratios (ICER) were developed in dollars per QALYs. Deterministic and probabilistic sensitivity analyses were performed to assess the factors affecting cost-effectiveness. Teleglaucoma had a 20% increase in ophthalmologist-referral rate; it reduced patient travel times by 61 hours and physician wait times by 30% in comparison to in-person examination (standard of care). Teleglaucoma costs $872 per patient screened which was 80% less than in-person examination. Teleglaucoma had a greater incremental effectiveness providing an additional 0.12 QALY per patient examination. It was more sensitive (86.5%) and less specific (78.6%) than in-person examination. Teleglaucoma was more cost-effective than in-person examination with an ICER of-$27,460/QALY. This indicated that teleglaucoma will save $27, 460 for each additional QALY gained. Long term benefits showed teleglaucoma prevents 24% cases of glaucoma blindness after 30 years. Teleglaucoma demonstrated improved health outcomes, as well as, cost benefits. It increases access to ophthalmic care and improves healthcare service efficiency, specifically in rural areas. Teleglaucoma is more cost-effective than current in-person examination and can improve the quality of life in glaucoma patients.

Green disease in optical coherence tomography diagnosis of glaucoma.

PubMed

Sayed, Mohamed S; Margolis, Michael; Lee, Richard K

2017-03-01

Optical coherence tomography (OCT) has become an integral component of modern glaucoma practice. Utilizing color codes, OCT analysis has rendered glaucoma diagnosis and follow-up simpler and faster for the busy clinician. However, green labeling of OCT parameters suggesting normal values may confer a false sense of security, potentially leading to missed diagnoses of glaucoma and/or glaucoma progression. Conditions in which OCT color coding may be falsely negative (i.e., green disease) are identified. Early glaucoma in which retinal nerve fiber layer (RNFL) thickness and optic disc parameters, albeit labeled green, are asymmetric in both eyes may result in glaucoma being undetected. Progressively decreasing RNFL thickness may reveal the presence of progressive glaucoma that, because of green labeling, can be missed by the clinician. Other ocular conditions that can increase RNFL thickness can make the diagnosis of coexisting glaucoma difficult. Recently introduced progression analysis features of OCT may help detect green disease. Recognition of green disease is of paramount importance in diagnosing and treating glaucoma. Understanding the limitations of imaging technologies coupled with evaluation of serial OCT analyses, prompt clinical examination, and structure-function correlation is important to avoid missing real glaucoma requiring treatment.

Awareness of glaucoma in the rural population of Southern India.

PubMed

Krishnaiah, Sannapaneni; Kovai, Vilas; Srinivas, Marmamula; Shamanna, Bindiganavale R; Rao, Gullapalli N; Thomas, Ravi

2005-09-01

To explore the awareness of glaucoma amongst the rural population of Andhra Pradesh, India. A total of 7775 subjects of all ages, representative of the rural population of Andhra Pradesh, participated in the Andhra Pradesh Eye Disease Study. The responses of subjects older than 15 years (n=5573) who completed a structured questionnaire regarding awareness (heard of glaucoma) and knowledge (understanding of disease) of glaucoma formed the basis of this study. Awareness of glaucoma (n=18; 0.32%) was very poor in this rural population, and females were significantly less aware (p=0.007). Awareness of glaucoma was also significantly less among illiterate persons (p<0.0001), and socially backward population (p<0.0001). Majority of the respondents who were aware of glaucoma (n=10; 55.6%) did not know if visual loss due to glaucoma was permanent or reversible. The major source of awareness of glaucoma in this population was TV/magazines and other media followed by information from a relative or acquaintance suffering from the disease. Awareness of glaucoma is very poor in the rural areas of southern India. The data suggest the need for community-based health education programmes to increase the level of awareness and knowledge about glaucoma.

Glaucoma Structural and Functional Progression in American and Korean Cohorts

PubMed Central

Kostanyan, Tigran; Sung, Kyung Rim; Schuman, Joel S.; Ling, Yun; Lucy, Katie A.; Bilonick, Richard A.; Ishikawa, Hiroshi; Kagemann, Larry; Lee, Jin Y.; Wollstein, Gadi

2016-01-01

Objective To compare the rate of glaucoma structural and functional progression in American and Korean cohorts. Design Retrospective longitudinal study. Participants 313 eyes from 189 glaucoma and glaucoma suspects, followed for an average of 38 months. Methods All subjects were examined semiannually with visual field (VF) testing and spectral-domain optical coherence tomography. All subjects had ≥5 reliable visits. Main Outcome Measurements The rates of change of retinal nerve fiber layer (RNFL) thickness, cup-to-disc (C/D) ratios, and VF mean deviation (MD) were compared between the cohorts. Variables affecting the rate of change for each parameter were determined, including ethnicity, refraction, baseline age and severity, disease subtype (high vs. normal tension glaucoma), clinical diagnosis (glaucoma vs. glaucoma suspect), and the interactions between variables. Results The Korean cohort was predominantly normal tension glaucoma, while the American cohort was high tension glaucoma. Cohorts had similar VF parameters at baseline, but the Korean eyes had significantly thinner mean RNFL and larger cups. Korean glaucoma eyes showed a faster thinning of mean RNFL (mean: −0.71 vs. −0.24μm/year, p<0.01). There was no detectable difference in the rate of change between the glaucoma cohorts for C/D ratios and VF MD and for all parameters in glaucoma suspect eyes. Different combinations of the tested variables significantly impacted the rate of change. Conclusion Ethnicity, baseline severity, disease subtype, and clinical diagnosis should be considered when comparing glaucoma progression studies. PMID:26778345

Clinical outcomes of Ahmed glaucoma valve implantation in pediatric glaucoma.

PubMed

Pakravan, Mohammad; Esfandiari, Hamed; Yazdani, Shahin; Doozandeh, Azadeh; Dastborhan, Zahra; Gerami, Ebrahim; Kheiri, Bahareh; Pakravan, Parastou; Yaseri, Mehdi; Hassanpour, Kiana

2018-03-01

To evaluate the outcomes of Ahmed glaucoma valve implantation in refractory primary congenital glaucoma as well as primary procedure in aphakic glaucoma. In this retrospective study, medical records of patients who underwent Ahmed glaucoma valve implantation for refractory glaucoma and aphakic glaucoma were reviewed. Primary outcome measures were the surgical success defined as intraocular pressure ≤21 mm Hg and decreased ≥20% and no secondary glaucoma surgery. Secondary outcome measures were the number of glaucoma medications, complications, best corrected visual acuity, and intraocular pressure. A total of 62 eyes of refractory primary congenital glaucoma patients (group 1) and 33 eyes of aphakic glaucoma patients (group 2) were included in our study. Mean follow-up was 51 ± 33 months in group 1 and 49 ± 41 months in group 2 (p = 0.82). The cumulative probability of success was 90% in both groups at the first year; however, the success rate was 52.5% in group 1 and 71.5% in group 2 at 5 years' follow-up visit. In group 1, the mean intraocular pressure ± standard deviation was 33.1 ± 8.6 mm Hg at the baseline and decreased to 17.1 ± 5.3 mm Hg at 1 year and 18.5 ± 6.4 at 3 years postoperatively (all p's < 0.001). Corresponding values for group 2 were 28.9 ± 6.1, 15.2 ± 4.6, and 16.0 ± 5.9 mm Hg, respectively (all p's < 0.001). The baseline number of glaucoma medications was 3 ± 0.7 that decreased to 2 ± 0.8 at final follow-up (p = 0.02). Ahmed glaucoma valve implantation has a moderate success rate in the management of refractory primary congenital glaucoma with an increased chance of tube-related complications. The surgical success rate is higher in case of primary Ahmed glaucoma valve implant for aphakic glaucoma with acceptable safety profile.

LOXL1 deficiency in the lamina cribrosa as candidate susceptibility factor for a pseudoexfoliation-specific risk of glaucoma.

PubMed

Schlötzer-Schrehardt, Ursula; Hammer, Christian M; Krysta, Anita W; Hofmann-Rummelt, Carmen; Pasutto, Francesca; Sasaki, Takako; Kruse, Friedrich E; Zenkel, Matthias

2012-09-01

To test the hypothesis that a primary disturbance in lysyl oxidase-like 1 (LOXL1) and elastin metabolism in the lamina cribrosa of eyes with pseudoexfoliation syndrome constitutes an independent risk factor for glaucoma development and progression. Observational, consecutive case series. Posterior segment tissues obtained from 37 donors with early and late stages of pseudoexfoliation syndrome without glaucoma, 37 normal age-matched control subjects, 5 eyes with pseudoexfoliation-associated open-angle glaucoma, and 5 eyes with primary open-angle glaucoma (POAG). Protein and mRNA expression of major elastic fiber components (elastin, fibrillin-1, fibulin-4), collagens (types I, III, and IV), and lysyl oxidase crosslinking enzymes (LOX, LOXL1, LOXL2) were assessed in situ by quantitative real-time polymerase chain reaction, (immuno)histochemistry, and light and electron microscopy. Lysyl oxidase-dependent elastin fiber assembly was assessed by primary optic nerve head astrocytes in vitro. Expression levels of elastic proteins, collagens, and lysyl oxidases in the lamina cribrosa. Lysyl oxidase-like 1 proved to be the major lysyl oxidase isoform in the normal lamina cribrosa in association with a complex elastic fiber network. Compared with normal and POAG specimens, lamina cribrosa tissues obtained from early and late stages of pseudoexfoliation syndrome without and with glaucoma consistently revealed a significant coordinated downregulation of LOXL1 and elastic fiber constituents on mRNA and protein level. In contrast, expression levels of collagens and other lysyl oxidase isoforms were not affected. Dysregulated expression of LOXL1 and elastic proteins was associated with pronounced (ultra)structural alterations of the elastic fiber network in the laminar beams of pseudoexfoliation syndrome eyes. Inhibition of LOXL1 interfered with elastic fiber assembly by optic nerve head astrocytes in vitro. The findings provide evidence for a pseudoexfoliation-specific elastinopathy of the lamina cribrosa resulting from a primary disturbance in LOXL1 regulation and elastic fiber homeostasis, possibly rendering pseudoexfoliation syndrome eyes more vulnerable to pressure-induced optic nerve damage and glaucoma development and progression. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Effect of early childhood malnutrition on tooth eruption in Haitian adolescents.

PubMed

Psoter, W; Gebrian, B; Prophete, S; Reid, B; Katz, R

2008-04-01

The objective of this retrospective cohort study was to determine the effects of early childhood protein-energy malnutrition (EC-PEM) and current nutritional status as defined by anthropomorphic measures on the exfoliation and eruption patterns of teeth among adolescents. Oral clinical examinations were conducted in 2005 using World Health Organization (WHO) diagnostic criteria on 498 11- to 13-year-old Haitians for whom early childhood malnutrition data were available. Anthropomorphic records (weight-for-age) from the Haitian Health Foundation computerized database on children from birth through 5-years old were utilized. Current heights and weights were ascertained. Both sets of data were converted to z-scores based on the National Center for Health Statistics (NCHS) referent database. Based upon these z-scores, EC-PEM and current malnutrition categories were developed for this study. The analyses separately regressed the number of primary and permanent teeth on age, gender, EC-PEM status and current nutritional status. Both a delayed exfoliation of primary teeth and a delayed eruption of permanent teeth were associated with EC-PEM and current stunting in adolescence. The observed associations were either direct and statistically significant or indirectly demonstrated by presenting evidence of confounding. The overall interpretation of the models is that malnutrition beginning in the earliest years and extending throughout childhood influences the exfoliation and eruption of teeth. These findings present evidence of an association between tooth exfoliation/eruption patterns and both EC-PEM and nutritional insufficiency (stunting) throughout childhood. This observed delay in the exfoliation of the primary dentition and in the eruption of the permanent dentition has practical significance in interpreting age-specific dental caries data from populations with different malnutrition experiences.

Pseudoexfoliation Syndrome and Sensorineural Hearing Loss

PubMed Central

Zojaji, Ramin; Alesheykh, Ali; Sedaghat, Mohammad Reza; Navia, Kiamarz; Mazloom Farsi Baf, Morteza; Khaki, Masoud; Raouf, Aliasghar

2011-01-01

Introduction: Pseudoexfoliation syndrome (PXS) occurs due to the deposition of extracellular fibrillar materials on the anterior chamber of the eye. This syndrome has been considered to be part of a systemic disease with the potential involvement of the inner ear called sensoroneural hearing loss (SNHL). In this study, we aimed on evaluating SNHL within PXS patients in Iran to compare them with other international reports. Materials and Methods: In total, 33 patients with PXS and 33 age and sex matched controls were enrolled prospectively in a case-control study. Both groups underwent complete ophthalmologic and otorhinolaryngologic examinations and pure tone audiometry (PTA) testing. Six frequencies (0.25, 0.5, 1, 2, 3, 4 and 6 KHz) were evaluated for PTA in the same ethnic group in order to select the case and control individuals. Data were analyzed using t-test and chi-square test. Results: Forty-nine out of 66 ears (75.2%) in the PXS group and 27 ears (40.9%) in the control group had SNHL (P<0.001). No significant difference was found between the existence of exfoliative glaucoma (EXG) and SNHL in the PXS patients (P=0.768). Conclusion: Our results indicate a significant association between PXS and SNHL and may support the systemic nature of this disease. PMID:24303375

Intermediate and Long-term Outcomes of Mitomycin C-enhanced Trabeculectomy as a First Glaucoma Procedure in Uveitic Glaucoma.

PubMed

Almobarak, Faisal A; Alharbi, Ali H; Morales, Jose; Aljadaan, Ibrahim

2017-05-01

To evaluate the intermediate and long-term outcomes of mitomycin C-enhanced trabeculectomy as a first glaucoma procedure in uveitic glaucoma. Retrospective cohort study included 70 eyes of 50 patients with uveitic glaucoma who underwent mitomycin C-enhanced trabeculectomy as a first glaucoma procedure at King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia between 1996 and 2014. The main outcome measures were: the intraocular pressure (IOP), the number of antiglaucoma medications, the presence of visually threatening complications, and the need for further surgeries to control the IOP. Surgical outcome of each eye was classified as an absolute success, qualified success, or failure, based on the main outcome measures. The mean follow-up period was 77.0 months (±40.9). The IOP and number of antiglaucoma medications decreased significantly from a mean of 39.5 mm Hg (±8.9) and 3.7 (±0.8) to 14.4 mm Hg (±6.9) and 1 (±1.3) at the last follow-up, respectively (P<0.001 for both). The cumulative probabilities of success were 60% and 35.7% at 36 and 60 months postoperatively, respectively. The most common complications were cataract development and progression (45.3%), hypotony (IOP ≤5 mm Hg) (30%) and IOP spike≥30 mm Hg (10%). Eighteen eyes (25.7%) needed a second procedure to control the IOP. Although mitomycin C-enhanced trabeculectomy offers reasonable intermediate and long-term IOP control and safety in uveitic glaucoma, a significant number of patients needed further procedures to control the pressure. Thus, continuous monitoring of the pressure and inflammation are crucial.

Frequency doubling technique perimetry and spectral domain optical coherence tomography in patients with early glaucoma.

PubMed

Horn, F K; Mardin, C Y; Bendschneider, D; Jünemann, A G; Adler, W; Tornow, R P

2011-01-01

To assess the combined diagnostic power of frequency-doubling technique (FDT)-perimetry and retinal nerve fibre layer (RNFL) thickness measurements with spectral domain optical coherence tomography (SDOCT). The study included 330 experienced participants in five age-related groups: 77 'preperimetric' open-angle glaucoma (OAG) patients, 52 'early' OAG, 50 'moderate' OAG, 54 ocular hypertensive patients, and 97 healthy subjects. For glaucoma assessment in all subjects conventional perimetry, evaluation of fundus photographs, FDT-perimetry and RNFL thickness measurement with SDOCT was done. Glaucomatous visual field defects were classified using the Glaucoma Staging System. FDT evaluation used a published method with casewise calculation of an 'FDT-score', including all missed localized probability levels. SDOCT evaluation used mean RNFL thickness and a new individual SDOCT-score considering normal confidence limits in 32 sectors of a peripapillary circular scan. To examine the joined value of both methods a combined score was introduced. Significance of the difference between Receiver-operating-characteristic (ROC) curves was calculated for a specificity of 96%. Sensitivity in the preperimetric glaucoma group was 44% for SDOCT-score, 25% for FDT-score, and 44% for combined score, in the early glaucoma group 83, 81, and 89%, respectively, and in the moderate glaucoma group 94, 94, and 98%, respectively, all at a specificity of 96%. ROC performance of the newly developed combined score is significantly above single ROC curves of FDT-score in preperimetric and early OAG and above RNFL thickness in moderate OAG. Combination of function and morphology by using the FDT-score and the SDOCT-score performs equal or even better than each single method alone.

Frequency doubling technique perimetry and spectral domain optical coherence tomography in patients with early glaucoma

PubMed Central

Horn, F K; Mardin, C Y; Bendschneider, D; Jünemann, A G; Adler, W; Tornow, R P

2011-01-01

Purpose To assess the combined diagnostic power of frequency-doubling technique (FDT)-perimetry and retinal nerve fibre layer (RNFL) thickness measurements with spectral domain optical coherence tomography (SDOCT). Methods The study included 330 experienced participants in five age-related groups: 77 ‘preperimetric' open-angle glaucoma (OAG) patients, 52 ‘early' OAG, 50 ‘moderate' OAG, 54 ocular hypertensivepatients, and 97 healthy subjects. For glaucoma assessment in all subjects conventional perimetry, evaluation of fundus photographs, FDT-perimetry and RNFL thickness measurement with SDOCT was done. Glaucomatous visual field defects were classified using the Glaucoma Staging System. FDT evaluation used a published method with casewise calculation of an ‘FDT-score', including all missed localized probability levels. SDOCT evaluation used mean RNFL thickness and a new individual SDOCT-score considering normal confidence limits in 32 sectors of a peripapillary circular scan. To examine the joined value of both methods a combined score was introduced. Significance of the difference between Receiver-operating-characteristic (ROC) curves was calculated for a specificity of 96%. Results Sensitivity in the preperimetric glaucoma group was 44% for SDOCT-score, 25% for FDT-score, and 44% for combined score, in the early glaucoma group 83, 81, and 89%, respectively, and in the moderate glaucoma group 94, 94, and 98%, respectively, all at a specificity of 96%. ROC performance of the newly developed combined score is significantly above single ROC curves of FDT-score in preperimetric and early OAG and above RNFL thickness in moderate OAG. Conclusion Combination of function and morphology by using the FDT-score and the SDOCT-score performs equal or even better than each single method alone. PMID:21102494

Ahmed Versus Baerveldt Glaucoma Drainage Implantation in Patients With Markedly Elevated Intraocular Pressure (≥30 mm Hg).

PubMed

Resende, Arthur F; Moster, Marlene R; Patel, Neal S; Lee, Daniel; Dhami, Hermandeep; Pro, Michael J; Waisbourd, Michael

2016-09-01

Glaucoma patients with markedly elevated intraocular pressure (IOP) are at risk for developing severe hypotony-related complications. The goal of this study was to compare the surgical outcomes of the Ahmed Glaucoma Valve (AGV) and the Baerveldt Glaucoma Implant (BGI) in this patient population. Patients with preoperative IOP≥30 mm Hg were included. Outcome measures were: (1) surgical failure (IOP>21 mm Hg or <30% reduction from baseline or IOP≤5 mm Hg on 2 consecutive follow-up visits after 3 mo, or additional glaucoma surgery, or loss of light perception) and (2) surgical complications. A total of 75 patients were included: 37 in the AGV group and 38 in the BGI group. The mean±SD follow-up was 2.3±1.6 years for the AGV group and 2.4±1.7 years for the BGI group (P=0.643). Mean preoperative IOP was 38.7±6.5 mm Hg for the AGV group and 40.8±7.6 mm Hg for the BGI group. At the last follow-up, 10 (27.0%) patients failed in the AGV group compared with 6 (15.8%) patients in the BGI group (P=0.379). The BGI group had higher rate of flat or shallow anterior chamber (n=4, 10%) compared with the AGV group (n=0, 0%) (P=0.043). Failure rates of AGV and BGI in patients with IOP≥30 mm Hg were comparable. There were more early hypotony-related complications in the BGI group; however, none were vision threatening. Both glaucoma drainage implants were effective in treating patients with uncontrolled glaucoma in an emergency setting.

Resource Planning in Glaucoma: A Tool to Evaluate Glaucoma Service Capacity.

PubMed

Batra, Ruchika; Sharma, Hannah E; Elaraoud, Ibrahim; Mohamed, Shabbir

2017-12-28

The National Patient Safety Agency (2009) publication advising timely follow-up of patients with established glaucoma followed several reported instances of visual loss due to postponed appointments and patients lost to follow-up. The Royal College of Ophthalmologists Quality Standards Development Group stated that all hospital appointments should occur within 15% of the intended follow-up period. To determine whether: 1. Glaucoma follow-up appointments at a teaching hospital occur within the requested time 2. Appointments are requested at appropriate intervals based on the NICE Guidelines 3. The capacity of the glaucoma service is adequate Methods: A two-part audit was undertaken of 98 and 99 consecutive patients respectively attending specialist glaucoma clinics. In the first part, the reasons for delayed appointments were recorded. In the second part the requested follow-up was compared with NICE guidelines where applicable. Based on the findings, changes were implemented and a re-audit of 100 patients was carried out. The initial audit found that although clinical decisions regarding follow-up intervals were 100% compliant with NICE guidelines where applicable, 24% of appointments were delayed beyond 15% of the requested period, due to administrative errors and inadequate capacity, leading to significant clinical deterioration in two patients. Following the introduction of an electronic appointment tracker and increased clinical capacity created by extra clinics and clinicians, the re-audit found a marked decrease in the percentage of appointments being delayed (9%). This audit is a useful tool to evaluate glaucoma service provision, assist in resource planning for the service and bring about change in a non-confrontational way. It can be widely applied and adapted for use in other medical specialities.

Epidemiology of Glaucoma in Sub-Saharan Africa: Prevalence, Incidence and Risk Factors

PubMed Central

Kyari, Fatima; Abdull, Mohammed M.; Bastawrous, Andrew; Gilbert, Clare E.; Faal, Hannah

2013-01-01

Purpose: The purpose of this study is to review the epidemiology of different types of glaucoma relevant to Sub-Saharan Africa (SSA) and to discuss the evidence regarding the risk factors for onset and progression of glaucoma, including risk factors for glaucoma blindness. Methods: Electronic databases (PubMed, MedLine, African Journals Online- AJOL) were searched using the full text, Medical Subject Headings (MeSH) terms, author(s) and title to identify publications since 1982 in the following areas: population-based glaucoma prevalence and incidence studies in SSA and in African-derived black populations outside Africa; population-based prevalence and incidence of blindness and visual impairment studies in SSA including rapid assessment methods, which elucidate the glaucoma-specific blindness prevalence; studies of risk factors for glaucoma; and publications that discussed public health approaches for the control of glaucoma in Africa. Results: Studies highlighted that glaucoma in SSA is a public health problem and predominantly open-angle glaucoma. It is the second-leading cause of blindness, has a high prevalence, an early onset and progresses more rapidly than in Caucasians. These factors are further compounded by poor awareness and low knowledge about glaucoma even by persons affected by the condition. Conclusion: Glaucoma care needs to be given high priority in Vision 2020 programs in Africa. Many questions remain unanswered and there is a need for further research in glaucoma in SSA in all aspects especially epidemiology and clinical care and outcomes involving randomized controlled trials. Genetic and genome-wide association studies may aid identification of high-risk groups. Social sciences and qualitative studies, health economics and health systems research will also enhance public health approaches for the prevention of blindness due to glaucoma. PMID:23741130

Short term outcome of Ahmed glaucoma valve implantation in management of refractory glaucoma in a tertiary hospital in Oman

PubMed Central

Shah, Manali R.; Khandekar, Rajiv B.; Zutshi, Rajiv; Mahrooqi, Rahima

2013-01-01

Background: We present outcomes of Ahmed Glaucoma Valve (AGV) implantation in treating refractory glaucoma in a tertiary hospital in Oman. Refractory glaucoma was defined as previously failed conventional glaucoma surgery and an uncontrolled intraocular pressure (IOP) of more than 21 mm Hg despite treatment with three topical and/or oral therapy. Materials and Methods: This historical cohort study was conducted in 2010. Details of medical and surgical treatment were recorded. Ophthalmologists examined eyes and performed glaucoma surgeries using AGV. The best corrected distant vision, IOP, and glaucoma medications were prospectively reviewed on 1st day, 1st, 6th, 12th week postoperatively, and at the last follow up. Result: Glaucoma specialists examined and treated 40 eyes with refractory glaucoma of 39 patients (20 males + 19 females). Neo-vascular glaucoma was present in 23 eyes. Vision before surgery was <3/60 in 21 eyes. At 12 weeks, one eye had vision better than 6/12, seven eyes had vision 6/18 to 6/60, and eight eyes had vision 6/60 to 3/60. Mean IOP was reduced from 42.9 (SD 16) to 14.2 (SD 8) and 19.1 (SD 7.8) mmHg at one and 12 weeks after surgery, respectively. At 12 weeks, five (12.5%) eyes had IOP controlled without medication. In 33 (77.5%) eyes, pressure was controlled by using one or two eye drops. The mean number of preoperative anti-glaucoma medications (2.38; SD 1.1) was reduced compared to the mean number of postoperative medications (1.92; SD 0.9) at 12 weeks. Conclusion: We succeeded in reducing visual disabilities and the number of anti-glaucoma medications used to treat refractory glaucoma by AGV surgery. PMID:23772122

Provider Agreement in the Assessment of Glaucoma Progression within a Team Model.

PubMed

Shah, Saumya; Choo, Clara; Odden, Jamie; Zhao, Bingying; Fang, Chengbo; Schornack, Muriel; Stalboerger, Gina; Bennett, Jeffrey R; Khanna, Cheryl L

2018-06-04

Glaucoma specialists and optometrists who work in a team model at a single institution utilize a common definition of glaucoma progression and treatment algorithm. The purpose of this study was to assess the consistency of agreement in identifying glaucoma progression among glaucoma specialists and optometrists of one team. 399 eyes of 200 patients age 18 or older with glaucoma were enrolled over two years. Clinical data, disc photographs, OCT, and visual fields were independently reviewed by two masked optometrists and two masked fellowship-trained glaucoma specialists. Each eye was judged as progression or no-progression of glaucomatous disease. The following were assessed: (1) agreement among optometrists; (2) agreement among glaucoma specialists; and (3) agreement among optometrists and glaucoma specialists. The frequency of use of testing modality to determine progression was also studied. Kappa statistics were used to evaluate agreements. Optometrists agreed with each other for 74.2% of the eyes assessed (κ=0.42), whereas glaucoma specialists agreed with each other for 78.7% of eyes (κ=0.39). All four providers agreed with each other for 54.4% of the eyes evaluated (κ=0.37). Providers had the highest agreement when the progression decision was based on disc hemorrhage (92%) and the lowest agreement when based on OCT progression analysis (36%). Compared to optometrists, glaucoma specialists used OCT (P= <0.01) more frequently to determine disease progression. Fair to moderate agreement levels were found among providers in their assessment of glaucoma progression, suggesting that a team approach to glaucoma management may be effective. Further work is needed to investigate ways to optimize consistency within the glaucoma team.

Separation medium containing thermally exfoliated graphite oxide

NASA Technical Reports Server (NTRS)

Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Herrera-Alonso, Margarita (Inventor)

2012-01-01

A separation medium, such as a chromatography filling or packing, containing a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g, wherein the thermally exfoliated graphite oxide has a surface that has been at least partially functionalized.

Angle closure glaucoma in congenital ectropion uvea.

PubMed

Wang, Grace M; Thuente, Daniel; Bohnsack, Brenda L

2018-06-01

Congenital ectropion uvea is a rare anomaly, which is associated with open, but dysplastic iridocorneal angles that cause childhood glaucoma. Herein, we present 3 cases of angle-closure glaucoma in children with congenital ectropion uvea. Three children were initially diagnosed with unilateral glaucoma secondary to congenital ectropion uvea at 7, 8 and 13 years of age. The three cases showed 360° of ectropion uvea and iris stromal atrophy in the affected eye. In one case, we have photographic documentation of progression to complete angle closure, which necessitated placement of a glaucoma drainage device 3 years after combined trabeculotomy and trabeculectomy. The 2 other cases, which presented as complete angle closure, also underwent glaucoma drainage device implantation. All three cases had early glaucoma drainage device encapsulation (within 4 months) and required additional surgery (cycloablation or trabeculectomy). Congenital ectropion uvea can be associated with angle-closure glaucoma, and placement of glaucoma drainage devices in all 3 of our cases showed early failure due to plate encapsulation. Glaucoma in congenital ectropion uvea requires attention to angle configuration and often requires multiple surgeries to obtain intraocular pressure control.

Engineering New Layered Solids from Exfoliated Inorganics: a Periodically Alternating Hydrotalcite – Montmorillonite Layered Hybrid

PubMed Central

Chalasani, Rajesh; Gupta, Amit; Vasudevan, Sukumaran

2013-01-01

Two-dimensional (2D) nanosheets obtained by exfoliating inorganic layered crystals have emerged as a new class of materials with unique attributes. One of the critical challenges is to develop robust and versatile methods for creating new nanostructures from these 2D-nanosheets. Here we report the delamination of layered materials that belonging to two different classes - the cationic clay, montmorillonite, and the anionic clay, hydrotalcite - by intercalation of appropriate ionic surfactants followed by dispersion in a non-polar solvent. The solids are delaminated to single layers of atomic thickness with the ionic surfactants remaining tethered to the inorganic and consequently the nanosheets are electrically neutral. We then show that when dispersions of the two solids are mixed the exfoliated sheets self-assemble as a new layered solid with periodically alternating hydrotalcite and montmorillonite layers. The procedure outlined here is easily extended to other layered solids for creating new superstructures from 2D-nanosheets by self-assembly. PMID:24336682

Atomically thin gallium layers from solid-melt exfoliation

PubMed Central

Kochat, Vidya; Samanta, Atanu; Zhang, Yuan; Bhowmick, Sanjit; Manimunda, Praveena; Asif, Syed Asif S.; Stender, Anthony S.; Vajtai, Robert; Singh, Abhishek K.; Tiwary, Chandra S.; Ajayan, Pulickel M.

2018-01-01

Among the large number of promising two-dimensional (2D) atomic layer crystals, true metallic layers are rare. Using combined theoretical and experimental approaches, we report on the stability and successful exfoliation of atomically thin “gallenene” sheets on a silicon substrate, which has two distinct atomic arrangements along crystallographic twin directions of the parent α-gallium. With a weak interface between solid and molten phases of gallium, a solid-melt interface exfoliation technique is developed to extract these layers. Phonon dispersion calculations show that gallenene can be stabilized with bulk gallium lattice parameters. The electronic band structure of gallenene shows a combination of partially filled Dirac cone and the nonlinear dispersive band near the Fermi level, suggesting that gallenene should behave as a metallic layer. Furthermore, it is observed that the strong interaction of gallenene with other 2D semiconductors induces semiconducting to metallic phase transitions in the latter, paving the way for using gallenene as promising metallic contacts in 2D devices. PMID:29536039

Ionic Liquid-Modified Thermosets and Their Nanocomposites: Dispersion, Exfoliation, Degradation, and Cure

NASA Astrophysics Data System (ADS)

Throckmorton, James A.

This dissertation explores the application of a room temperature ionic liquid (RTIL) to problems in the chemistry, processing, and modification of thermosetting polymers. In particular, the solution properties and reaction chemistry of 1-ethyl-3-methyl imidazolium dicyanamide (EMIM-DCN) are applied to problems of nanoparticle dispersion and processing, graphite exfoliation, cyanate ester (CE) cure, and the environmental degradation of CEs. Nanoparticle Dispersion: Nanocomposite processing can be simplified by using the same compound as both a nanoparticle solvent and an initiator for polymerization. This dual-function molecule can be designed both for solvent potential and reaction chemistry. EMIM-DCN, previously shown by our lab to act as an epoxy initiator, is used in the synthesis of silica and acid expanded graphite composites. These composites are then characterized for particle dispersion and physical properties. Individual particle dispersion of silica nanocomposites is shown, and silica nanocomposites at low loading show individual particle dispersion and improved modulus and fracture toughness. GNP nanocomposites show a 70% increase in modulus along with a 10-order of magnitude increase in electrical conductivity at 6.5 vol%, and an electrical percolation threshold of 1.7 vol%. Direct Graphite Exfoliation By Laminar Shear: This work presents a laminar-shear alternative to chemical processing and chaotic flow-fields for the direct exfoliation of graphite and the single-pot preparation of nanocomposites. Additionally, we develop the theory of laminar flow through a 3-roll mill, and apply that theory to the latest developments in the theory of graphite interlayer shear. The resulting nanocomposite shows low electrical percolation (0.5 vol%) and low thickness (1-3 layer) graphite/graphene flakes. Additionally, the effect of processing conditions by rheometry and comparison with solvent-free conditions reveal the interactions between processing and matrix properties and provide insight into the theory of the chemical and physical exfoliation of graphite crystals and the resulting polymer matrix dispersion. Cyanate Ester Cure: Dicyanamide-containing ionic liquids decrease the cure temperature of bi- and tri-functional CEs. During the cure reaction, the dicyanamide anion completely reacts and is incorporated into the triazine network. The cure effect was found in many dicyanamide-containing ionic liquids with diverse cations. This invention creates a novel, ionic thermoset polymer. The dicyanamide initiator provides an alternative to metal and hydroxyl catalysts (which have been shown to accelerate degradation and possess human and environmental toxicity). Additionally, the ionic character of the new polymer, rare among thermosets, lends itself to future research and novel applications. RTIL initiation also paves the way to new CE technologies, including RTIL-CE nanocomposites, prepared by graphite exfoliation and nanocomposite dispersion techniques developed herin.

Glaucoma: Hot Topics in Pharmacology.

