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Sample records for experimental glaucoma filtration

  1. Cellular proliferation after experimental glaucoma filtration surgery

    SciTech Connect

    Jampel, H.D.; McGuigan, L.J.; Dunkelberger, G.R.; L'Hernault, N.L.; Quigley, H.A.

    1988-01-01

    We used light microscopic autoradiography to determine the time course of cellular incorporation of tritiated thymidine (a correlate of cell division) following glaucoma filtration surgery in seven eyes of four cynomolgus monkeys with experimental glaucoma. Incorporation of tritiated thymidine was detected as early as 24 hours postoperatively. Peak incorporation occurred five days postoperatively and had returned to baseline levels by day 11. Cells incorporating tritiated thymidine included keratocytes, episcleral cells, corneal and capillary endothelial cells, and conjunctival and corneal epithelial cells. Transmission electron microscopy was correlated with the autoradiographic results to demonstrate that fibroblasts were dividing on the corneoscleral margin. These findings have potential clinical implications for the use of antiproliferative agents after filtration surgery.

  2. Bevacizumab-Loaded Polyurethane Subconjunctival Implants: Effects on Experimental Glaucoma Filtration Surgery

    PubMed Central

    Ribeiro, Vanessa Raquel Coimbra; Chahud, Fernando; Cannellini, Roberta; Monteiro, Tassia Cristina; de Lima Gomes, Elionai Cassiana; Reinach, Peter Sol; Veronese Rodrigues, Maria de Lourdes; Silva-Cunha, Armando

    2013-01-01

    Abstract Purpose Vascular endothelial growth factor (VEGF) may contribute to the scarring process resulting from glaucoma filtration surgery, since this cytokine may stimulate fibroblast proliferation. The aim of this study was to describe a new bevacizumab-loaded polyurethane implant (BPUI) and to evaluate its effectiveness as a new drug delivery system of anti-VEGF antibody in a rabbit model of glaucoma filtration surgery. Methods An aqueous dispersion of polyurethane was obtained via the conventional process. Bevacizumab (1.5 mg) was then incorporated into the dispersion and was subsequently dried to form the polymeric films. Films with dimensions of 3×3×1 mm that either did (group BPUI, n=10) or did not contain bevacizumab (group PUI, n=10) were implanted in the subconjunctival space, at the surgical site in 1 eye of each rabbit. The in vitro bevacizumab release was evaluated using size-exclusion high-performance liquid chromatography (HPLC), and the in vivo effects of the drug were investigated in a rabbit experimental trabeculectomy model by examining the bleb characteristics and collagen accumulation, and by performing immunohistological analyses of VEGF expression. Results HPLC showed that only 10% of the bevacizumab in the implants had been released by postoperative day 5. In vivo studies demonstrated that the drug had no adverse effects; however, no significant differences in either the bleb area score or the collagen deposit intensity between the group PUI and the group that BPUI were observed. Moreover, the group BPUI presented a significantly lower proportion of VEGF-expressing fibroblasts than group PUI (0.17±0.03 vs. 0.35±0.05 cells/field, P=0.005). Conclusions This study demonstrated that bevacizumab release from the BPUIs only occurred for a short time probably from the surface of the films. Nevertheless, they were well tolerated in rabbit eyes and reduced the number of VEGF-expressing fibroblasts. PMID:23391327

  3. Angiogenesis in glaucoma filtration surgery and neovascular glaucoma: A review.

    PubMed

    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 the severe secondary glaucoma called neovascular glaucoma (NVG). Upregulation 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 investigation of the ability of anti-vascular endothelial growth factor therapy to improve outcomes, and we examine the findings with respect to the safety and efficacy of anti-vascular endothelial growth factor agents, mainly bevacizumab and ranibizumab, in eyes that have undergone glaucoma filtration surgery or have NVG. Combining conventional therapies-such as antimetabolites after filtration surgery and panretinal photocoagulation in NVG-and anti-vascular endothelial growth factor drugs may produce a synergetic effect, although further studies are required to evaluate the long-term efficacy of combination treatments. PMID:25980779

  4. 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

  5. Effects of topical mitomycin C on glaucoma filtration surgery.

    PubMed

    Hong, C; Hyung, S M; Song, K Y; Kim, D M; Youn, D H

    1993-06-01

    We studied the efficacy and safety of using topical mitomycin C (MMC) as an adjunct to glaucoma filtration surgery. Trabeculectomy was performed in 23 eyes of 19 patients with poor surgical prognosis. After the preparation of a scleral flap, 0.2 mg or 0.4 mg/ml MMC was applied to the exposed tissue for 5 minutes. The wound was then irrigated with 250ml of normal saline. The mean follow-up period was 7.8 months. Preoperative mean intraocular pressure (IOP) was 33.8mmHg, and the mean IOPs on 1, 3, 6, and 12 months after operation were 10.3, 12.5, 12.4 and 12.3mmHg, respectively. At postoperative 12 months, 74.7% achieved an IOP of less than or equal to 20mmHg without any antiglaucoma medication. There were early postoperative complications of aqueous leaking from conjunctival wounds in 3 eyes (13.0%), shallow anterior chamber in 2 eyes, and hyphema in one eye and one eye had long-term hypotony lasting more than 3 months. Although MMC is simple to use, it is a potent adjunct to glaucoma filtration surgery, more work should follow to determine the mechanism of action, indications, dosage and optimal exposure time of MMC. PMID:8230774

  6. Stab Incision Glaucoma Surgery: A Modified Guarded Filtration Procedure for Primary Open Angle Glaucoma

    PubMed Central

    Jacob, Soosan; Figus, Michele; Ashok Kumar, Dhivya; Areeckal Incy, Saijimol

    2016-01-01

    Purpose. To describe a modified guarded filtration surgery, stab incision glaucoma surgery (SIGS), for primary open angle glaucoma (POAG). Methods. This prospective, interventional case series included patients with POAG (IOP ≥21 mmHg with glaucomatous visual field defects). After sliding superior conjunctiva down over limbus, 2.8 mm bevel-up keratome was used to create conjunctival entry and superficial corneoscleral tunnel in a single step starting 1.5 mm behind limbus. Lamellar corneoscleral tunnel was carefully dissected 0.5–1 mm into cornea and anterior chamber (AC) was entered. Kelly Descemet's punch (1 mm) was slid along the tunnel into AC to punch internal lip of the tunnel, thereby compromising it. Patency of ostium was assessed by injecting fluid in AC and visualizing leakage from tunnel. Conjunctival incision alone was sutured. Results. Mean preoperative IOP was 27.41 ± 5.54 mmHg and mean postoperative IOP was 16.47 ± 4.81 mmHg (n = 17). Mean reduction in IOP was 38.81 ± 16.55%. There was significant reduction of IOP (p < 0.000). 64.7% had IOP at final follow-up of <18 mmHg without medication and 82.35% had IOP <18 mmHg with ≤2 medications. No sight threatening complications were encountered. Conclusion. Satisfactory IOP control was noted after SIGS in interim follow-up (14.18 ± 1.88 months). PMID:27144015

  7. 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

  8. Experimental Contact Lens to Prevent Glaucoma-Induced Blindness

    MedlinePlus

    ... Articles | Inside Life Science Home Page An Experimental Contact Lens to Prevent Glaucoma-Induced Blindness By Sharon Reynolds Posted January 23, 2014 An experimental contact lens design releases a glaucoma medicine at a ...

  9. Effects of bevacizumab loaded PEG-PCL-PEG hydrogel intracameral application on intraocular pressure after glaucoma filtration surgery.