PubMed

Balendra, Shiama I; Shah, Parth Arvind; Jain, Mishank; Grzybowski, Andrzej; Cordeiro, Maria F

2017-01-01

Glaucoma comprises a group of neurodegenerative diseases resulting in retinal ganglion cell death within the optic nerve head. It is projected to affect almost 80 million people worldwide by 2020. The condition's asymptomatic nature translates to over half of glaucoma sufferers being unaware of their condition. By the time of diagnosis, irreversible blindness is likely to have occurred. Prime areas of glaucoma research therefore include identification and optimization of risk factors for the disease, accurate and early diagnostic tools and novel therapeutic methods. The goal of this review was to summarize main areas of latest glaucoma research into risk factors of glaucoma, diagnostic tools and treatments. PubMed was used to search for terms including glaucoma risk factors, glaucoma diagnostics, glaucoma treatment, glaucoma drug delivery and glaucoma IOP. The evidence for risk factors of low CSF pressure, IOP, smoking, vascular risk factors and light toxicity is described. Latest diagnostic and monitoring techniques for glaucoma include SD-OCT, DARC and IOP telemetry. Current and emerging medical and surgical treatments in glaucoma are discussed. Rho kinase inhibitors have the potential to both lower IOP and also provide neuroprotection, several of which are in clinical trials. Several other new medical treatments such as calcium channel blockers and neurotrophic agents also have the capacity to provide neuroprotection. Minimally Invasive Glaucoma Surgery (MIGS) devices provide an improved safety profile compared to traditional trabeculectomy; the latest ab interno and ab externo devices are described. Novel drug delivery methods, including punctual plugs and contact lenses, help overcome the challenges with patient adherence. The ultimate goals are to reduce the individual patient risk factors associated with glaucoma, diagnose the condition early and to find treatments that not only reduce IOP but also reverse neurodegeneration of RGCs. The usage of combinations of novel medical and surgical treatments may help maximize IOP reduction and neuroprotection. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Efficacy of intravitreal ranibizumab combined with Ahmed glaucoma valve implantation for the treatment of neovascular glaucoma.

PubMed

Tang, Min; Fu, Yang; Wang, Ying; Zheng, Zhi; Fan, Ying; Sun, Xiaodong; Xu, Xun

2016-01-09

Neovascular glaucoma is a refractive glaucoma. Recently, anti-VEGF factors have been used alone or in combination for the treatment of neovascular glaucoma. However, the medium- and long-term efficacy of such drugs remains to be evaluated. This study was to determine the efficacy of intravitreal ranibizumab combined with Ahmed glaucoma valve implantation for the treatment of neovascular glaucoma. In this prospective non-randomized study, 43 neovascular glaucoma patients (43 eyes) were assigned to receive either 0.5 mg intravitreal ranibizumab for three to 14 days before Ahmed glaucoma valve implantation (injection group, n = 21) or Ahmed glaucoma valve implantation alone (control group, n = 22). The patients were followed up for six to 12 months. Differences in surgical success rate, intraocular pressure, best corrected visual acuity, anti-glaucoma medications and postoperative complications were compared between the two groups. Surgical success was defined as IOP > = 6 mm Hg and < = 21 mm Hg, with or without the use of anti-glaucoma medications, and without severe complications or reoperation. Of the 43 patients, 40 completed the 6-month follow-up and 37 completed the 1-year follow-up. Success rate was 73.7% vs. 71.4% at six months and 72.2% vs. 68.4% at 12 months in the injection group and the control group respectively. No significant difference was noted between the two groups (six months: P = 0.87, 12 months: P = 1.00). There were no significant differences in the two groups with respect to intraocular pressure, best corrected visual acuity, anti-glaucoma medications or postoperative complications at six months or 12 months. Single intravitreal ranibizumab (0.5 mg) before surgery has no significant effect on the medium- or long-term outcomes of neovascular glaucoma treated with Ahmed glaucoma valve implantation. Chinese Clinical Trial Registry ( ChiCTR-OOC-14005709, Trial registration date: 2014-12-01).

Ethnicity and Deprivation are Associated With Blindness Among Adults With Primary Glaucoma in Nigeria: Results From the Nigeria National Blindness and Visual Impairment Survey.

PubMed

Kyari, Fatima; Wormald, Richard; Murthy, Gudlavalleti V S; Evans, Jennifer R; Gilbert, Clare E

2016-10-01

We explored the risk factors for glaucoma blindness among adults aged 40 years and above with primary glaucoma in Nigeria. A total of 13,591 participants aged 40 years and above were examined in the Nigeria Blindness Survey; 682 (5.02%; 95 CI, 4.60%-5.47%) had glaucoma by ISGEO's criteria. This was a case-control study (n=890 eyes of 629 persons): glaucoma blind persons were cases and glaucoma not-blind were controls. Education and occupation were used to determine socioeconomic status scores, which were divided into 3 tertiles (affluent, medium, deprived). We assessed sociodemographic, biophysical, and ocular factors by logistic regression analysis for association with glaucoma blindness. Multinomial regression analysis was also performed with nonglaucoma as the reference category. A total of 119/629 (18.9%; 95% CI, 15.9%-22.4%) persons were blind in both eyes; 510 were controls. There was interethnic variation in odds of blindness; age, male sex, socioeconomic status, prior diagnosis of glaucoma, hypertension, intraocular pressure, and lens opacity were associated with glaucoma blindness. Axial length, mean ocular perfusion pressure, and angle-closure glaucoma were associated with blind glaucoma eyes. In multivariate analysis, Igbo ethnicity (OR=2.79; 95% CI, 1.03-7.57) had higher risk as was being male (OR=4.59; 95% CI, 1.73-12.16) and unmarried (OR=2.50; 95% CI, 1.03-6.07). Deprivation (OR=3.57; 95% CI, 1.46-8.72), prior glaucoma diagnosis (OR=5.89; 95% CI, 1.79-19.40), and intraocular pressure (OR=1.07; 95% CI, 1.04-1.09) were also independent risk factors for glaucoma blindness. Approximately 1 in 5 people with primary glaucoma were blind. Male sex, ethnicity and deprivation were strongly associated with blindness. Services for glaucoma need to improve in Nigeria, focusing on poor communities and men.

Ultrasound exfoliation of inorganic analogues of graphene

PubMed Central

2014-01-01

High-intensity ultrasound exfoliation of a bulk-layered material is an attractive route for large-scale preparation of monolayers. The monolayer slices could potentially be prepared with a high yield (up to 100%) in a few minutes. Exfoliation of natural minerals (such as tungstenite and molybdenite) or bulk synthetic materials (including hexagonal boron nitride (h-BN), hexagonal boron carbon nitride (h-BCN), and graphitic carbon nitride (g-C3N4)) in liquids leads to the breakdown of the 3D graphitic structure into a 2D structure; the efficiency of this process is highly dependent upon the physical effects of the ultrasound. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were employed to verify the quality of the exfoliation. Herein, this new method of exfoliation with ultrasound assistance for application to mono- and bilayered materials in hydrophobic and hydrophilic environments is presented. PMID:24708572

Ultrasound exfoliation of inorganic analogues of graphene.

PubMed

Stengl, Václav; Henych, Jiří; Slušná, Michaela; Ecorchard, Petra

2014-04-05

High-intensity ultrasound exfoliation of a bulk-layered material is an attractive route for large-scale preparation of monolayers. The monolayer slices could potentially be prepared with a high yield (up to 100%) in a few minutes. Exfoliation of natural minerals (such as tungstenite and molybdenite) or bulk synthetic materials (including hexagonal boron nitride (h-BN), hexagonal boron carbon nitride (h-BCN), and graphitic carbon nitride (g-C3N4)) in liquids leads to the breakdown of the 3D graphitic structure into a 2D structure; the efficiency of this process is highly dependent upon the physical effects of the ultrasound. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were employed to verify the quality of the exfoliation. Herein, this new method of exfoliation with ultrasound assistance for application to mono- and bilayered materials in hydrophobic and hydrophilic environments is presented.

Simultaneous Graphite Exfoliation and N Doping in Supercritical Ammonia.

PubMed

Sasikala, Suchithra Padmajan; Huang, Kai; Giroire, Baptiste; Prabhakaran, Prem; Henry, Lucile; Penicaud, Alain; Poulin, Philippe; Aymonier, Cyril

2016-11-16

We report the exfoliation of graphite and simultaneous N doping of graphene by two methods: supercritical ammonia treatment and liquid-phase exfoliation with NH 4 OH. While the supercritical ammonia allowed N doping at a level of 6.4 atom % in 2 h, the liquid-phase exfoliation with NH 4 OH allowed N doping at a level of 2.7 atom % in 6 h. The N doped graphene obtained via the supercritical ammonia route had few layers (<5) and showed large lateral flake size (∼8 μm) and low defect density (I D /I G < 0.6) in spite of their high level of N doping. This work is the first demonstration of supercritical ammonia as an exfoliation agent and N doping precursor for graphene. Notably, the N doped graphene showed electrocatalytic activity toward oxygen reduction reaction with high durability and good methanol tolerance compared to those of commercial Pt/C catalyst.

High-efficiency exfoliation of large-area mono-layer graphene oxide with controlled dimension.

PubMed

Park, Won Kyu; Yoon, Yeojoon; Song, Young Hyun; Choi, Su Yeon; Kim, Seungdu; Do, Youngjin; Lee, Junghyun; Park, Hyesung; Yoon, Dae Ho; Yang, Woo Seok

2017-11-27

In this work, we introduce a novel and facile method of exfoliating large-area, single-layer graphene oxide using a shearing stress. The shearing stress reactor consists of two concentric cylinders, where the inner cylinder rotates at controlled speed while the outer cylinder is kept stationary. We found that the formation of Taylor vortex flow with shearing stress can effectively exfoliate the graphite oxide, resulting in large-area single- or few-layer graphene oxide (GO) platelets with high yields (>90%) within 60 min of reaction time. Moreover, the lateral size of exfoliated GO sheets was readily tunable by simply controlling the rotational speed of the reactor and reaction time. Our approach for high-efficiency exfoliation of GO with controlled dimension may find its utility in numerous industrial applications including energy storage, conducting composite, electronic device, and supporting frameworks of catalyst.

Exfoliation of graphene sheets via high energy wet milling of graphite in 2-ethylhexanol and kerosene.

PubMed

Al-Sherbini, Al-Sayed; Bakr, Mona; Ghoneim, Iman; Saad, Mohamed

2017-05-01

Graphene sheets have been exfoliated from bulk graphite using high energy wet milling in two different solvents that were 2-ethylhexanol and kerosene. The milling process was performed for 60 h using a planetary ball mill. Morphological characteristics were investigated using scanning electron microscope (SEM) and transmission electron microscope (TEM). On the other hand, the structural characterization was performed using X-ray diffraction technique (XRD) and Raman spectrometry. The exfoliated graphene sheets have represented good morphological and structural characteristics with a valuable amount of defects and a good graphitic structure. The graphene sheets exfoliated in the presence of 2-ethylhexanol have represented many layers, large crystal size and low level of defects, while the graphene sheets exfoliated in the presence of kerosene have represented fewer number of layers, smaller crystal size and higher level of defects.

A retrospective study of a modified 1-minute formocresol pulpotomy technique part 2: effect on exfoliation times and successors.

PubMed

Kurji, Zahra A; Sigal, Michael J; Andrews, Paul; Titley, Keith

2011-01-01

The purposes of this study were to evaluate the: effect of a 1-minute application of full-strength Buckley's formocresol with concur- rent hemostasis using the medicated cotton pledget in human primary teeth on their successors; and exfoliation times compared to the contralateral nonpulpotomized tooth. Using a retrospective chart review, clinical and radiographic data were available for 557 primary molars in 320 patients. There was no difference between treated and control teeth in the number of enamel defects of succedaneous teeth (P<.45). Approximately 66% exfoliated at the same time as their contralateral counterpart and approximately 29% exfoliated earlier (P<.001). This 1-minute technique showed a tendency toward early exfoliation, but no effect on clinical management, and no increase in incidence of defects on succedaneous teeth was observed. The 1-minute full-strength formocresol technique may be considered an acceptable alternative to the 5-minute formocresol pulpotomy.

Trabeculectomy versus Ahmed Glaucoma Valve implantation in neovascular glaucoma

PubMed Central

Shen, Christopher C; Salim, Sarwat; Du, Haiming; Netland, Peter A

2011-01-01

Purpose: To compare surgical outcomes in neovascular glaucoma patients who underwent trabeculectomy with mitomycin C versus Ahmed Glaucoma Valve implantation. Patients and methods: This was a retrospective comparative case series. We reviewed 40 eyes of 39 patients with underlying diagnosis of neovascular glaucoma, divided into two groups: Ahmed Glaucoma Valve (N = 20) and trabeculectomy with mitomycin C (N = 20). Surgical success was defined as 6 mm Hg ≤ intraocular pressure ≤21 mm Hg, with or without the use of glaucoma medications, with no further glaucoma surgery, and light perception or better vision. Early postoperative hypotony was defined as intraocular pressure <5 mm Hg during the first postoperative week. Results: The average follow-up was 31 months (range 6–87 months) for the Ahmed Glaucoma Valve group and 25 months (6–77 months) for the trabeculectomy group. Although the mean number of postoperative intraocular pressure-lowering medications was significantly higher in the trabeculectomy group compared with the Ahmed Glaucoma Valve group at 3 and 6 month time points, there was no statistically significant difference at any other time point. There was no statistically significant difference between both groups in postoperative visual acuity and intraocular pressure. Success was 70% and 65% at 1 year and 60% and 55% at 2 years after Ahmed Glaucoma Valve and trabeculectomy, respectively. Kaplan–Meier survival curve analysis showed no significant difference in success between the two groups (P = 0.815). Hyphema was the most common complication in both groups. Conclusion: We found similar results after trabeculectomy with mitomycin C and Ahmed Glaucoma Valve implantation in eyes with neovascular glaucoma. PMID:21468334

Lifestyles guide and glaucoma (II). Diet, supplements, drugs, sleep, pregnancy, and systemic hypertension.

PubMed

Antón-López, A; Moreno-Montañés, J; Duch-Tuesta, S; Corsino Fernández-Vila, P; García-Feijoo, J; Millá-Griñó, E; Muñoz-Negrete, F J; Pablo-Júlvez, L; Rodríguez-Agirretxe, I; Urcelay-Segura, J L; Ussa-Herrera, F; Villegas-Pérez, M P

2018-02-01

To establish evidence based guidelines to advise patients on the relationship between habits, diet, certain circumstances, diseases and glaucoma. Review of all published articles on glaucoma and sports or other activities. The papers were classified according to the level of scientific evidence based on the Oxford Centre for Evidence-based Medicine classification. The evidence on the relationship between diet or supplements and the incidence or progression of glaucoma is insufficient to make a general recommendation for glaucoma patients. Although some studies on normal tension glaucoma suggest that Gingko biloba could reduce glaucoma progression, the results do not allow a general recommendation for all these patients. Similarly, the evidence on the usefulness of vitamin supplements is not conclusive. The studies on smoking do not clearly demonstrate the relationship between this habit and incidence of glaucoma. Marihuana is not a useful treatment for glaucoma. Although the results on the relationship between sleep apnoea and glaucoma are heterogeneous, it is recommended that patients with moderate to intense apnoea are tested for glaucoma. Pregnancy does not influence the course of the disease, but several hypotensive drugs may be harmful for the foetus. Nocturnal systemic hypotension is a risk factor for glaucoma progression. Certain habits, circumstances, or diseases may have an influence on the onset or progression of glaucoma. It is important to have adequate information about the scientific evidence in the publications in order to properly advise patients. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Perspectives on biomechanical growth and remodeling mechanisms in glaucoma⋆

PubMed Central

Grytz, Rafael; Girkin, Christopher A.; Libertiaux, Vincent; Downs, J. Crawford

2012-01-01

Glaucoma is a blinding diseases in which damage to the axons results in loss of retinal ganglion cells. Experimental evidence indicates that chronic intraocular pressure elevation initiates axonal insult at the level of the lamina cribrosa. The lamina cribrosa is a porous collagen structure through which the axons pass on their path from the retina to the brain. Recent experimental studies revealed the extensive structural changes of the lamina cribrosa and its surrounding tissues during the development and progression of glaucoma. In this perspective paper we review the experimental evidence for growth and remodeling mechanisms in glaucoma including adaptation of tissue anisotropy, tissue thickening/thinning, tissue elongation/shortening and tissue migration. We discuss the existing predictive computational approaches that try to elucidate the potential biomechanical basis of theses growth and remodeling mechanisms and highlight open questions, challenges, and avenues for further development. PMID:23109748

Developing novel anti-fibrotic therapeutics to modulate post-surgical wound healing in glaucoma: big potential for small molecules

PubMed Central

Yu-Wai-Man, Cynthia; Khaw, Peng Tee

2015-01-01

Ocular fibrosis leads to significant visual impairment and blindness in millions of people worldwide, and is one of the largest areas of unmet need in clinical ophthalmology. The antimetabolites, mitomycin C and 5-fluorouracil, are the current gold standards used primarily to prevent fibrosis after glaucoma surgery, but have potentially blinding complications like tissue damage, breakdown and infection. This review thus focuses on the development of new classes of small molecule therapeutics to prevent post-surgical fibrosis in the eye, especially in the context of glaucoma filtration surgery. We discuss recent advances and innovations in ophthalmic wound healing research, including antibodies, RNAi, gene therapy, nanoparticles, liposomes, dendrimers, proteoglycans and small molecule inhibitors. We also review the challenges involved in terms of drug delivery, duration of action and potential toxicity of new anti-fibrotic agents in the eye. PMID:25983855

Childhood glaucoma surgery in the 21st Century

PubMed Central

Papadopoulos, M; Edmunds, B; Fenerty, C; Khaw, P T

2014-01-01

Most children with glaucoma will require surgery in their lifetime, often in their childhood years. The surgical management of childhood glaucoma is however challenging, largely because of its greater potential for failure and complications as compared with surgery in adults. The available surgical repertoire for childhood glaucoma has remained relatively unchanged for many years with most progress owing to modifications to existing surgery. Although the surgical approach to childhood glaucoma varies around the world, angle surgery remains the preferred initial surgery for primary congenital glaucoma and a major advance has been the concept of incising the whole of the angle (circumferential trabeculotomy). Simple modifications to the trabeculectomy technique have been shown to considerably minimise complications. Glaucoma drainage devices maintain a vital role for certain types of glaucoma including those refractory to other surgery. Cyclodestruction continues to have a role mainly for patients following failed drainage/filtering surgery. Although the prognosis for childhood glaucoma has improved significantly since the introduction of angle surgery, there is still considerable progress to be made to ensure a sighted lifetime for children with glaucoma all over the world. Collaborative approaches to researching and delivering this care are required, and this paper highlights the need for more high-quality prospective surgical trials in the management of the childhood glaucoma. PMID:24924446

Glaucoma with Descemet's membrane detachment in five horses.

PubMed

Henriksen, Michala de Linde; La Croix, Noelle; Wilkie, David A; Lassaline-Utter, Mary; Brantman, Karen R; Beamer, Gillian L; Teixeira, Leandro B C; Dubielzig, Richard R

2017-05-01

To describe the clinical and histopathologic features of glaucoma associated with Descemet's membrane (DM) detachment in five horses without prior history of intraocular surgery. Three Appaloosa horses and two Thoroughbreds were included in this study. The affected horses ranged in age from 16 to 27 years and presented with severe diffuse corneal edema. Five eyes were enucleated due to intraocular hypertension and/or chronic corneal ulceration. The enucleated globes were evaluated by the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). Each globe was routinely processed for histopathology and analyzed by light microscopy. A histologic diagnosis of glaucoma was reached by demonstrating a loss of optic nerve axonal tissue by measuring neurofilament-immunopositive axons with automated image analysis software. All five horses presented with unilateral severe diffuse corneal edema that had developed between 2 and 16 weeks prior to enucleation. Intraocular pressures for the affected eyes were between 9 and 87 mmHg prior to enucleation. Descemet's membrane detachment was identified histopathologically in all five globes (5/5, 100%). All five eyes had an avascular spindle cell proliferation filling the space between the displaced peripheral DM and the corneal stroma. Neurofilament immunostaining revealed axonal loss consistent with glaucoma. Equine glaucoma may be associated with Descemet's membrane detachment. This detachment and glaucoma is a possible differential diagnosis for severe equine corneal edema. In this case series, an eye with a DM detachment had a poor prognosis for retention. © 2016 American College of Veterinary Ophthalmologists.

Validation of the Glaucoma Filtration Surgical Mouse Model for Antifibrotic Drug Evaluation

PubMed Central

Seet, Li-Fong; Lee, Wing Sum; Su, Roseline; Finger, Sharon N; Crowston, Jonathan G; Wong, Tina T

2011-01-01

Glaucoma is a progressive optic neuropathy, which, if left untreated, leads to blindness. The most common and most modifiable risk factor in glaucoma is elevated intraocular pressure (IOP), which can be managed surgically by filtration surgery. The postoperative subconjunctival scarring response, however, remains the major obstacle to achieving long-term surgical success. Antiproliferatives such as mitomycin C are commonly used to prevent postoperative scarring. Efficacy of these agents has been tested extensively on monkey and rabbit models of glaucoma filtration surgery. As these models have inherent limitations, we have developed a model of glaucoma filtration surgery in the mouse. We show, for the first time, that the mouse model typically scarred within 14 d, but when augmented with mitomycin C, more animals maintained lower intraocular pressures for a longer period of time concomitant with prolonged bleb survival to beyond 28 d. The morphology of the blebs following mitomycin C treatment also resembled well-documented clinical observations, thus confirming the validity and clinical relevance of this model. We demonstrate that the antiscarring response to mitomycin C is likely to be due to its effects on conjunctival fibroblast proliferation, apoptosis and collagen deposition and the suppression of inflammation. Indeed, we verified some of these properties on mouse conjunctival fibroblasts cultured in vitro. These data support the suitability of this mouse model for studying the wound healing response in glaucoma filtration surgery, and as a potentially useful tool for the in vivo evaluation of antifibrotic therapeutics in the eye. PMID:21229189

Genetics Home Reference: early-onset glaucoma

MedlinePlus

... called a syndrome. If glaucoma appears before the age of 5 without other associated abnormalities, it is called primary congenital glaucoma. Other individuals experience early onset of primary open-angle glaucoma, the most ...

The Ex-PRESS Glaucoma Filtration Device Implantation in Uveitic Glaucoma.

PubMed

Dhanireddy, Swetha; Kombo, Ninani C; Payal, Abhishek R; Freitas-Neto, Clovis Arcoverde; Preble, Janine; Foster, C Stephen

2017-12-01

To evaluate the outcomes of the Ex-PRESS Filtration Device in patients with uveitic glaucoma. We reviewed 23 eyes, comparing control simple glaucoma patients (n = 11) to uveitic glaucoma patients (n = 12). Intraocular pressure (IOP) and glaucoma medications at the preoperative examination were compared with those at the 6-month and 10-14-month postoperative examination. Surgical success was defined as ≥25% decrease in intraocular pressure without hypotony, and/or decrease in glaucoma medications at 6 months follow-up. Statistically significant reduction in mean IOP from preoperative levels occurred in both groups at 6 months follow-up (p<0.0001) and 10-14 months follow-up (p = 0.0007) and in the mean number of medications in the uveitic glaucoma (UG) group (p = 0.0313). Surgical success was seen in 10 eyes in the control group (90.9%) and nine eyes (75%) in the UG group (p = 0.314). Ex-PRESS implantation is an effective surgical intervention for the management of uveitic glaucoma.

Intercalation Pseudocapacitance of Exfoliated Molybdenum Disulfide for Ultrafast Energy Storage

DOE PAGES

Yoo, Hyun Deog; Li, Yifei; Liang, Yanliang; ...

2016-05-23

In this study, we report intercalation pseudocapacitance of 250 F g -1 for exfoliated molybdenum disulfide (MoS 2) in non-aqueous electrolytes that contain lithium ions. The exfoliated MoS 2 shows surface-limited reaction kinetics with high rate capability up to 3 min of charge or discharge. The intercalation pseudocapacitance originates from the extremely fast kinetics due to the enhanced ionic and electronic transport enabled by the slightly expanded layer structure as well as the metallic 1T-phase. The exfoliated MoS 2 could be also used in a Li-Mg-ion hybrid capacitor, which shows full cell specific capacitance of 240 F g -1.

Mechanisms of nanoclay-enhanced plastic foaming processes: effects of nanoclay intercalation and exfoliation

NASA Astrophysics Data System (ADS)

Wong, Anson; Wijnands, Stephan F. L.; Kuboki, Takashi; Park, Chul B.

2013-08-01

The foaming behaviors of high-density polypropylene-nanoclay composites with intercalated and exfoliated nanoclay particles blown with carbon dioxide were examined via in situ observation of the foaming processes in a high-temperature/high-pressure view-cell. The intercalated nanoclay particles were 300-600 nm in length and 50-200 nm in thickness, while the exfoliated nanoclay particles were 100-200 nm in length and 1 nm in thickness. Contrary to common belief, it was discovered that intercalated nanoclay yielded higher cell density than exfoliated nanoclay despite its lower particle density. This was attributed to the higher tensile stresses generated around the larger and stiffer intercalated nanoclay particles, which led to increase in supersaturation level for cell nucleation. Also, the coupling agent used to exfoliate nanoclay would increase the affinity between polymer and surface of nanoclay particles. Consequently, the critical work needed for cell nucleation would be increased; pre-existing microvoids, which could act as seeds for cell nucleation, were also less likely to exist. Meanwhile, exfoliated nanoclay had better cell stabilization ability to prevent cell coalescence and cell coarsening. This investigation clarifies the roles of nanoclay in plastic foaming processes and provides guidance for the advancement of polymer nanocomposite foaming technology.

A rare case report and appraisal of the literature on spontaneous tooth exfoliation associated with trigeminal herpes zoster.

PubMed

Kaur, Rupinder; Rani, Pooja; Malhotra, Divye; Kaur, Rajwant; Dass, Praveen Kumar

2016-09-01

Reports of post herpetic maxillofacial complications have been very rarely documented in the literature that includes periapical lesions, calcified and devitalized pulps, resorption of roots, osteonecrosis, and spontaneous exfoliation of teeth. The atypical feature of the case of concern to the dental surgeon is the rare complication of spontaneous tooth exfoliation following herpes zoster. This case reports a male patient of age 47 years who reported to the Department of Periodontology with the chief complaint of mobility in the left upper central incisor. Patient history revealed herpes zoster infection that began 11 days earlier along with underlying diabetes mellitus condition. We hereby report a known diabetic patient with history of herpes zoster infection who presented with rare complication of spontaneous tooth exfoliation involving the maxillary division of the trigeminal nerve. Limited number of cases has been reported in the literature regarding spontaneous teeth exfoliation secondary to herpes zoster. The exact pathogenesis regarding the spontaneous exfoliation of teeth in herpes zoster patient is still controversial. Thus, an oral health care provider should be aware of this rare complication while managing a case of tooth mobility with the previous history of herpes zoster of trigeminal nerve.

Structure, temperature and frequency dependent electrical conductivity of oxidized and reduced electrochemically exfoliated graphite

NASA Astrophysics Data System (ADS)

Radoń, Adrian; Włodarczyk, Patryk; Łukowiec, Dariusz

2018-05-01

The article presents the influence of reduction by hydrogen in statu nascendi and modification by hydrogen peroxide on the structure and electrical conductivity of electrochemically exfoliated graphite. It was confirmed that the electrochemical exfoliation can be used to produce oxidized nanographite with an average number of 25 graphene layers. The modified electrochemical exfoliated graphite and reduced electrochemical exfoliated graphite were characterized by high thermal stability, what was associated with removing of labile oxygen-containing groups. The presence of oxygen-containing groups was confirmed using Fourier-transform infrared spectroscopy. Influence of chemical modification by hydrogen and hydrogen peroxide on the electrical conductivity was determined in wide frequency (0.1 Hz-10 kHz) and temperature range (-50 °C-100 °C). Material modified by hydrogen peroxide (0.29 mS/cm at 0 °C) had the lowest electrical conductivity. This can be associated with oxidation of unstable functional groups and was also confirmed by analysis of Raman spectra. The removal of oxygen-containing functional groups by hydrogen in statu nascendi resulted in a 1000-fold increase in the electrical conductivity compared to the electrochemical exfoliated graphite.

Shear-Assisted Production of Few-Layer Boron Nitride Nanosheets by Supercritical CO2 Exfoliation and Its Use for Thermally Conductive Epoxy Composites.

PubMed

Tian, Xiaojuan; Li, Yun; Chen, Zhuo; Li, Qi; Hou, Liqiang; Wu, Jiaye; Tang, Yushu; Li, Yongfeng

2017-12-19

Boron nitride nanosheets (BNNS) hold the similar two-dimensional structure as graphene and unique properties complementary to graphene, which makes it attractive in application ranging from electronics to energy storage. The exfoliation of boron nitride (BN) still remains challenge and hinders the applications of BNNS. In this work, the preparation of BNNS has been realized by a shear-assisted supercritical CO 2 exfoliation process, during which supercritical CO 2 intercalates and diffuses between boron nitride layers, and then the exfoliation of BN layers is obtained in the rapid depressurization process by overcoming the van der Waals forces. Our results indicate that the bulk boron nitride has been successfully exfoliated into thin nanosheets with an average 6 layers. It is found that the produced BNNS is well-dispersed in isopropyl alcohol (IPA) with a higher extinction coefficient compared with the bulk BN. Moreover, the BNNS/epoxy composite used as thermal interface materials has been prepared. The introduction of BNNS results in a 313% enhancement in thermal conductivity. Our results demonstrate that BNNS produced by supercritical CO 2 exfoliation show great potential applications for heat dissipation of high efficiency electronics.

The Philadelphia Glaucoma Detection and Treatment Project

PubMed Central

Waisbourd, Michael; Pruzan, Noelle L.; Johnson, Deiana; Ugorets, Angela; Crews, John E.; Saaddine, Jinan B.; Henderer, Jeffery D.; Hark, Lisa A.; Katz, L. Jay

2016-01-01

Purpose To evaluate the detection rates of glaucoma-related diagnoses and the initial treatments received in the Philadelphia Glaucoma Detection and Treatment Project, a community-based initiative aimed at improving the detection, treatment, and follow-up care of individuals at risk for glaucoma. Design Retrospective analysis. Participants A total of 1649 individuals at risk for glaucoma who were examined and treated in 43 community centers located in underserved communities of Philadelphia. Methods Individuals were enrolled if they were African American aged ≥50 years, were any other adult aged ≥60 years, or had a family history of glaucoma. After attending an informational glaucoma workshop, participants underwent a targeted glaucoma examination including an ocular, medical, and family history; visual acuity testing, intraocular pressure (IOP) measurement, and corneal pachymetry; slit-lamp and optic nerve examination; automated visual field testing; and fundus color photography. If indicated, treatments included selective laser trabeculoplasty (SLT), laser peripheral iridotomy (LPI), or IOP-lowering medications. Follow-up examinations were scheduled at the community sites after 4 to 6 weeks or 4 to 6 months, depending on the clinical scenario. Main Outcome Measures Detection rates of glaucoma-related diagnoses and types of treatments administered. Results Of the 1649 individuals enrolled, 645 (39.1%) received a glaucoma-related diagnosis; 20.0% (n = 330) were identified as open-angle glaucoma (OAG) suspects, 9.2% (n = 151) were identified as having narrow angles (or as a primary angle closure/suspect), and 10.0% (n = 164) were diagnosed with glaucoma, including 9.0% (n = 148) with OAG and 1.0% (n = 16) with angle-closure glaucoma. Overall, 39.0% (n = 64 of 164) of those diagnosed with glaucoma were unaware of their diagnosis. A total of 196 patients (11.9%) received glaucoma-related treatment, including 84 (5.1%) who underwent LPI, 13 (0.8%) who underwent SLT, and 103 (6.2%) who were prescribed IOP-lowering medication. Conclusions Targeting individuals at risk for glaucoma in underserved communities in Philadelphia yielded a high detection rate (39.1%) of glaucoma-related diagnoses. Providing examinations and offering treatment, including first-line laser procedures, at community-based sites providing services to older adults are effective to improve access to eye care by underserved populations. PMID:27221736

Composite fibrous glaucoma drainage implant

NASA Astrophysics Data System (ADS)

Klapstova, A.; Horakova, J.; Shynkarenko, A.; Lukas, D.

2017-10-01

Glaucoma is a frequent reason of loss vision. It is usually caused by increased intraocular pressure leading to damage of optic nerve head. This work deals with the development of fibrous structure suitable for glaucoma drainage implants (GDI). Commercially produced metallic glaucoma implants are very effective in lowering intraocular pressure. However, these implants may cause adverse events such as damage to adjacent tissue, fibrosis, hypotony or many others [1]. The aim of this study is to reduce undesirable properties of currently produced drains and improve their properties by creating of the composite fibrous drain for achieve a normal intraocular pressure. Two types of electrospinning technologies were used for the production of very small tubular implants. First type was focused for production of outer part of tubular drain and the second type of electrospinning method made the inner part of shape follows the connections of both parts. Complete implant had a special properties suitable for drainage of fluid. Morphological parameters, liquid transport tests and in-vitro cell adhesion tests were detected.

Glaucoma: Symptoms, Diagnosis, Treatment and Latest Research

MedlinePlus

... Feature: Glaucoma Glaucoma: Symptoms, Diagnosis, Treatment and Latest Research Past Issues / Fall 2009 Table of Contents Symptoms ... patients may need to keep taking drugs. Latest Research Researchers are studying the causes of glaucoma, looking ...

Glaucoma: Symptoms and Causes

MedlinePlus

... damage. The types of glaucoma include the following: Open-angle glaucoma Open-angle glaucoma is the most common form of ... angle formed by the cornea and iris remains open, but the trabecular meshwork is partially blocked. This ...

Undetected angle closure in patients with a diagnosis of open-angle glaucoma.