    PubMed

    Han, Qian; Wang, Yuqi; Li, Xiabin; Peng, Ribo; Li, Ailing; Qian, Zhiyong; Yu, Ling

    2015-08-01

    PEG-PCL-PEG (PECE) hydrogel for intracameral injection as a sustained delivery system can get a stable release of the medication and achieve an effective local concentration. The injectable PECE hydrogel is thermosensitive nano-material which is flowing sol at low temperature and can shift to nonflowing gel at body temperature. This study evaluated the intracameral injection of bevacizumab combined with a PECE hydrogel drug release system on postoperative scarring and bleb survival after experimental glaucoma filtration surgery. The best result was achieved in the bevacizumab loaded PECE hydrogels group, which presented the lowest IOP values after surgery. And the blebs were significantly more persistent in this group. Histology, Massion trichrome staining and immunohistochemistry further demonstrated that glaucoma filtration surgery in combination with bevacizumab loaded PECE hydrogel resulted in good bleb survival due to scar formation inhibition. In conclusions, this study demonstrated that bevacizumab-loaded PECE hydrogel for intracameral injection as a sustained delivery system provide a great opportunity to increase the therapeutic efficacy of glaucoma filtration surgery. PMID:26286760

  10. Glaucoma

    MedlinePlus

    ... version of this page please turn Javascript on. Glaucoma What is Glaucoma? Glaucoma is a group of diseases that can ... is much greater for people over 60. How Glaucoma Develops There are several different types of glaucoma. ...

  11. Experimentally Induced Mammalian Models of Glaucoma

    PubMed Central

    Yoshitomi, Takeshi; Zorumski, Charles F.; Izumi, Yukitoshi

    2015-01-01

    A wide variety of animal models have been used to study glaucoma. Although these models provide valuable information about the disease, there is still no ideal model for studying glaucoma due to its complex pathogenesis. Animal models for glaucoma are pivotal for clarifying glaucoma etiology and for developing novel therapeutic strategies to halt disease progression. In this review paper, we summarize some of the major findings obtained in various glaucoma models and examine the strengths and limitations of these models. PMID:26064891

  12. Topical minoxidil for glaucoma filtration surgery in the rabbit.

    PubMed

    Sharir, M

    1994-12-01

    Studies evaluated the effect of topical minoxidil on the proliferation of limbal fibroblasts in rabbits following filtration surgery. New Zealand white rabbits underwent unguarded trabeculectomies in a masked, randomized, paired-design prospective study. Rabbits were treated topically every 3 hr around the clock for 1, 2 or 4 days post-operatively, with one drop of a 50-microliters solution containing either 20, 40 or 120 nM minoxidil or the vehicle alone. Another group of animals continued to receive 120 nM minoxidil topically every 8 hr for up to 10 days. Intraocular pressure (IOP), bleb appearance, signs of ocular toxicity and anterior chamber reaction were monitored. Animals were killed and tissues immediately surrounding the trabeculectomy ostium were removed and processed for vimentin detection by immunohistochemistry. Minoxidil, in 20 and 40 nM concentrations, did not induce a significant IOP reduction, nor prolonged bleb survival at any time point, and the changes in fibroblast counts between treated and control eyes were insignificant (P > 0.05). Fibroblast counts in the 120 mM minoxidil-treated eyes were significantly reduced by 42.6% within 24 hr compared to control (P < 0.001). This inhibitory effect remained for at least 2 days after surgery (P < 0.05), the critical period for scar formation. The blebs in this group remained consistently higher than in any other group, and some blebs survived for up to 8 days after surgery. IOP remained below preoperative level for at least 6 days in 50% of the eyes treated with 120 mM minoxidil (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7698263

  13. Optical coherence tomographic assessment of retinal nerve fiber layer thickness changes before and after glaucoma filtration surgery

    PubMed Central

    Sarkar, Kumaresh Chandra; Das, Palash; Pal, Ranabir; Shaw, Chattaranjan

    2014-01-01

    Background: Glaucomatous Optic Neuropathy (GON) is very common in the glaucoma patients, and impaired effect of glaucoma is measured by the Retinal Nerve Fiber Layer (RNFL) thickness. Objective: The study was conducted to find out the mean RNFL thickness, RNFL thickness in different quadrants, Intra-Ocular Pressure (IOP) changes, and visual field changes after filtration surgery in different ages and genders using Optical Coherence Tomography (OCT). Materials and Methods: The study was an interventional case-series conducted at the Glaucoma Clinic at the Regional Institute of Ophthalmology at Kolkata from March 2009 to August 2010. Fifty-one eyes of 43 open angle glaucoma patients had been selected for clinical and ophthalmologic evaluation. All the eyes of glaucoma patients who fulfilled the inclusion criteria were registered in the study population. The glaucoma filtration surgery was done in these patients. The RNFL thickness, IOP, visual field changes were measured before and after intervention of filtration surgery. Pre-operative OCT images of RNFL were obtained 0 to 120 days before surgery, and post-operative images were obtained from 60 to 120 days after surgery. Data collected in a standard data collection form included schedule. Results: Paired t-test was used. RNFL thickness was (pre-operative: 52.56 ± 17.40, post-operative: 58.48 ± 20.20, P < 0.0001) significantly increased after filtration surgery measured by OCT with significant reduction of IOP (r = - 0.38, P = 0.005) irrespective of age and gender. Conclusions: An increase in RNFL thickness was observed after glaucoma filtration surgery that correlated with IOP reduction. PMID:24799793

  14. Glaucoma.

    PubMed

    Gupta, Divakar; Chen, Philip P

    2016-04-15

    Glaucoma is a set of irreversible, progressive optic neuropathies that can lead to severe visual field loss and blindness. The two most common forms of glaucoma, primary open-angle glaucoma and primary angle-closure glaucoma, affect more than 2 million Americans and are increasing in prevalence. Many patients with glaucoma are asymptomatic and do not know they have the disease. Risk factors for primary open-angle glaucoma include older age, black race, Hispanic origin, family history of glaucoma, and diabetes mellitus. Risk factors for primary angle-closure glaucoma include older age, Asian descent, and female sex. Advanced disease at initial presentation and treatment nonadherence put patients with glaucoma at risk of disease progression to blindness. The U.S. Preventive Services Task Force has concluded that the evidence is insufficient to assess the potential benefits and harms of screening for glaucoma in the primary care setting. Regular eye examinations for adults are recommended by the American Academy of Ophthalmology, with the interval depending on patient age and risk factors. Diagnosis of glaucoma requires careful optic nerve evaluation and functional studies assessing a patient's visual field. The goal of treatment with eye drops, laser therapy, or surgery is to slow visual field loss by lowering intraocular pressure. Family physicians can contribute to lowering morbidity from glaucoma through early identification of high-risk patients and by emphasizing treatment adherence in patients with glaucoma. PMID:27175839

  15. Scleral fibroblast response to experimental glaucoma in mice

    PubMed Central

    Tezel, Gülgün; Cone-Kimball, Elizabeth; Steinhart, Matthew R.; Jefferys, Joan; Pease, Mary E.; Quigley, Harry A.

    2016-01-01

    Purpose To study the detailed cellular and molecular changes in the mouse sclera subjected to experimental glaucoma. Methods Three strains of mice underwent experimental bead-injection glaucoma and were euthanized at 3 days and 1, 3, and 6 weeks. Scleral protein expression was analyzed with liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) using 16O/18O labeling for quantification in 1- and 6-week tissues. Sclera protein samples were also analyzed with immunoblotting with specific antibodies to selected proteins. The proportion of proliferating scleral fibroblasts was quantified with Ki67 and 4’,6-diamidino-2-phenylindole (DAPI) labeling, and selected proteins were studied with immunohistochemistry. Results Proteomic analysis showed increases in molecules involved in integrin-linked kinase signaling and actin cytoskeleton signaling pathways at 1 and 6 weeks after experimental glaucoma. The peripapillary scleral region had more fibroblasts than equatorial sclera (p=0.001, n=217, multivariable regression models). There was a sixfold increase in proliferating fibroblasts in the experimental glaucoma sclera at 1 week and a threefold rise at 3 and 6 weeks (p=0.0005, univariate regression). Immunoblots confirmed increases for myosin, spectrin, and actinin at 1 week after glaucoma. Thrombospondin-1 (TSP-1), HINT1, vimentin, actinin, and α-smooth muscle actin were increased according to immunohistochemistry. Conclusions Scleral fibroblasts in experimental mouse glaucoma show increases in actin cytoskeleton and integrin-related signaling, increases in cell division, and features compatible with myofibroblast transition. PMID:26900327

  16. Glaucoma

    MedlinePlus

    ... vision Nausea and vomiting Rainbow-like halos around lights Red eye Eye feels swollen CONGENITAL GLAUCOMA Symptoms are most ... Enlargement of 1 eye or both eyes Red eye Sensitivity to light Tearing SECONDARY GLAUCOMA Symptoms are most often related ...