PubMed

Varma, Devesh K; Simpson, Sarah M; Rai, Amandeep S; Ahmed, Iqbal Ike K

2017-08-01

The aim of this study was to identify the proportion of patients referred to a tertiary glaucoma centre with a diagnosis of open-angle glaucoma (OAG) who were found to have angle closure glaucoma. Retrospective chart review. Consecutive new patients referred for glaucoma management to a tertiary centre between July 2010 and December 2011 were reviewed. Patients whose referrals for glaucoma assessment specified angle status as "open" were included. The data collected included glaucoma specialist's angle assessment, diagnosis, and glaucoma severity. The status of those with 180 degrees or more Shaffer angle grading of 0 was classified as "closed." From 1234 glaucoma referrals, 179 cases were specified to have a diagnosis of OAG or when angles were known to be open. Of these, 16 (8.9%) were found on examination by the glaucoma specialist to have angle closure. Pseudoexfoliation was present in 4 of 16 patients (25%) in the missed angle-closure glaucoma (ACG) group and 22 of 108 patients (13.5%) in the remaining OAG group. There was no difference found in demographic or ocular biometric parameters between those with confirmed OAG versus those with missed ACG. Almost 1 in 11 patients referred by ophthalmologists to a tertiary glaucoma centre with a diagnosis of OAG were in fact found to have angle closure. Given the different treatment approaches for ACG versus OAG, this study suggests a need to strengthen angle evaluations. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

SpalLoop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabau, Adrian; Wright, Ian

Boiler tubes in steam power plants experience tube blockages due to exfoliation of oxide grown on the inner side of the tubes. In extreme cases, significant tube blockages can lead to forced power plant outages. It is thus desired to predict through modeling the amount of tube blockage in order to inform power plant operators of possible forced outages. SpalLoop solves for the stress-strain equations in an axisymmetric geometry, tracking the stress/strain evolution during boiler operation including outages for the entire boiler tube length. At each operational outage, i.e., temperature excursions down to room temperature, the amount of exfoliated areamore » for the entire tube loop is estimated the amount of tube blockage is predicted based assumed blockage geometry and site. The SpaLLoop code contains modules developed for oxide growth, stress analysis, tube loop geometry, blockage area by taking into account the following phenomena and features, (a) Plant operation schedule with periodic alternate full-load and partial-load regimes and shut-downs, i.e., temperature excursions from high-load to room temperature, (b) axisymmetric formulation for cylindrical tubes, (c) oxide growth in a temperature gradient with multiple oxide layers, (d) geometry of a boiler tube with a single tube loop or two tube loops, (e) temperature variation along the tube length based on hot gas temperature distribution outside the tube and inlet steam temperature, (f) non-uniform oxide growth along the tube length according to the local steam tube temperature, (g) exfoliated area module: at each operational outage considered, the amount of exfoliated area and exfoliated volume along the tube is estimated, (h) blockage module: at each operational outage considered, the exfoliated volume/mass for each tube loop is estimated from which the amount of tube blockage is predicted based on given blockage geometry (length, location, and geometry). The computer program is written in FORTRAN90. Its modular structure was sought for allowing the best flexibility in updating the program by implementing new constitutive equations due to availability of new material property data and/or new physical phenomena.« less

Raman exfoliative cytology for oral precancer diagnosis

NASA Astrophysics Data System (ADS)

Sahu, Aditi; Gera, Poonam; Pai, Venkatesh; Dubey, Abhishek; Tyagi, Gunjan; Waghmare, Mandavi; Pagare, Sandeep; Mahimkar, Manoj; Murali Krishna, C.

2017-11-01

Oral premalignant lesions (OPLs) such as leukoplakia, erythroplakia, and oral submucous fibrosis, often precede oral cancer. Screening and management of these premalignant conditions can improve prognosis. Raman spectroscopy has previously demonstrated potential in the diagnosis of oral premalignant conditions (in vivo), detected viral infection, and identified cancer in both oral and cervical exfoliated cells (ex vivo). The potential of Raman exfoliative cytology (REC) in identifying premalignant conditions was investigated. Oral exfoliated samples were collected from healthy volunteers (n=20), healthy volunteers with tobacco habits (n=20), and oral premalignant conditions (n=27, OPL) using Cytobrush. Spectra were acquired using Raman microprobe. Spectral acquisition parameters were: λex: 785 nm, laser power: 40 mW, acquisition time: 15 s, and average: 3. Postspectral acquisition, cell pellet was subjected to Pap staining. Multivariate analysis was carried out using principal component analysis and principal component-linear discriminant analysis using both spectra- and patient-wise approaches in three- and two-group models. OPLs could be identified with ˜77% (spectra-wise) and ˜70% (patient-wise) sensitivity in the three-group model while with 86% (spectra-wise) and 83% (patient-wise) in the two-group model. Use of histopathologically confirmed premalignant cases and better sampling devices may help in development of improved standard models and also enhance the sensitivity of the method. Future longitudinal studies can help validate potential of REC in screening and monitoring high-risk populations and prognosis prediction of premalignant lesions.

Turbulence-assisted shear exfoliation of graphene using household detergent and a kitchen blender

NASA Astrophysics Data System (ADS)

Varrla, Eswaraiah; Paton, Keith R.; Backes, Claudia; Harvey, Andrew; Smith, Ronan J.; McCauley, Joe; Coleman, Jonathan N.

2014-09-01

To facilitate progression from the lab to commercial applications, it will be necessary to develop simple, scalable methods to produce high quality graphene. Here we demonstrate the production of large quantities of defect-free graphene using a kitchen blender and household detergent. We have characterised the scaling of both graphene concentration and production rate with the mixing parameters: mixing time, initial graphite concentration, rotor speed and liquid volume. We find the production rate to be invariant with mixing time and to increase strongly with mixing volume, results which are important for scale-up. Even in this simple system, concentrations of up to 1 mg ml-1 and graphene masses of >500 mg can be achieved after a few hours mixing. The maximum production rate was ~0.15 g h-1, much higher than for standard sonication-based exfoliation methods. We demonstrate that graphene production occurs because the mean turbulent shear rate in the blender exceeds the critical shear rate for exfoliation.To facilitate progression from the lab to commercial applications, it will be necessary to develop simple, scalable methods to produce high quality graphene. Here we demonstrate the production of large quantities of defect-free graphene using a kitchen blender and household detergent. We have characterised the scaling of both graphene concentration and production rate with the mixing parameters: mixing time, initial graphite concentration, rotor speed and liquid volume. We find the production rate to be invariant with mixing time and to increase strongly with mixing volume, results which are important for scale-up. Even in this simple system, concentrations of up to 1 mg ml-1 and graphene masses of >500 mg can be achieved after a few hours mixing. The maximum production rate was ~0.15 g h-1, much higher than for standard sonication-based exfoliation methods. We demonstrate that graphene production occurs because the mean turbulent shear rate in the blender exceeds the critical shear rate for exfoliation. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03560g

Evaluation of Ocular Surface Disease in Patients with Glaucoma

PubMed Central

Mathews, Priya M.; Ramulu, Pradeep Y.; Friedman, David S.; Utine, Canan A.; Akpek, Esen K.

2013-01-01

Purpose To evaluate the subjective and objective measures of ocular surface disease in patients with glaucoma. Design Cross-sectional study. Participants Sixty-four glaucoma subjects with bilateral visual field (VF) loss and 59 glaucoma suspects with normal VFs. Methods Consecutive patients were recruited prospectively from the Wilmer Eye Institute Glaucoma Clinic. Main Outcome Measures Tear film breakup time (TBUT), corneal staining score (0–15), and Schirmer’s test results were included as objective metrics, whereas the Ocular Surface Disease Index (OSDI) questionnaire was administered to assess symptoms. Total OSDI score, vision-related subscore (derived from questions about vision and task performance), and discomfort-related subscore (derived from questions about ocular surface discomfort) were calculated for each subject. Results Seventy-five percent (48/64) of glaucoma subjects and 41% (24/59) of glaucoma suspects were receiving topical medications. The corneal staining grade was greater in glaucoma subjects than in glaucoma suspects (6.4 vs. 4.1; P<0.001), but groups did not differ with regard to TBUT or Schirmer’s results (P>0.20 for both). Multivariate regression models showed that topical glaucoma therapy burden was associated with a significantly higher total corneal staining grade (β, +0.9 for each additional glaucoma drop; 95% confidence interval [CI], 0.5–1.3; P<0.001), but not with TBUT or Schirmer’s results (P>0.20 for both). Glaucoma subjects had significantly higher total OSDI scores than glaucoma suspects (16.7 vs. 7.9; P<0.001). This largely was the result of higher vision-related subscores in the glaucoma group (11.1 vs. 3.3; P<0.001). Ocular discomfort–related subscores, however, were similar in both groups (5.7 vs. 4.6; P = 0.30). In multivariate analyses, each 5-decibel decrement in better-eye VF mean deviation was associated with a 4.7-point increase in total OSDI score (95% CI, 1.9–7.5; P = 0.001) and a 3.7-point increase in the vision-related subscore (95% CI, 1.7–5.6; P<0.001) but did not predict a higher discomfort-related subscore (β, 1.1 point; P = 0.07). Topical glaucoma therapy burden was not associated with higher total OSDI score or vision- or discomfort-related subscore (P>0.20 for all). Conclusions Glaucoma is associated with significant ocular surface disease, and topical glaucoma therapy burden seems predictive of corneal staining severity. However, OSDI is a poor metric for capturing ocular surface disease in glaucoma because symptoms seem to be related largely to VF loss. PMID:23714318

Pseudoexfoliation syndrome in Ethiopian glaucoma patients.

PubMed

Bedri, A; Alemu, B

1999-05-01

Pseudoexfoliation syndrome (PXS) has variable prevalence rates in the glaucoma population depending on geographic location and racial composition of the population studied. There is no data available on this subject in Ethiopia. To determine the prevalence of PXS among Ethiopian glaucoma clinic population. A prospective study. The Glaucoma Clinic of Menelik-II-Hospital, which is a tertiary eye care centre in Addis Ababa, Ethiopia. All new patients with glaucoma or ocular hypertension (ocular HPN) seen during the study period from 1st April to 30th September 1996 were included in the study. Our of the 432 new patients of glaucoma or ocular HPN seen during the study, 108 patients (25%) had PXS. The age of PXS cases ranged from 32 years to 86 years (mean 62.3 years). There were 80 males and 28 females. Of the PXS patients, 104 (96.3%) were cases of chronic open angle glaucoma, while angle closure glaucoma and ocular HPN were rare comprising only two patients (1.85%) each. The relatively high prevalence rate of PXS among Ethiopian glaucoma clinic population found in this study stresses the need for further community-based research in order to prevent blindness due to glaucoma associated with PXS.

Graphene via Molecule-Assisted Ultrasound-Induced Liquid-Phase Exfoliation: A Supramolecular Approach

NASA Astrophysics Data System (ADS)

Eredia, Matilde; Ciesielski, Artur; Samorì, Paolo

2016-12-01

Graphene is a two-dimensional (2D) material holding unique optical, mechanical, thermal and electrical properties. The combination of these exceptional characteristics makes graphene an ideal model system for fundamental physical and chemical studies as well as technologically ground breaking material for a large range of applications. Graphene can be produced either following a bottom-up or top-down method. The former is based on the formation of covalent networks suitably engineered molecular building blocks undergoing chemical reaction. The latter takes place through the exfoliation of bulk graphite into individual graphene sheets. Among them, ultrasound-induced liquid-phase exfoliation (UILPE) is an appealing method, being very versatile and applicable to different environments and on various substrate types. In this chapter, we describe the recently reported methods to produce graphene via molecule-assisted UILPE of graphite, aiming at the generation of high-quality graphene. In particular, we will focus on the supramolecular approach, which consists in the use of suitably designed organic molecules during the UILPE of graphite. These molecules act as graphene dispersion-stabilizing agents during the exfoliation. This method relying on the joint effect of a solvent and ad hoc molecules to foster the exfoliation of graphite into graphene in liquid environment represents a promising and modular method toward the improvement of the process of UILPE in terms of the concentration and quality of the exfoliated material. Furthermore, exfoliations in aqueous and organic solutions are presented and discussed separately.

Nanoimprint-Assisted Shear Exfoliation (NASE) for Producing Multilayer MoS2 Structures as Field-Effect Transistor Channel Arrays.

PubMed

Chen, Mikai; Nam, Hongsuk; Rokni, Hossein; Wi, Sungjin; Yoon, Jeong Seop; Chen, Pengyu; Kurabayashi, Katsuo; Lu, Wei; Liang, Xiaogan

2015-09-22

MoS2 and other semiconducting transition metal dichalcogenides (TMDCs) are of great interest due to their excellent physical properties and versatile chemistry. Although many recent research efforts have been directed to explore attractive properties associated with MoS2 monolayers, multilayer/few-layer MoS2 structures are indeed demanded by many practical scale-up device applications, because multilayer structures can provide sizable electronic/photonic state densities for driving upscalable electrical/optical signals. Currently there is a lack of processes capable of producing ordered, pristine multilayer structures of MoS2 (or other relevant TMDCs) with manufacturing-grade uniformity of thicknesses and electronic/photonic properties. In this article, we present a nanoimprint-based approach toward addressing this challenge. In this approach, termed as nanoimprint-assisted shear exfoliation (NASE), a prepatterned bulk MoS2 stamp is pressed into a polymeric fixing layer, and the imprinted MoS2 features are exfoliated along a shear direction. This shear exfoliation can significantly enhance the exfoliation efficiency and thickness uniformity of exfoliated flakes in comparison with previously reported exfoliation processes. Furthermore, we have preliminarily demonstrated the fabrication of multiple transistors and biosensors exhibiting excellent device-to-device performance consistency. Finally, we present a molecular dynamics modeling analysis of the scaling behavior of NASE. This work holds significant potential to leverage the superior properties of MoS2 and other emerging TMDCs for practical scale-up device applications.

Prevalence of Glaucoma in the United States: The 2005–2008 National Health and Nutrition Examination Survey

PubMed Central

Gupta, Priya; Zhao, Di; Guallar, Eliseo; Ko, Fang; Boland, Michael V.; Friedman, David S.

2016-01-01

Purpose To estimate the prevalence of glaucoma in the US population based on optic nerve head photography, to estimate the prevalence of glaucoma awareness, and to identify demographic and ocular risk factors for being unaware of having glaucoma. Methods The study included 5746 men and women 40 years of age and older participating in the National Health and Nutrition Examination Survey (NHANES) 2005–2008. Each participant had 45° photographs of the macula and optic disc of both eyes. Fundus photographs were first graded by a reading center, and those with a cup-to-disc ratio (CDR) ≥ 0.6 were regraded by three glaucoma specialists to determine the presence or absence of glaucoma. Analyses were performed using NHANES weights to account for the complex multistage probability sampling design. Results The estimated overall prevalence of glaucoma in the US civilian, noninstitutionalized population 40 years of age and older was 2.1% (95% confidence interval [CI], 1.7%–2.6%). Glaucoma affected 2.9 million individuals, including 1.4 million women; 1.5 million men; 2.3 million people 60 years of age and older; and 0.9 million blacks, Mexican Americans, and people of other races. The prevalence of glaucoma was highest in non-Hispanic blacks, followed by non-Hispanic whites, Mexican Americans, and others. Over half of participants with glaucoma were unaware that they had the disease. Conclusions The prevalence of glaucoma based on optic nerve fundus photography assessment in the general US population 40 years of age and older was 2.1%. Approximately half of glaucoma cases were previously undiagnosed. Studies to determine whether and how to identify undiagnosed glaucoma are an important next step. PMID:27168366

Costs of a community-based glaucoma detection programme: analysis of the Philadelphia Glaucoma Detection and Treatment Project.

PubMed

Pizzi, Laura T; Waisbourd, Michael; Hark, Lisa; Sembhi, Harjeet; Lee, Paul; Crews, John E; Saaddine, Jinan B; Steele, Deon; Katz, L Jay

2018-02-01

Glaucoma is the foremost cause of irreversible blindness, and more than 50% of cases remain undiagnosed. Our objective was to report the costs of a glaucoma detection programme operationalised through Philadelphia community centres. The analysis was performed using a healthcare system perspective in 2013 US dollars. Costs of examination and educational workshops were captured. Measures were total programme costs, cost/case of glaucoma detected and cost/case of any ocular disease detected (including glaucoma). Diagnoses are reported at the individual level (therefore representing a diagnosis made in one or both eyes). Staff time was captured during site visits to 15 of 43 sites and included time to deliver examinations and workshops, supervision, training and travel. Staff time was converted to costs by applying wage and fringe benefit costs from the US Bureau of Labor Statistics. Non-staff costs (equipment and mileage) were collected using study logs. Participants with previously diagnosed glaucoma were excluded. 1649 participants were examined. Mean total per-participant examination time was 56 min (SD 4). Mean total examination cost/participant was $139. The cost/case of glaucoma newly identified (open-angle glaucoma, angle-closure glaucoma, glaucoma suspect, or primary angle closure) was $420 and cost/case for any ocular disease identified was $273. Glaucoma examinations delivered through this programme provided significant health benefit to hard-to-reach communities. On a per-person basis, examinations were fairly low cost, though opportunities exist to improve efficiency. Findings serve as an important benchmark for planning future community-based glaucoma examination programmes. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

The use of Ahmed glaucoma valve in the management of pediatric glaucoma.

PubMed

Balekudaru, Shantha; Vadalkar, Juhie; George, Ronnie; Vijaya, Lingam

2014-08-01

To assess the intraocular pressure control (IOP), changes in visual acuity, complications, reoperation rates and risk factors for failure following Ahmed glaucoma valve implantation in pediatric eyes with glaucoma. The medical records of consecutive patients with glaucoma who underwent Ahmed glaucoma valve implantation from January 2000 to December 2009) were retrospectively reviewed. Only one eye of each patient was included. Subgroup analysis was performed in three groups; group 1 included phakic eyes with primary congenital glaucoma, juvenile open-angle glaucoma, or glaucoma associated with ocular anomalies; group 2 included eyes with glaucoma in aphakia or pseudophakia; group 3 included eyes with other diagnoses. A successful outcome was defined as final IOP between 6 mm Hg and 18 mm Hg without loss of light perception or reoperation for glaucoma. A total of 71 eyes in 71 patients: 15 (21%) in group 1, 47 (66%) in group 2, and 9 (13%) in group 3 were included Successful IOP control was achieved in 44 eyes of 44 patients (62%). Cumulative probabilities of success by Kaplan-Meier analysis at 12 and 24 months was 97% and 80% for the entire group, 100% and 82% for group 1, 95% and 86% for group 2, and 90% and 42% for group 3. Reoperation was necessary for 18 patients (25%), either for tube-related complications or for IOP control. The only significant risk factor for failure was the category of diagnosis (P = 0.029). Ahmed glaucoma valve implantation is an option in the management of pediatric glaucoma; however, reoperations for tube related complications or for persistent elevated IOP is frequently needed. Copyright © 2014 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Prevalence, types and awareness of glaucoma in a multi-ethnic population in rural China: the Yunnan Minority Eye Study.

PubMed

Pan, Chen-Wei; Zhao, Chun-Hua; Yu, Min-Bin; Cun, Qing; Chen, Qin; Shen, Wei; Li, Jun; Xu, Jian-Gang; Yuan, Yuansheng; Zhong, Hua

2016-11-01

To determine the prevalence, types and awareness of glaucoma in a rural community in China and to examine possible ethnic variations. The Yunnan Minority Eye Study was a multi-ethnic community-based eye survey using random cluster sampling strategies. 2133 Bai, 2205 Han and 2208 Yi Chinese aged 50 years or older participated in this study. Glaucoma including primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG) and secondary glaucoma was defined based on the International Society of Geographical and Epidemiological Ophthalmology criteria. The overall age-standardized prevalence of all glaucoma was 2.6% (95% confidence interval [CI]: 2.2-3.1%) in this population. It was 1.8% (95% CI: 1.1-1.9%) for POAG and 0.5% (95% CI: 0.9-1.6%) for PACG, respectively. Among 29 people with secondary glaucoma, 27 (93%) were blind in at least one eye. The presence of primary open-angle glaucoma was associated with male gender (odds ratio [OR] = 2.94; comparing men with women), Yi ethnicity (OR = 2.27; comparing Yi with Han people), higher IOP (OR = 1.09 per mmHg increase), and the presence of myopia (OR = 1.84). Of the 212 participants with glaucoma, only 38 (18%) were aware of the disease and had been diagnosed previously as having glaucoma or suspected glaucoma. Patients who were better educated tended to be aware of the disease. Significant ethnic difference in the prevalence of POAG was observed in this study. The low awareness of glaucoma highlights the pressing need to increase public awareness of this potentially blinding condition in rural China. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

The association between clinical parameters and glaucoma-specific quality of life in Chinese primary open-angle glaucoma patients.

PubMed

Lee, Jacky W Y; Chan, Catherine W S; Chan, Jonathan C H; Li, Q; Lai, Jimmy S M

2014-08-01

OBJECTIVE. To investigate the association between clinical measurements and glaucoma-specific quality of life in Chinese glaucoma patients. DESIGN. Cross-sectional study. SETTING. An academic hospital in Hong Kong. PATIENTS. A Chinese translation of the Glaucoma Quality of Life-15 questionnaire was completed by 51 consecutive patients with bilateral primary open-angle glaucoma. The binocular means of several clinical measurements were correlated with Glaucoma Quality of Life-15 findings using Pearson's correlation coefficient and linear regression. The measurements were the visual field index and pattern standard deviation from the Humphrey Field Analyzer, Snellen best-corrected visual acuity, presenting intra-ocular pressure, current intra-ocular pressure, average retinal nerve fibre layer thickness via optical coherence tomography, and the number of topical anti-glaucoma medications being used. RESULTS. In these patients, there was a significant correlation and linear relationship between a poorer Glaucoma Quality of Life-15 score and a lower visual field index (r=0.3, r(2)=0.1, P=0.01) and visual acuity (r=0.3, r(2)=0.1, P=0.03). A thinner retinal nerve fibre layer also correlated with a poorer Glaucoma Quality of Life-15 score, but did not attain statistical significance (r=0.3, P=0.07). There were no statistically significant correlations for the other clinical parameters with the Glaucoma Quality of Life-15 scores (all P values being >0.7). The three most problematic activities affecting quality of life were "adjusting to bright lights", "going from a light to a dark room or vice versa", and "seeing at night". CONCLUSION. For Chinese primary open-angle glaucoma patients, binocular visual field index and visual acuity correlated linearly with glaucoma-specific quality of life, and activities involving dark adaptation were the most problematic.

The direction of research into visual disability and quality of life in glaucoma.

PubMed

Glen, Fiona C; Crabb, David P; Garway-Heath, David F

2011-08-04

Glaucoma will undoubtedly impact on a person's ability to function as they go about their day-to-day life. The purpose of this study is to investigate the amount of published knowledge in quality of life (QoL) and visual disability studies for glaucoma, and make comparisons with similar research in other chronic conditions. A systematic literature search of the Global Health, EMBASE Psychiatry and MEDLINE databases. Title searches for glaucoma and six other example chronic diseases were entered alongside a selection of keywords chosen to capture studies focusing on QoL and everyday task ability. These results were further filtered during a manual search of resulting abstracts. Outcomes were the number of publications per year for each disease, number relating to QoL and type of glaucoma QoL research. Fifteen years ago there were no published studies relating to the impact of glaucoma on QoL but by 2009 this had risen to 1.2% of all glaucoma articles. The number of papers relating to QoL as a proportion of all papers in glaucoma in the past 10 years (0.6%) is smaller than for AMD and some other disabling chronic diseases. Most QoL studies in glaucoma (82%) involve questionnaires. QoL studies in glaucoma are increasing in number but represent a tiny minority of the total publications in glaucoma research. There are fewer QoL articles in glaucoma compared to some other disabling chronic conditions. The majority of QoL articles in glaucoma research use questionnaires; performance-based measures of visual disability may offer an additional method of determining how the disease impacts on QoL.

Cost and detection rate of glaucoma screening with imaging devices in a primary care center

PubMed Central

Anton, Alfonso; Fallon, Monica; Cots, Francesc; Sebastian, María A; Morilla-Grasa, Antonio; Mojal, Sergi; Castells, Xavier

2017-01-01

Purpose To analyze the cost and detection rate of a screening program for detecting glaucoma with imaging devices. Materials and methods In this cross-sectional study, a glaucoma screening program was applied in a population-based sample randomly selected from a population of 23,527. Screening targeted the population at risk of glaucoma. Examinations included optic disk tomography (Heidelberg retina tomograph [HRT]), nerve fiber analysis, and tonometry. Subjects who met at least 2 of 3 endpoints (HRT outside normal limits, nerve fiber index ≥30, or tonometry ≥21 mmHg) were referred for glaucoma consultation. The currently established (“conventional”) detection method was evaluated by recording data from primary care and ophthalmic consultations in the same population. The direct costs of screening and conventional detection were calculated by adding the unit costs generated during the diagnostic process. The detection rate of new glaucoma cases was assessed. Results The screening program evaluated 414 subjects; 32 cases were referred for glaucoma consultation, 7 had glaucoma, and 10 had probable glaucoma. The current detection method assessed 677 glaucoma suspects in the population, of whom 29 were diagnosed with glaucoma or probable glaucoma. Glaucoma screening and the conventional detection method had detection rates of 4.1% and 3.1%, respectively, and the cost per case detected was 1,410 and 1,435€, respectively. The cost of screening 1 million inhabitants would be 5.1 million euros and would allow the detection of 4,715 new cases. Conclusion The proposed screening method directed at population at risk allows a detection rate of 4.1% and a cost of 1,410 per case detected. PMID:28243057

Get Tested for Glaucoma!

MedlinePlus

... of this page please turn Javascript on. Feature: Glaucoma Get Tested for Glaucoma! Past Issues / Fall 2009 Table of Contents Taylor ... aoa.org/ When were you finally diagnosed with glaucoma? Not until 1969, after a game of basketball. ...

Does Marijuana Help Treat Glaucoma?

MedlinePlus

... Ophthalmologist Patient Stories Español Eye Health / Tips & Prevention Marijuana Sections Does Marijuana Help Treat Glaucoma? Why Eye ... Don't Recommend Marijuana for Glaucoma Infographic Does Marijuana Help Treat Glaucoma? Leer en Español: La marihuana ...

[Preservative-free glaucoma treatment : Selection of the correct treatment in 1 min].

PubMed

Pfennigsdorf, S; Eschstruth, P

2016-05-01

The presence of preservatives in topical glaucoma treatments may impact ocular surface function and structure. For treatment to be effective, side effects need to be minimized, in order to promote compliance and allow continuation of therapy. Therefore, in daily clinical practice, it needs to be decided on an individual basis whether a preservative-free treatment is required. This study aimed to develop a questionnaire which helps to quickly and easily identify patients who require preservative-free treatment. A questionnaire was prepared to collect relevant clinical findings needed to make a therapeutic decision (preservative-free required? Yes/No). Moreover, a rating scheme was developed to enable efficient final assessment of the collected data. To check their practicability in daily clinical practice, both instruments were tested in 11 ophthalmological centers in Germany. The questionnaire and rating scheme were easy to use, integrated efficiently into everyday routine, and performed in about 1 min. Data of 1150 glaucoma patients were collected and preservative-free eyedrops recommended for 586 (51 %). Parameters most frequently associated with such a recommendation were a reduced tear film break-up time of < 10 s (87.5 %) or marked corneal staining (65.5 %). The presented approach helps to decide within 1 min, in daily clinical practice, whether preservative-free glaucoma threatment should be recommended. Individualized therapy decisions can thus be made, allowing goal-oriented use of preservative-free antiglaucomatosa. This might help to promote compliance and lead to reduced progression of glaucoma.

Comparison of single thickness and double thickness processed pericardium patch graft in glaucoma drainage device surgery: a single surgeon comparison of outcome.

PubMed

Lankaranian, Dara; Reis, Ricardo; Henderer, Jeffrey D; Choe, Sung; Moster, Marlene R

2008-01-01

To compare the incidence of conjuctival erosions with single thickness versus double thickness allograft processed pericardium used in mitomycin-C (MMC) augmented glaucoma drainage device (GDD) sugery. In a retrospective comparative case series, medical records of 84 consecutive glaucoma patients who underwent GDD surgery between July 1996 to December 2004 were reviewed. All surgeries were done by one glaucoma surgeon (M.R.M.). MMC was adminstered in all cases over the plate area and either single thickness processed pericardium patch graft (STPP) or double thickness processed pericardium patch graft (DTPP) was used to cover the external silicone tube of the glaucoma device at the limbus. The principal outcome measure was the incidence of conjunctival erosions associated with GDD surgery. Eighty-four patients (90 eyes) who met the eligibility criteria were enrolled in the study. Thirty-one consecutive eyes received a STPP, and 59 consecutive eyes received a DTPP. Five eyes (16.0%) in the STPP group developed conjunctival erosion. None of the eyes in DTPP group developed conjunctival erosion. The Mann-Whitney U test difference in the rate of conjunctival erosion was statistically significant between 2 groups (P=0.002). For the STPP group, the average time to conjunctival erosion was 9 months (range, 4 to 14 mo). All erosions were surgically corrected using DTPP and followed up for a mean of 8.6 months after repair with no additional conjunctival erosions. DTPP placed over the silicone tube significantly reduced the incidence of conjunctival erosion after MMC augmented GDD surgery.

A temperature-induced and shear-reversible assembly of latanoprost-loaded amphiphilic chitosan colloids: characterization and in vivo glaucoma treatment.

PubMed

Hsiao, Meng-Hsuan; Chiou, Shih-Hwa; Larsson, Mikael; Hung, Kuo-Hsuan; Wang, Yi-Ling; Liu, Catherine Jui-Ling; Liu, Dean-Mo

2014-07-01

Hydrogels composed of assembled colloids is a material class that is currently receiving much interest and shows great promise for use in biomedical applications. This emerging material class presents unique properties derived from the combination of nanosized domains in the form of colloidal particles with a continuous gel network and an interspersed liquid phase. Here we developed an amphiphilic chitosan-based, thermogelling, shear-reversible colloidal gel system for improved glaucoma treatment and addressed how preparation procedures and loading with the anti-glaucoma drug latanoprost and commonly used preservative benzalkonium chloride influenced the mechanical properties of and drug release from the colloidal gels. The results highlight that incorporated substances and preparation procedures have effects both on mechanical properties and drug release, but that the release of drug loaded in the colloidal carriers is mainly limited by transport out of the carriers, rather than by diffusion within the gel. The developed colloidal chitosan based gels hold outstanding biomedical potential, as confirmed by the ease of preparation and administration, low cytotoxicity in MTT assay, excellent biocompatibility and lowering of intraocular pressure for 40 days in a rabbit glaucoma model. The findings clearly justify further investigations towards clinical use in the treatment of glaucoma. Furthermore, the use of this shear-reversible colloidal gel could easily be extended to localized treatment of a number of critical conditions, from chronic disorders to cancer, potentially resulting in a number of new therapeutics with improved clinical performance. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Primary Congenital Glaucoma Versus Glaucoma Following Congenital Cataract Surgery: Comparative Clinical Features and Long-term Outcomes.

PubMed

Neustein, Rebecca F; Bruce, Beau B; Beck, Allen D

2016-10-01

To report and compare visual and glaucoma outcomes in primary congenital glaucoma (PCG) vs glaucoma following congenital cataract surgery (GFCS). Retrospective, observational, comparative case series. Setting: Emory Eye Center, Atlanta, Georgia. Pediatric glaucoma patients (age 0-18 years) treated at Emory by 1 clinician with ≥2-year follow-up. Glaucoma was defined according to the 9th Consensus Report of the World Glaucoma Association. Snellen-equivalent logMAR visual acuity (VA) and glaucoma control (IOP ≤21, no devastating complications, no recommendation for further glaucoma surgery). Asymptotic Wilcoxon-Mann-Whitney rank sum tests were employed to compare glaucoma subgroups. Included were 72 PCG and 56 GFCS cases, with mean follow-up time of 7.4 ± 4.1 and 8.0 ± 3.8 years, respectively. At last follow-up, PCG showed better median VA than GFCS in worse-seeing eyes (20/60 [interquartile range (IQR) 20/30-20/200] vs 20/400 [IQR 20/70-hand motion], respectively, P < .0001) and in better-seeing eyes of bilaterally-affected children (20/30 [IQR 20/20-20/60] vs 20/70 [IQR 20/35-20/100], respectively, P = .024).The following variables characterized the PCG and GFCS groups' glaucoma status, respectively: mean age at diagnosis (years), 0.70 ± 1.3 vs 3.3 ± 3.5 (P < .0001); median IOP (mm Hg), 15.50 [IQR 12.1-19.4] vs 17.50 [IQR 14.9-22], P = .037; median number of glaucoma medications at last follow-up, 1.49 [IQR 0-2] vs 2.54 [IQR 1-4], P < .0001; median number of glaucoma surgeries, 1.0 [IQR 1-2] vs 1.25 [IQR 0.5-2.0], P = .09. Children with PCG (vs those with GFCS) presented earlier, had better vision, required fewer medications to control disease, and had lower IOP at last follow-up. Copyright © 2016 Elsevier Inc. All rights reserved.

Glaucoma in atomic bomb survivors.