  17. Glaucoma

    MedlinePlus

    Glaucoma is a group of diseases that can damage the eye's optic nerve. It is a leading ... no symptoms at first. Without treatment, people with glaucoma will slowly lose their peripheral, or side vision. ...

  18. Management of hypotony and flat anterior chamber associated with glaucoma filtration surgery

    PubMed Central

    Tunç, Yavuz; Tetikoglu, Mehmet; Kara, Necip; Sagdık, Haci Murat; Özarpaci, Selahattin; Elçioğlu, Mustafa Nuri

    2015-01-01

    AIM To determine the effectiveness of pharmacological and interventional treatment of hypotony and flat anterior chamber (FAC) resulting from glaucoma filtration surgery. METHODS We retrospectively examined the medical records of fifty-two trabeculectomy patients (52 eyes) who developed postoperative hypotony and FAC. The management and associated complications of hypotony, changing intraocular pressure (IOP) and best corrected visual acuity (BCVA) were evaluated. RESULT Of the 52 patients with hypotony, 29 (56%) had a grade 1 FAC, 21 (40%) had a grade 2 FAC, and only 2 had a grade 3 FAC. There was no significant difference between the mean preoperative IOP and the mean IOP at three and six months after surgery. Thirteen eyes (25%) required antiglaucomatous medication three months after surgery. The mean BCVA at 6mo after surgery was significantly reduced as compared with the mean preoperative BCVA. CONCLUSION Hypotonia and FAC following trabeculectomy are associated with troublesome complications that require pharmacological and/or surgical treatment. Thus, close follow-up is essential for affected patients. PMID:26558207

  19. Glaucoma

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    ... Funding Division of Extramural Activities Division of Extramural Science Programs Funding Opportunity Announcements Funding Mechanisms Supported by ... Amaurosis Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Glaucoma NEI ...

  20. Glaucoma

    PubMed Central

    2009-01-01

    Introduction Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure, but 40% of people with glaucoma have normal intraocular pressure and only 10% of people with raised intraocular pressure are at risk of optic-nerve damage. Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people than in white populations. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for established primary open-angle glaucoma, ocular hypertension, or both? What are the effects of lowering intraocular pressure in people with normal-tension glaucoma? What are the effects of treatment for acute angle-closure glaucoma? We searched: Medline, Embase, The Cochrane Library, and other important databases up to November 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 20 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: laser trabeculoplasty (alone or plus topical medical treatment); topical medical treatments; and surgical trabeculectomy.

  1. Glaucoma

    PubMed Central

    2011-01-01

    Introduction Glaucoma is characterised by progressive optic neuropathy and peripheral visual field loss. It affects 1% to 2% of white people aged over 40 years and accounts for 8% of new blind registrations in the UK. The main risk factor for glaucoma is raised intraocular pressure, but 40% of people with glaucoma have normal intraocular pressure and only 10% of people with raised intraocular pressure are at risk of optic-nerve damage. Glaucoma is more prevalent, presents earlier, and is more difficult to control in black people than in white populations. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for established primary open-angle glaucoma, ocular hypertension, or both? What are the effects of lowering intraocular pressure in people with normal-tension glaucoma? What are the effects of treatment for acute angle-closure glaucoma? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 12 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: laser trabeculoplasty (alone or plus topical medical treatment), topical medical treatments, and surgical trabeculectomy. PMID:21658300

  2. Anti-proliferation effects of Sirolimus sustained delivery film in rabbit glaucoma filtration surgery

    PubMed Central

    Yan, Zhi-chao; Bai, Yu-jing; Tian, Zhen; Hu, Hai-yan; You, Xiu-hua; Lin, Jian-xian; Liu, Shao-rui; Zhuo, Ye-hong

    2011-01-01

    Purpose To investigate the efficacy, safety, and mechanisms of Sirolimus sustained delivery film on prevention of scar formation in a rabbit model of glaucoma filtration surgery. Methods Sixty-four New Zealand white rabbits who underwent trabeculectomy in the right eye were randomly allocated to one of the four treatment regimens: Sirolimus sustained delivery film treatment group (Group A), or drug-free film treatment group (Group B), or 30 ng/ml Sirolimus-soaked sponge treatment group (Group C), or no adjunctive treatment group (Group D), and each group consists of 16 rabbits. Intraocular pressure (IOP), morphologic changes of bleb, anterior chamber flare, and corneal endothelial cell count and complications were evaluated over a 28-day period follow-up time. Aqueous humor samples were gathered from Group A, and the concentration of Sirolimus was measured regularly post-operation. Rabbits were sacrificed on the 7th, 14th, and 28th day post-operation separately, and the fibroblast hypertrophy, infiltration of inflammatory, and proliferation of new collagen fiber formation in each group were evaluated with HE and Masson staining. Proliferative cell nuclear antigen (PCNA) and fibroblast apoptosis were evaluated by immunohistochemistry and terminal deoxynucleotidyl transferasemediated dUTP nick end labeling (TUNEL) assay at the 28th day post-operation. Results Both Sirolimus sustained delivery film (Group A) and Sirolimus alone (Group C) were well tolerated in this model, and significantly prolonged bleb survival compared with no drug treatment group (Group B and D; p<0.001). Group A had the longest bleb survival time in comparison with other groups (p<0.001). There were significant differences in IOP readings between Group A and other groups at the last follow-up (p<0.05). The concentration of Group A maintained stable for over 2 weeks, drops from (10.56 ±0.05) ng/ml at day 3 to (7.74 ±0.05) ng/ml at day 14. The number of corneal endothelial cells of Group A was

  3. Changes in Scleral Collagen Organization in Murine Chronic Experimental Glaucoma

    PubMed Central

    Pijanka, Jacek K.; Kimball, Elizabeth C.; Pease, Mary E.; Abass, Ahmed; Sorensen, Thomas; Nguyen, Thao D.; Quigley, Harry A.; Boote, Craig

    2014-01-01

    Purpose. The organization of scleral collagen helps to determine the eye's biomechanical response to intraocular pressure (IOP), and may therefore be important in glaucoma. This study provides a quantitative assessment of changes in scleral collagen fibril organization in bead-induced murine experimental glaucoma. Methods. Wide-angle X-ray scattering was used to study the effect of bead-induced glaucoma on posterior scleral collagen organization in one eye of 12 CD1 mice, with untreated fellow eyes serving as controls. Three collagen parameters were measured: the local preferred fibril directions, the degree of collagen anisotropy, and the total fibrillar collagen content. Results. The mouse sclera featured a largely circumferential orientation of fibrillar collagen with respect to the optic nerve head canal. Localized alteration to fibril orientations was evident in the inferior peripapillary sclera of bead-treated eyes. Collagen anisotropy was significantly (P < 0.05) reduced in bead-treated eyes in the superior peripapillary (Treated: 43 ± 8%; Control: 49 ± 6%) and midposterior (Treated: 39 ± 4%; Control: 43 ± 4%) sclera, and in the peripapillary region overall (Treated: 43 ± 6%; Control: 47 ± 3%). No significant differences in total collagen content were found between groups. Conclusions. Spatial changes in collagen fibril anisotropy occur in the posterior sclera of mice with bead-induced chronic IOP elevation and axonal damage. These results support the idea that dynamic changes in scleral form and structure play a role in the development of experimental glaucoma in mice, and potentially in human glaucoma. PMID:25228540

  4. A comparative study of the safety and efficacy effect of 5-fluorouracil or mitomycin C mounted biological delivery membranes in a rabbit model of glaucoma filtration surgery

    PubMed Central

    Wu, Zhihong; Li, Shuning; Wang, Ningli; Liu, Wanshun; Liu, Wen

    2013-01-01

    Purpose To investigate the potential usage of biological delivery membranes containing mitomycin C (MMC) or 5-fluorouracil (5-FU) in the construction of glaucoma-filtering blebs, and to evaluate their safety and efficacy. Methods Chitosan was selected as the biological membrane carrier to prepare sustained-released membranes. Twelve micrograms of 5-FU or MMC was covalently conjugated onto the membranes by solvent volatilization. Rabbits underwent glaucoma filtration surgery and were randomly allocated into one of the four treatment regimens: glaucoma filtration operation with no implantation of chitosan membrane group (as control), drug-free chitosan membrane implantation group (blank/placebo group), membrane containing 5-FU treatment group (5-FU group), and membrane containing MMC treatment group (MMC group). Each group consisted of 12 rabbits. Intraocular pressure (IOP) was measured and evaluated over a 28-day period follow-up preoperatively, then after surgery on days 1, 3, 5, 7, 14, 21, and 28 by Tono-Pen. The aqueous humor was analyzed in each experimental and control groups at days 4, 6, 8, 10, 12, 14, 16, and 20 after operation. Bleb survival and anterior segment were examined with a slit lamp microscope and photographed simultaneously. Two rabbits from each group were killed on day 28 and eight eye samples obtained for histopathological study. Corneas and lenses were examined by transmission and scanning electron microscopy. Results Both 5-FU and MMC significantly prolonged bleb survival compared with control groups. The filtering bleb’s survival period was significantly more prolonged in the MMC and 5-FU groups (maintained 14 days) than the other two groups (maintained 7 days). Significantly lower IOP was observed within the control, blank, and 5-FU groups after surgery on day 14 compared with that before operation, with F-values of 6.567, 11.426, and 13.467, respectively (P < 0.01). The most significant lower IOP was recorded in the MMC group on day 28

  5. [Glutamate receptor-mediated retinal neuronal injury in experimental glaucoma].

    PubMed

    Wang, Zhong-Feng; Yang, Xiong-Li

    2016-08-25

    Glaucoma, the second leading cause of blindness, is a neurodegenerative disease characterized by optic nerve degeneration related to apoptotic death of retinal ganglion cells (RGCs). In the pathogenesis of RGC death following the onset of glaucoma, functional changes of glutamate receptors are commonly regarded as important risk factors. During the past several years, we have explored the mechanisms underlying RGC apoptosis and retinal Müller cell reactivation (gliosis) in a rat chronic ocular hypertension (COH) model. We demonstrated that elevated intraocular pressure in COH rats may induce changes of various signaling pathways, which are involved in RGC apoptosis by modulating glutamate NMDA and AMPA receptors. Moreover, we also demonstrated that over-activation of group I metabotropic glutamate receptors (mGluR I) by excessive extracellular glutamate in COH rats could contribute to Müller cell gliosis by suppressing Kir4.1 channels. In this review, incorporating our results, we discuss glutamate receptor- mediated RGC apoptosis and Müller cell gliosis in experimental glaucoma. PMID:27546508

  6. Bleb morphology and histology in a rabbit model of glaucoma filtration surgery using Ozurdex® or mitomycin-C

    PubMed Central

    SooHoo, Jeffrey R.; Seibold, Leonard K.; Laing, Ashley E.

    2012-01-01

    Purpose To determine the effect of a sustained-release dexamethasone implant (Ozurdex®) on wound healing after glaucoma filtration surgery in a rabbit model. Methods Twelve New Zealand white rabbits were divided into three groups: filtration surgery with intraoperative subconjunctival implantation of Ozurdex® (n=6), filtration surgery with intraoperative topical application of mitomycin-C (MMC; n=6), and filtration surgery with intraoperative topical application of balanced salt solution (BSS; n=12). A standard scale was used to grade bleb vascularity at three and six weeks after the initial operation. Bleb survival was also recorded for comparison between the three groups. Histologic analysis was performed with attention to cellularity and collagen deposition. Results MMC-treated blebs demonstrated decreased numbers of goblet cells compared to all other groups. Blebs treated with Ozurdex® maintained a near normal number of goblet cells with modest collagen deposition. The control eyes treated with only BSS had significant collagen deposition and increased cellularity compared to both the Ozurdex® and MMC groups. Bleb vascularity was not significantly different among groups at the three and six week post-operative evaluations. MMC-treated and Ozurdex®-treated blebs had significantly prolonged bleb survival compared to blebs treated with only BSS. In addition, MMC-treated blebs had significantly longer survival compared to Ozurdex®-treated blebs. Conclusions The results of this study support the utility of extended-release dexamethasone (Ozurdex®) as a wound modulating agent in a rabbit model of filtration surgery. Further animal and human studies are needed to better characterize a possible role for Ozurdex® in filtration surgery. PMID:22509101

  7. Sequential Therapy with Saratin, Bevacizumab and Ilomastat to Prolong Bleb Function following Glaucoma Filtration Surgery in a Rabbit Model

    PubMed Central

    Martorana, Gina M.; Schaefer, Jamie L.; Levine, Monica A.; Lukowski, Zachary L.; Min, Jeff; Meyers, Craig A.; Schultz, Gregory S.; Sherwood, Mark B.

    2015-01-01

    To determine if sequential treatment with Bevacizumab (Avastin), a monoclonal, VEGF antibody that blocks angiogenesis; Saratin, a 12 kD polypeptide with anti-inflammatory and anti-thrombotic properties; and Ilomastat, a matrix metalloproteinase (MMP) inhibitor, prolongs bleb life following glaucoma filtration surgery (GFS) in a rabbit model. Thirty-two New Zealand White rabbits (eight rabbits per group) underwent GFS in the left eye. Group 1 received a perioperative injection of both Saratin and Bevacizumab, and later, subconjuctival injections of Ilomastat on days 8 and 15. Group 2 received only Saratin perioperatively, and also received Ilomastat injections on days 8 and 15. Group 3, the negative control, received a single perioperative injection of Balanced Saline Solution (BSS) along with post-operative BSS injections on days 8 and 15. Group 4, the positive control, received topical treatment with Mitomycin-C (MMC) at the time of surgery with no further treatment. Blebs were evaluated by an observer masked to treatment every third day. Histology was obtained on two eyes in each group on post-op day twelve as well as all eyes following bleb failure. Eyes in group 1 had a mean bleb survival time of 29 ± 2.7 days, whereas those in group 2 that received the experimental treatment without Bevacizumab had a mean survival time of 25.5 ± 2.7 days. An ANOVA test showed that the Saratin/Ilomastat/Bevacizumab group demonstrated a significant prolongation of bleb survival compared to the BSS control—mean survival time of 19.7 ±2.7 days—(p = 0.0252) and was not significantly different from the MMC positive control group (p = 0.4238)—mean survival time of 32.5 ± 3.3. From tissue histology at day 12, the four different groups showed marked differences in the cellularity and capsule fibrosis. The MMC eyes showed minimal cellularity, were avascular and had minimal fibrous tissue. BSS group showed high cellularity, moderate to high fibrosis, and thicker and more

  8. Trabeculectomy Versus Ex-Press Glaucoma Filtration Device in Silicomacrophagocytic Open Angle Glaucoma Secondary to Silicone Oil Emulsification

    PubMed Central

    Errico, Donato; Scrimieri, Francesca Luigia; Riccardi, Roberta; Iarossi, Giancarlo