PubMed

Kiuchi, Yoshiaki; Yokoyama, Tomoko; Takamatsu, Michiya; Tsuiki, Eiko; Uematsu, Masafumi; Kinoshita, Hirofumi; Kumagami, Takeshi; Kitaoka, Takashi; Minamoto, Atsushi; Neriishi, Kazuo; Nakashima, Eiji; Khattree, Ravindra; Hida, Ayumi; Fujiwara, Saeko; Akahoshi, Masazumi

2013-10-01

Radiation has been associated with increases in noncancerous diseases. An effect of low-dose radiation on the prevalence of clinically detected glaucoma has not been previously reported. We therefore investigated the prevalence of glaucoma in A-bomb survivors and its possible association with radiation dose. A total of 1,589 people who participated in the clinical examination program for A-bomb survivors at the Radiation Effects Research Foundation (RERF) between October 2006 and September 2008 and who had reconstructed radiation doses, were recruited into this cross-sectional screening study. The prevalence of glaucoma and its dose-response relationship to A-bomb radiation were measured. Each subject underwent an initial screening consisting of an interview and ophthalmological examination. Questionable cases with any indication of ocular disease, including glaucoma, were referred to local hospitals for more comprehensive evaluation. A diagnosis of glaucoma was made based on specific optic disc appearance, perimetric results and other ocular findings. Of 1,589 eligible people, we detected 284 (17.9%) cases of glaucoma overall, including 36 (2.3%) cases of primary open-angle glaucoma with intraocular pressure levels greater than 21 mmHg, 226 (14.2%) cases of normal-tension glaucoma and 25 (1.6%) cases of primary angle-closure glaucoma. Seven glaucoma risk factors were examined as potential confounders but only two needed to be included in the final model. Binary regression using a generalized estimating equation method, with adjustment for gender, age, city, cataract surgery or diabetes mellitus, revealed an odds ratio at 1 Gy of 1.31 (95% confidence interval 1.11-1.53, P = 0.001) in the case of normal-tension glaucoma, but no association for other types of glaucoma. The prevalence of normal-tension glaucoma may increase with A-bomb radiation dose, but uncertainties associated with nonparticipation (59% participation) suggest caution in the interpretation of these results until they are confirmed by other studies.

Clinical impact of 8 prospective, randomized, multicenter glaucoma trials.

PubMed

Panarelli, Joseph F; Banitt, Michael R; Sidoti, Paul A; Budenz, Donald L; Singh, Kuldev

2015-01-01

To determine the impact of 8 multicenter randomized clinical trials (RCTs) on glaucoma practice. An electronic survey was distributed to the members of the American Glaucoma Society (AGS). Each participant was asked 2 study-specific questions and 1 standard question common to all 8 RCTs assessing the study's impact on clinical practice. RCTs included in the survey were the Advanced Glaucoma Intervention Study (AGIS), Collaborative Initial Glaucoma Treatment Study (CIGTS), Collaborative Normal Tension Glaucoma (CNTG) Study, European Glaucoma Prevention Study (EGPS), Early Manifest Glaucoma Trial (EMGT), Glaucoma Laser Trial (GLT), Ocular Hypertension Treatment Study (OHTS), and Tube Versus Trabeculectomy (TVT) Study. A 5-point Likert scale was used for rating all responses. The practice setting and duration of glaucoma practice was determined for all AGS members who responded. A total of 206 (23.0%) of 894 AGS members participated in the survey. Among those who responded, 46.4% were self classified as academic practitioners and 53.6% worked in a private practice setting. Mean Likert scores for the standard question evaluating the overall impact of the RCT were OHTS 4.47, CNTG Study 4.13, AGIS 3.78, TVT Study 3.53, EMGT 3.48, CIGTS 3.44, GLT 3.39, and 2.69 EGPS. Substantial differences were observed in the clinical impact of several RCTs in glaucoma. The reported impact of each study likely reflects several factors including study timing, design, conduct, and interpretation of results.

High prevalence of narrow angles among Chinese-American glaucoma and glaucoma suspect patients.

PubMed

Seider, Michael I; Pekmezci, Melike; Han, Ying; Sandhu, Simi; Kwok, Shiu Y; Lee, Roland Y; Lin, Shan C

2009-01-01

To evaluate the prevalence of gonioscopically narrow angles in a Chinese-American population with glaucoma or glaucoma suspicion. Charts from all Chinese-American patients seen in a comprehensive ophthalmology clinic in the Chinatown district of San Francisco in 2002 were reviewed. One eye from each patient with glaucoma or glaucoma suspicion that met inclusion criteria was included (n=108). Data were collected for sex, age, race (self-declared), refraction (spherical equivalent), intraocular pressure, gonioscopy, and vertical cup-to-disk ratio. Sixty percent (n=65) of Chinese-American eyes with glaucoma or glaucoma suspicion had gonioscopically narrow angles (Shaffer grade < or = 2 in 3 or more quadrants). Those with narrow angles were significantly older (P=0.004) than their open angle counterparts, but the 2 groups did not differ in terms of sex, refraction, intraocular pressure, or cup-to-disk ratio (all, P > or = 0.071). In a multivariate model including age, sex, and refraction as predictors of angle grade (open or narrow), only age was a significant predictor of angle grade (P=0.004). A large proportion of Chinese-Americans in our study population with glaucoma or glaucoma suspicion had gonioscopically narrow angles. In multivariate analysis, patients with narrow angles were older than those with open angles but did not differ from them in terms of sex or refraction. Continued evaluation of angle closure glaucoma risk among Chinese-Americans is needed.

Management of Blood Pressure in Patients with Glaucoma.

PubMed

Levine, Russell M; Yang, Alina; Brahma, Venkatesh; Martone, James F

2017-09-19

Ocular perfusion pressure (OPP) is defined as the difference between BP and intraocular pressure (IOP). With low BP comes low OPP and resultant ischemic damage to the optic nerve, leading to glaucoma progression. The purpose of this article is to review the literature on BP as it relates to glaucoma and to create a forum of discussion between ophthalmologists and internal medicine specialists. Both high and low BP has been linked glaucoma. Low BP is particularly associated with glaucoma progression in normal-tension glaucoma (NTG) patients. Patients who have low nighttime BP readings are at highest risk of progression of their glaucoma. Internal medicine specialists and ophthalmologists should consider the relationship between BP and glaucoma when treating patients with concomitant disease. Too-low nighttime BP should be avoided. Ambulatory blood pressure monitoring is a useful tool to identify patients at greatest risk for progression.

Innovative approaches to glaucoma management of Boston keratoprosthesis type 1.

PubMed

Vajaranant, Thasarat S; Liu, Jessica; Wilensky, Jacob; Cortina, M Soledad; Aref, Ahmad A

2016-09-01

Glaucoma remains a prevalent disorder and visual limiting factor after Boston keratoprosthesis type 1 implantation. Patients with glaucoma have worse initial and late visual acuity outcomes after otherwise successful keratoprosthesis implantation. Management of glaucoma in the setting of a keratoprosthesis is challenging because of relatively rapid progression and an inability to accurately measure intraocular pressure (IOP). In addition, there are no standard guidelines for glaucoma surveillance and monitoring after keratoprosthesis surgery. This report provides a review of the current literature and offers innovative strategies that will overcome the challenges in managing glaucoma in the setting of a Boston keratoprosthesis type 1 implant. The topics that will be discussed in this section include alternative methods for IOP measurement, rationales and surgical techniques for a pars plana tube placement for glaucoma drainage device, effective medical and laser treatment, the risk for IOP elevations after YAG laser, and practical guides to glaucoma surveillance and monitoring.

Angiogenesis in Glaucoma Filtration Surgery and Neovascular Glaucoma-A Review

PubMed Central

Kim, Megan; Lee, Chelsea; Payne, Rachael; Yue, Beatrice Y.J.T.; Chang, Jin-Hong; Ying, Hongyu

2015-01-01

Angiogenesis may pose a clinical challenge in glaucoma, for example during the wound healing phase after glaucoma filtration surgery and in a severe form of secondary glaucoma called neovascular glaucoma (NVG). Up regulation of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, occurs in eyes that have undergone glaucoma filtration surgery, as well as those with NVG. This has led to studies investigating the ability of anti-VEGF therapy to improve outcomes, and we examine their findings with respect to the safety and efficacy of anti-VEGF agents, mainly bevacizumab and ranibizumab, in eyes that have undergone glaucoma filtration surgery or have NVG. Combining conventional therapies—such as anti-metabolites after filtration surgery and panretinal photocoagulation in NVG—and anti-VEGF drugs may achieve a synergetic effect, although further studies are required to evaluate the long-term efficacy of combination treatments. PMID:25980779

Rebamipide protects against glaucoma eyedrop-induced ocular surface disorders in rabbits

PubMed Central

Kawaguchi, Ichiro; Higashide, Tomomi; Takeji, Yasuhiro; Sakurai, Kazushi; Kawaguchi, Chiaki; Sugiyama, Kazuhisa

2017-01-01

Purpose This study aimed to determine if rebamipide eyedrops can improve ocular surface damage caused by the use of glaucoma eyedrops. Methods Female Kbl:Dutch rabbits were used to evaluate glaucoma eyedrop-induced ocular surface damage; one eye of each rabbit was untreated and the other was administered glaucoma eyedrops for 30 days. To evaluate the effects of rebamipide on ocular surface damage, one eye of each rabbit was administered vehicle-treated glaucoma eyedrops and the other was administered rebamipide-treated glaucoma eyedrops for 30 days. Corneal and conjunctival epithelial damage was evaluated using fluorescein and rose bengal staining, respectively. Conjunctival inflammation was observed by light microscopy with hematoxylin-eosin staining. Dark cells (in which the corneal microvilli were damaged) were analyzed by scanning electron microscopy. Results There were no significant differences in fluorescein staining between the untreated and glaucoma eyedrop-treated groups; however, rose bengal staining and the number of inflammatory cells in the conjunctiva significantly increased after glaucoma eyedrop treatment. There was a four-fold increase in the number of dark cells in the glaucoma eyedrop-treated group compared to untreated. In contrast, in the conjunctiva of the rebamipide-treated glaucoma eyedrop group, rose bengal staining scores, the number of inflammatory cells, and the number of dark cells were decreased compared to the vehicle-treated glaucoma eyedrop group. Conclusions Results from our in vivo rabbit study demonstrated that short-term use of glaucoma eyedrops induces corneal epithelium disorders at the cellular level, but that simultaneous use of rebamipide has the potential to protect and repair the ocular surface. PMID:29049370

Rebamipide protects against glaucoma eyedrop-induced ocular surface disorders in rabbits.

PubMed

Kawaguchi, Ichiro; Kobayashi, Akira; Higashide, Tomomi; Takeji, Yasuhiro; Sakurai, Kazushi; Kawaguchi, Chiaki; Sugiyama, Kazuhisa

2017-01-01

This study aimed to determine if rebamipide eyedrops can improve ocular surface damage caused by the use of glaucoma eyedrops. Female Kbl:Dutch rabbits were used to evaluate glaucoma eyedrop-induced ocular surface damage; one eye of each rabbit was untreated and the other was administered glaucoma eyedrops for 30 days. To evaluate the effects of rebamipide on ocular surface damage, one eye of each rabbit was administered vehicle-treated glaucoma eyedrops and the other was administered rebamipide-treated glaucoma eyedrops for 30 days. Corneal and conjunctival epithelial damage was evaluated using fluorescein and rose bengal staining, respectively. Conjunctival inflammation was observed by light microscopy with hematoxylin-eosin staining. Dark cells (in which the corneal microvilli were damaged) were analyzed by scanning electron microscopy. There were no significant differences in fluorescein staining between the untreated and glaucoma eyedrop-treated groups; however, rose bengal staining and the number of inflammatory cells in the conjunctiva significantly increased after glaucoma eyedrop treatment. There was a four-fold increase in the number of dark cells in the glaucoma eyedrop-treated group compared to untreated. In contrast, in the conjunctiva of the rebamipide-treated glaucoma eyedrop group, rose bengal staining scores, the number of inflammatory cells, and the number of dark cells were decreased compared to the vehicle-treated glaucoma eyedrop group. Results from our in vivo rabbit study demonstrated that short-term use of glaucoma eyedrops induces corneal epithelium disorders at the cellular level, but that simultaneous use of rebamipide has the potential to protect and repair the ocular surface.

Protecting retinal ganglion cells.

PubMed

Khatib, T Z; Martin, K R

2017-02-01

Retinal ganglion cell degeneration underlies several conditions which give rise to significant visual compromise, including glaucoma, hereditary optic neuropathies, ischaemic optic neuropathies, and demyelinating disease. In this review, we discuss the emerging strategies for neuroprotection specifically in the context of glaucoma, including pharmacological neuroprotection, mesenchymal stem cells, and gene therapy approaches. We highlight potential pitfalls that need to be considered when developing these strategies and outline future directions, including the prospects for clinical trials.

Automatic CDR Estimation for Early Glaucoma Diagnosis

PubMed Central

Sarmiento, A.; Sanchez-Morillo, D.; Jiménez, S.; Alemany, P.

2017-01-01

Glaucoma is a degenerative disease that constitutes the second cause of blindness in developed countries. Although it cannot be cured, its progression can be prevented through early diagnosis. In this paper, we propose a new algorithm for automatic glaucoma diagnosis based on retinal colour images. We focus on capturing the inherent colour changes of optic disc (OD) and cup borders by computing several colour derivatives in CIE L∗a∗b∗ colour space with CIE94 colour distance. In addition, we consider spatial information retaining these colour derivatives and the original CIE L∗a∗b∗ values of the pixel and adding other characteristics such as its distance to the OD centre. The proposed strategy is robust due to a simple structure that does not need neither initial segmentation nor removal of the vascular tree or detection of vessel bends. The method has been extensively validated with two datasets (one public and one private), each one comprising 60 images of high variability of appearances. Achieved class-wise-averaged accuracy of 95.02% and 81.19% demonstrates that this automated approach could support physicians in the diagnosis of glaucoma in its early stage, and therefore, it could be seen as an opportunity for developing low-cost solutions for mass screening programs. PMID:29279773

Novel drug delivery systems for glaucoma

PubMed Central

Lavik, E; Kuehn, M H; Kwon, Y H

2011-01-01

Reduction of intraocular pressure (IOP) by pharmaceutical or surgical means has long been the standard treatment for glaucoma. A number of excellent drugs are available that are effective in reducing IOP. These drugs are typically applied as eye drops. However, patient adherence can be poor, thus reducing the clinical efficacy of the drugs. Several novel delivery systems designed to address the issue of adherence and to ensure consistent reduction of IOP are currently under development. These delivery systems include contact lenses-releasing glaucoma medications, injectables such as biodegradable micro- and nanoparticles, and surgically implanted systems. These new technologies are aimed at increasing clinical efficacy by offering multiple delivery options and are capable of managing IOP for several months. There is also a desire to have complementary neuroprotective approaches for those who continue to show progression, despite IOP reduction. Many potential neuroprotective agents are not suitable for traditional oral or drop formulations. Their potential is dependent on developing suitable delivery systems that can provide the drugs in a sustained, local manner to the retina and optic nerve. Drug delivery systems have the potential to improve patient adherence, reduce side effects, increase efficacy, and ultimately, preserve sight for glaucoma patients. In this review, we discuss benefits and limitations of the current systems of delivery and application, as well as those on the horizon. PMID:21475311

Through the Looking Glass: A Review of the Literature Investigating the Impact of Glaucoma on Crash Risk, Driving Performance, and Driver Self-Regulation in Older Drivers.

PubMed

Blane, Alison

2016-01-01

Glaucoma can result in insidious degradation of the peripheral visual field. This can severely affect everyday life and impact fitness-to-drive. Despite the high prevalence of glaucoma in older adults and the increasing longevity of the overall population, the impact of glaucoma on driving performance, driving practices, and crash risk remains unclear and under examined. This review examines the literature that investigates glaucoma and crash risk, driving performance, cognitive demand, driving self-regulation, and driving cessation in older drivers. A search of the literature relating to driving performance, crash risk, driver self-regulation, and cognitive workload in drivers with glaucoma was conducted between September 2013 and December 2013. This review has identified that the literature related to glaucoma and driving performance, crash risk, cognitive demand, and driving practices in older adults is inconsistent. There is a particular lack of consensus about whether glaucoma is associated with an increased risk of a car crash, although further information available relating to driving performance and driver habits suggests that there is a negative impact of glaucoma. Specifically, when the driving performance of glaucoma patients with moderate to severe visual field loss is assessed using either on-road or off-road techniques, they are found to perform poorly. There is also some debate around the amount of insight glaucoma patients have into the effect of the disease on their driving ability. The research suggests that patients with glaucoma find driving situations (particularly driving at night) increasingly difficult. Furthermore, there appears to be a tendency for drivers with glaucoma to alter their driving habits or to voluntarily cease driving completely; however, this is not the case for all glaucoma patients and the finding may differ depending on the laterality of visual field loss. There is little literature available that investigates glaucoma and its relationship with driving. The few studies that have been conducted are varied in methodology and the results available are highly inconsistent. With an ageing population and heavy reliance on driving for personal mobility, further research into measuring the impact of glaucoma and driving is crucial to ensure a sustained quality of life for the elderly. The potential for future research is discussed.

[Focus on popular science education of glaucoma and reduce glaucomatous low vision and blindness].

PubMed

Sun, X H

2017-02-11

The prevention of blindness caused by glaucoma is a difficult task. In order to accomplish the task better, we need the participation of whole society and popularize relevant medical knowledge. Popular science and related knowledge of glaucoma are needed to the people especially for high risk population. If people know glaucoma better and actively join the screening of glaucoma, we can find and diagnose glaucoma earlier, avoid late treatment and reduce the glaucomatous visual function impairment. For patients who had been diagnosed with glaucoma, they should aware and accept new medical concept and technique through systemic popular science education. They should actively participate the whole procedure of the disease management and improve their compliance and confidence. Academic organization of ophthalmology should participate and guide the patient education, improve the individualized comprehensive health care for the diagnosis and treatment and third-order health care system that is suitable for the condition of our country, help improving the prognosis of glaucoma and life quality related to vision for advanced and late glaucoma. (Chin J Ophthalmol, 2017, 53: 81-84) .

Epoxy based nanocomposites with fully exfoliated unmodified clay: mechanical and thermal properties.

PubMed

Li, Binghai; Zhang, Xiaohong; Gao, Jianming; Song, Zhihai; Qi, Guicun; Liu, Yiqun; Qiao, Jinliang

2010-09-01

The unmodified clay has been fully exfoliated in epoxy resin with the aid of a novel ultrafine full-vulcanized powdered rubber. Epoxy/rubber/clay nanocomposites with exfoliated morphology have been successfully prepared. The microstructures of the nanocomposites were characterized by means of X-ray diffraction and transmission electron microscopy. It was found that the unmodified clay was fully exfoliated and uniformly dispersed in the resulting nanocomposite. Characterizations of mechanical properties revealed that the impact strength of this special epoxy/rubber/clay nanocomposite increased up 107% over the neat epoxy resin. Thermal analyses showed that thermal stability of the nanocomposite was much better than that of epoxy nanocomposite based on organically modified clay.

A Proteomics View of the Molecular Mechanisms and Biomarkers of Glaucomatous Neurodegeneration

PubMed Central

Tezel, Gülgün

2013-01-01

Despite improving understanding of glaucoma, key molecular players of neurodegeneration that can be targeted for treatment of glaucoma, or molecular biomarkers that can be useful for clinical testing, remain unclear. Proteomics technology offers a powerful toolbox to accomplish these important goals of the glaucoma research and is increasingly being applied to identify molecular mechanisms and biomarkers of glaucoma. Recent studies of glaucoma using proteomics analysis techniques have resulted in the lists of differentially expressed proteins in human glaucoma and animal models. The global analysis of protein expression in glaucoma has been followed by cell-specific proteome analysis of retinal ganglion cells and astrocytes. The proteomics data have also guided targeted studies to identify post-translational modifications and protein-protein interactions during glaucomatous neurodegeneration. In addition, recent applications of proteomics have provided a number of potential biomarker candidates. Proteomics technology holds great promise to move glaucoma research forward toward new treatment strategies and biomarker discovery. By reviewing the major proteomics approaches and their applications in the field of glaucoma, this article highlights the power of proteomics in translational and clinical research related to glaucoma and also provides a framework for future research to functionally test the importance of specific molecular pathways and validate candidate biomarkers. PMID:23396249

[Risk factors in the results of the colour vision test Roth 28-hue (E) desaturated in glaucoma patients].

PubMed

Jass, C M; Böhringer, D; Erb, C; Jordan, J F

2013-11-01

Glaucoma is an ocular disease with typical progressive damage of the optic nerve. In the past it was postulated that glaucoma induces acquired colour vision disorders. Until now all studies about glaucoma and colour vision disorders did not include vascular risk factors. In the present study we determined several vascular risk factors concerning the results of the colour vision test Roth 28-hue (E) desaturated in glaucoma patients. On the basis of an analysis of variance (ANOVA) we determined the influence of several risk factors, such as arteriosclerotic and vasospastic risk factors, on the results of the colour vision test Roth 28-hue (E) desaturated in glaucoma patients. 353 glaucoma patients were included in this study. We detected a strong influence of age and mean defect in perimetry and an additional effect of arteriosclerotic and vasospastic risk factors on the results of the colour vision test Roth 28-hue (E) desaturated in glaucoma patients. We suspect that arteriosclerotic and vasospastic risk factors independently to glaucoma have an influence on colour vision. In the future attention additionally has to be given to vascular risk factors in the colour vision testing of glaucoma patients. Georg Thieme Verlag KG Stuttgart · New York.

Epidemiology and clinical characteristics of patients with glaucoma: An analysis of hospital data between 2003 and 2012.

PubMed

Zhao, Yang; Fu, Jia-Li; Li, Yu-Li; Li, Ping; Lou, Feng-Lan

2015-11-01

To assess demographic and clinical characteristics of glaucoma patients in an Ophthalmologic Hospital of Jinan, China from 2003 to 2012. Medical charts of patients with primary open-angle glaucoma (POAG), primary angle closure glaucoma (PACG), and secondary glaucoma (SG) were reviewed. The main outcome measures of patients with glaucoma included basic demographic data (age at presentation, gender, and residence), clinical characteristics (admission date, intraocular pressure, and naked vision), and previous history (injury, cardiovascular disease, diabetes mellitus, hypertension, smoking, and alcohol consumption). Data from 1458 glaucoma patients were reviewed, of which PACG and SG patients accounted for 45.40% and 47.19%, respectively. The average age of all patients with glaucoma increased from 56.05 years in 2003 to 57.83 years in 2012, and the proportion of patients from rural areas rose from 46.43% to 59.13% during 10-year period. Female gender, cardiovascular disease, and hypertension were associated with PACG. POAG was related to smoking and alcohol consumption. There was positive correlation between SG and history of injury and diabetes mellitus. PACG and SG are the major types of glaucoma. Gender, injury, diabetes mellitus, cardiovascular disease, hypertension, smoking, and alcohol consumption were associated with different types of glaucoma.

Large scale production of highly-qualified graphene by ultrasonic exfoliation of expanded graphite under the promotion of (NH4)2CO3 decomposition.

PubMed

Wang, Yunwei; Tong, Xili; Guo, Xiaoning; Wang, Yingyong; Jin, Guoqiang; Guo, Xiangyun

2013-11-29

Highly-qualified graphene was prepared by the ultrasonic exfoliation of commercial expanded graphite (EG) under the promotion of (NH4)2CO3 decomposition. The yield of graphene from the first exfoliation is 7 wt%, and it can be increased to more than 65 wt% by repeated exfoliations. Atomic force microscopy, x-ray photoelectron spectroscopy and Raman analysis show that the as-prepared graphene only has a few defects or oxides, and more than 95% of the graphene flakes have a thickness of ~1 nm. The electrochemical performance of the as-prepared graphene is comparable to reduced graphene oxide in the determination of dopamine (DA) from the mixed solution of ascorbic acid, uric acid and DA. These results show that the decomposition of (NH4)2CO3 molecules in the EG layers under ultrasonication promotes the exfoliation of graphite and provides a low-priced route for large scale production of highly-quality graphene.

Sequential structural and optical evolution of MoS2 by chemical synthesis and exfoliation

NASA Astrophysics Data System (ADS)

Kim, Ju Hwan; Kim, Jungkil; Oh, Si Duck; Kim, Sung; Choi, Suk-Ho

2015-06-01

Various types of MoS2 structures are successfully obtained by using economical and facile sequential synthesis and exfoliation methods. Spherically-shaped lumps of multilayer (ML) MoS2 are prepared by using a conventional hydrothermal method and were subsequently 1st-exfoliated in hydrazine while being kept in autoclave to be unrolled and separated into five-to-six-layer MoS2 pieces of several-hundred nm in size. The MoS2 MLs are 2nd-exfoliated in sodium naphthalenide under an Ar ambient to finally produce bilayer MoS2 crystals of ~100 nm. The sequential exfoliation processes downsize MoS2 laterally and reduce its number of layers. The three types of MoS2 allotropes exhibit particular optical properties corresponding to their structural differences. These results suggest that two-dimensional MoS2 crystals can be prepared by employing only chemical techniques without starting from high-pressure-synthesized bulk MoS2 crystals.

Large scale production of highly-qualified graphene by ultrasonic exfoliation of expanded graphite under the promotion of (NH4)2CO3 decomposition

NASA Astrophysics Data System (ADS)

Wang, Yunwei; Tong, Xili; Guo, Xiaoning; Wang, Yingyong; Jin, Guoqiang; Guo, Xiangyun

2013-11-01

Highly-qualified graphene was prepared by the ultrasonic exfoliation of commercial expanded graphite (EG) under the promotion of (NH4)2CO3 decomposition. The yield of graphene from the first exfoliation is 7 wt%, and it can be increased to more than 65 wt% by repeated exfoliations. Atomic force microscopy, x-ray photoelectron spectroscopy and Raman analysis show that the as-prepared graphene only has a few defects or oxides, and more than 95% of the graphene flakes have a thickness of ˜1 nm. The electrochemical performance of the as-prepared graphene is comparable to reduced graphene oxide in the determination of dopamine (DA) from the mixed solution of ascorbic acid, uric acid and DA. These results show that the decomposition of (NH4)2CO3 molecules in the EG layers under ultrasonication promotes the exfoliation of graphite and provides a low-priced route for large scale production of highly-quality graphene.

High-efficiency exfoliation of layered materials into 2D nanosheets in switchable CO2/Surfactant/H2O system

NASA Astrophysics Data System (ADS)

Wang, Nan; Xu, Qun; Xu, Shanshan; Qi, Yuhang; Chen, Meng; Li, Hongxiang; Han, Buxing

2015-11-01

Layered materials present attractive and important properties due to their two-dimensional (2D) structure, allowing potential applications including electronics, optoelectronics, and catalysis. However, fully exploiting the outstanding properties will require a method for their efficient exfoliation. Here we present that a series of layered materials can be successfully exfoliated into single- and few-layer nanosheets using the driving forces coming from the phase inversion, i.e., from micelles to reverse micelles in the emulsion microenvironment built by supercritical carbon dioxide (SC CO2). The effect of variable experimental parameters including CO2 pressure, ethanol/water ratio, and initial concentration of bulk materials on the exfoliation yield have been investigated. Moreover, we demonstrate that the exfoliated 2D nanosheets have their worthwhile applications, for example, graphene can be used to prepare conductive paper, MoS2 can be used as fluorescent label to perform cellular labelling, and BN can effectively reinforce polymers leading to the promising mechanical properties.

Efficient fluorescence quenching in electrochemically exfoliated graphene decorated with gold nanoparticles

NASA Astrophysics Data System (ADS)

Hurtado-Morales, M.; Ortiz, M.; Acuña, C.; Nerl, H. C.; Nicolosi, V.; Hernández, Y.

2016-07-01

High surface area graphene sheets were obtained by electrochemical exfoliation of graphite in an acid medium under constant potential conditions. Filtration and centrifugation processes played an important role in order to obtain stable dispersions in water. Scanning electron microscopy and transmission electron microscopy imaging revealed highly exfoliated crystalline samples of ∼5 μm. Raman, Fourier transform infrared and x-ray photoelectron spectroscopy further confirmed the high quality of the exfoliated material. The electrochemically exfoliated graphene (EEG) was decorated with gold nanoparticles (AuNPs) using sodium cholate as a buffer layer. This approach allowed for a non-covalent functionalization without altering the desirable electronic properties of the EEG. The AuNP-EEG samples were characterized with various techniques including absorbance and fluorescence spectroscopy. These samples displayed a fluorescence signal using an excitation wavelength of 290 nm. The calculated quantum yield (Φ) for these samples was 40.04%, a high efficiency compared to previous studies using solution processable graphene.

Two-dimensional materials from high-throughput computational exfoliation of experimentally known compounds.

PubMed

Mounet, Nicolas; Gibertini, Marco; Schwaller, Philippe; Campi, Davide; Merkys, Andrius; Marrazzo, Antimo; Sohier, Thibault; Castelli, Ivano Eligio; Cepellotti, Andrea; Pizzi, Giovanni; Marzari, Nicola

2018-03-01

Two-dimensional (2D) materials have emerged as promising candidates for next-generation electronic and optoelectronic applications. Yet, only a few dozen 2D materials have been successfully synthesized or exfoliated. Here, we search for 2D materials that can be easily exfoliated from their parent compounds. Starting from 108,423 unique, experimentally known 3D compounds, we identify a subset of 5,619 compounds that appear layered according to robust geometric and bonding criteria. High-throughput calculations using van der Waals density functional theory, validated against experimental structural data and calculated random phase approximation binding energies, further allowed the identification of 1,825 compounds that are either easily or potentially exfoliable. In particular, the subset of 1,036 easily exfoliable cases provides novel structural prototypes and simple ternary compounds as well as a large portfolio of materials to search from for optimal properties. For a subset of 258 compounds, we explore vibrational, electronic, magnetic and topological properties, identifying 56 ferromagnetic and antiferromagnetic systems, including half-metals and half-semiconductors.

Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation.

PubMed

Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

2016-03-30

Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors.

Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation

PubMed Central

Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

2016-01-01

Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors. PMID:27026070

High-efficiency exfoliation of layered materials into 2D nanosheets in switchable CO2/Surfactant/H2O system.

PubMed

Wang, Nan; Xu, Qun; Xu, Shanshan; Qi, Yuhang; Chen, Meng; Li, Hongxiang; Han, Buxing

2015-11-16

Layered materials present attractive and important properties due to their two-dimensional (2D) structure, allowing potential applications including electronics, optoelectronics, and catalysis. However, fully exploiting the outstanding properties will require a method for their efficient exfoliation. Here we present that a series of layered materials can be successfully exfoliated into single- and few-layer nanosheets using the driving forces coming from the phase inversion, i.e., from micelles to reverse micelles in the emulsion microenvironment built by supercritical carbon dioxide (SC CO2). The effect of variable experimental parameters including CO2 pressure, ethanol/water ratio, and initial concentration of bulk materials on the exfoliation yield have been investigated. Moreover, we demonstrate that the exfoliated 2D nanosheets have their worthwhile applications, for example, graphene can be used to prepare conductive paper, MoS2 can be used as fluorescent label to perform cellular labelling, and BN can effectively reinforce polymers leading to the promising mechanical properties.

Electrical bistabilities and memory mechanisms of nonvolatile organic bistable devices based on exfoliated muscovite-type mica nanoparticle/poly(methylmethacrylate) nanocomposites

NASA Astrophysics Data System (ADS)

Lim, Won Gyu; Lee, Dea Uk; Na, Han Gil; Kim, Hyoun Woo; Kim, Tae Whan

2018-02-01

Organic bistable devices (OBDs) with exfoliated mica nanoparticles (NPs) embedded into an insulating poly(methylmethacrylate) (PMMA) layer were fabricated by using a spin-coating method. Current-voltage (I-V) curves for the Al/PMMA/exfoliated mica NP/PMMA/indium-tin-oxide/glass devices at 300 K showed a clockwise current hysteresis behavior due to the existence of the exfoliated muscovite-type mica NPs, which is an essential feature for bistable devices. Write-read-erase-read data showed that the OBDs had rewritable nonvolatile memories and an endurance number of ON/OFF switching for the OBDs of 102 cycles. An ON/OFF ratio of 1 × 103 was maintained for retention times larger than 1 × 104 s. The memory mechanisms of the fabricated OBDs were described by using the trapping and the tunneling processes within a PMMA active layer containing exfoliated muscovite-type mica NPs on the basis of the energy band diagram and the I-V curves.

Two-dimensional materials from high-throughput computational exfoliation of experimentally known compounds

NASA Astrophysics Data System (ADS)

Mounet, Nicolas; Gibertini, Marco; Schwaller, Philippe; Campi, Davide; Merkys, Andrius; Marrazzo, Antimo; Sohier, Thibault; Castelli, Ivano Eligio; Cepellotti, Andrea; Pizzi, Giovanni; Marzari, Nicola

2018-02-01

Two-dimensional (2D) materials have emerged as promising candidates for next-generation electronic and optoelectronic applications. Yet, only a few dozen 2D materials have been successfully synthesized or exfoliated. Here, we search for 2D materials that can be easily exfoliated from their parent compounds. Starting from 108,423 unique, experimentally known 3D compounds, we identify a subset of 5,619 compounds that appear layered according to robust geometric and bonding criteria. High-throughput calculations using van der Waals density functional theory, validated against experimental structural data and calculated random phase approximation binding energies, further allowed the identification of 1,825 compounds that are either easily or potentially exfoliable. In particular, the subset of 1,036 easily exfoliable cases provides novel structural prototypes and simple ternary compounds as well as a large portfolio of materials to search from for optimal properties. For a subset of 258 compounds, we explore vibrational, electronic, magnetic and topological properties, identifying 56 ferromagnetic and antiferromagnetic systems, including half-metals and half-semiconductors.

Predicting Vision-Related Disability in Glaucoma.