    2016-01-01

    Purpose: To compare the outcomes of Ex-PRESS device implantation versus trabeculectomy in patients with ocular hypertension after pars plana vitrectomy and silicone oil injection (SOI). Materials and Methods: Twenty-six consecutive eyes with ocular hypertension after pars plana vitrectomy and SOI were included in this study and randomized to one of two groups: A group treated with Ex-PRESS (model P50) placed under a scleral flap (Ex-PRESS group), and a group treated with trabeculectomy (trabeculectomy group). Complete success (intraocular pressure [IOP] <21 mmHg without medication) and qualified success rates (IOP <21 mmHg with one or two glaucoma medications) at 2 years postoperatively were analyzed. Between-groups comparison was performed with the Mann-Whitney U-test for continuous variables, and Fischer exact test for categorical data. Success rates between groups were compared using Kaplan-Meier life analysis and the log-rank test. P < 0.05 was considered statistically significant. Results: In the Ex-PRESS group, complete success was achieved in 73% eyes and qualified success in 81.8% of eyes. In the trabeculectomy group, complete success was achieved in 40% and qualified success was achieved in 60% of eyes. The difference in mean IOP between groups was statistically significant from the 3rd postoperative month onward (P = 0.007 at 3 months, P = 0.003 at 6 months, and P = 0.03 at 24 months). Conclusion: Ex-PRESS implantation was more effective than trabeculectomy in controlling IOP in ocular hypertensives after pars plana vitrectomy and SOI, but the surgical technique may require improvement. PMID:27162449

  9. 193-nm excimer laser sclerostomy using a modified open mask delivery system in rhesus monkeys with experimental glaucoma.

    PubMed

    Allan, B D; van Saarloos, P P; Cooper, R L; Keogh, E J; Constable, I J

    1993-11-01

    Excimer laser sclerostomy is a new glaucoma filtration procedure in which the argon fluoride excimer laser at 193 nm is delivered ab externo through a modified open mask system incorporating an en-face air jet to dry the target area and preserve hemostasis during ablation and a conjunctival plication mechanism, which allows the conjunctival and scleral wounds created by through-and-through ablation to separate once the mask is removed. No preparatory dissection of the conjunctiva is required. Five 200-microns and five 500-microns sclerostomies were formed by ablation at a pulse repetition rate of 20 Hz and a fluence per pulse of 400 mJ/cm2 in fellow eyes of five rhesus monkeys with experimental glaucoma. Overall, seven of the ten eyes attained a functional result, with intraocular pressures remaining below 21 mmHg for 6 +/- 1 days and rising to the pre-operative level after 10 +/- 3 days without adjunctive antifibroblast medication. The duration of filtration for 200-microns and 500-microns sclerostomies was similar, and parallels that previously observed for posterior lip sclerectomy in the same animal model. The three eyes with no functional result all had incorrectly positioned sclerostomies. Choroidal detachment and significant shallowing of the anterior chamber did not occur. Excimer laser sclerostomy appears to be a viable technique for filtration, provided that mask placement is accurate. PMID:8258402

  10. Changes in choroidal thickness, axial length, and ocular perfusion pressure accompanying successful glaucoma filtration surgery

    PubMed Central

    Kara, N; Baz, O; Altan, C; Satana, B; Kurt, T; Demirok, A

    2013-01-01

    Purpose To investigate the changes in choroidal thickness (CT), axial length (AL), and ocular perfusion pressure (OPP) accompanying intraocular pressure (IOP) reduction after trabeculectomy. Methods Thirty-nine eyes of 39 patients with primary open-angle glaucoma uncontrolled by medical therapy were included in this prospective and interventional study. All patients underwent a fornix-based trabeculectomy. The CT was measured by enhanced depth imaging-optical coherence tomography. IOP, AL, and systolic/diastolic blood pressure were also measured, and OPP was calculated. All measurements were performed at baseline and 1 month after surgery. Results The mean IOP was 25.0±5.8 mm Hg at baseline and 11.7±2.6 mm Hg after trabeculectomy (P<0.001), and the mean subfoveal CT was 295±84 mm Hg at baseline and 331±82 mm Hg after trabeculectomy (P<0.001). The mean AL was 23.64±0.98 mm at baseline and 23.54±0.96 mm after trabeculectomy (P<0.001), whereas the mean OPP was 38.8±6.2 mm Hg preoperatively, and 51.1±7.3 mm Hg postoperatively (P<0.001). The change in CT negatively correlated with the change in IOP (r=−0.785, P<0.001) and AL (r=−0.693, P<0.001), whereas it positively correlated with the change in OPP (r=0.418, P=0.008). Conclusion These results suggest that the large IOP decrease following trabeculectomy causes choroidal thickening. In addition, CT changes are associated with IOP and AL reduction as well as OPP increase. PMID:23743533

  11. Effect of CNTF on Retinal Ganglion Cell Survival in Experimental Glaucoma

    PubMed Central

    Pease, Mary Ellen; Zack, Donald J; Berlinicke, Cynthia; Bloom, Kristen; Cone, Frances; Wang, Yuxia; Klein, Ronald L.; Hauswirth, William W.; Quigley, Harry A.

    2009-01-01

    Purpose To assess the neuroprotective effect of virally-mediated over-expression of ciliary derived neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) in experimental rat glaucoma. Methods Laser-induced glaucoma was produced in one eye of 224 Wistar rats after injection of adeno-associated viral vectors (type 2) containing either CNTF, BDNF or both, using saline injected eyes and uninjected glaucoma eyes as controls. IOP was measured with the TonoLab and semi-automated optic nerve axon counts were performed by masked observers. IOP exposure over time was adjusted in multivariate regression analysis to calculate the effect of CNTF and BDNF. Results By multivariate regression, CNTF had a significant protective effect, with 15% less RGC axon death (p < 0.01). Both combined CNTF—BDNF and BDNF over-expression alone had no statistically significant improvement in RGC axon survival. By Western blot, there was a quantitative increase in CNTF and BDNF expression in retinas exposed to single viral vectors carrying each gene, but no increase with sequential injection of both vectors. Conclusion These data confirm that CNTF can exert a protective effect in experimental glaucoma. The reason for a lack of observed effect with the BDNF overexpression groups is unclear, but may be a function of the level of neurotrophin expression achieved. PMID:19060281

  12. [An experimental model of data base organization in glaucoma with computer processing (a preliminary note)].

    PubMed

    Bărar, A; Cristina, V; Brumaru, G; Lupşa, C; Iacob, M; Croitoru, D

    1989-01-01

    The authors report on an experimental model of data base set up for glaucoma with possibilities of statistical-mathematical processing. The application is designed for miniprocessors of the INDEPENDENT or CORAL type in FORTRAN 77. The paper presents the level structure of the display, and the ways of using the information under the form of assisted diagnosis and prognosis, according to which the attention is then directed to the rhythm and detailed content of the future examination. PMID:2529593

  13. Experimental scleral cross-linking increases glaucoma damage in a mouse model

    PubMed Central

    Kimball, Elizabeth C.; Nguyen, Cathy; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary E.; Oglesby, Ericka N.; Oveson, Brian C.; Quigley, Harry A.

    2014-01-01

    The purpose of this study was to assess the effect of a scleral cross-linking agent on susceptibility to glaucoma damage in a mouse model. CD1 mice underwent 3 subconjunctival injections of 0.5 M glyceraldehyde (GA) in 1 week, then had elevated intraocular pressure (IOP) induced by bead injection. Degree of cross-linking was measured by enzyme-linked immunosorbent assay (ELISA), scleral permeability was measured by fluorescence recovery after photobleaching (FRAP), and the mechanical effects of GA exposure were measured by inflation testing. Control mice had buffer injection or no injection in 2 separate glaucoma experiments. IOP was monitored by Tonolab and retinal ganglion cell (RGC) loss was measured by histological axon counting. To rule out undesirable effects of GA, we performed electroretinography and detailed histology of the retina. GA exposure had no detectable effects on RGC number, retinal structure or function either histologically or electrophysiologically. GA increased cross-linking of sclera by 37% in an ELISA assay, decreased scleral permeability (FRAP, p = 0.001), and produced a steeper pressure—strain behavior by in vitro inflation testing. In two experimental glaucoma experiments, GA-treated eyes had greater RGC axon loss from elevated IOP than either buffer-injected or control eyes, controlling for level of IOP exposure over time (p = 0.01, and 0.049, multivariable regression analyses). This is the first report that experimental alteration of the sclera, by cross-linking, increases susceptibility to RGC damage in mice. PMID:25285424

  14. Femtosecond laser for glaucoma treatment: the comparison between simulation and experimentation results on ocular tissue removal

    NASA Astrophysics Data System (ADS)

    Hou, Dong Xia; Ngoi, Bryan K. A.; Hoh, Sek Tien; Koh, Lee Huat K.; Deng, Yuan Zi

    2005-04-01

    In ophthalmology, the use of femtosecond lasers is receiving more attention than ever due to its extremely high intensity and ultra short pulse duration. It opens the highly beneficial possibilities for minimized side effects during surgery process, and one of the specific areas is laser surgery in glaucoma treatment. However, the sophisticated femtosecond laser-ocular tissue interaction mechanism hampers the clinical application of femtosecond laser to treat glaucoma. The potential contribution in this work lies in the fact, that this is the first time a modified moving breakdown theory is applied, which is appropriate for femtosecond time scale, to analyze femtosecond laser-ocular tissue interaction mechanism. Based on this theory, energy deposition and corresponding thermal increase are studied by both simulation and experimentation. A simulation model was developed using Matlab software, and the simulation result was validated through in-vitro laser-tissue interaction experiment using pig iris. By comparing the theoretical and experimental results, it is shown that femtosecond laser can obtain determined ocular tissue removal, and the thermal damage is evidently reduced. This result provides a promising potential for femtosecond laser in glaucoma treatment.

  15. Neuroprotective and antioxidant effects of ghrelin in an experimental glaucoma model

    PubMed Central

    Can, Nagehan; Catak, Onur; Turgut, Burak; Demir, Tamer; Ilhan, Nevin; Kuloglu, Tuncay; Ozercan, Ibrahim Hanifi

    2015-01-01

    Damage to retinal ganglion cells due to elevation of intraocular pressure (IOP) is responsible for vision loss in glaucoma. Given that loss of these cells is irreversible, neuroprotection is crucial in the treatment of glaucoma. In this study, we investigated the possible antioxidant and neuroprotective effects of ghrelin on the retina in an experimental glaucoma model. Twenty-one Sprague–Dawley rats were randomly assigned to three groups comprising seven rats each. The rats in the control group were not operated on and did not receive any treatment. In all rats in the other groups, IOP was increased by cauterization of the limbal veins. After creation of the IOP increase, saline 1 mL/kg or ghrelin 40 μg/kg was administered intraperitoneally every day for 14 days in the vehicle control group and ghrelin groups, respectively. On day 14 of the study, the eyes were enucleated. Levels of malondialdehyde (MDA), nitric oxide (NO), and nitric oxide synthase-2 (NOS2) in anterior chamber fluid were measured. The retinas were subjected to immunohistochemistry staining for glial fibrillary acidic protein (GFAP), S-100, and vimentin expression. Mean levels of MDA, NO, and NOS2 in the aqueous humor were higher in the vehicle control group than in the control group (P<0.05). Mean levels of MDA, NO, and NOS2 in the ghrelin group did not show a significant increase compared with levels in the control group (P>0.05). Retinal TUNEL and immunohistochemistry staining in the vehicle control group showed an increase in apoptosis and expression of GFAP, S-100, and vimentin compared with the control group (P<0.05). In the ghrelin group, apoptosis and expression of GFAP, S-100, and vimentin was significantly lower than in the vehicle control group (P<0.05). This study suggests that ghrelin has antioxidant and neuroprotective effects on the retina in an experimental glaucoma model. PMID:26082612

  16. Prevention of Ocular Scarring Post Glaucoma Filtration Surgery Using the Inflammatory Cell and Platelet Binding Modulator Saratin in a Rabbit Model

    PubMed Central

    Min, Jeff; Lukowski, Zachary L.; Levine, Monica A.; Meyers, Craig A.; Beattie, Ashley R.; Schultz, Gregory S.; Samuelson, Don A.; Sherwood, Mark B.

    2012-01-01

    Clinical Relevance Late complications can occur with use of current antimetabolites to prevent scarring following glaucoma filtration surgery (GFS). Safer, more targeted, anti-fibrosis agents are sought. Objectives The protein saratin has been shown to exhibit anti-fibrotic and anti-thrombotic properties in response to injury, but had not been used for glaucoma surgery. The goal of this study was to compare the efficacy of saratin with that of the widely accepted mitomycin-C (MMC) in prolonging bleb survival following GFS in the rabbit model. Two saratin delivery routes were compared; a single intraoperative topical application versus a combination of intraoperative topical application with two additional postoperative injections. Methods Twenty-four New Zealand White rabbits underwent GFS and received either intraoperative topical saratin, intraoperative topical saratin plus two injections on post-operative days 4 and 8, balanced saline solution (BSS), or MMC. The bleb tissues and their elevation durations were compared based on clinical and histological findings. Results Rabbits receiving topical+injections of saratin had a mean bleb survival of 33.6±8.5 days, significantly higher than the negative BSS controls, which averaged 17.4±6.0 days (p = 0.018). No improvement over BSS was seen for rabbits receiving topical saratin only (15.5±4.8 days, p = 0.749). Rabbits receiving saratin did not develop bleb avascularity and thinning associated with MMC treatment and there were no apparent clinical signs of toxicity. Conclusions Treatment with a single intraoperative topical application plus two additional postoperative injections significantly prolonged bleb elevation comparable to MMC, but without toxicity; however, topical application alone was ineffective. PMID:22558182

  17. Assessment of Filtration Bleb and Endplate Positioning Using Magnetic Resonance Imaging in Eyes Implanted with Long-Tube Glaucoma Drainage Devices

    PubMed Central

    Sano, Ichiya; Tanito, Masaki; Uchida, Koji; Katsube, Takashi; Kitagaki, Hajime; Ohira, Akihiro

    2015-01-01

    Background To evaluate ocular fluid filtration and endplate positioning in glaucomatous eyes with long-tube glaucoma drainage devices (GDDs) using magnetic resonance imaging (MRI) and the effects of various factors on postoperative intraocular pressure (IOP). Methods This observational case series included 27 consecutive glaucomatous eyes (18 men, 7 women; mean age ± standard error, 63.0±2.0 years) who underwent GDD implantation (n = 8 Ahmed Glaucoma Valves [AGV] and n = 19 Baerveldt Glaucoma Implants [BGI]). Tubes were inserted into the pars plana in 23 eyes and anterior chamber in 4 eyes. Six months postoperatively, high-resolution orbital images were obtained using 3-Tesla MRI with head-array coils, and the filtering bleb volume, bleb height, and distances between the anterior endplate edge and corneal center or limbus or between the endplate and orbital wall were measured. Results In MR images obtained by three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequences, the shunt endplate was identified as low-intensity signal, and the filtering bleb was identified as high-intensity signals above and below the endplate in all eyes. The 6-month-postoperative IOP level was correlated negatively with bleb volume (r = -0.4510, P = 0.0182) and bleb height (r = -0.3954, P = 0.0412). The postoperative IOP was significantly (P = 0.0026) lower in BGI-implanted eyes (12.2±0.7 mmHg) than AGV-implanted eyes (16.7±1.2 mmHg); bleb volume was significantly (P = 0.0093) larger in BGI-implanted eyes (478.8±84.2 mm3) than AGV-implanted eyes (161.1±52.3 mm3). Other parameters did not differ. Conclusions The presence of intraorbital/periocular accumulation of ocular fluid affects postoperative IOP levels in eyes implanted with long-tube GDDs. Larger filtering blebs after BGI than AGI implantations explain lower postoperative IOP levels achieved with BGI than AGV. The findings will contribute to better understanding of IOP reducing mechanism of long

  18. Losartan Treatment Protects Retinal Ganglion Cells and Alters Scleral Remodeling in Experimental Glaucoma

    PubMed Central

    Pitha, Ian F.; Nguyen, Cathy; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary Ellen; Oglesby, Ericka N.; Berlinicke, Cynthia A.; Mitchell, Katherine L.; Kim, Jessica; Jefferys, Joan J.