PubMed

Abe, Ricardo Y; Diniz-Filho, Alberto; Costa, Vital P; Wu, Zhichao; Medeiros, Felipe A

2018-01-01

To present a new methodology for investigating predictive factors associated with development of vision-related disability in glaucoma. Prospective, observational cohort study. Two hundred thirty-six patients with glaucoma followed up for an average of 4.3±1.5 years. Vision-related disability was assessed by the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) at baseline and at the end of follow-up. A latent transition analysis model was used to categorize NEI VFQ-25 results and to estimate the probability of developing vision-related disability during follow-up. Patients were tested with standard automated perimetry (SAP) at 6-month intervals, and evaluation of rates of visual field change was performed using mean sensitivity (MS) of the integrated binocular visual field. Baseline disease severity, rate of visual field loss, and duration of follow-up were investigated as predictive factors for development of disability during follow-up. The relationship between baseline and rates of visual field deterioration and the probability of vision-related disability developing during follow-up. At baseline, 67 of 236 (28%) glaucoma patients were classified as disabled based on NEI VFQ-25 results, whereas 169 (72%) were classified as nondisabled. Patients classified as nondisabled at baseline had 14.2% probability of disability developing during follow-up. Rates of visual field loss as estimated by integrated binocular MS were almost 4 times faster for those in whom disability developed versus those in whom it did not (-0.78±1.00 dB/year vs. -0.20±0.47 dB/year, respectively; P < 0.001). In the multivariate model, each 1-dB lower baseline binocular MS was associated with 34% higher odds of disability developing over time (odds ratio [OR], 1.34; 95% confidence interval [CI], 1.06-1.70; P = 0.013). In addition, each 0.5-dB/year faster rate of loss of binocular MS during follow-up was associated with a more than 3.5 times increase in the risk of disability developing (OR, 3.58; 95% CI, 1.56-8.23; P = 0.003). A new methodology for classification and analysis of change in patient-reported quality-of-life outcomes allowed construction of models for predicting vision-related disability in glaucoma. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Exfoliation and Reassembly of Cobalt Oxide Nanosheets into a Reversible Lithium-Ion Battery Cathode

DTIC Science & Technology

2012-01-01

REPORT Exfoliation and Reassembly of Cobalt Oxide Nanosheets into a Reversible Lithium-Ion Battery Cathode 14. ABSTRACT 16. SECURITY CLASSIFICATION OF...battery fabrication, cobalt oxide Owen C. Compton, Ali Abouimrane, Zhi An, Marc J. Palmeri, L. Catherine Brinson, Khalil Amine, SonBinh T. Nguyen...Exfoliation and Reassembly of Cobalt Oxide Nanosheets into a Reversible Lithium-Ion Battery Cathode Report Title ABSTRACT An exfoliation–reassembly

The effect of the non-steroidal anti-inflammatory drug choline magnesium trisalicylate on gastric mucosal cell exfoliation.

PubMed Central

Mitchell, K G; Hearns, J; Crean, G P

1984-01-01

Gastric mucosal cell exfoliation was measured in 10 normal subjects taking choline magnesium trisalicylate (CMT), aspirin and placebo. Both drugs resulted in significantly elevated rates of exfoliation although the serum salicylate levels achieved with aspirin were lower than those achieved by CMT. Side-effects of tinnitus, nausea and increased faecal blood loss were more common while subjects were taking CMT. PMID:6691886

The effect of the non-steroidal anti-inflammatory drug choline magnesium trisalicylate on gastric mucosal cell exfoliation.

PubMed

Mitchell, K G; Hearns, J; Crean, G P

1984-01-01

Gastric mucosal cell exfoliation was measured in 10 normal subjects taking choline magnesium trisalicylate (CMT), aspirin and placebo. Both drugs resulted in significantly elevated rates of exfoliation although the serum salicylate levels achieved with aspirin were lower than those achieved by CMT. Side-effects of tinnitus, nausea and increased faecal blood loss were more common while subjects were taking CMT.

Chronic Glaucoma in Dogs: Relationships Between Histologic Lesions and the Gonioscopic Diagnosis of Pectinate Ligament Dysplasia.

PubMed

Bauer, B S; Sandmeyer, L S; Philibert, H; Feng, C X; Grahn, B H

2016-11-01

Pectinate ligament dysplasia (PLD) is a common cause of canine glaucoma and the definitive clinical diagnosis is based on gonioscopy. Although the histologic lesions of PLD have been described, it has not been determined whether these changes are specific for PLD or if similar histologic changes can develop as a consequence of secondary glaucoma. The filtration angles of 61 enucleated canine globes with chronic glaucoma were evaluated with light microscopy by 3 examiners who were masked to the clinical history, signalment, and gonioscopic results. A histologic diagnosis of PLD versus non-PLD was determined by each examiner based on previously reported morphologic criteria and compared with the clinical gonioscopic diagnosis. Of the 61 enucleated glaucomatous eyes, 40 were clinically diagnosed with PLD. For all 3 examiners, a histologic diagnosis of PLD corresponded poorly with the clinical diagnosis of PLD (range of kappa score: 0.149-0.269; range of AUC: 0.592-0.621). There was no difference between examiners in their ability to correctly diagnose PLD histologically (P = .978). A fair degree of agreement was noted among examiners in obtaining their suspected histologic diagnosis of PLD (kappa score 0.256). No individual or sets of histologic ICA features were consistent with clinical PLD. The results indicate the histologic ICA changes proposed to be characteristic of PLD are also noted in canine globes affected with chronic secondary glaucoma. Therefore, using routine histologic evaluation, a histologic diagnosis of PLD is not possible in the face of chronic canine glaucoma. © The Author(s) 2016.

Modeling Glaucoma: Retinal Ganglion Cells Generated from Induced Pluripotent Stem Cells of Patients with SIX6 Risk Allele Show Developmental Abnormalities.

PubMed

Teotia, Pooja; Van Hook, Matthew J; Wichman, Christopher S; Allingham, R Rand; Hauser, Michael A; Ahmad, Iqbal

2017-11-01

Glaucoma represents a group of multifactorial diseases with a unifying pathology of progressive retinal ganglion cell (RGC) degeneration, causing irreversible vision loss. To test the hypothesis that RGCs are intrinsically vulnerable in glaucoma, we have developed an in vitro model using the SIX6 risk allele carrying glaucoma patient-specific induced pluripotent stem cells (iPSCs) for generating functional RGCs. Here, we demonstrate that the efficiency of RGC generation by SIX6 risk allele iPSCs is significantly lower than iPSCs-derived from healthy, age- and sex-matched controls. The decrease in the number of RGC generation is accompanied by repressed developmental expression of RGC regulatory genes. The SIX6 risk allele RGCs display short and simple neurites, reduced expression of guidance molecules, and immature electrophysiological signature. In addition, these cells have higher expression of glaucoma-associated genes, CDKN2A and CDKN2B, suggesting an early onset of the disease phenotype. Consistent with the developmental abnormalities, the SIX6 risk allele RGCs display global dysregulation of genes which map on developmentally relevant biological processes for RGC differentiation and signaling pathways such as mammalian target of rapamycin that integrate diverse functions for differentiation, metabolism, and survival. The results suggest that SIX6 influences different stages of RGC differentiation and their survival; therefore, alteration in SIX6 function due to the risk allele may lead to cellular and molecular abnormalities. These abnormalities, if carried into adulthood, may make RGCs vulnerable in glaucoma. Stem Cells 2017;35:2239-2252. © 2017 AlphaMed Press.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng

An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the firstmore » exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.« less

Two-stage preparation of magnetic sorbent based on exfoliated graphite with ferrite phases for sorption of oil and liquid hydrocarbons from the water surface

NASA Astrophysics Data System (ADS)

Pavlova, Julia A.; Ivanov, Andrei V.; Maksimova, Natalia V.; Pokholok, Konstantin V.; Vasiliev, Alexander V.; Malakho, Artem P.; Avdeev, Victor V.

2018-05-01

Due to the macropore structure and the hydrophobic properties, exfoliated graphite (EG) is considered as a perspective sorbent for oil and liquid hydrocarbons from the water surface. However, there is the problem of EG collection from the water surface. One of the solutions is the modification of EG by a magnetic compound and the collection of EG with sorbed oil using the magnetic field. In this work, the method of the two-stage preparation of exfoliated graphite with ferrite phases is proposed. This method includes the impregnation of expandable graphite in the mixed solution of iron (III) chloride and cobalt (II) or nickel (II) nitrate in the first stage and the thermal exfoliation of impregnated expandable graphite with the formation of exfoliated graphite containing cobalt and nickel ferrites in the second stage. Such two-stage method makes it possible to obtain the sorbent based on EG modified by ferrimagnetic phases with high sorption capacity toward oil (up to 45-51 g/g) and high saturation magnetization (up to 42 emu/g). On the other hand, this method allows to produce the magnetic sorbent in a short period of time (up to 10 s) during which the thermal exfoliation is carried out in the air atmosphere.

Diagnostic Accuracy of Nonmydriatic Fundus Photography for the Detection of Glaucoma in Diabetic Patients.

PubMed

Muñoz-Negrete, Francisco J; Contreras, Inés; Oblanca, Noelia; Pinazo-Durán, M Dolores; Rebolleda, Gema

2015-01-01

To determine the diagnostic accuracy for glaucoma of a set of criteria with nonmydriatic monoscopic fundus photography (NMFP) in diabetics. Diabetics recruited from a screening program for diabetic retinopathy and diabetic glaucoma patients recruited from our glaucoma unit were included. Any patient with evidence of diabetic retinopathy was excluded. Diabetic patients had to have no visual field defects to be included as controls. Glaucoma patients had to have a glaucomatous field defect in at least one eye to be included. One NMFP was taken per eye for all subjects. These photographs were evaluated by two masked glaucoma specialists for the presence of the following: bilateral cup to disc (C/D) ratio ≥ 0.6, notching or thinning of the neuroretinal rim, disc hemorrhages, and asymmetry in the C/D ratio between both eyes ≥ 0.2. This evaluation led to a dichotomous classification: if any of the above criteria was present, the patient was classified as glaucoma. If none were present, the patient was classified as normal. 72 control subjects and 72 glaucoma patients were included. Evaluation of NMFP had a sensitivity of 79.17% and a specificity of 80.56% for specialist 1 and a sensitivity of 72.22% and a specificity of 88.88% for specialist 2 for the detection of glaucoma. The overall accuracy was 79.83% and 80.55%, respectively. NMFP evaluation by a glaucoma specialist may be useful for the detection of glaucoma in diabetics.

High Prevalence of Narrow Angles among Chinese-American Glaucoma and Glaucoma Suspect Patients

PubMed Central

Seider, Michael I; Pekmezci, Melike; Han, Ying; Sandhu, Simi; Kwok, Shiu Y; Lee, Roland Y; Lin, Shan C

2009-01-01

Purpose To evaluate the prevalence of gonioscopically narrow angles in a Chinese-American population with glaucoma or glaucoma suspicion. Patients and Methods Charts from all Chinese-American patients seen in a comprehensive ophthalmology clinic in the Chinatown district of San Francisco in 2002 were reviewed. One eye from each patient with glaucoma or glaucoma suspicion that met inclusion criteria was included (n=108). Data was collected for gender, age, race (self-declared), refraction (spherical equivalent), intraocular pressure (IOP), gonioscopy and vertical cup-to-disk ratio (CDR). Results Sixty percent (n=65) of Chinese-American eyes with glaucoma or glaucoma suspicion had gonioscopically narrow angles (Shaffer grade ≤2 in three or more quadrants). Those with narrow angles were significantly older (P=0.004) than their open angle counterparts, but the two groups did not differ in terms of gender, refraction, IOP or CDR (all, P≥0.071). In a multivariate model including age, gender and refraction as predictors of angle grade (open or narrow), only age was a significant predictor of angle grade (P=0.004). Conclusions A large proportion of Chinese-Americans in our study population with glaucoma or glaucoma suspicion had gonioscopically narrow angles. In multivariate analysis, patients with narrow angles were older than those with open angles but did not differ from them in terms of gender or refraction. Continued evaluation of angle closure glaucoma risk among Chinese-Americans is needed. PMID:19826385

Early detection of glaucoma by means of a novel 3D computer‐automated visual field test

PubMed Central

Nazemi, Paul P; Fink, Wolfgang; Sadun, Alfredo A; Francis, Brian; Minckler, Donald

2007-01-01

Purpose A recently devised 3D computer‐automated threshold Amsler grid test was used to identify early and distinctive defects in people with suspected glaucoma. Further, the location, shape and depth of these field defects were characterised. Finally, the visual fields were compared with those obtained by standard automated perimetry. Patients and methods Glaucoma suspects were defined as those having elevated intraocular pressure (>21 mm Hg) or cup‐to‐disc ratio of >0.5. 33 patients and 66 eyes with risk factors for glaucoma were examined. 15 patients and 23 eyes with no risk factors were tested as controls. The recently developed 3D computer‐automated threshold Amsler grid test was used. The test exhibits a grid on a computer screen at a preselected greyscale and angular resolution, and allows patients to trace those areas on the grid that are missing in their visual field using a touch screen. The 5‐minute test required that the patients repeatedly outline scotomas on a touch screen with varied displays of contrast while maintaining their gaze on a central fixation marker. A 3D depiction of the visual field defects was then obtained that was further characterised by the location, shape and depth of the scotomas. The exam was repeated three times per eye. The results were compared to Humphrey visual field tests (ie, achromatic standard or SITA standard 30‐2 or 24‐2). Results In this pilot study 79% of the eyes tested in the glaucoma‐suspect group repeatedly demonstrated visual field loss with the 3D perimetry. The 3D depictions of visual field loss associated with these risk factors were all characteristic of or compatible with glaucoma. 71% of the eyes demonstrated arcuate defects or a nasal step. Constricted visual fields were shown in 29% of the eyes. No visual field changes were detected in the control group. Conclusions The 3D computer‐automated threshold Amsler grid test may demonstrate visual field abnormalities characteristic of glaucoma in glaucoma suspects with normal achromatic Humphrey visual field testing. This test may be used as a screening tool for the early detection of glaucoma. PMID:17504855

Whole exome sequencing implicates eye development, the unfolded protein response and plasma membrane homeostasis in primary open-angle glaucoma

PubMed Central

Souzeau, Emmanuelle; Sharma, Shiwani; Landers, John; Mills, Richard; Goldberg, Ivan; Healey, Paul R.; Graham, Stuart; Hewitt, Alex W.; Mackey, David A.; Galanopoulos, Anna; Casson, Robert J.; Ruddle, Jonathan B.; Ellis, Jonathan; Leo, Paul; Brown, Matthew A.; MacGregor, Stuart; Lynn, David J.; Burdon, Kathryn P.; Craig, Jamie E.

2017-01-01

Purpose To identify biological processes associated with POAG and its subtypes, high-tension (HTG) and normal-tension glaucoma (NTG), by analyzing rare potentially damaging genetic variants. Methods A total of 122 and 65 unrelated HTG and NTG participants, respectively, with early onset advanced POAG, 103 non-glaucoma controls and 993 unscreened ethnicity-matched controls were included in this study. Study participants without myocilin disease-causing variants and non-glaucoma controls were subjected to whole exome sequencing on an Illumina HiSeq2000. Exomes of participants were sequenced on an Illumina HiSeq2000. Qualifying variants were rare in the general population (MAF < 0.001) and potentially functionally damaging (nonsense, frameshift, splice or predicted pathogenic using SIFT or Polyphen2 software). Genes showing enrichment of qualifying variants in cases were selected for pathway and network analysis using InnateDB. Results POAG cases showed enrichment of rare variants in camera-type eye development genes (p = 1.40×10–7, corrected p = 3.28×10–4). Implicated eye development genes were related to neuronal or retinal development. HTG cases were significantly enriched for key regulators in the unfolded protein response (UPR) (p = 7.72×10–5, corrected p = 0.013). The UPR is known to be involved in myocilin-related glaucoma; our results suggest the UPR has a role in non-myocilin causes of HTG. NTG cases showed enrichment in ion channel transport processes (p = 1.05×10–4, corrected p = 0.027) including calcium, chloride and phospholipid transporters involved in plasma membrane homeostasis. Network analysis also revealed enrichment of the MHC Class I antigen presentation pathway in HTG, and the EGFR1 and cell-cycle pathways in both HTG and NTG. Conclusion This study suggests that mutations in eye development genes are enriched in POAG. HTG can result from aberrant responses to protein misfolding which may be amenable to molecular chaperone therapy. NTG is associated with impaired plasma membrane homeostasis increasing susceptibility to apoptosis. PMID:28264060

Eye Anatomy

MedlinePlus

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Comparison on exfoliated graphene nano-sheets and triturated graphite nano-particles for mode-locking the Erbium-doped fibre lasers

NASA Astrophysics Data System (ADS)

Yang, Chun-Yu; Lin, Yung-Hsiang; Wu, Chung-Lun; Cheng, Chih-Hsien; Tsai, Din-Ping; Lin, Gong-Ru

2018-06-01

Comparisons on exfoliated graphene nano-sheets and triturated graphite nano-particles for mode-locking the Erbium-doped fiber lasers (EDFLs) are performed. As opposed to the graphite nano-particles obtained by physically triturating the graphite foil, the tri-layer graphene nano-sheets is obtained by electrochemically exfoliating the graphite foil. To precisely control the size dispersion and the layer number of the exfoliated graphene nano-sheet, both the bias of electrochemical exfoliation and the speed of centrifugation are optimized. Under a threshold exfoliation bias of 3 volts and a centrifugation at 1000 rpm, graphene nano-sheets with an average diameter of 100  ±  40 nm can be obtained. The graphene nano-sheets with an area density of 15 #/µm2 are directly imprinted onto the end-face of a single-mode fiber made patchcord connector inside the EDFL cavity. Such electrochemically exfoliated graphene nano-sheets show comparable saturable absorption with standard single-graphene and perform the self-amplitude modulation better than physically triturated graphite nano-particles. The linear transmittance and modulation depth of the inserted graphene nano-sheets are 92.5% and 53%, respectively. Under the operation with a power gain of 21.5 dB, the EDFL can be passively mode-locked to deliver a pulsewidth of 454.5 fs with a spectral linewidth of 5.6 nm. The time-bandwidth product of 0.31 is close to the transform limit. The Kelly sideband frequency spacing of 1.34 THz is used to calculate the chirp coefficient as  ‑0.0015.

Magnesium and zinc borate enhance osteoblastic differentiation of stem cells from human exfoliated deciduous teeth in vitro.

PubMed

Liu, Yao-Jen; Su, Wen-Ta; Chen, Po-Hung

2018-01-01

Various biocompatible and biodegradable scaffolds blended with biochemical signal molecules with adequate osteoinductive and osteoconductive properties have attracted significant interest in hard tissue engineering regeneration. We evaluated the distinct effects of magnesium borate, zinc borate, and boric acid blended into chitosan scaffold for osteogenic differentiation of stem cells from exfoliated deciduous teeth. Stem cells from exfoliated deciduous teeth cells are a potential source of functional osteoblasts for applications in bone tissue engineering, but the efficiency of osteoblastic differentiation is low, thereby significantly limiting their clinical applications. Divalent metal borates have potential function in bone remodeling because they can simulate bone formation and decrease bone resorption. These magnesium, zinc, and B ions can gradually be released into the culture medium from the scaffold and induce advanced osteoblastic differentiation from stem cells from exfoliated deciduous teeth. Stem cells from exfoliated deciduous teeth with magnesium borate or zinc borate as inducer demonstrated more osteoblastic differentiation after 21 days of culture. Differentiated cells exhibited activity of alkaline phosphatase, bone-related gene expression of collagen type I, runt-related transcription factor 2, osteopontin, osteocalcin, vascular endothelial growth factor, and angiopoietin-1, as noted via real-time polymerase chain reaction analysis, as well as significant deposits of calcium minerals. Divalent mental magnesium and zinc and nonmetal boron can be an effective inducer of osteogenesis for stem cells from exfoliated deciduous teeth. This experiment might provide useful inducers for osteoblastic differentiation of stem cells from exfoliated deciduous teeth for tissue engineering and bone repair.

Neisseria gonorrhoeae infects the human endocervix by activating non-muscle myosin II-mediated epithelial exfoliation

PubMed Central

Yu, Qian; Lin, Brian; Qiu, Jessica; Stein, Daniel C.

2017-01-01

Colonization and disruption of the epithelium is a major infection mechanism of mucosal pathogens. The epithelium counteracts infection by exfoliating damaged cells while maintaining the mucosal barrier function. The sexually transmitted bacterium Neisseria gonorrhoeae (GC) infects the female reproductive tract primarily from the endocervix, causing gonorrhea. However, the mechanism by which GC overcome the mucosal barrier remains elusive. Using a new human tissue model, we demonstrate that GC can penetrate into the human endocervix by inducing the exfoliation of columnar epithelial cells. We found that GC colonization causes endocervical epithelial cells to shed. The shedding results from the disassembly of the apical junctions that seal the epithelial barrier. Apical junction disruption and epithelial exfoliation increase GC penetration into the endocervical epithelium without reducing bacterial adherence to and invasion into epithelial cells. Both epithelial exfoliation and junction disruption require the activation and accumulation of non-muscle myosin II (NMII) at the apical surface and GC adherent sites. GC inoculation activates NMII by elevating the levels of the cytoplasmic Ca2+ and NMII regulatory light chain phosphorylation. Piliation of GC promotes, but the expression of a GC opacity-associated protein variant, OpaH that binds to the host surface proteins CEACAMs, inhibits GC-induced NMII activation and reorganization and Ca2+ flux. The inhibitory effects of OpaH lead to reductions in junction disruption, epithelial exfoliation, and GC penetration. Therefore, GC phase variation can modulate infection in the human endocervix by manipulating the activity of NMII and epithelial exfoliation. PMID:28406994

Liquid phase exfoliated graphene for electronic applications

NASA Astrophysics Data System (ADS)

Sukumaran, Sheena S.; Jinesh, K. B.; Gopchandran, K. G.

2017-09-01

Graphene dispersions were prepared using the liquid phase exfoliation method with three different surfactants. One surfactant was used from each of the surfactant types, anionic, cationic, and non-ionic; those used, were sodium dodecylbenzene sulfonate (SDBS), cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP), respectively. Raman spectroscopy was used to investigate the number of layers and the nature of any defects present in the exfoliated graphene. The yield of graphene was found to be less with the non-ionic surfactant, PVP. The deconvolution of 2D peaks at ~2700 cm-1 indicated that graphene prepared using these surfactants resulted in sheets consisting of few-layer graphene. The ratio of intensity of the D and G bands in the Raman spectra showed that edge defect density is high for samples prepared with SDBS compared to the other two, and is attributed to the smaller size of the graphene sheets, as shown in the electron micrographs. In the case of the dispersion in PVP, it is found that the sizes of the graphene sheets are highly sensitive to the concentration of the surfactant used. Here, we have made an attempt to investigate the local density of states in the graphene sheets by measuring the tunnelling current-voltage characteristics. Graphene layers have shown consistent p-type behaviour when exfoliated with SDBS and n-type behaviour when exfoliated with CTAB, with a larger band gap for graphene exfoliated using CTAB. Hence, in addition to the known advantages of liquid phase exfoliation, we found that by selecting suitable surfactants, to a certain extent it is possible to tune the band gap and determine the type of majority carriers.

Oculoplastic technique of connecting a glaucoma valve shunt to extraorbital locations in cases of severe glaucoma.

PubMed

Rubin, Peter A D; Chang, Eli; Bernardino, Carlo Roberto; Hatton, Mark P; Dohlman, Claes H

2004-09-01

To describe a technique for inserting glaucoma shunts to the sinuses or the lacrimal sac as a means of lowering intraocular pressure in patients with refractory glaucoma associated with severe ocular surface disease. Nineteen patients with severe ocular surface disease necessitating a keratoprosthesis and with intractable glaucoma underwent placement of a modified Ahmed shunt to direct aqueous in the maxillary or ethmoid sinus or lacrimal sac. Intraocular pressure is presently well controlled without glaucoma medications in two thirds of patients. None of the patients had endophthalmitis. Established oculoplastic surgery techniques may be used to redirect aqueous to extraorbital locations and effectively lower intraocular pressure in patients with severe ocular surface disease and refractory glaucoma. This procedure has not been associated with endophthalmitis.

Diagnostic ability of macular ganglion cell-inner plexiform layer thickness in glaucoma suspects.

PubMed

Xu, Xiaoyu; Xiao, Hui; Guo, Xinxing; Chen, Xiangxi; Hao, Linlin; Luo, Jingyi; Liu, Xing

2017-12-01

The purpose is to assess the diagnostic ability for early glaucoma of macular ganglion cell-inner plexiform layer (GCIPL) thickness in a Chinese population including glaucoma suspects.A total of 367 eyes with primary open-angle glaucoma (168 early glaucoma, 78 moderate glaucoma, and 121 advanced glaucoma), 52 eyes with ocular hypertension (OHT), 59 eyes with enlarged cup-to-disc ratio (C/D), and 225 normal eyes were included. GCIPL thickness (average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal), retinal nerve fiber layer (RNFL) thickness, and optic nerve head (ONH) parameters were measured using Cirrus high-definition optical coherence tomography (OCT) and compared. The diagnostic ability of OCT parameters was assessed by area under receiver operating characteristic curve (AUROC) in 3 distinguishing groups: normal eyes and eyes with early glaucoma, normal eyes and eyes with glaucoma regardless of disease stage, and nonglaucomatous eyes (normal eyes, eyes with OHT, and enlarged C/D) and early glaucomatous eyes.Glaucomatous eyes showed a significant reduction in GCIPL thickness compared with nonglaucomatous eyes. In all 3 distinguishing groups, best-performing parameters of GCIPL thickness, RNFL thickness, and ONH parameters were minimum GCIPL thickness (expressed in AUROC, 0.899, 0.952, and 0.900, respectively), average RNFL thickness (0.904, 0.953, and 0.892, respectively), and rim area (0.861, 0.925, and 0.824, respectively). There was no statistical significance of AUROC between minimum GCIPL thickness and average RNFL thickness (all P > .05).GCIPL thickness could discriminate early glaucoma from normal and glaucoma suspects with good sensitivity and specificity. The glaucoma diagnostic ability of GCIPL thickness was comparable to that of RNFL thickness. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Ophthalmologists' practice patterns and challenges in achieving optimal management for glaucoma in Nigeria: results from a nationwide survey.

PubMed

Kyari, Fatima; Nolan, Winifred; Gilbert, Clare

2016-10-11

Glaucoma, a chronic non-communicable disease, and leading cause of irreversible blindness worldwide is a public health problem in Nigeria, with a prevalence of 5.02% in people aged ≥40 years. The purpose of this nationwide survey was to assess Nigerian ophthalmologists' practice patterns and their constraints in managing glaucoma. Ophthalmologists were sent a semistructured questionnaire on how they manage glaucoma, their training in glaucoma care, where they practice, their access to equipment for diagnosis and treatment, whether they use protocols and the challenges they face in managing patients with glaucoma. 153/250 ophthalmologists in 80 centres completed questionnaires. Although 79% felt their training was excellent or good, 46% needed more training in glaucoma diagnosis and surgery. All had ophthalmoscopes, 93% had access to applanation tonometers, 81% to visual field analysers and 29% to laser machines (in 19 centres). 3 ophthalmologists had only ophthalmoscopes and schiøtz tonometers. For 85%, a glaucomatous optic disc was the most important feature that would prompt glaucoma work-up. Only 56% routinely performed gonioscopy and 61% used slit-lamp stereoscopic biomicroscopy for disc assessment. Trabeculectomy (with/without antimetabolites) was the only glaucoma surgery performed with one mention of canaloplasty. Poor compliance with medical treatment (78%) and low acceptance of surgery (71%) were their greatest challenges. This study indicates that a systems-oriented approach is required to enhance ophthalmologist's capability for glaucoma care. Strategies to improve glaucoma management include strengthening poorly equipped centres including provision of lasers and training, and improving patients' awareness and education on glaucoma. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

The Ahmed Glaucoma Valve in Refractory Glaucoma: Experiences in Southwest Ethiopia.

PubMed

Gessesse, Girum W

2015-07-01

The management of refractory glaucoma is a challenging task for any glaucoma surgeon. This study is aimed to evaluate the efficacy of Ahmed Glaucoma Valve implantation in refractory glaucomas in South-West Ethiopia. A retrospective review was conducted on the charts of consecutive patients treated with Ahmed glaucoma valve implantation at Jimma University Specialized Hospital between August 2012 and August 2014. Success was defined as Intraocular Pressure (IOP) less than 22 mm Hg and greater than 5mm Hg at 6 months, with at least 30% reduction from baseline, without medical therapy (complete success) or either with or without medication (qualified successes). A total of 12 eyes of 11 patients were included. The mean age of patients was 40.7 (SD= 19.0) years; 63.6% of them were males. The main types of glaucoma were pseudoexfoliative (3 eyes), uveitic (2 eyes), chronic angle closure (2 eyes) and Juvenile Open Angle (JOAG) (2 eyes). The mean IOP was reduced from preoperative level (32.75±7.14 mmHg) to (15.75 ±4.35 mmHg) at six postoperative months, (P<0.001); 66.7% eyes had complete successes while 83.3% had qualified success. Intra-operative complications were encountered in 2(16.7%) eyes, while 5/12 (41.7%) eyes had post-operative complications-hypotony (one with choroidal effusion) and progression of cataract in 2 eyes each. Hypertensive phase was diagnosed in 2(16.7%) eyes. The Ahmed glaucoma valve implant appears to be effective and relatively safe for treating complicated glaucomas with success rate comparable with those reported from other studies. Ahmed glaucoma valve, refractory glaucoma, complications, Ethiopia.

Ophthalmologists' practice patterns and challenges in achieving optimal management for glaucoma in Nigeria: results from a nationwide survey

PubMed Central

Kyari, Fatima; Nolan, Winifred; Gilbert, Clare

2016-01-01

Purpose of the study Glaucoma, a chronic non-communicable disease, and leading cause of irreversible blindness worldwide is a public health problem in Nigeria, with a prevalence of 5.02% in people aged ≥40 years. The purpose of this nationwide survey was to assess Nigerian ophthalmologists’ practice patterns and their constraints in managing glaucoma. Study design Ophthalmologists were sent a semistructured questionnaire on how they manage glaucoma, their training in glaucoma care, where they practice, their access to equipment for diagnosis and treatment, whether they use protocols and the challenges they face in managing patients with glaucoma. Results 153/250 ophthalmologists in 80 centres completed questionnaires. Although 79% felt their training was excellent or good, 46% needed more training in glaucoma diagnosis and surgery. All had ophthalmoscopes, 93% had access to applanation tonometers, 81% to visual field analysers and 29% to laser machines (in 19 centres). 3 ophthalmologists had only ophthalmoscopes and schiøtz tonometers. For 85%, a glaucomatous optic disc was the most important feature that would prompt glaucoma work-up. Only 56% routinely performed gonioscopy and 61% used slit-lamp stereoscopic biomicroscopy for disc assessment. Trabeculectomy (with/without antimetabolites) was the only glaucoma surgery performed with one mention of canaloplasty. Poor compliance with medical treatment (78%) and low acceptance of surgery (71%) were their greatest challenges. Conclusions This study indicates that a systems-oriented approach is required to enhance ophthalmologist's capability for glaucoma care. Strategies to improve glaucoma management include strengthening poorly equipped centres including provision of lasers and training, and improving patients’ awareness and education on glaucoma. PMID:27729348

Glaucoma in Patients with Eyes Close to Areas Affected by Port-wine Stain has Lateral and Gender Predilection.

PubMed

Wu, Yue; Yu, Ru-Jing; Chen, Di; Xu, Li; Li, Mao; Zhu, Li; Guo, Chun-Yu; Guo, Wen-Yi

2017-12-20

The location of facial port-wine stain (PWS) may be helpful for predicting some associated anomalies; high glaucoma incidence is found in patients with eyes close to PWS-affected areas (V1, ophthalmic branch area of the trigeminal nerve). This study aimed to investigate the characteristics of glaucoma in V1-affected PWS. A total of 569 patients with V1 area-affected PWS were reviewed in the study. The large series was based on the referral system between the Department of Plastic and Reconstructive Surgery and the Department of Ophthalmology. All patients were screened for glaucoma with assessments of intraocular pressure, cup-to-disc ratio, corneal diameter (only for infants), and axial length. Of the 569 patients, 110 (19.3%) patients had glaucoma. Among the patients, 18.1% (76/420) had early-onset glaucoma (under 4-year-old group). In the 4 to 18-year-old age group, 29.3% (29/99) of the patients had glaucoma. Compared with right lateral and bilateral PWS, left-sided PWS had a lower risk of glaucoma in this study (odds ratio = 0.432 [95% confidence interval, 0.264-0.706], P = 0.01). The under 4-year-old group showed a slight predominance of males (61.8%) in glaucoma. High glaucoma incidence was observed in patients with eyes close to PWS. More attention should be paid to glaucoma screening for right lateral and bilateral PWS patients. The predominance of males in Sturge-Weber syndrome (SWS) early-onset glaucoma patients might be due to the limitation of the case number; however, it might also provide us a new clue of potential relationship between SWS and PCG.

Cannabinoids and glaucoma

PubMed Central

Tomida, I; Pertwee, R G; Azuara-Blanco, A

2004-01-01

Glaucoma is one of the leading causes of blindness in the world. In spite of the diverse therapeutic possibilities, new and better treatments for glaucoma are highly desirable. Cannabinoids effectively lower the intraocular pressure (IOP) and have neuroprotective actions. Thus, they could potentially be useful in the treatment of glaucoma. The purpose of this article is to provide the reader with an overview of the latest achievements in research into the potential use of cannabinoids for glaucoma. PMID:15090428

Ocular Hypertension and Chronic Open-Angle Glaucoma in USAF Pilots and Navigators

DTIC Science & Technology

1974-12-01

nontreat- ment (close observation) of the preglaucoma category and treatment wit; epinephrine only of those classified glaucoma ha* been carried out now...concepts of glaucoma and glaucoma treatment versus the new "contemporary school" approach (differentiating ocular hypertension from glaucoma). This study...acute attack rather than the screening program. Onset ages for the secondary cases ranged from 28 to 53; 5 of these were secondary to uveitis , and

Outcomes of Gonioscopy-assisted Transluminal Trabeculotomy (GATT) in Eyes With Prior Incisional Glaucoma Surgery.