    2015-01-01

    Purpose To determine if oral losartan treatment decreases the retinal ganglion cell (RGC) death caused by experimental intraocular pressure (IOP) elevation in mice. Methods We produced IOP increase in CD1 mice and performed unilateral optic nerve crush. Mice received oral losartan, spironolactone, enalapril, or no drug to test effects of inhibiting angiotensin receptors. IOP was monitored by Tonolab, and blood pressure was monitored by tail cuff device. RGC loss was measured in masked axon counts and RGC bodies by β-tubulin labeling. Scleral changes that could modulate RGC injury were measured including axial length, scleral thickness, and retinal layer thicknesses, pressure-strain behavior in inflation testing, and study of angiotensin receptors and pathways by reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry. Results Losartan treatment prevented significant RGC loss (median loss = 2.5%, p = 0.13), while median loss with water, spironolactone, and enalapril treatments were 26%, 28% and 43%; p < 0.0001). The lower RGC loss with losartan was significantly less than the loss with spironolactone or enalapril (regression model p = 0.001; drug treatment group term p = 0.01). Both losartan and enalapril significantly lowered blood pressure (p< 0.001), but losartan was protective, while enalapril led to worse than water-treated RGC loss. RGC loss after crush injury was unaffected by losartan treatment (difference from control p = 0.9). Survival of RGC in cell culture was not prolonged by sartan treatment. Axonal transport blockade after 3 day IOP elevations was less in losartan-treated than in control glaucoma eyes (p = 0.007). Losartan inhibited effects of glaucoma, including reduction in extracellular signal-related kinase activity and modification of glaucoma-related changes in scleral thickness and creep under controlled IOP. Conclusions The neuroprotective effect of losartan in mouse glaucoma is associated with adaptive changes

  19. Regional Choroidal Blood Flow and Multifocal Electroretinography in Experimental Glaucoma in Rhesus Macaques

    PubMed Central

    Nork, T. Michael; Kim, Charlene B. Y.; Munsey, Kaitlyn M.; Dashek, Ryan J.; Hoeve, James N. Ver

    2014-01-01

    Purpose. To test a hypothesis of regional variation in the effect of experimental glaucoma on choroidal blood flow (ChBF) and retinal function. Methods. Five rhesus macaques underwent laser trabecular destruction (LTD) to induce elevated intraocular pressure (IOP). Intraocular pressures were elevated for 56 to 57 weeks. Multifocal electroretinographic (mfERG) and multifocal visual evoked cortical potential (mfVEP) testing were performed at regular intervals before and during the period of IOP elevation. At euthanasia, the IOP was manometrically controlled at 35 (experimentally glaucomatous eye) and 15 (fellow control eye) mm Hg. Fluorescent microspheres were injected into the left ventricle. Regional ChBF was determined. Results. All of the experimentally glaucomatous eyes exhibited supranormal first-order kernel (K1) root mean square (RMS) early portions of the mfERG waveforms and decreased amplitudes of the late waveforms. The supranormality was somewhat greater in the central macula. Second-order kernel, first slice (K2.1) RMS mfVEP response was inversely correlated (R2 = 0.97) with axonal loss. Total ChBF was reduced in the experimentally glaucomatous eyes. The mean blood flow was 893 ± 123 and 481 ± 37 μL/min in the control and glaucomatous eyes, respectively. The ChBF showed regional variability with the greatest proportional decrement most often found in the central macula. Conclusions. This is the first demonstration of globally reduced ChBF in chronic experimental glaucoma in the nonhuman primate. Both the alteration of mfERG waveform components associated with outer retinal function and the reduction in ChBF were greatest in the macula, suggesting that there may be a spatial colocalization between ChBF and some outer retinal effects in glaucoma. PMID:25370515

  20. Pressure filtration of ceramic pastes. 4: Treatment of experimental data

    NASA Technical Reports Server (NTRS)

    Torrecillas, A. S.; Polo, J. F.; Perez, A. A.

    1984-01-01

    The use of data processing method based on the algorithm proposed by Kalman and its application to the filtration process at constant pressure are described, as well as the advantages of this method. This technique is compared to the least squares method. The operation allows the precise parameter adjustment of the equation in direct relationship to the specific resistance of the cake.

  1. Modulation of morphological changes of microglia and neuroprotection by monocyte chemoattractant protein-1 in experimental glaucoma

    PubMed Central

    Chiu, Kin; Yeung, Sze-Chun; So, Kwok-Fai; Chang, Raymond Chuen-Chung

    2010-01-01

    Monocyte chemoattractant protein-1 (MCP-1)/CCL2 is a C–C chemokine involved in the activation and recruitment of monocytic cells to injury sites. MCP-1/CCL2 can induce either neuroprotection or neurodestruction in vitro, depending on the experimental model. We aim to use MCP-1/CCL2 as an experimental tool to investigate the morphological changes of microglia when loss of healthy retinal ganglion cells (RGCs) is exacerbated or attenuated in an experimental glaucoma model. While a high concentration (1000 ng) of MCP-1/CCL2 and lipopolysaccharide (LPS)-exacerbated RGC loss, 100 ng MCP-1/CCL2 provided neuroprotection towards RGC. Neuroprotective MCP-1/CCL2 (100 ng) also upregulated insulin-like growth factor-1 (IGF-1) immunoreactivity in the RGCs. The neuroprotective effect of MCP-1/CCL2 was not due to the massive infiltration of microglia/macrophages. Taken together, this is the first report showing that an appropriate amount of MCP-1/CCL2 can protect RGCs in experimental glaucoma. PMID:20081877

  2. Experimental study of head loss and filtration for LOCA debris

    SciTech Connect

    Rao, D.V.; Souto, F.J.

    1996-02-01

    A series of controlled experiments were conducted to obtain head loss and filtration characteristics of debris beds formed of NUKON{trademark} fibrous fragments, and obtain data to validate the semi-theoretical head loss model developed in NUREG/CR-6224. A thermally insulated closed-loop test set-up was used to conduct experiments using beds formed of fibers only and fibers intermixed with particulate debris. A total of three particulate mixes were used to simulate the particulate debris. The head loss data were obtained for theoretical fiber bed thicknesses of 0.125 inches to 4.0 inches; approach velocities of 0.15 to 1.5 ft/s; temperatures of 75 F and 125 F; and sludge-to-fiber nominal concentration ratios of 0 to 60. Concentration measurements obtained during the first flushing cycle were used to estimate the filtration efficiencies of the debris beds. For test conditions where the beds are fairly uniform, the head loss data were predictable within an acceptable accuracy range by the semi-theoretical model. The model was equally applicable for both pure fiber beds and the mixed beds. Typically the model over-predicted the head losses for very thin beds and for thin beds at high sludge-to-fiber mass ratios. This is attributable to the non-uniformity of such debris beds. In this range the correlation can be interpreted to provide upper bound estimates of head loss. This is pertinent for loss of coolant accidents in boiling water reactors.

  3. [The refractory glaucomas].