PubMed

Grover, Davinder S; Godfrey, David G; Smith, Oluwatosin; Shi, Wei; Feuer, William J; Fellman, Ronald L

2017-01-01

To report on outcomes of gonioscopy-assisted transluminal trabeculotomy (GATT) in eyes with prior incisional glaucoma surgery. A retrospective review was performed for all patients who underwent a GATT procedure with a history of prior incisional glaucoma surgery. Thirty-five eyes of 35 patients were treated. The mean age was 67.7 years. Nineteen eyes had a prior trabeculectomy, 13 eyes had a prior glaucoma drainage device, 4 eyes had a prior trabectome, and 5 eyes had prior endocyclophotocoagulation. Mean follow-up time was 22.7 months. For all eyes, the mean preoperative intraocular pressure (IOP) (SD) was 25.7 (6.5) mm Hg on 3.2 (1.0) glaucoma medications and at 24 months, the mean IOP (SD) was 15.4 (4.9) mm Hg on 2.0 (1.4) glaucoma medications (P<0.001). The prior trabeculectomy group had a preoperative IOP (SD) of 24.6 (6.4) mm Hg on 3.2 (1.0) medications and at month 24, the mean IOP (SD) was 16.7 (5.6) mm Hg on 2.1 (1.4) glaucoma medications. In the prior glaucoma drainage device group, the mean preoperative IOP (SD) was 27.0 (7.1) mm Hg on 3.4 (1.1) glaucoma medications and at 24 months, the mean IOP (SD) was 12.9 (2.6) mm Hg on 2.1 (1.2) glaucoma medications. At 24 months, the cumulative proportion of failure was 0.4 and the cumulative proportion of reoperation was 0.29. GATT appears to be safe and successful in treating 60% to 70% of open-angle patients with prior incisional glaucoma surgery. When considering all eyes, there was a significant decrease in IOP and required glaucoma medications at 24 months. This surgery should be considered in certain patients with open angles who have failed a primary traditional glaucoma surgery.

Importance of Corneal Thickness

MedlinePlus

... Glaucoma Facts and Stats Glossary Symptoms of Open-Angle Glaucoma Types of Glaucoma » See All Articles Where the Money Goes Have a Question? Browse Our Q&A » Or e-mail us: question@ glaucoma.org For medical advice, contact your doctor. Our Newsletter Stay up-to-date ...

Protecting retinal ganglion cells

PubMed Central

Khatib, T Z; Martin, K R

2017-01-01

Retinal ganglion cell degeneration underlies several conditions which give rise to significant visual compromise, including glaucoma, hereditary optic neuropathies, ischaemic optic neuropathies, and demyelinating disease. In this review, we discuss the emerging strategies for neuroprotection specifically in the context of glaucoma, including pharmacological neuroprotection, mesenchymal stem cells, and gene therapy approaches. We highlight potential pitfalls that need to be considered when developing these strategies and outline future directions, including the prospects for clinical trials. PMID:28085136

Propionibacterium acnes endophthalmitis in Ahmed glaucoma valve.

PubMed

Gutiérrez-Díaz, E; Montero-Rodríguez, M; Mencía-Gutiérrez, E; Fernández-González, M C; Pérez-Blázquez, E

2001-01-01

To report a case of Propionibacterium acnes endophthalmitis in a patient with an Ahmed glaucoma valve. A nine-year-old boy with bilateral congenital glaucoma, with an Ahmed glaucoma valve implanted in the left eye, had recurrent conjunctival dehiscence and endophthalmitis. Vitreous cultures demonstrated the presence of Propionibacterium acnes. This is the first reported case of Propionibacterium acnes endophthalmitis in an Ahmed glaucoma valve and the second one in a glaucoma drainage device. We strongly recommend using a patch graft to prevent and treat tube exposure. Conjunctival grafts may be useful to close the conjunctiva when there is marked scarring to prevent patch exposure and melting or extrusion.

Glaucoma treatment trends: a review.

PubMed

Conlon, Ronan; Saheb, Hady; Ahmed, Iqbal Ike K

2017-02-01

Glaucoma is one of the most common causes of blindness worldwide, and its prevalence is increasing. The aim of the present review is to describe the current medical and surgical treatment trends in the management of open-angle glaucoma. There has been an increase in the availability of glaucoma medications and the use of laser trabeculoplasty over the past decade, with a subsequent decrease in invasive incisional surgery. In addition, a new class of glaucoma procedures, termed microinvasive glaucoma surgery, has emerged, which aims to fill the gap between conservative medical management and more invasive surgery. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Neovascular glaucoma in a patient with X-linked juvenile retinoschisis.

PubMed

Zuo, Chengguo; Chen, Changzheng; Xing, Yiqiao; Du, Lei

2005-09-01

To report the rubeosis iridis and neovascular glaucoma findings in one patient of X-linked juvenile retinoschisis(XLRS). Color fundus photography, fluorescein angiography (FFA), OCT and B-scan were performed in a patient with X-linked juvenile retinoschisis complicated with neovascular glaucoma. Color fundus photography, fluorescein angiography (FFA), OCT and B-scan unveiled a rare condition of XLRS complicated with neovascular glaucoma. XLRS may complicate with neovascular glaucoma. It is necessary to test OCT, FFA, ERG and carefully examine the fundus of the follow eye when it comes to uncertain neovascular glaucoma of youth and child. And only in this way, can we exclude XLRS.

Assessment and diagnosis of suspected glaucoma in patients with mucopolysaccharidosis.

PubMed

Ashworth, Jane; Flaherty, Maree; Pitz, Susanne; Ramlee, Azura

2015-03-01

The mucopolysaccharidoses (MPS) are a group of rare lysosomal storage disorders, characterized by the accumulation of glycosaminoglycans within multiple organ systems including the eye. This study aimed to determine the prevalence of glaucoma in patients with MPS, as well as the characteristics, diagnosis and management of patients with MPS and glaucoma. A multicentre retrospective case-note review was carried out by ophthalmologists from four tertiary referral centres to identify patients with MPS who had been treated for glaucoma. Clinical ophthalmological data were collected using standardized data collection forms. Fourteen patients were identified (27 eyes) of 294 patients with MPS. The prevalence of glaucoma ranged from 2.1% to 12.5%. The median age at diagnosis of glaucoma was 8 years. Diagnostic evaluation of glaucoma was incomplete in many patients: intraocular pressure was documented in all eyes, but optic disc appearance was only assessed in 67%, central corneal thickness in 26%, visual fields in 19% and iridocorneal angle in 15%. Patients with MPS need regular assessment for possible glaucoma including during childhood. Multiple factors contribute to the challenges of assessment, diagnosis and monitoring of glaucoma in these patients. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

High rate of incidental glaucoma detection in New Zealand.

PubMed

LaHood, Benjamin R; Erceg, Joshua; Bevin, Tui H; Sanderson, Gordon

2016-12-02

To investigate how glaucoma is initially detected in New Zealanders and what factors aroused disease suspicion. A postal survey of 500 randomly selected members of the Glaucoma New Zealand database was undertaken in 2012 to analyse factors relating to their initial presentation and diagnosis of glaucoma. Online surveys and telephone interviews were used to increase the response rate. The overall response rate was 80% (376/468) of eligible participants. The sample had an average age of 76 years. Prior to diagnosis, 80% (290/361) of participants who responded to this question reported no suspicion of glaucoma. A positive family history for glaucoma was the most common reason (71%) for presenting to a health care professional with a suspicion of glaucoma (13% of total sample). After diagnosis, 95% (357/376) of respondents reported that they had informed family members of their diagnosis. This study confirmed that the majority of glaucoma was discovered through incidental findings. A positive family history was the most common risk factor prompting examination, knowledge about which appeared to increase dramatically post-diagnosis. These findings indicated that there was potential to educate the public about glaucoma in order to raise awareness and diagnose the disease earlier.

Central corneal thickness in glaucoma.

PubMed

Sng, Chelvin C A; Ang, Marcus; Barton, Keith

2017-03-01

The purpose of this review is to summarize the role of central corneal thickness (CCT) in the clinical management of a glaucoma patient. The prognostic value of CCT is well recognized in patients with ocular hypertension. However, its predictive value in other glaucoma suspects and patients with established glaucoma is less certain. Tonometry artefacts can result from variations in CCT. However, an adequately validated correction algorithm for Goldmann applanation tonometry measurements does not exist. Newer methods of tonometry are potentially less influenced by CCT but are limited in their clinical use. There may also be biological and genetic associations between corneal thickness and glaucoma. Demographics, environmental factors, glaucoma treatment and the measurement device used have a significant influence on CCT, and should be considered when interpreting the effect of cornea thickness in patients with glaucoma. New measurements of the biomechanical properties of the cornea are likely to be better approximations of the globe biomechanics than CCT, but these require further evaluation. The clinical significance of CCT is well recognized in the context of glaucoma diagnosis and management, though the extent of its importance remains debatable. Corneal biomechanical properties may be more significantly associated with glaucoma than CCT.

Outcomes of glaucoma reoperations in the Tube Versus Trabeculectomy (TVT) Study.

PubMed

Saheb, Hady; Gedde, Steven J; Schiffman, Joyce C; Feuer, William J

2014-06-01

To describe the incidence and outcomes of reoperations for glaucoma in the Tube Versus Trabeculectomy (TVT) Study. Cohort study of patients in a multicenter randomized clinical trial. The TVT Study enrolled 212 patients with medically uncontrolled glaucoma who had previous cataract and/or glaucoma surgery. Randomization assigned 107 patients to surgery with a tube shunt (350 mm(2) Baerveldt glaucoma implant) and 105 patients to trabeculectomy with mitomycin C (0.4 mg/mL for 4 minutes). Data were analyzed from patients who failed their assigned treatment and had additional glaucoma surgery. Outcome measures included intraocular pressure (IOP), use of glaucoma medications, visual acuity, surgical complications, and failure (IOP >21 mm Hg or not reduced by 20%, IOP ≤5 mm Hg, additional glaucoma surgery, or loss of light perception vision). Additional glaucoma surgery was performed in 8 patients in the tube group and 18 patients in the trabeculectomy group in the TVT Study, and the 5-year cumulative reoperation rate was 9% in the tube group and 29% in the trabeculectomy group (P = .025). Follow-up (mean ± SD) after additional glaucoma surgery was 28.0 ± 16.0 months in the tube group and 30.5 ± 20.4 months in the trabeculectomy group (P = .76). At 2 years after a glaucoma reoperation, IOP (mean ± SD) was 15.0 ± 5.5 mm Hg in the tube group and 14.4 ± 6.6 mm Hg in the trabeculectomy group (P = .84). The number of glaucoma medications (mean ± SD) after 2 years of follow-up was 1.1 ± 1.3 in the tube group and 1.4 ± 1.4 in the trabeculectomy group (P = .71). The cumulative probability of failure at 1, 2, 3, and 4 years after additional glaucoma surgery was 0%, 43%, 43%, and 43%, respectively, in the tube group, and 0%, 9%, 20%, and 47% in the trabeculectomy group (P = .28). Reoperations to manage complications were required in 1 patient in the tube group and 5 patients in the trabeculectomy group (P = .63). The rate of reoperation for glaucoma was higher following trabeculectomy with mitomycin C than tube shunt surgery in the TVT Study. Similar surgical outcomes were observed after additional glaucoma surgery, irrespective of initial randomized treatment in the study. Copyright © 2014 Elsevier Inc. All rights reserved.

Outcomes of Glaucoma Reoperations in the Tube Versus Trabeculectomy (TVT) Study

PubMed Central

Saheb, Hady; Gedde, Steven J.; Schiffman, Joyce C.; Feuer, William J.

2017-01-01

Purpose To describe the incidence and outcomes of reoperations for glaucoma in the Tube Versus Trabeculectomy (TVT) Study. Design Cohort study of patients in a multicenter randomized clinical trial. Methods The TVT Study enrolled 212 patients with medically uncontrolled glaucoma who had previous cataract and/or glaucoma surgery. Randomization assigned 107 patients to surgery with a tube shunt (350-mm2 Baerveldt glaucoma implant) and 105 patients to trabeculectomy with mitomycin C (0.4 mg/ml for 4 minutes). Data were analyzed from patients who failed their assigned treatment and had additional glaucoma surgery. Outcome measures included intraocular pressure (IOP), use of glaucoma medications, visual acuity, surgical complications, and failure (IOP > 21 mm Hg or not reduced by 20%, IOP ≤ 5 mm Hg, additional glaucoma surgery, or loss of light perception vision). Results Additional glaucoma surgery was performed in 8 patients in the tube group and 18 patients in the trabeculectomy group in the TVT Study, and the 5-year cumulative reoperation rate was 9% in the tube group and 29% in the trabeculectomy group (p = .025). Follow-up (mean ± SD) after additional glaucoma surgery was 28.0 ± 16.0 months in tube group and 30.5 ± 20.4 months in the trabeculectomy group (p = .76). At 2 years after a glaucoma reoperation, IOP (mean ± SD) was 15.0 ± 5.5 mm Hg in the tube group and 14.4 ± 6.6 mm Hg in the trabeculectomy group (p = .84). The number of glaucoma medications (mean ± SD) after 2 years of follow-up was 1.1 ± 1.3 in the tube group and 1.4 ± 1.4 in the trabeculectomy group (p = .71). The cumulative probability of failure at 1, 2, 3, and 4 years after additional glaucoma surgery was 0%, 43%, 43%, and 43% respectively in the tube group, and 0%, 9%, 20%, and 47% in the trabeculectomy group (p = .28). Reoperations to manage complications were required in 1 (13%) patient in the tube group and 5 (28%) patients in the trabeculectomy group (p = .63). Conclusions The rate of reoperation for glaucoma was higher following trabeculectomy with mitomycin C than tube shunt surgery in the TVT Study. Similar surgical outcomes were observed after additional glaucoma surgery, irrespective of initial randomized treatment in the study. PMID:24531027

Determination of morphological, biometric and biochemical susceptibilities in healthy Eurasier dogs with suspected inherited glaucoma.

PubMed

Boillot, Thomas; Rosolen, Serge G; Dulaurent, Thomas; Goulle, Frédéric; Thomas, Philippe; Isard, Pierre-François; Azoulay, Thierry; Lafarge-Beurlet, Stéphanie; Woods, Mike; Lavillegrand, Sylvie; Ivkovic, Ivana; Neveux, Nathalie; Sahel, José-Alain; Picaud, Serge; Froger, Nicolas

2014-01-01

In both humans and dogs, the primary risk factor for glaucoma is high intraocular pressure (IOP), which may be caused by iridocorneal angle (ICA) abnormalities. Oxidative stress has also been implicated in retinal ganglion cell damage associated with glaucoma. A suspected inherited form of glaucoma was recently identified in Eurasier dogs (EDs), a breed for which pedigrees are readily available. Because of difficulties in assessing ICA morphology in dogs with advanced glaucoma, we selected a cohort of apparently healthy dogsfor the investigation of ICA morphological status, IOP and plasma concentrations of oxidative stress biomarkers. We aimed to establish correlations between these factors, to identify predictive markers of glaucoma in this dog breed. A cohort of 28 subjects, volunteered for inclusion by their owners, was selected by veterinary surgeons. These dogs were assigned to four groups: young males, young females (1-3 years old), adult males and adult females (4-8 years old). Ocular examination included ophthalmoscopy, tonometry, gonioscopy, biometry and ultrasound biomicroscopy (UBM), and the evaluation of oxidative stress biomarkers consisting of measurements of plasma glutathione peroxidase (GP) activity and taurine and metabolic precursor (methionine and cysteine) concentrations in plasma. The prevalence of pectinate ligament abnormalities was significantly higher in adult EDs than in young dogs. Moreover, in adult females, high IOP was significantly correlated with a short axial globe length, and a particularly large distance between Schwalbe's line and the anterior lens capsule. GP activity levels were significantly lower in EDs than in a randomized control group of dogs, and plasma taurine concentrations were higher. Hence, ICA abnormalities were associated with weaker antioxidant defenses in EDs, potentially counteracted by higher plasma taurine concentrations. This study suggests that EDs may constitute an appropriate canine model for the development of glaucoma. This cohort will be used as a sentinel for longitudinal monitoring.

Determination of Morphological, Biometric and Biochemical Susceptibilities in Healthy Eurasier Dogs with Suspected Inherited Glaucoma

PubMed Central

Goulle, Frédéric; Thomas, Philippe; Isard, Pierre-François; Azoulay, Thierry; Lafarge-Beurlet, Stéphanie; Woods, Mike; Lavillegrand, Sylvie; Ivkovic, Ivana; Neveux, Nathalie; Sahel, José-Alain; Picaud, Serge; Froger, Nicolas

2014-01-01

In both humans and dogs, the primary risk factor for glaucoma is high intraocular pressure (IOP), which may be caused by iridocorneal angle (ICA) abnormalities. Oxidative stress has also been implicated in retinal ganglion cell damage associated with glaucoma. A suspected inherited form of glaucoma was recently identified in Eurasier dogs (EDs), a breed for which pedigrees are readily available. Because of difficulties in assessing ICA morphology in dogs with advanced glaucoma, we selected a cohort of apparently healthy dogsfor the investigation of ICA morphological status, IOP and plasma concentrations of oxidative stress biomarkers. We aimed to establish correlations between these factors, to identify predictive markers of glaucoma in this dog breed. A cohort of 28 subjects, volunteered for inclusion by their owners, was selected by veterinary surgeons. These dogs were assigned to four groups: young males, young females (1–3 years old), adult males and adult females (4–8 years old). Ocular examination included ophthalmoscopy, tonometry, gonioscopy, biometry and ultrasound biomicroscopy (UBM), and the evaluation of oxidative stress biomarkers consisting of measurements of plasma glutathione peroxidase (GP) activity and taurine and metabolic precursor (methionine and cysteine) concentrations in plasma. The prevalence of pectinate ligament abnormalities was significantly higher in adult EDs than in young dogs. Moreover, in adult females, high IOP was significantly correlated with a short axial globe length, and a particularly large distance between Schwalbe's line and the anterior lens capsule. GP activity levels were significantly lower in EDs than in a randomized control group of dogs, and plasma taurine concentrations were higher. Hence, ICA abnormalities were associated with weaker antioxidant defenses in EDs, potentially counteracted by higher plasma taurine concentrations. This study suggests that EDs may constitute an appropriate canine model for the development of glaucoma. This cohort will be used as a sentinel for longitudinal monitoring. PMID:25380252

Relationship between high serum ferritin level and glaucoma in a South Korean population: the Kangbuk Samsung health study.

PubMed

Gye, Hyo Jung; Kim, Joon Mo; Yoo, Chungkwon; Shim, Seong Hee; Won, Yu Sam; Sung, Ki Chul; Lee, Mi Yeon; Park, Ki Ho

2016-12-01

To investigate the association between serum ferritin levels and glaucoma in a South Korean population. This retrospective cross-sectional study included 164 029 subjects who underwent screening at Kangbuk Samsung Hospital Health Screening Center between August 2012 and July 2013. All subjects underwent a physical examination, answered sociodemographic and behavioural questions, and provided samples for laboratory analyses. A digital fundus photograph of both eyes was taken, and all photographs were reviewed by ophthalmologists. The ophthalmologists determined if an eye had glaucoma based on criteria set forth by the International Society of Geographical and Epidemiological Ophthalmology and the appearance of the retinal nerve fibre layer and optic disc. The mean serum ferritin level was 56.98 ng/mL in women and 223.82 ng/mL in men. After adjusting for age, serum iron, total iron-binding capacity (TIBC), transferrin saturation, white blood cell (WBC) count, high-sensitivity C-reactive protein (HsCRP) and total vitamin D level, males in the highest quartile for serum ferritin level had a higher OR for glaucoma than males in the lowest quartile (OR=1.176, 95% CI 1.030 to 1.342, p=0.016); we did not observe this relationship among women. Other markers of iron metabolism, such as iron level, transferrin saturation and TIBC, and inflammation measures, including WBC, HsCRP and total vitamin D, were not associated with glaucoma. High serum ferritin level was associated with a high risk of glaucoma in men, but not in women. Because serum ferritin is related to oxidative stress and inflammation, it might play a role in glaucoma development. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Note: Mechanical in situ exfoliation of van der Waals materials

NASA Astrophysics Data System (ADS)

Pásztor, Á.; Scarfato, A.; Renner, Ch.

2017-07-01

Exfoliation, namely, the peeling of layered materials down to a single unit-cell thin foil, opens promising avenues to fabricate novel electronic materials. New properties and original functionalities emerge in the single and few layer configurations of a number of layered compounds, in particular in transition metal dichalcogenides. However, many of these thin exfoliated materials are very sensitive to ambient conditions impeding the exploration of this new and fascinating parameter space. Here we describe a method of mechanical exfoliation in ultra-high vacuum (UHV). This technique is easily adaptable to any UHV system and allows preparing and studying air sensitive nanoflakes in situ. We present the basic design and proof-of-concept scanning tunneling microscopy imaging of VSe2 nanoflakes.

Detecting thermally driven cyclic deformation of an exfoliation sheet with lidar and radar

USGS Publications Warehouse

Collins, Brian D.; Stock, Greg M.

2014-01-01

Rock falls from steep, exfoliating cliffs are common in many landscapes. Of the many mechanisms known to trigger rock falls, thermally driven deformation is among the least quantified, despite potentially being a prevalent trigger due to its occurrence at all times of year. Here we present the results of a field-based monitoring program using instrumentation, ground-based lidar, and ground-based radar to investigate the process of thermally driven deformation of an exfoliation sheet, and the ability of remote sensing tools to capture cyclic expansion and contraction patterns. Our results indicate that thermally driven exfoliation occurs on diurnal cycles and can be measured at the submillimeter to centimeter scale using high-resolution strain gauges, short-range (2 km) radar interfer-ometry.

[Intraocular pressure after ND: YAG laser capsulotomy in pseudophakic patients with glaucoma].

PubMed

Sesar, Antonio; Petric, Irena; Sesar, Ivanka; Lacmnovic-Loncar, Valentina; Jurisić, Darija; Tomić, Zeljka; Mandić, Zdravko

2006-01-01

The aim of the study was to analyze changes in intraocular pressure after Nd: YAG laser capsulotomy in pseudophakic patients with glaucoma. Intraocular pressure was recorded before, and 1 and 3 hours after YAG laser capsulotomy in 69 pseudophakic patients with glaucoma. Twenty eight patients received no therapy before capsulotomy, 21 patients received topical brimonidine 0.2%, and 20 patients received topical dorzolamide 2% 1 hour before laser capsulotomy. All patients received topical tropicamide 1% and tetracaine 0.5%. Nd: YAG laser posterior capsulotomy was performed using inverted-U technique to make a 3-4 mm diameter capsulotomy. After capsulotomy, all eyes received topical fluorometholone for 10 days. A pressure rise was greater in patients without any therapy before YAG laser capsulotomy. Eight patients with glaucoma showed intraocular pressure rise of 5 mm Hg, and 2 patients pressure rise of 10 mm Hg after laser capsulotomy. A reduction of intraocular pressure rise was found in patients who received dorzolamide 2% or brimonidine 0.2%, only 1 patient in each group developed a pressure rise of 5 mm Hg. In all patients a significant pressure rise developed within the first hour. It is difficult to compare different studies due to different techniques of cataract surgery and different intraocular lense material and design. Barnes showed that 6 of 29 (21%) developed a pressure rise of 5 mm Hg, and 1 of 29 (3%) patients a pressure rise of 10 mm Hg. In our study, 29% of patients had a pressure rise of > or =5 mm Hg, and 7% of patients had a rise of > or =10 mm Hg after laser capsulotomy. These results may be associated with a large proportion of extracapsular cataract extraction (71%) versus phacoemulsification (29%) in our patients. Pretreatment with dorzolamide 2% or brimonidine 0.2% reduce the intraocular pressure rise after Nd: YAG laser capsulotomy in pseudophakic patients with glaucoma.

Diagnostic utility of combined retinal ganglion cell count estimates in Japanese glaucoma patients.

PubMed

Sakamoto, Mari; Mori, Sotaro; Ueda, Kaori; Akashi, Azusa; Inoue, Yukako; Kurimoto, Takuji; Kanamori, Akiyasu; Yamada, Yuko; Nakamura, Makoto

2018-01-01

To assess the combined estimate of retinal ganglion cell (RGC) count developed by Medeiros et al. as a tool for diagnosis of glaucoma in Japanese patients. Cross-sectional study. Thirty-one eyes of 19 healthy controls and 106 eyes of 70 glaucoma patients underwent standard automated perimetry (SAP) and three types of spectral domain optical coherence tomography (SD-OCT) imaging using the Cirrus, RTVue, and 3D-OCT instruments. RGC counts derived from SAP and SD-OCT data were estimated using the Harwerth model (SAPrgc and OCTrgc, respectively), from which the combined RGC count estimates (CRGC) were calculated using the formula developed by Medeiros et al. Receiver operating characteristic curve (ROC) analyses were conducted for mean deviation (MD), retinal nerve fiber layer thickness (RNFLT), and CRGC. The mean OCTrgc derived from the Cirrus, RTVue, and 3D-OCT instruments were 1150, 1245, and 1316 (× 1000 cells), respectively, for the control group and 463, 519, and 516 (× 1000 cells), respectively, for the patient group. SAPrgc of the controls' group was 1526 and the patients' group, 731 (× 1000 cells), and were consistently greater than OCTrgc in both groups (a generalized estimating equation model, p < 0.001). Partial area under the curve (pAUC) of MD was 0.178, and that of RNFLT and CRGC for the three OCT instruments were 0.185, 0.18, 0.189 and 0.196, 0.196, 0.197, respectively. CRGC had larger pAUC than MD, whereas there was no or marginal difference in pAUC between CRGC and cpRNFLT, irrespective of OCT device used or glaucoma severity. CRGC proved well suited to discriminate glaucoma patients from controls. However, its clinical utility did not seem to overwhelm isolated structural measures in the tested Japanese patients.

Development of a novel CsA-PLGA drug delivery system based on a glaucoma drainage device for the prevention of postoperative fibrosis.

PubMed

Dai, Zhaoxing; Yu, Xiaobo; Hong, Jiaxu; Liu, Xi; Sun, Jianguo; Sun, Xinghuai

2016-09-01

The formation of a scar after glaucoma surgery often leads to unsuccessful control of intraocular pressure, and should be prevented by using a variety of methods. We designed and developed a novel drug delivery system (DDS) comprising cyclosporine A (CsA) and poly(lactic-co-glycolic acid) (PLGA) based on a glaucoma drainage device (GDD) that can continuously release CsA to prevent postoperative fibrosis following glaucoma surgery. The CsA@PLGA@GDD DDS was observed by field emission scanning electron microscopy and revealed an asymmetric pore structure. Thermogravimetric analysis was performed to measure the weight loss and evaluate the thermal stability of the CsA@PLGA@GDD DDS. The in vitro drug release profile of the DDS was studied using high performance liquid chromatography, which confirmed that the DDS released CsA at a stable rate and maintained adequate CsA concentrations for a relatively long time. The biocompatibility of the DDS and the inhibitory effects on the postoperative fibrosis were investigated in vitro using rabbit Tenon's fibroblasts. The in vivo safety and efficacy of the DDS were examined by implanting the DDS into Tenon's capsules in New Zealand rabbits. Bleb morphology, intraocular pressure, anterior chamber reactions, and anterior chamber angiography were studied at a series of set times. The DDS kept the filtration pathway unblocked for a longer time compared with the control GDD. The results indicate that the CsA@PLGA@GDD DDS represents a safe and effective strategy for preventing scar formation after glaucoma surgery. Copyright © 2016 Elsevier B.V. All rights reserved.

Trans-scleral selective laser trabeculoplasty (SLT) without a gonioscopy lens (Conference Presentation)

NASA Astrophysics Data System (ADS)

Belkin, Michael; Geffen, Noa; Goldenfeld, Modi; Ofir, Shay; Belkin, Avner; Assia, Ehud

2016-03-01

Developing a one-second automatic glaucoma treatment using trans-scleral laser trabeculoplasty (LTP) without a gonioscopy lens Purpose: Developing an LTP device for delivering multiple simultaneous trans-scleral applications of low energy laser irradiation to the trabecular meshwork (TM) for reducing Intraocular Pressure (IOP). Methods: Concept proof: A randomized, masked, controlled one was performed on open angle glaucoma patients. The control group underwent conventional SLT (100 laser spots through a gonioscope for 360 degrees directly on the TM). The trial group underwent irradiation by the same laser at the same irradiation parameters on the sclera overlying the TM. Topical glaucoma therapy was not changed during the 12 months trial. Feasibility trial: Using optimized laser parameters, 60 discrete applications were administered on similar locations of patients' sclera. Results: Concept proof: Trans-scleral applications: (N=15), IOP decrease from 20.21 mmHg before treatment to 16.00 (27.1%) at one year. The corresponding numbers for the control group (n=15), were 21.14 mmHg and 14.30 (23.4%). There was no statistical difference between the two groups in IOP reduction. The complications rate was significantly higher in the control group. Trial 2: IOP was reduced from an of 25.3 mmHg to 19.3 (23.7%) in the 11 patients. Conclusions: Laser coherency, lost in tissue transmission, is not required for the therapeutic effect. The new method will possibly enable treatment of angle closure glaucoma as well as simultaneous applications of all laser spots to the sclera. When used conjointly with target acquisition, will make feasible an automatic glaucoma treatment in less than one second.

Malignant glaucoma after cataract surgery.

PubMed

Varma, Devesh K; Belovay, Graham W; Tam, Diamond Y; Ahmed, Iqbal Ike K

2014-11-01

To report a series of eyes that developed malignant glaucoma after cataract surgery. Private academic practice, Toronto, Ontario, Canada. Retrospective case series. Eyes that developed malignant glaucoma after cataract surgery were treated with medical therapy. This was followed by laser iridozonulohyaloidotomy, anterior chamber reformation and intraocular lens (IOL) pushback, and finally with surgical iridozonulohyaloidovitrectomy if all other measures were unsuccessful. Refraction, intraocular pressure (IOP), gonioscopy, and anterior chamber depth (ACD) by anterior segment optical coherence tomography were analyzed before treatment and after treatment. The study evaluated 20 eyes of 18 female patients aged 44 to 86 years. Preoperatively, the mean refraction was +3.11 diopters (D) ± 2.89 (SD), the mean axial length was 21.30 ± 1.40 mm, and all eyes had narrow or closed angles. Malignant glaucoma was diagnosed a mean of 5.8 ± 7.1 weeks postoperatively. At diagnosis, the mean refraction was -2.15 ± 2.95 D; the mean ACD, 2.49 ± 0.72 mm; and the mean IOP, 28.3 ± 10.8 mm Hg on a mean of 1.3 ± 1.6 medications. Two eyes responded to cycloplegia, 7 to laser iridozonulohyaloidotomy, and 6 to anterior chamber reformation-IOL pushback; 5 eyes required vitrectomy. Posttreatment, the mean refraction was -0.56 ± 1.07 D; the mean ACD, 3.30 ± 0.50 mm; and the mean IOP, 14.4 ± 4.60 mm Hg on a mean of 1.2 ± 1.4 medications. Cycloplegia was discontinued in 17 eyes. Malignant glaucoma can occur after phacoemulsification and presents with myopic surprise, anterior chamber shallowing and, possibly, elevated IOP. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Benzalkonium Chloride and Glaucoma

PubMed Central

Kaufman, Paul L.; Kiland, Julie A.

2014-01-01

Abstract Glaucoma patients routinely take multiple medications, with multiple daily doses, for years or even decades. Benzalkonium chloride (BAK) is the most common preservative in glaucoma medications. BAK has been detected in the trabecular meshwork (TM), corneal endothelium, lens, and retina after topical drop installation and may accumulate in those tissues. There is evidence that BAK causes corneal and conjunctival toxicity, including cell loss, disruption of tight junctions, apoptosis and preapoptosis, cytoskeleton changes, and immunoinflammatory reactions. These same effects have been reported in cultured human TM cells exposed to concentrations of BAK found in common glaucoma drugs and in the TM of primary open-angle glaucoma donor eyes. It is possible that a relationship exists between chronic exposure to BAK and glaucoma. The hypothesis that BAK causes/worsens glaucoma is being tested experimentally in an animal model that closely reflects human physiology. PMID:24205938

Understanding practice patterns of glaucoma sub-specialists in India

PubMed Central

Choudhari, Nikhil S.; Pathak-Ray, Vanita; Kaushik, Sushmita; Vyas, Prateep; George, Ronnie

2017-01-01

AIM To obtain information on the prevailing practice patterns of glaucoma specialists in India. METHODS Glaucoma specialists attending the Annual Conference of the Glaucoma Society of India (GSI) were surveyed. This survey, conducted in 2013, was based on an interactive audience response system. RESULTS The information was obtained from 146 glaucoma specialists. Approximately half (n=83; 57%) had ≥10y of experience in managing glaucoma and were in institutional practice (n=74, 51%). Goldmann applanation tonometry was preferred by 103 (72%) specialists whilst n=25 (17.4%) used non-contact tonometer. Indentation gonioscopy was favoured by two-thirds (n=90, 66%) whereas stereoscopic optic disc examination and visual fields using Humphrey perimeter was performed by a majority of the specialists surveyed (n=115, 86% and n=114; 83% respectively). Nearly three quarter specialists (n=96; 72%) preferred optical coherence tomography for imaging. The primary choice for treatment of angle closure disease and primary open angle glaucoma was laser (iridotomy, n=117; 93%) and medical management (prostaglandin analogue, n=104; 78%), respectively. Approximately only a third of the specialists surveyed (n=37; 28%) were performing both trabeculectomy and implantation of a glaucoma drainage device and about half (n=64; 47%) were not operating on congenital glaucoma at all. CONCLUSION This survey has found conformance with preferred practice patterns in several areas of diagnosis and management of glaucoma, but there was diversity in a few areas. The information is a significant step towards improvement of glaucoma care in India, including planning for future strategies. PMID:29062779

[Clinical observation on the treatment of untreatable childhood glaucoma with microcatheter-assisted trabeculotomy].

PubMed

Wang, H Z; Li, M; Hu, M; Wang, Y W; Shi, Y; Wang, W W; Wang, N L

2017-03-11

Objective: To evaluate the efficacy of microcatheter-assisted trabeculotomy for untreatable childhood glaucoma with traditional surgeries repeatedly. Methods: Clinical charts of fifteen cases (16 eyes) with childhood glaucoma patients from Beijing Tongren Hospital were retrospectively analyzed. All eyes had previously received 2 or more traditional anti-glaucoma surgeries. We performed microcatheter-assisted trabeculotomy for these patients. The intraocular pressure (IOP), numbers of anti-glaucoma medications and post-operative complications were analyzed. The differences between pre-operative and last post-operative IOP and numbers of anti-glaucoma medications were compared using paried t test and wilcoxon signed rank test. Results: Thirteen male and 2 female children aged between 2-10 (median: 4) years old were recruited. 11 cases (12 eyes) were diagnosed as primary congenital glaucoma, 3 eyes of 3 cases were late-onset childhood glaucoma, and 1 eye was secondary glaucoma. The mean pre-operative IOP was (35.69 ± 6.27) mmHg (1 mmHg=0.133 kPa) on a mean of 3(1-4) medications for childhood glaucoma patients. The mean post-operative IOP decreased to (17.88 ± 7.74) mmHg ( t =6.97, P < 0.01) and the median post operative medications decreased to 0(0-3)( Z =-3.15, P <0.01) at last visit. Twelve cases and 14 cases achieved complete and qualified success, respectively. No severe complications were observed for all patients. Conclusion: Microcatheter-assisted trabeculotomy got lower introcular pressure results for 15 childhood glaucoma patients with untreadtable traditional surgeries repeatedly with minimal complications. ( Chin J Ophthalmol , 2017 , 53 :203-206).

Awareness and Knowledge of Glaucoma in Central India: A Hospital-Based Study.

PubMed

Maharana, Prafulla K; Rai, Vaishali G; Pattebahadur, Rajesh; Singhi, Shipra; Chauhan, Ashish K

2017-01-01

To assess the awareness and knowledge of glaucoma among people attending the ophthalmology outpatient department at a tertiary care hospital in central India. A prospective observational study. A questionnaire-based study was conducted, involving persons aged 18 and above attending the ophthalmology outpatient department from October 2014 to September 2015. Data on awareness and knowledge of glaucoma was collected through a face-to-face interview. Fourteen hundred people participated in the study. The mean age of participants was 43 ± 15 years (range, 18-85). The study participants included 53% men and 47% women. Only 27% (n = 380/1400) of the participants were aware of glaucoma. Age, sex, and presence or type of refractive error had no impact on glaucoma awareness. Awareness level was greater in individuals with higher education levels and those belonging to an upper socioeconomic class (SEC). Multiple logistic regression analysis revealed significantly higher levels of glaucoma awareness among participants belonging to the upper 2 SECs (P = 0.05) and those educated above the high school level (P = 0.001). The most common source of awareness was close acquaintance with relatives, famly members, and friends of glaucoma patients. Awareness of glaucoma in India is low. Lack of education and lower socioeconomic status are the major risk factors for late preentation of glaucoma. Continuous presence of a low level of awareness and the same factors accounting for it warrants the need for an aggressive and refined approach to increase awareness of glaucoma to prevent glaucoma-related blindness. Copyright 2017 Asia-Pacific Academy of Ophthalmology.

Assessing the Role of the Family/Support System Perspective in Patients With Glaucoma.

PubMed

Shtein, Roni M; Newman-Casey, Paula A; Herndon, Leon; Coleman, Anne L; Lee, Paul P

2016-07-01

To investigate the role of the family/friends support system for patients with glaucoma and their perspective on barriers to effective glaucoma management. Six focus groups were conducted in 3 geographically and ethnically diverse areas of the United States (Los Angeles, CA; Rochester, MN; Durham, NC) that included 31 participants; 68% (21/31) were family members and friends of glaucoma patients with poor vision and 32% (10/31) were support system individuals of patients with good vision. Content analysis was used to identify important themes. Semiquantitative analysis was used to measure the frequency of each theme. A total of 134 relevant comments were made in the 6 focus groups and 72% of relevant comments were made by individuals providing support for patients with poor vision. Family members and friends mentioned the following areas of concern regarding patients' glaucoma care: patient education (19.4%), doctor-patient relationship (17.9%), their own lack of involvement in the patient's medical care (17.2%), frustration with glaucoma and with the patient (14.9%), patient dependency on caregivers (14.9%), patient frustration with the disease (10.4%), and sex differences in coping mechanisms (5.2%). Support system individuals tend to be minimally involved in the patient's glaucoma status and care. This is especially true for support system members of patients with glaucoma who maintain good vision and those who do not have any other personal experiences with difficulties from glaucoma. Many of these family members express an interest in acquiring more education about glaucoma and becoming more involved in the patient's glaucoma care.

Lack of Association of Mutations in Optineurin With Disease in Patients With Adult-onset Primary Open-angle Glaucoma

PubMed Central

Wiggs, Janey L.; Auguste, Josette; Allingham, R. Rand; Flor, Jason D.; Pericak-Vance, Margaret A.; Rogers, Kathryn; LaRocque, Karen R.; Graham, Felicia L.; Broomer, Bob; Del Bono, Elizabeth; Haines, Jonathan L.; Hauser, Michael

2005-01-01

Objective: To determine whether mutations in the optineurin gene contribute to susceptibility to adult-onset primary open-angle glaucoma. Methods: The optineurin gene was screened in 86 probands with adult-onset primary open-angle glaucoma and in 80 age-matched control subjects. Exons 4 and 5, containing the recurrent mutations identified in patients with normal-tension glaucoma, were sequenced in all individuals studied, while the remaining exons were screened for DNA sequence variants with denaturing high-performance liquid chromatography. Results: The recurrent mutation, Met98Lys, previously found to be associated with an increased risk of disease was found in 8 (9%) of 86 probands. We also found the Met98Lys mutation in 10% of individuals from a control population of similar age, sex, and ethnicity. Consistent segregation of the mutation with the disease was not demonstrated in any of the 8 families. No other DNA changes altering the amino acid structure of the protein were found. Conclusion: The mutations in the optineurin gene associated with normal-tension glaucoma are not associated with adult-onset primary open-angle glaucoma in this patient population. Clinical Relevance: Genetic abnormalities that render the optic nerve susceptible to degeneration are excellent candidates for genetic factors that could contribute to adult-onset primary open-angle glaucoma. Mutations in optineurin have been associated with normal-tension glaucoma, but are not associated with disease in patients with adult-onset primary open-angle glaucoma. This result may indicate that normal-tension glaucoma is not necessarily part of the phenotypic spectrum of adult open-angle glaucoma. PMID:12912697

Detection of early changes in lung cell cytology by flow-systems analysis techniques, July 1--December 31, 1975

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinkamp, J.A.; Ingram, M.; Hansen, K.M.

1976-03-01

This report summarizes results of preliminary experiments to demonstrate the feasibility of using automated flow-systems analysis in detecting early changes of respiratory epithelium exposed to physical and chemical agents associated with the by-products of nonnuclear energy production. The Syrian hamster was selected as the experimental test animal to begin investigation of the effects of toxic agents to cells of the respiratory tract. Since initiation of the program approximately six months ago, the goals have been acquisition of adequate numbers of exfoliated cells from the lung; adaptation of cytological techniques developed on human exfoliated gynecological samples to hamster lung epithelium formore » obtaining single-cell suspensions; utilization of existing cell staining methods to measure DNA content in lung cells; and analysis of DNA content and cell size. As the flow-system cell analysis technology is adapted to the measurement of exfoliated lung cells, rapid and quantitative determination of early changes in the physical and biochemical cellular properties will be attempted as a function of exposure to the toxic agents. (auth)« less

Ultrahigh performance heat spreader based on gas-liquid exfoliation boron nitride nanosheets.

PubMed

Ding, Jiheng; Zhao, Hongran; Wang, Qiaolei; Peng, Wanjun; Yu, Haibin

2017-11-24

Due to their high thermal conductivity and insulation performance, boron nitride nanosheets (BNNS) have great promise to fabricate thermal management equipment for application in power electronics. The liquid-phase exfoliation route has been regarded as the most commonly used approach to produce single and few-layered BNNS for many research fields. However, this process takes a long time, and the production yield is extremely low. In this work, an efficient technique to obtain few-layered (mostly < 5 layers), high-yield (∼33%), and plane-defect-free BNNS by the combination of liquid N 2 (L-N 2 ) gasification and liquid exfoliation was developed. The as-obtained BNNS suspensions could be vacuum filtered to make a thermal conductive film named a BNNS heat spreader which possessed a superior thermal conductivity of 61.2 W m -1 K -1 at room temperature. In addition, we also proved that the thermal conductivity of the BNNS heat spreader increased with the increase of density, creating an approach for fine tuning the thermal property of this heat spreader.

Self-surface charge exfoliation and electrostatically coordinated 2D hetero-layered hybrids

PubMed Central

Yang, Min-Quan; Xu, Yi-Jun; Lu, Wanheng; Zeng, Kaiyang; Zhu, Hai; Xu, Qing-Hua; Ho, Ghim Wei

2017-01-01

At present, the technological groundwork of atomically thin two-dimensional (2D) hetero-layered structures realized by successive thin film epitaxial growth is in principle constrained by lattice matching prerequisite as well as low yield and expensive production. Here, we artificially coordinate ultrathin 2D hetero-layered metal chalcogenides via a highly scalable self-surface charge exfoliation and electrostatic coupling approach. Specifically, bulk metal chalcogenides are spontaneously exfoliated into ultrathin layers in a surfactant/intercalator-free medium, followed by unconstrained electrostatic coupling with a dissimilar transition metal dichalcogenide, MoSe2, into scalable hetero-layered hybrids. Accordingly, surface and interfacial-dominated photocatalysis reactivity is used as an ideal testbed to verify the reliability of diverse 2D ultrathin hetero-layered materials that reveal high visible-light photoreactivity, efficient charge transfer and intimate contact interface for stable cycling and storage purposes. Such a synthetic approach renders independent thickness and composition control anticipated to advance the development of ‘design-and-build' 2D layered heterojunctions for large-scale exploration and applications. PMID:28146147

Ultrahigh performance heat spreader based on gas-liquid exfoliation boron nitride nanosheets

NASA Astrophysics Data System (ADS)

Ding, Jiheng; Zhao, Hongran; Wang, Qiaolei; Peng, Wanjun; Yu, Haibin

2017-11-01

Due to their high thermal conductivity and insulation performance, boron nitride nanosheets (BNNS) have great promise to fabricate thermal management equipment for application in power electronics. The liquid-phase exfoliation route has been regarded as the most commonly used approach to produce single and few-layered BNNS for many research fields. However, this process takes a long time, and the production yield is extremely low. In this work, an efficient technique to obtain few-layered (mostly < 5 layers), high-yield (˜33%), and plane-defect-free BNNS by the combination of liquid N2 (L-N2) gasification and liquid exfoliation was developed. The as-obtained BNNS suspensions could be vacuum filtered to make a thermal conductive film named a BNNS heat spreader which possessed a superior thermal conductivity of 61.2 W m-1 K-1 at room temperature. In addition, we also proved that the thermal conductivity of the BNNS heat spreader increased with the increase of density, creating an approach for fine tuning the thermal property of this heat spreader.

Bio-Based Nano Composites from Plant Oil and Nano Clay

NASA Astrophysics Data System (ADS)

Lu, Jue; Hong, Chang K.; Wool, Richard P.

2003-03-01

We explored the combination of nanoclay with new chemically functionalized, amphiphilic, plant oil resins to form bio-based nanocomposites with improved physical and mechanical properties. These can be used in many new applications, including the development of self-healing nanocomposites through controlled reversible exfoliation/intercalation, and self-assembled nano-structures. Several chemically modified triglyceride monomers of varying polarity, combined with styrene (ca 30include acrylated epoxidized soybean oil (AESO), maleated acrylated epoxidized soybean oil (MAESO) and soybean oil pentaerythritol glyceride maleates (SOPERMA), containing either hydroxyl group or acid functionality or both. The clay used is a natural montmorillonite modified with methyl tallow bis-2-hydroxyethyl quaternary ammonium chloride, which has hydroxyl groups. Both XRD and TEM showed a completely exfoliated structure at 3 wtwhen the clay content is above 5 wtconsidered a mix of intercalated and partially exfoliated structure. The controlled polarity of the monomer has a major effect on the reversible dispersion of clay in the polymer matrix. The bio-based nanocomposites showed a significant increase in flexural modulus and strength. Supported by EPA and DoE

In vivo performance of a drug-eluting contact lens to treat glaucoma for a month

PubMed Central

Ciolino, Joseph B.; Stefanescu, Cristina F.; Ross, Amy E.; Salvador-Culla, Borja; Cortez, Priscila; Ford, Eden M.; Wymbs, Kate A.; Sprague, Sarah L.; Mascoop, Daniel R.; Rudina, Shireen S.; Trauger, Sunia A.; Cade, Fabiano; Kohane, Daniel S.

2013-01-01

For nearly half a century, contact lenses have been proposed as a means of ocular drug delivery, but achieving controlled drug release has been a significant challenge. We have developed a drug-eluting contact lens designed for prolonged delivery of latanoprost for the treatment of glaucoma, the leading cause of irreversible blindness worldwide. Latanoprost-eluting contact lenses were created by encapsulating latanoprost–poly(lactic-co-glycolic acid) films in methafilcon by ultraviolet light polymerization. In vitro and in vivo studies showed an early burst of drug release followed by sustained release for one month. Contact lenses containing thicker drug–polymer films demonstrated released a greater amount of drug after the initial burst. In vivo, single contact lenses were able to achieve, for at least one month, latanoprost concentrations in the aqueous humor that were comparable to those achieved with topical latanoprost solution, the current first-line treatment for glaucoma. The lenses appeared safe in cell culture and animal studies. This contact lens design can potentially be used as a treatment for glaucoma and as a platform for other ocular drug delivery applications. PMID:24094935

Patterns of functional vision loss in glaucoma determined with archetypal analysis

PubMed Central

Elze, Tobias; Pasquale, Louis R.; Shen, Lucy Q.; Chen, Teresa C.; Wiggs, Janey L.; Bex, Peter J.

2015-01-01

Glaucoma is an optic neuropathy accompanied by vision loss which can be mapped by visual field (VF) testing revealing characteristic patterns related to the retinal nerve fibre layer anatomy. While detailed knowledge about these patterns is important to understand the anatomic and genetic aspects of glaucoma, current classification schemes are typically predominantly derived qualitatively. Here, we classify glaucomatous vision loss quantitatively by statistically learning prototypical patterns on the convex hull of the data space. In contrast to component-based approaches, this method emphasizes distinct aspects of the data and provides patterns that are easier to interpret for clinicians. Based on 13 231 reliable Humphrey VFs from a large clinical glaucoma practice, we identify an optimal solution with 17 glaucomatous vision loss prototypes which fit well with previously described qualitative patterns from a large clinical study. We illustrate relations of our patterns to retinal structure by a previously developed mathematical model. In contrast to the qualitative clinical approaches, our results can serve as a framework to quantify the various subtypes of glaucomatous visual field loss. PMID:25505132

Summary of studies on the blue-green autofluorescence and light transmission of the ocular lens

NASA Astrophysics Data System (ADS)

Van Best, Jaap A.; Kuppens, Esmeralda V.

1996-07-01

This paper reviews previous work done to demonstrate the clinical relevance of the measurement of blue-green autofluorescence and light transmission of the ocular lens. These can be determined quantitatively with fluorophotometry in a few seconds. Autofluorescence and transmission values are determined in healthy volunteers, in patients with insulin-dependent diabetes mellitus, and in patients with untreated glaucoma or untreated ocular hypertension. The lens autofluorescence of healthy volunteers increased linearly and transmission decreased exponentially with age. Each year of diabetes induced an increase of autofluorescence equal to one extra year of age. Untreated glaucoma or ocular hypertension had no significant effect on lens autofluorescence and transmission. Increased autofluorescence and decreased transmission values in comparison with values of a healthy population are proved to be indicative for an increased risk of developing cataract and the clinical usefulness of these measures is demonstrated. Diabetes is a risk factor for developing cataracts while untreated glaucoma or ocular hypertension is not.

Cell and protein adhesion studies in glaucoma drainage device development

PubMed Central

The, A

1999-01-01

AIM—To examine in vitro whether phosphorylcholine coating of poly(methylmethacrylate) can reduce the adhesion of fibrinogen, fibrin, human scleral fibroblast and macrophage compared with current biomaterials used in the construction of glaucoma drainage devices.
METHODS—Sample discs (n=6) of poly(methylmethacrylate), silicone, polypropylene, PTFE, and phosphorylcholine coated poly(methylmethacrylate) were seeded with fibrinogen, fibrin, fibroblast, and macrophages and incubated for variable lengths of time. The quantification was performed using radioactivity, spectrophotometry, ATP dependent luminometry, and immunohistochemistry respectively.
RESULTS—Fibrinogen and fibrin adhesion to phosphorylcholine coated poly(methylmethacrylate) were significantly lower than PMMA (p=0.004). Phosphorylcholine coating of poly(methylmethacrylate) also significantly reduced the adhesion of human scleral fibroblast (p=0.002) and macrophage (p=0.01) compared with PMMA. All the other biomaterials showed either similar or insignificantly different levels of adhesion to all the proteins and cells tested compared with PMMA.
CONCLUSION—Phosphorylcholine coating is a new material technology that offers considerable promise in the field of glaucoma drainage device development.

 PMID:10502580

Development of diagnostic and treatment strategies for glaucoma through understanding and modification of scleral and lamina cribrosa connective tissue

PubMed Central

Quigley, Harry A.; Cone, Frances E.

2013-01-01

There is considerable evidence that the state of ocular connective tissues and their response in glaucomatous disease affects the degree of glaucoma damage. Both experimental and clinical data suggest that improved diagnostic and prognostic information could be derived from assessment of the mechanical responsiveness of the sclera and lamina cribrosa to intraocular pressure (IOP). Controlled mutagenesis of the sclera has produced a mouse strain that is relatively resistant to increased IOP. Alteration of the baseline scleral state could be accomplished through either increased cross-linking of fibrillar components or their reduction. The sclera is a dynamic structure, altering its structure and behavior in response to IOP change. The biochemical pathways that control these responses are fertile areas for new glaucoma treatments. PMID:23535950

Causes of blindness in a special education school.

PubMed

Onakpoya, O H; Adegbehingbe, B O; Omotoye, O J; Adeoye, A O

2011-01-01

Blind children and young adults have to overcome a lifetime of emotional, social and economic difficulties. They employ non-vision dependent methods for education. To assess the causes of blindness in a special school in southwestern Nigeria to aid the development of efficient blindness prevention programmes. A cross-sectional survey of the Ekiti State Special Education School, Nigeria was conducted in May-June 2008 after approval from the Ministry of Education. All students in the blind section were examined for visual acuity, pen-torch eye examination and dilated fundoscopy in addition to taking biodata and history. Thirty blind students with mean age of 18±7.3 years and male: female ratio of 1.7:1 were examined. Blindness resulted commonly from cataract eight (26.7%), glaucoma six (20%) retinitis pigmentosa four (16.7%) and posttraumatic phthysis bulbi two (6.7%). Blindness was avoidable in 18 (61%) of cases. Glaucoma blindness was associated with redness, pain, lacrimation and photophobia in 15 (50%) and hyphaema in 16.7% of students; none of these students were on any medication at the time of study. The causes of blindness in rehabilitation school for the blind are largely avoidable and glaucoma-blind pupils face additional painful eye related morbidity during rehabilitation. While preventive measures and early intervention are needful against childhood cataract and glaucoma, regular ophthalmic consultations and medications are needed especially for glaucoma blind pupils.

Exclusion of chromosome 1q21-q31 from linkage to three pedigrees affected by the pigment-dispersion syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paglinauan, C.; Haines, J.L.; Del Bono, E.A.

1995-05-01

The pigment-dispersion syndrome is a form of open-angle glaucoma that usually affects individuals in the first 3 decades of life. In addition to the typical optic-nerve degeneration seen in all types of glaucoma, the pigment-dispersion syndrome is characterized by distinctive clinical features including the deposition of pigment granules from the iris epithelium on a variety of ocular structures including the trabecular meshwork. Frequently this disorder affects young myopic individuals. In the early stages of the disease, affected individuals may have clinical evidence of dispersed pigment without an associated elevation of intraocular pressure and optic-nerve degeneration. However, as the disease processmore » progresses, many affected individuals ({approximately}50%) will develop elevated intraocular pressure and degeneration of the optic nerve, causing a permanent loss of sight. The pigment-dispersion syndrome shares several clinical features with the form of autosomal dominant juvenile open-angle glaucoma that recently has been mapped to the 1q21-q31 region of chromosome 1. Our results indicate that the pigment-dispersion syndrome, a form of glaucoma that may also affect the juvenile population, is genetically unrelated to the autosomal dominant form of juvenile glaucoma caused by a defect in a gene located in the 1q21-q31 region of chromosome 1. 15 refs., 2 figs., 1 tab.« less

Heparan sulfate deficiency leads to Peters anomaly in mice by disturbing neural crest TGF-β2 signaling

PubMed Central

Iwao, Keiichiro; Inatani, Masaru; Matsumoto, Yoshihiro; Ogata-Iwao, Minako; Takihara, Yuji; Irie, Fumitoshi; Yamaguchi, Yu; Okinami, Satoshi; Tanihara, Hidenobu

2009-01-01

During human embryogenesis, neural crest cells migrate to the anterior chamber of the eye and then differentiate into the inner layers of the cornea, the iridocorneal angle, and the anterior portion of the iris. When proper development does not occur, this causes iridocorneal angle dysgenesis and intraocular pressure (IOP) elevation, which ultimately results in developmental glaucoma. Here, we show that heparan sulfate (HS) deficiency in mouse neural crest cells causes anterior chamber dysgenesis, including corneal endothelium defects, corneal stroma hypoplasia, and iridocorneal angle dysgenesis. These dysfunctions are phenotypes of the human developmental glaucoma, Peters anomaly. In the neural crest cells of mice embryos, disruption of the gene encoding exostosin 1 (Ext1), which is an indispensable enzyme for HS synthesis, resulted in disturbed TGF-β2 signaling. This led to reduced phosphorylation of Smad2 and downregulated expression of forkhead box C1 (Foxc1) and paired-like homeodomain transcription factor 2 (Pitx2), transcription factors that have been identified as the causative genes for developmental glaucoma. Furthermore, impaired interactions between HS and TGF-β2 induced developmental glaucoma, which was manifested as an IOP elevation caused by iridocorneal angle dysgenesis. These findings suggest that HS is necessary for neural crest cells to form the anterior chamber via TGF-β2 signaling. Disturbances of HS synthesis might therefore contribute to the pathology of developmental glaucoma. PMID:19509472

Overexpression of soluble Fas ligand following AAV gene therapy prevents retinal ganglion cell death in chronic and acute murine models of glaucoma

PubMed Central

Krishnan, Anitha; Fei, Fei; Jones, Alexander; Busto, Patricia; Marshak-Rothstein, Ann; Ksander, Bruce R.; Gregory-Ksander, Meredith

2016-01-01

Glaucoma is a multifactorial disease resulting in the death of retinal ganglion cells (RGCs) and irreversible blindness. Glaucoma-associated RGC cell death depends on the pro-apoptotic and proinflammatory activity of membrane-bound FasL (mFasL). In contrast to mFasL, the natural soluble FasL cleavage product (sFasL) inhibits mFasL-mediated apoptosis and inflammation and is therefore a mFasL antagonist. DBA/2J (D2) mice spontaneously develop glaucoma and predictably RGC destruction is exacerbated by expression of a mutated membrane-only FasL (mFasL) gene that lacks the extracellular cleavage site. Remarkably, one time intraocular adeno-associated virus-mediated gene delivery of sFasL (AAV2.sFasL) provides complete and sustained neuroprotection in both the chronic D2 and acute microbead-induced models of glaucoma, even in the presence of elevated intraocular pressure (IOP). This protection correlated with inhibition of glial activation, reduced production of TNFα, and decreased apoptosis of RGCs and loss of axons. These data indicate that cleavage of FasL under homeostatic conditions, and the ensuing release of sFasL, normally limits the neurodestructive activity of FasL. The data further support the notion that sFasL, and not mFasL, contributes to the immune privileged status of the eye. PMID:27849168

Biomarkers and surrogate endpoints in glaucoma clinical trials

PubMed Central

Medeiros, Felipe A

2015-01-01

Surrogate endpoints are often used as replacements for true clinically relevant endpoints in several areas of medicine, as they enable faster and less expensive clinical trials. However, without proper validation, the use of surrogates may lead to incorrect conclusions about the efficacy and safety of treatments. This article reviews the general requirements for validating surrogate endpoints and provides a critical assessment of the use of intraocular pressure (IOP), visual fields, and structural measurements of the optic nerve as surrogate endpoints in glaucoma clinical trials. A valid surrogate endpoint must be able to predict the clinically relevant endpoint and fully capture the effect of an intervention on that endpoint. Despite its widespread use in clinical trials, no proper validation of IOP as a surrogate endpoint has ever been conducted for any class of IOP-lowering treatments. Evidence has accumulated with regard to the role of imaging measurements of optic nerve damage as surrogate endpoints in glaucoma. These measurements are predictive of functional losses in the disease and may explain, at least in part, treatment effects on clinically relevant endpoints. The use of composite endpoints in glaucoma trials may overcome weaknesses of the use of structural or functional endpoints in isolation. Unless research is dedicated to fully develop and validate suitable endpoints that can be used in glaucoma clinical trials, we run the risk of inappropriate judgments about the value of new therapies. PMID:25034049

Biomechanical aspects of axonal damage in glaucoma: a brief review1

PubMed Central

Stowell, Cheri; Burgoyne, Claude; Tamm, Ernst R.; Ethier, C. Ross

2017-01-01

The biomechanical environment within the optic nerve head (ONH) is complex and is likely directly involved in the loss of retinal ganglion cells (RGCs) in glaucoma. Unfortunately, our understanding of this process is poor. Here we describe factors that influence ONH biomechanics, including ONH connective tissue microarchitecture and anatomy; intraocular pressure (IOP); and cerebrospinal fluid pressure (CSFp). We note that connective tissue factors can vary significantly from one individual to the next, as well as regionally within an eye, and that the understanding of ONH biomechanics is hindered by anatomical differences between small-animal models of glaucoma (rats and mice) and humans. Other challenges of using animal models of glaucoma to study the role of biomechanics include the complexity of assessing the degree of glaucomatous progression; and inadequate tools for monitoring and consistently elevating IOP in animal models. We conclude with a consideration of important open research questions/challenges in this area, including: (i) Creating a systems biology description of the ONH; (ii) addressing the role of astrocyte connective tissue remodeling and reactivity in glaucoma; (iii) providing a better characterization of ONH astrocytes and non-astrocytic constituent cells; (iv) better understanding the role of ONH astrocyte phagocytosis, proliferation and death; (v) collecting gene expression and phenotype data on a larger, more coordinated scale; and (vi) developing an implantable IOP sensor. PMID:28223180

Glaucoma Drainage Device Erosion Following Ptosis Surgery.

PubMed

Bae, Steven S; Campbell, Robert J

2017-09-01

To highlight the potential risk of glaucoma drainage device erosion following ptosis surgery. Case report. A 71-year-old man underwent uncomplicated superotemporal Ahmed glaucoma valve implantation in the left eye in 2008. Approximately 8 years later, the patient underwent bilateral ptosis repair, which successfully raised the upper eyelid position. Three months postoperatively, the patient's glaucoma drainage implant tube eroded through the corneal graft tissue and overlying conjunctiva to become exposed. A graft revision surgery was successfully performed with no further complications. Caution and conservative lid elevation may be warranted when performing ptosis repair in patients with a glaucoma drainage implant, and patients with a glaucoma implant undergoing ptosis surgery should be followed closely for signs of tube erosion.

Electrochemical Exfoliation of Graphite in Aqueous Sodium Halide Electrolytes toward Low Oxygen Content Graphene for Energy and Environmental Applications.

PubMed

Munuera, J M; Paredes, J I; Enterría, M; Pagán, A; Villar-Rodil, S; Pereira, M F R; Martins, J I; Figueiredo, J L; Cenis, J L; Martínez-Alonso, A; Tascón, J M D

2017-07-19

Graphene and graphene-based materials have shown great promise in many technological applications, but their large-scale production and processing by simple and cost-effective means still constitute significant issues in the path of their widespread implementation. Here, we investigate a straightforward method for the preparation of a ready-to-use and low oxygen content graphene material that is based on electrochemical (anodic) delamination of graphite in aqueous medium with sodium halides as the electrolyte. Contrary to previous conflicting reports on the ability of halide anions to act as efficient exfoliating electrolytes in electrochemical graphene exfoliation, we show that proper choice of both graphite electrode (e.g., graphite foil) and sodium halide concentration readily leads to the generation of large quantities of single-/few-layer graphene nanosheets possessing a degree of oxidation (O/C ratio down to ∼0.06) lower than that typical of anodically exfoliated graphenes obtained with commonly used electrolytes. The halide anions are thought to play a role in mitigating the oxidation of the graphene lattice during exfoliation, which is also discussed and rationalized. The as-exfoliated graphene materials exhibited a three-dimensional morphology that was suitable for their practical use without the need to resort to any kind of postproduction processing. When tested as dye adsorbents, they outperformed many previously reported graphene-based materials (e.g., they adsorbed ∼920 mg g -1 for methyl orange) and were useful sorbents for oils and nonpolar organic solvents. Supercapacitor cells assembled directly from the as-exfoliated products delivered energy and power density values (up to 15.3 Wh kg -1 and 3220 W kg -1 , respectively) competitive with those of many other graphene-based devices but with the additional advantage of extreme simplicity of preparation.

Electrolytic exfoliation of graphite in water with multifunctional electrolytes: en route towards high quality, oxide-free graphene flakes.

PubMed

Munuera, J M; Paredes, J I; Villar-Rodil, S; Ayán-Varela, M; Martínez-Alonso, A; Tascón, J M D

2016-02-07

Electrolytic--usually referred to as electrochemical--exfoliation of graphite in water under anodic potential holds enormous promise as a simple, green and high-yield method for the mass production of graphene, but currently suffers from several drawbacks that hinder its widespread adoption, one of the most critical being the oxidation and subsequent structural degradation of the carbon lattice that is usually associated with such a production process. To overcome this and other limitations, we introduce and implement the concept of multifunctional electrolytes. The latter are amphiphilic anions (mostly polyaromatic hydrocarbons appended with sulfonate groups) that play different relevant roles as (1) an intercalating electrolyte to trigger exfoliation of graphite into graphene flakes, (2) a dispersant to afford stable aqueous colloidal suspensions of the flakes suitable for further use, (3) a sacrificial agent to prevent graphene oxidation during exfoliation and (4) a linker to promote nanoparticle anchoring on the graphene flakes, yielding functional hybrids. The implementation of this strategy with some selected amphiphiles even furnishes anodically exfoliated graphenes of a quality similar to that of flakes produced by direct, ultrasound- or shear-induced exfoliation of graphite in the liquid phase (i.e., almost oxide- and defect-free). These high quality materials were used for the preparation of catalytically efficient graphene-Pt nanoparticle hybrids, as demonstrated by model reactions (reduction of nitroarenes). The multifunctional performance of these electrolytes is also discussed and rationalized, and a mechanistic picture of their oxidation-preventing ability is proposed. Overall, the present results open the prospect of anodic exfoliation as a competitive method for the production of very high quality graphene flakes.

One-pot exfoliation, functionalization, and size manipulation of graphene sheets: efficient system for biomedical applications.

PubMed

Bani, Farhad; Bodaghi, Ali; Dadkhah, Abbas; Movahedi, Soodabeh; Bodaghabadi, Narges; Sadeghizadeh, Majid; Adeli, Mohsen

2018-05-01

In this work, we reported a facile method to produce stable aqueous graphene dispersion through direct exfoliation of graphite by modified hyperbranched polyglycerol. Size of graphene sheets was manipulated by simultaneous exfoliation and sonication of graphite, and functionalized graphene sheets with narrow size distribution were obtained. The polyglycerol-functionalized graphene sheets exhibited highly efficient cellular uptake and photothermal conversion, enabling it to serve as a photothermal agent for cancer therapy.

Coupling Graphene Sheets with Iron Oxide Nanoparticles for Energy Storage and Microelectronics

DTIC Science & Technology

2015-12-18

obtained from three different synthetic methods: (i) electrochemical exfoliation of highly oriented pyrolytic graphite ( HOPG ) [8], (ii) reduction of ...Fe2O3 -Graphene Sheets Graphene sheets are obtained from electrochemical exfoliation of highly oriented pyrolytic graphite ( HOPG ) flake. Two...fringes of ɤ-Fe2O3 nanoparticles in graphene sheet is shown. Typical X-ray diffraction ( XRD ) patterns of the HOPG , exfoliated graphene, PyDop1-ɤ-Fe2O3

The Results of the Use of Ahmed Valve in Refractory Glaucoma Surgery

PubMed Central

Bikbov, Mukharram Mukhtaramovich

2015-01-01

ABSTRACT The treatment of refractory glaucoma (RG) is challenging. The commonly adopted strategy in RG treatment is a glaucoma drainage device (GDD) implantation, which despite its radical nature may not always provide the desired intraocular pressure (IOP) levels for a long term. This review is based on the scientific literature on Ahmed glaucoma valve (AGV) implantation for refractory glaucoma. The technique of AGV implantation is described and data for both the types, FP7 and FP8 performance are presented. The outcome with adjunct antimetabolite and anti-VEGF drugs are also highlighted. An insight is given about experimental and histological examinations of the filtering bleb encapsulation. The article also describes various complications and measures to prevent them. How to cite this article: Bikbov MM, Khusnitdinov II. The Results of the Use of Ahmed Valve in Refractory Glaucoma Surgery. J Curr Glaucoma Pract 2015;9(3):86-91. PMID:26997843

Glaucoma and cataract surgery: two roads merging into one.

PubMed

Shah, Manjool; Law, Geoffrey; Ahmed, Iqbal Ike K

2016-01-01

To discuss the increasing utilization of cataract extraction in the management of glaucoma and to highlight advances in surgical care that can promote synergistic treatment of these comorbid conditions. Recent years have demonstrated significant advances in the management of glaucoma through the use of novel microinvasive glaucoma devices. Furthermore, an increased understanding of the role of cataract surgery in the treatment of various glaucomas warrants review. Nevertheless, cataract surgery in the glaucoma patient warrants specific preoperative, intraoperative, and postoperative planning to optimize visual function and quality of life while mitigating potential risk factors for adverse events. Although the challenges of performing cataract extraction on glaucoma patients exist, the potential benefit to these patients is substantial. With attention to pre- and perioperative surgical planning and intraoperative technique, as well as with awareness and potential utilization of novel devices and treatment strategies, cataract extraction offers a unique platform for anatomical and functional improvement in this increasingly common cohort of patients.

Glaucoma and Corneal Transplant Procedures

PubMed Central

Al-Mahmood, Ammar M.; Al-Swailem, Samar A.; Edward, Deepak P.

2012-01-01

Glaucoma after corneal transplantation is a leading cause of ocular morbidity after penetrating keratoplasty. The incidence reported is highly variable and a number of etiologic factors have been identified. A number of treatment options are available; surgical intervention for IOP control is associated with a high incidence of graft failure. IOP elevation is less frequently seen following deep anterior lamellar keratoplasty. Descemet's striping-automated endothelial keratoplasty is also associated with postprocedure intraocular pressure elevation and secondary glaucoma and presents unique surgical challenges in patients with preexisting glaucoma surgeries. Glaucoma exists in up to three-quarters of patients who undergo keratoprosthesis surgery and the management if often challenging. The aim of this paper is to highlight the incidence, etiology, and management of glaucoma following different corneal transplant procedures. It also focuses on the challenges in the diagnosis of glaucoma and intraocular pressure monitoring in this group of patients. PMID:22315661

Alternative therapy in glaucoma management: is there any role?

PubMed

Parikh, Rajul S; Parikh, Shefali R

2011-01-01

Glaucoma is one of the leading causes of blindness worldwide. Various randomized controlled clinical trials have shown that lowering intraocular pressure (IOP) does reduce progression of primary open-angle glaucoma. However, there is lots of interest in nonpharmacological options that includes lifestyle adjustment and alternative and complementary therapy (ACT). At least 5% glaucoma population uses ACT. Various lifestyle activities like exercise and alcohol can reduce IOP by 1 to 2 mm Hg but would have small effect on glaucoma. The psychological stress can increase IOP. Hypothetically and few studies do show neuroprotective effect (or effect on ocular blood flow) of alcohol, Gingko biloba, bilberry, but the current evidence is weak for its routine use. We must also remember the side effects of 'medications' (e.g., marijuana, alcohol) before promoting as remedy for glaucoma. In current armamentarium of glaucoma management, ACT cannot substitute the conventional treatment available to lower IOP.

Topical treatment of glaucoma: established and emerging pharmacology.

PubMed

Dikopf, Mark S; Vajaranant, Thasarat S; Edward, Deepak P

2017-06-01

Glaucoma is a collection of optic neuropathies consisting of retinal ganglion cell death and corresponding visual field loss. Glaucoma is the leading cause of irreversible vision loss worldwide and is forecasted to precipitously increase in prevalence in the coming decades. Current treatment options aim to lower intraocular pressure (IOP) via topical or oral therapy, laser treatment to the trabecular meshwork or ciliary body, and incisional surgery. Despite increasing use of trabecular laser therapy, topical therapy remains first-line in the treatment of most forms of glaucoma. Areas covered: Novel glaucoma therapies are a long-standing focus of investigational study. More than two decades have passed since the last United States Food and Drug Administration (FDA) approval of a topical glaucoma drug. Here, the authors review established topical glaucoma drops as well as those currently in FDA phase 2 and 3 clinical trial, nearing clinical use. Expert opinion: Current investigational glaucoma drugs lower IOP, mainly through enhanced trabecular meshwork outflow. Although few emerging therapies show evidence of retinal ganglion cell and optic nerve neuroprotection in animal models, emerging drugs are focused on lowering IOP, similar to established medicines.

Molecular and clinical characterization of a patient with a chromosome 4p deletion, Wolf-Hirschhorn syndrome, and congenital glaucoma.

PubMed

Finzi, S; Pinto, C F; Wiggs, J L

2001-03-01

Wolf-Hirschhorn syndrome is a developmental disorder associated with hemizygous deletion of the distal short arm of chromosome 4. We have identified a patient affected with Wolf-Hirschhorn syndrome and early onset glaucoma. Five other patients with Wolf-Hirschhorn syndrome and early onset glaucoma or ocular anomalies associated with early onset glaucoma have been previously described, suggesting that the association with Wolf-Hirschhorn syndrome is not coincidental. The infrequent association of early onset glaucoma suggests that the chromosomal region commonly deleted in Wolf-Hirschhorn patients does not contain genes responsible for early onset glaucoma. In this study, we performed a molecular characterization of the deleted chromosome 4 to determine the extent of the deletion in an attempt to begin to identify the chromosomal region responsible for the associated glaucoma. Using microsatellite repeat markers located on 4p, we determined that the deletion spanned a 60-cM region including the minimal Wolf-Hirschhorn region. The proximal breakpoint occurred between markers D4S3045 and D4S2974. These results support the hypothesis that patients with Wolf-Hirschhorn syndrome and early onset glaucoma may have large deletions of 4p that include a gene(s) that may be responsible for a dominant form of congenital glaucoma.

Whole-Exome Sequencing of Congenital Glaucoma Patients Reveals Hypermorphic Variants in GPATCH3, a New Gene Involved in Ocular and Craniofacial Development

PubMed Central

Ferre-Fernández, Jesús-José; Aroca-Aguilar, José-Daniel; Medina-Trillo, Cristina; Bonet-Fernández, Juan-Manuel; Méndez-Hernández, Carmen-Dora; Morales-Fernández, Laura; Corton, Marta; Cabañero-Valera, María-José; Gut, Marta; Tonda, Raul; Ayuso, Carmen; Coca-Prados, Miguel; García-Feijoo, Julián; Escribano, Julio

2017-01-01

Congenital glaucoma (CG) is a heterogeneous, inherited and severe optical neuropathy that originates from maldevelopment of the anterior segment of the eye. To identify new disease genes, we performed whole-exome sequencing of 26 unrelated CG patients. In one patient we identified two rare, recessive and hypermorphic coding variants in GPATCH3, a gene of unidentified function, and 5% of a second group of 170 unrelated CG patients carried rare variants in this gene. The recombinant GPATCH3 protein activated in vitro the proximal promoter of CXCR4, a gene involved in embryo neural crest cell migration. The GPATCH3 protein was detected in human tissues relevant to glaucoma (e.g., ciliary body). This gene was expressed in the dermis, skeletal muscles, periocular mesenchymal-like cells and corneal endothelium of early zebrafish embryos. Morpholino-mediated knockdown and transient overexpression of gpatch3 led to varying degrees of goniodysgenesis and ocular and craniofacial abnormalities, recapitulating some of the features of zebrafish embryos deficient in the glaucoma-related genes pitx2 and foxc1. In conclusion, our data suggest the existence of high genetic heterogeneity in CG and provide evidence for the role of GPATCH3 in this disease. We also show that GPATCH3 is a new gene involved in ocular and craniofacial development. PMID:28397860

Neuroprotective therapies in glaucoma: II. Genetic nanotechnology tools.

PubMed

Nafissi, Nafiseh; Foldvari, Marianna

2015-01-01

Neurotrophic factor genome engineering could have many potential applications not only in the deeper understanding of neurodegenerative disorders but also in improved therapeutics. The fields of nanomedicine, regenerative medicine, and gene/cell-based therapy have been revolutionized by the development of safer and efficient non-viral technologies for gene delivery and genome editing with modern techniques for insertion of the neurotrophic factors into clinically relevant cells for a more sustained pharmaceutical effect. It has been suggested that the long-term expression of neurotrophic factors is the ultimate approach to prevent and/or treat neurodegenerative disorders such as glaucoma in patients who do not respond to available treatments or are at the progressive stage of the disease. Recent preclinical research suggests that novel neuroprotective gene and cell therapeutics could be promising approaches for both non-invasive neuroprotection and regenerative functions in the eye. Several progenitor and retinal cell types have been investigated as potential candidates for glaucoma neurotrophin therapy either as targets for gene therapy, options for cell replacement therapy, or as vehicles for gene delivery. Therefore, in parallel with deeper understanding of the specific protective effects of different neurotrophic factors and the potential therapeutic cell candidates for glaucoma neuroprotection, the development of non-invasive and highly specific gene delivery methods with safe and effective technologies to modify cell candidates for life-long neuroprotection in the eye is essential before investing in this field.

Is there an association between glaucoma and capillaroscopy in patients with systemic sclerosis?

PubMed

Gomes, Beatriz Fiuza; Souza, Rebeca; Valadão, Thiago; Kara-Junior, Newton; Moraes, Haroldo Vieira; Santhiago, Marcony R

2018-02-01

To evaluate the relationship between glaucoma diagnosis and the nailfold capillaroscopy pattern in patients with systemic sclerosis. An observational study in a cohort of patients with SSc was conducted. Patients with at least one nailfold videocapillaroscopy and one ophthalmology examination at the same year were included. Data collected were: age, sex; type of systemic sclerosis according to the degree of skin impairment, self-reported ethnicity, disease duration, current use and dosage of systemic corticosteroid, current use and dosage of bosentan ® , intraocular pressure, central corneal thickness, diagnosis of glaucoma and capillaroscopy pattern. Thirty-one patients with systemic sclerosis were enrolled, 23% had glaucoma. There was no statistically significant association between glaucoma diagnosis and the capillaroscopic pattern (p = 0.86). There was also no significant difference (p = 0.66) regarding intraocular pressure between patients with mild (13.9 ± 3.8 mmHg) and severe capillaroscopic pattern (14.4 ± 2.8 mmHg). The odds ratio of glaucoma for severe capillaroscopic pattern compared to mild was 1.6 (95% confidence interval: 0.3-9.5). Up to 23% of patients with SSc have glaucoma. The high prevalence of glaucoma in SSc suggests a possible systemic vascular disturbance as the cause. However, there seems to be no significant association between the capillaroscopy pattern and glaucoma in systemic sclerosis. Further research is required to improve the understanding of glaucoma in the context of systemic sclerosis.

Retinal nerve fiber layer reflectance for early glaucoma diagnosis.

PubMed

Liu, Shuang; Wang, Bingqing; Yin, Biwei; Milner, Thomas E; Markey, Mia K; McKinnon, Stuart J; Rylander, Henry G

2014-01-01

Compare performance of normalized reflectance index (NRI) and retinal nerve fiber layer thickness (RNFLT) parameters determined from optical coherence tomography (OCT) images for glaucoma and glaucoma suspect diagnosis. Seventy-five eyes from 71 human subjects were studied: 33 controls, 24 glaucomatous, and 18 glaucoma-suspects. RNFLT and NRI maps were measured using 2 custom-built OCT systems and the commercial instrument RTVue. Using area under the receiver operating characteristic curve, RNFLT and NRI measured in 7 RNFL locations were analyzed to distinguish between control, glaucomatous, and glaucoma-suspect eyes. The mean NRI of the control group was significantly larger than the means of glaucomatous and glaucoma-suspect groups in most RNFL locations for all 3 OCT systems (P<0.05 for all comparisons). NRI performs significantly better than RNFLT at distinguishing between glaucoma-suspect and control eyes using RTVue OCT (P=0.008). The performances of NRI and RNFLT for classifying glaucoma-suspect versus control eyes were statistically indistinguishable for PS-OCT-EIA (P=0.101) and PS-OCT-DEC (P=0.227). The performances of NRI and RNFLT for classifying glaucomatous versus control eyes were statistically indistinguishable (PS-OCT-EIA: P=0.379; PS-OCT-DEC: P=0.338; RTVue OCT: P=0.877). NRI is a promising measure for distinguishing between glaucoma-suspect and control eyes and may indicate disease in the preperimetric stage. Results of this pilot clinical study warrant a larger study to confirm the diagnostic power of NRI for diagnosing preperimetric glaucoma.

Corneal hysteresis in patients with glaucoma-like optic discs, ocular hypertension and glaucoma.

PubMed

Murphy, Melissa L; Pokrovskaya, Olya; Galligan, Marie; O'Brien, Colm

2017-01-10

To compare corneal hysteresis (CH) measurements between patients with glaucoma, ocular hypertension (OHT) and glaucoma-like optic discs (GLD)- defined as a cup to disc ratio greater than or equal to 0.6 with normal intraocular pressure (IOP) and visual fields. The secondary aim was to investigate whether corneal resistance factor (CRF) and central corneal thickness (CCT) differ between patient groups. In this cross sectional study a total of 123 patients (one eye each) were recruited from a glaucoma outpatient department to undergo ocular response analyser (ORA) testing and ultrasound pachymetry as well as clinical examination. A One-way Analysis of Covariance (ANCOVA) was conducted to evaluate the mean difference in CH between the three diagnostic groups (glaucoma, OHT and GLD) correcting for potential confounding factors, IOP and age. Analysis was repeated for CRF and CCT. There was a significant difference in mean CH across the three diagnosis groups; F(2, 115) = 96.95; p < 0.001. Mean CH significantly higher for GLD compared to glaucoma (mean difference 1.83, p < 0.001), and significantly higher for OHT compared to glaucoma (mean difference 2.35, p < 0.001). Mean CH was slightly lower in patients with GLD than those with OHT but this difference was not statistically significant. A similar pattern was seen when the analysis was repeated for CRF and CCT. Higher CH in GLD and OHT compared to glaucoma suggests increased viscoelasticity of ocular tissues may have a protective role against glaucoma.

Association between zolpidem use and glaucoma risk: a Taiwanese population-based case-control study.

PubMed

Ho, Yi-Hao; Chang, Yue-Cune; Huang, Wei-Cheng; Chen, Hsin-Yi; Lin, Che-Chen; Sung, Fung-Chang

2015-01-01

To date, the relationship between zolpidem use and subsequent risk of glaucoma in a Taiwanese population has not been assessed. We used data from the National Health Insurance system to investigate whether zolpidem use was related to glaucoma risk. A 1:4 matched case-control study was conducted. The cases were patients newly diagnosed with glaucoma from 2001 to 2010. The controls were randomly selected non-glaucoma subjects matched by sex and age (± 5 years). Zolpidem exposure and/or the average dosage of zolpidem used (mg/year) were evaluated. Medical comorbidities were considered as confounding factors. Multiple logistic regression models were used to evaluate the potential risk of zolpidem exposure on glaucoma with/without adjustment for the effects of confounding variables. The exposure rate of zolpidem use in the glaucoma group was significantly higher than that of the control group (2.8% vs. 2.0%, P < 0.0001). The adjusted odds ratio (OR) of the risk of glaucoma for those with zolpidem use vs. those without was 1.19 (95% confidence interval [CI], 1.02-1.38). Compared to non-zolpidem users, zolpidem users with an average dose of more than 200 mg/year had significantly increased risk of glaucoma (OR 1.31, 95% CI 1.03-1.68). This study suggests that the use of zolpidem might increase the risk of subsequent glaucoma. Further confirmatory studies are recommended to clarify this important issue.

Association Between Zolpidem Use and Glaucoma Risk: A Taiwanese Population-Based Case-Control Study

PubMed Central

Ho, Yi-Hao; Chang, Yue-Cune; Huang, Wei-Cheng; Chen, Hsin-Yi; Lin, Che-Chen; Sung, Fung-Chang

2015-01-01

Background To date, the relationship between zolpidem use and subsequent risk of glaucoma in a Taiwanese population has not been assessed. Methods We used data from the National Health Insurance system to investigate whether zolpidem use was related to glaucoma risk. A 1:4 matched case-control study was conducted. The cases were patients newly diagnosed with glaucoma from 2001 to 2010. The controls were randomly selected non-glaucoma subjects matched by sex and age (±5 years). Zolpidem exposure and/or the average dosage of zolpidem used (mg/year) were evaluated. Medical comorbidities were considered as confounding factors. Multiple logistic regression models were used to evaluate the potential risk of zolpidem exposure on glaucoma with/without adjustment for the effects of confounding variables. Results The exposure rate of zolpidem use in the glaucoma group was significantly higher than that of the control group (2.8% vs. 2.0%, P < 0.0001). The adjusted odds ratio (OR) of the risk of glaucoma for those with zolpidem use vs. those without was 1.19 (95% confidence interval [CI], 1.02–1.38). Compared to non-zolpidem users, zolpidem users with an average dose of more than 200 mg/year had significantly increased risk of glaucoma (OR 1.31, 95% CI 1.03–1.68). Conclusions This study suggests that the use of zolpidem might increase the risk of subsequent glaucoma. Further confirmatory studies are recommended to clarify this important issue. PMID:25720944

Association Between Zolpidem Use and Glaucoma Risk: A Taiwanese Population-Based Case-Control Study.

PubMed

Ho, Yi-Hao; Chang, Yue-Cune; Huang, Wei-Cheng; Chen, Hsin-Yi; Lin, Che-Chen; Sung, Fung-Chang

2014-08-23

Background: To date, the relationship between zolpidem use and subsequent risk of glaucoma in a Taiwanese population has not been assessed.Methods: We used data from the National Health Insurance system to investigate whether zolpidem use was related to glaucoma risk. A 1:4 matched case-control study was conducted. The cases were patients newly diagnosed with glaucoma from 2001 to 2010. The controls were randomly selected non-glaucoma subjects matched by sex and age (±5 years). Zolpidem exposure and/or the average dosage of zolpidem used (mg/year) were evaluated. Medical comorbidities were considered as confounding factors. Multiple logistic regression models were used to evaluate the potential risk of zolpidem exposure on glaucoma with/without adjustment for the effects of confounding variables.Results: The exposure rate of zolpidem use in the glaucoma group was significantly higher than that of the control group (2.8% vs. 2.0%, P < 0.0001). The adjusted odds ratio (OR) of the risk of glaucoma for those with zolpidem use vs. those without was 1.19 (95% confidence interval [CI], 1.02-1.38). Compared to non-zolpidem users, zolpidem users with an average dose of more than 200 mg/year had significantly increased risk of glaucoma (OR 1.31, 95% CI 1.03-1.68).Conclusions: This study suggests that the use of zolpidem might increase the risk of subsequent glaucoma. Further confirmatory studies are recommended to clarify this important issue.

What Do Patients With Glaucoma See? Visual Symptoms Reported by Patients With Glaucoma

PubMed Central

Hu, Cindy X.; Zangalli, Camila; Hsieh, Michael; Gupta, Lalita; Williams, Alice L.; Richman, Jesse

2014-01-01

Abstract: Background: Vision loss from glaucoma has traditionally been described as loss of “peripheral vision.” In this prospective study, we aimed to improve our clinical understanding of the visual symptoms caused by glaucoma by asking patients specific detailed questions about how they see. Methods: Patients who were clinically diagnosed with various types and stages of glaucoma were included. All had a comprehensive ocular examination, including Octopus visual field testing. Patients were excluded if they had other ocular conditions that affected their vision, including cornea, lens or retina pathologies. Patients responded to an oral questionnaire about their visual symptoms. We investigated the visual symptoms described by patients with glaucoma and correlated the severity of visual field loss with visual symptoms reported. Results: Ninety-nine patients completed the questionnaire. Most patients (76%) were diagnosed with primary open-angle glaucoma. The most common symptoms reported by all patients, including patients with early or moderate glaucoma, were needing more light and blurry vision. Patients with a greater amount of field loss (Octopus mean defect >+9.4 dB) were more likely to report difficulty seeing objects to one or both sides, as if looking through dirty glasses and trouble differentiating boundaries and colors. Conclusions: Vision loss in patients with glaucoma is not as simple as the traditional view of loss of peripheral vision. Needing more light and blurry vision were the most common symptoms reported by patients with glaucoma. PMID:24992392

Cambridge community Optometry Glaucoma Scheme.

PubMed

Keenan, Jonathan; Shahid, Humma; Bourne, Rupert R; White, Andrew J; Martin, Keith R

2015-04-01

With a higher life expectancy, there is an increased demand for hospital glaucoma services in the United Kingdom. The Cambridge community Optometry Glaucoma Scheme (COGS) was initiated in 2010, where new referrals for suspected glaucoma are evaluated by community optometrists with a special interest in glaucoma, with virtual electronic review and validation by a consultant ophthalmologist with special interest in glaucoma. 1733 patients were evaluated by this scheme between 2010 and 2013. Clinical assessment is performed by the optometrist at a remote site. Goldmann applanation tonometry, pachymetry, monoscopic colour optic disc photographs and automated Humphrey visual field testing are performed. A clinical decision is made as to whether a patient has glaucoma or is a suspect, and referred on or discharged as a false positive referral. The clinical findings, optic disc photographs and visual field test results are transmitted electronically for virtual review by a consultant ophthalmologist. The number of false positive referrals from initial referral into the scheme. Of the patients, 46.6% were discharged at assessment and a further 5.7% were discharged following virtual review. Of the patients initially discharged, 2.8% were recalled following virtual review. Following assessment at the hospital, a further 10.5% were discharged after a single visit. The COGS community-based glaucoma screening programme is a safe and effective way of evaluating glaucoma referrals in the community and reducing false-positive referrals for glaucoma into the hospital system. © 2014 Royal Australian and New Zealand College of Ophthalmologists.

Northern Alberta remote teleglaucoma program: clinical outcomes and patient disposition.

PubMed

Verma, Sanam; Arora, Sourabh; Kassam, Faazil; Edwards, Marianne C; Damji, Karim F

2014-04-01

To review the diagnostic outcomes and clinical referral pathways of patients assessed and managed through a collaborative care patient-centred teleglaucoma program. Retrospective cohort study. Eligible patients were those assessed by the referring optometrist or ophthalmologist to be open-angle glaucoma suspects or to have definite early open-angle glaucoma. A glaucoma specialist graded each case through virtual consultation. Clinical referral pathways were noted: in-person consultation with glaucoma specialist, repeat teleconsultation, collaborative glaucoma management with optometrist, or referral for nonglaucomatous ophthalmic pathology. A total of 247 patients were referred to the program from 2008 to 2012. Of all teleconsults, 31.1% were diagnosed with glaucoma, 42.1% were suspects, and 26.7% were unaffected. Of all patients, 27% were referred for in-person glaucoma evaluation; 69% of patients could be managed by their referring optometrist, with 48% of patients requiring repeat teleconsultation. Treatment was initiated before being seen for 87% of patients with definite glaucoma and 28% of glaucoma suspects. Of all patients seen through the remote teleglaucoma program, most did not require an in-person consultation with an ophthalmologist and could be managed through distance collaboration. For the approximately one third who were diagnosed with glaucoma based on virtual assessment, medication was started in the majority of cases and in-person consultation was arranged. Further studies to validate and consider cost-effectiveness of this system are under way. © 2013 Canadian Ophthalmological Society Published by Canadian Ophthalmological Society All rights reserved.

Early immune responses are independent of RGC dysfunction in glaucoma with complement component C3 being protective.

PubMed

Harder, Jeffrey M; Braine, Catherine E; Williams, Pete A; Zhu, Xianjun; MacNicoll, Katharine H; Sousa, Gregory L; Buchanan, Rebecca A; Smith, Richard S; Libby, Richard T; Howell, Gareth R; John, Simon W M

2017-05-09

Various immune response pathways are altered during early, predegenerative stages of glaucoma; however, whether the early immune responses occur secondarily to or independently of neuronal dysfunction is unclear. To investigate this relationship, we used the Wld s allele, which protects from axon dysfunction. We demonstrate that DBA/2J .Wld s mice develop high intraocular pressure (IOP) but are protected from retinal ganglion cell (RGC) dysfunction and neuroglial changes that otherwise occur early in DBA/2J glaucoma. Despite this, immune pathways are still altered in DBA/2J .Wld s mice. This suggests that immune changes are not secondary to RGC dysfunction or altered neuroglial interactions, but may be directly induced by the increased strain imposed by high IOP. One early immune response following IOP elevation is up-regulation of complement C3 in astrocytes of DBA/2J and DBA/2J. Wld s mice. Unexpectedly, because the disruption of other complement components, such as C1Q, is protective in glaucoma, C3 deficiency significantly increased the number of DBA/2J eyes with nerve damage and RGC loss at an early time point after IOP elevation. Transcriptional profiling of C3-deficient cultured astrocytes implicated EGFR signaling as a hub in C3-dependent responses. Treatment with AG1478, an EGFR inhibitor, also significantly increased the number of DBA/2J eyes with glaucoma at the same early time point. These findings suggest that C3 protects from early glaucomatous damage, a process that may involve EGFR signaling and other immune responses in the optic nerve head. Therefore, therapies that target specific components of the complement cascade, rather than global inhibition, may be more applicable for treating human glaucoma.

Detection and measurement of clinically meaningful visual field progression in clinical trials for glaucoma.

PubMed

De Moraes, C Gustavo; Liebmann, Jeffrey M; Levin, Leonard A

2017-01-01

Glaucomatous visual field progression has both personal and societal costs and therefore has a serious impact on quality of life. At the present time, intraocular pressure (IOP) is considered to be the most important modifiable risk factor for glaucoma onset and progression. Reduction of IOP has been repeatedly demonstrated to be an effective intervention across the spectrum of glaucoma, regardless of subtype or disease stage. In the setting of approval of IOP-lowering therapies, it is expected that effects on IOP will translate into benefits in long-term patient-reported outcomes. Nonetheless, the effect of these medications on IOP and their associated risks can be consistently and objectively measured. This helps to explain why regulatory approval of new therapies in glaucoma has historically used IOP as the outcome variable. Although all approved treatments for glaucoma involve IOP reduction, patients frequently continue to progress despite treatment. It would therefore be beneficial to develop treatments that preserve visual function through mechanisms other than lowering IOP. The United States Food and Drug Administration (FDA) has stated that they will accept a clinically meaningful definition of visual field progression using Glaucoma Change Probability criteria. Nonetheless, these criteria do not take into account the time (and hence, the speed) needed to reach significant change. In this paper we provide an analysis based on the existing literature to support the hypothesis that decreasing the rate of visual field progression by 30% in a trial lasting 12-18 months is clinically meaningful. We demonstrate that a 30% decrease in rate of visual field progression can be reliably projected to have a significant effect on health-related quality of life, as defined by validated instruments designed to measure that endpoint. Copyright © 2016 Elsevier Ltd. All rights reserved.

Early immune responses are independent of RGC dysfunction in glaucoma with complement component C3 being protective

PubMed Central

Harder, Jeffrey M.; Braine, Catherine E.; Williams, Pete A.; Zhu, Xianjun; MacNicoll, Katharine H.; Sousa, Gregory L.; Buchanan, Rebecca A.; Smith, Richard S.; Howell, Gareth R.; John, Simon W. M.

2017-01-01

Various immune response pathways are altered during early, predegenerative stages of glaucoma; however, whether the early immune responses occur secondarily to or independently of neuronal dysfunction is unclear. To investigate this relationship, we used the Wlds allele, which protects from axon dysfunction. We demonstrate that DBA/2J.Wlds mice develop high intraocular pressure (IOP) but are protected from retinal ganglion cell (RGC) dysfunction and neuroglial changes that otherwise occur early in DBA/2J glaucoma. Despite this, immune pathways are still altered in DBA/2J.Wlds mice. This suggests that immune changes are not secondary to RGC dysfunction or altered neuroglial interactions, but may be directly induced by the increased strain imposed by high IOP. One early immune response following IOP elevation is up-regulation of complement C3 in astrocytes of DBA/2J and DBA/2J.Wlds mice. Unexpectedly, because the disruption of other complement components, such as C1Q, is protective in glaucoma, C3 deficiency significantly increased the number of DBA/2J eyes with nerve damage and RGC loss at an early time point after IOP elevation. Transcriptional profiling of C3-deficient cultured astrocytes implicated EGFR signaling as a hub in C3-dependent responses. Treatment with AG1478, an EGFR inhibitor, also significantly increased the number of DBA/2J eyes with glaucoma at the same early time point. These findings suggest that C3 protects from early glaucomatous damage, a process that may involve EGFR signaling and other immune responses in the optic nerve head. Therefore, therapies that target specific components of the complement cascade, rather than global inhibition, may be more applicable for treating human glaucoma. PMID:28446616

Gene therapy with brain-derived neurotrophic factor as a protection: retinal ganglion cells in a rat glaucoma model.

PubMed

Martin, Keith R G; Quigley, Harry A; Zack, Donald J; Levkovitch-Verbin, Hana; Kielczewski, Jennifer; Valenta, Danielle; Baumrind, Lisa; Pease, Mary Ellen; Klein, Ronald L; Hauswirth, William W

2003-10-01

To develop a modified adenoassociated viral (AAV) vector capable of efficient transfection of retinal ganglion cells (RGCs) and to test the hypothesis that use of this vector to express brain-derived neurotrophic factor (BDNF) could be protective in experimental glaucoma. Ninety-three rats received one unilateral, intravitreal injection of either normal saline (n = 30), AAV-BDNF-woodchuck hepatitis posttranscriptional regulatory element (WPRE; n = 30), or AAV-green fluorescent protein (GFP)-WPRE (n = 33). Two weeks later, experimental glaucoma was induced in the injected eye by laser application to the trabecular meshwork. Survival of RGCs was estimated by counting axons in optic nerve cross sections after 4 weeks of glaucoma. Transgene expression was assessed by immunohistochemistry, Western blot analysis, and direct visualization of GFP. The density of GFP-positive cells in retinal wholemounts was 1,828 +/- 299 cells/mm(2) (72,273 +/- 11,814 cells/retina). Exposure to elevated intraocular pressure was similar in all groups. Four weeks after initial laser treatment, axon loss was 52.3% +/- 27.1% in the saline-treated group (n = 25) and 52.3% +/- 24.2% in the AAV-GFP-WPRE group (n = 30), but only 32.3% +/- 23.0% in the AAV-BDNF-WPRE group (n = 27). Survival in AAV-BDNF-WPRE animals increased markedly and the difference was significant compared with those receiving either AAV-GFP-WPRE (P = 0.002, t-test) or saline (P = 0.006, t-test). Overexpression of the BDNF gene protects RGC as estimated by axon counts in a rat glaucoma model, further supporting the potential feasibility of neurotrophic therapy as a complement to the lowering of IOP in the treatment of glaucoma.

Detection and measurement of clinically meaningful visual field progression in clinical trials for glaucoma

PubMed Central

De Moraes, C. Gustavo; Liebmann, Jeffrey M.; Levin, Leonard A.

2016-01-01

Glaucomatous visual field progression has both personal and societal costs and therefore has a serious impact on quality of life. At the present time, intraocular pressure (IOP) is considered to be the most important modifiable risk factor for glaucoma onset and progression. Reduction of IOP has been repeatedly demonstrated to be an effective intervention across the spectrum of glaucoma, regardless of subtype or disease stage. In the setting of approval of IOP-lowering therapies, it is expected that effects on IOP will translate into benefits in long-term patient-reported outcomes. Nonetheless, the effect of these medications on IOP and their associated risks can be consistently and objectively measured. This helps to explain why regulatory approval of new therapies in glaucoma has historically used IOP as the outcome variable. Although all approved treatments for glaucoma involve IOP reduction, patients frequently continue to progress despite treatment. It would therefore be beneficial to develop treatments that preserve visual function through mechanisms other than lowering IOP. The United States Food and Drug Administration (FDA) has stated that they will accept a clinically meaningful definition of visual field progression using Glaucoma Change Probability criteria. Nonetheless, these criteria do not take into account the time (and hence, the speed) needed to reach significant change. In this paper we provide an analysis based on the existing literature to support the hypothesis that decreasing the rate of visual field progression by 30% in a trial lasting 12–18 months is clinically meaningful. We demonstrate that a 30% decrease in rate of visual field progression can be reliably projected to have a significant effect on health-related quality of life, as defined by validated instruments designed to measure that endpoint. PMID:27773767

Fast circulation of cerebrospinal fluid: an alternative perspective on the protective role of high intracranial pressure in ocular hypertension.

PubMed

Wostyn, Peter; De Groot, Veva; Van Dam, Debby; Audenaert, Kurt; Killer, Hanspeter Esriel; De Deyn, Peter Paul

2016-05-01

As ocular hypertension refers to a condition in which the intraocular pressure is consistently elevated but without development of glaucoma, study of it may provide important clues to factors that may play a protective role in glaucoma. β-amyloid, one of the key histopathological findings in Alzheimer's disease, has been reported to increase by chronic elevation of intraocular pressure in animals with experimentally induced ocular hypertension and to cause retinal ganglion cell death, pointing to similarities in molecular cell death mechanisms between glaucoma and Alzheimer's disease. On the other hand, recent studies have reported that intracranial pressure is higher in patients with ocular hypertension compared with controls, giving rise to the idea that elevated intracranial pressure may provide a protective effect for the optic nerve by decreasing the trans-lamina cribrosa pressure difference. The speculation that the higher intracranial pressure reported in ocular hypertension patients may protect against glaucoma mainly through a lower trans-lamina cribrosa pressure difference remains at least questionable. Here, we present an alternative viewpoint, according to which the protective effect of higher intracranial pressure could be due, at least in part, to a pressure-independent mechanism, namely faster cerebrospinal fluid production leading to increased cerebrospinal fluid turnover with enhanced removal of potentially neurotoxic waste products that accumulate in the optic nerve. This suggests a new hypothesis for glaucoma, which, just like Alzheimer's disease, may be considered then as an imbalance between production and clearance of neurotoxins, including β-amyloid. If confirmed, then strategies to improve cerebrospinal fluid flow are reasonable and could provide a new therapeutic approach for stopping the neurotoxic β-amyloid pathway in glaucoma. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.