    PubMed

    Valtot, F

    2003-10-01

    Refractory types of glaucoma continue to present a therapeutic challenge to ophthalmologists. Approaches toward the management of these difficult glaucomas are addressed in this paper. The first part devotes special attention to understand the cause(s) of the failure of previous filtering surgery(ies). The next part emphasizes filtration surgery with intraoperative application of antimetabolites: 5-fluorouracil or mitomycin C and the surgical and pharmacological management of failing filtration. In case of failure of multiple filtering surgery with application of antimetabolites, surgeons have to consider cyclodestructive procedures (transscleral diode laser or endoscopic cyclophotocoagulation) to reduce aqueous production, or fistulizing procedures with tube implants or other drainage devices (valves). PMID:14646834

  4. 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

  5. Size exclusion deep bed filtration: Experimental and modelling uncertainties

    SciTech Connect

    Badalyan, Alexander You, Zhenjiang; Aji, Kaiser; Bedrikovetsky, Pavel; Carageorgos, Themis; Zeinijahromi, Abbas

    2014-01-15

    A detailed uncertainty analysis associated with carboxyl-modified latex particle capture in glass bead-formed porous media enabled verification of the two theoretical stochastic models for prediction of particle retention due to size exclusion. At the beginning of this analysis it is established that size exclusion is a dominant particle capture mechanism in the present study: calculated significant repulsive Derjaguin-Landau-Verwey-Overbeek potential between latex particles and glass beads is an indication of their mutual repulsion, thus, fulfilling the necessary condition for size exclusion. Applying linear uncertainty propagation method in the form of truncated Taylor's series expansion, combined standard uncertainties (CSUs) in normalised suspended particle concentrations are calculated using CSUs in experimentally determined parameters such as: an inlet volumetric flowrate of suspension, particle number in suspensions, particle concentrations in inlet and outlet streams, particle and pore throat size distributions. Weathering of glass beads in high alkaline solutions does not appreciably change particle size distribution, and, therefore, is not considered as an additional contributor to the weighted mean particle radius and corresponded weighted mean standard deviation. Weighted mean particle radius and LogNormal mean pore throat radius are characterised by the highest CSUs among all experimental parameters translating to high CSU in the jamming ratio factor (dimensionless particle size). Normalised suspended particle concentrations calculated via two theoretical models are characterised by higher CSUs than those for experimental data. The model accounting the fraction of inaccessible flow as a function of latex particle radius excellently predicts normalised suspended particle concentrations for the whole range of jamming ratios. The presented uncertainty analysis can be also used for comparison of intra- and inter-laboratory particle size exclusion data.

  6. Comparison of Modeling and Experimental Approaches for Improved Modeling of Filtration in Granular and Consolidated Media

    NASA Astrophysics Data System (ADS)

    Mirabolghasemi, M.; Prodanovic, M.; DiCarlo, D. A.

    2014-12-01

    Filtration is relevant to many disciplines from colloid transport in environmental engineering to formation damage in petroleum engineering. In this study we compare the results of the novel numerical modeling of filtration phenomenon on pore scale with the complementary experimental observations on laboratory scale and discuss how the results of comparison can be used to improve macroscale filtration models for different porous media. The water suspension contained glass beads of 200 micron diameter and flows through a packing of 1mm diameter glass beads, and thus the main filtration mechanism is straining and jamming of particles. The numerical model simulates the flow of suspension through a realistic 3D structure of an imaged, disordered sphere pack, which acts as the filter medium. Particle capture through size exclusion and jamming is modeled via a coupled Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) approach. The coupled CFD-DEM approach is capable of modeling the majority of particle-particle, particle-wall, and particle-fluid interactions. Note that most of traditional approaches require spherical particles both in suspension and the filtration medium. We adapted the interface between the pore space and the spherical grains to be represented as a triangulated surface and this allows extensions to any imaged media. The numerical and experimental results show that the filtration coefficient of the sphere pack is a function of the flow rate and concentration of the suspension, even for constant total particle flow rate. An increase in the suspension flow rate results in a decrease in the filtration coefficient, which suggests that the hydrodynamic drag force plays the key role in hindering the particle capture in random sphere packs. Further, similar simulations of suspension flow through a sandstone sample, which has a tighter pore space, show that filtration coefficient remains almost constant at different suspension flow rates. This

  7. Cataract Surgery in the Glaucoma Patient

    PubMed Central

    Kung, Jennifer S.; Choi, Daniel Y.; Cheema, Anjum S.; Singh, Kuldev

    2015-01-01

    To summarize the role of cataract surgery in the glaucoma patient, in terms of the effect on intraocular pressure (IOP) as well as diagnostic and therapeutic considerations for those with both conditions. Recent evidence suggests that cataract extraction may produce a significant and sustained IOP reduction in individuals with open-angle glaucoma, ocular hypertension, and angle-closure glaucoma. Cataract removal may improve the practitioner's ability to interpret perimetric testing, and re-establishing perimetric and optic nerve imaging baselines is recommended after cataract surgery. The sequence of cataract surgery relative to glaucoma surgery impacts the likelihood of complications and surgical success. There are multiple benefits to perform cataract surgery prior to glaucoma surgery while cataract surgery after trabeculectomy increases the risk of subsequent filtration failure. As “minimally invasive glaucoma surgeries” continue to improve in terms of efficacy, there is an evolving role for combined cataract and glaucoma surgery in patients with early to moderate stages of glaucoma. PMID:25624668

  8. Longitudinal Hemodynamic Changes Within the Optic Nerve Head in Experimental Glaucoma

    PubMed Central

    Cull, Grant; Burgoyne, Claude F.; Fortune, Brad; Wang, Lin

    2013-01-01

    Purpose. To characterize longitudinal changes in basal blood flow (BF) of the optic nerve head (ONH) during progression of structural damage in experimental glaucoma (EG). Methods. Unilateral elevation of IOP was induced in 15 adult rhesus macaques by laser treatment to the trabecular meshwork. Prior to and after laser, retinal nerve fiber layer thickness (RNFLT) and ONH BF were measured biweekly by spectral-domain optical coherence tomography and a laser speckle flowgraphy device (LSFG), respectively. Results. Average postlaser IOP was 20.2 ± 5.9 mm Hg in EG eyes and 12.3 ± 2.6 mm Hg in control eyes (P < 0.0001). Longitudinal changes in basal ONH BF were strongly associated with changes in RNFLT as EG progressed from early through moderately advanced stages of damage, with Pearson correlation coefficients ranging from 0.64 to 0.97 (average = 0.81) and an average slope of 1.0. During early stage (RNFLT loss < 10%), basal ONH BF was mildly increased (9% ± 10%, P = 0.004) relative to baseline and compared with fellow controls (P = 0.02). Basal ONH BF declined continuously throughout subsequent stages in EG eyes reaching 25.0% ± 9.6% (P < 0.0001) below baseline at the final stage studied (RNFLT loss > 40%). In fellow control eyes, there was no significant change in basal ONH BF over time (P = 0.27). Conclusions. In EG based on chronic mild-to-moderate IOP elevation, a two-phase pattern of ONH BF alteration was observed. ONH BF increased during the earliest stage (while RNFLT was within 10% of baseline) followed by a linear decline that was strongly correlated with loss of RNFLT. PMID:23737471

  9. Longitudinal Alterations in the Dynamic Autoregulation of Optic Nerve Head Blood Flow Revealed in Experimental Glaucoma

    PubMed Central

    Wang, Lin; Cull, Grant; Burgoyne, Claude F.; Thompson, Simon; Fortune, Brad

    2014-01-01

    Purpose. To use a novel dynamic autoregulation analysis (dAR) to test the hypothesis that the optic nerve head (ONH) blood flow (BF) autoregulation is disrupted during early stages of experimental glaucoma (EG) in nonhuman primates. Methods. Retinal nerve fiber layer thickness (RNFLT, assessed by optical coherence tomography) and ONH BF (assessed by laser speckle imaging technique) were measured biweekly before and after unilateral laser treatment to the trabecular meshwork. Each nonhuman primate was followed until reaching either an early stage of damage (RNFLT loss < 20%, n = 6) or moderate to advanced stages of damage (RNFLT loss > 20%, n = 9). At each test, dAR was assessed by characterizing ONH BF changes during the first minute of rapid manometrical intraocular pressure (IOP) elevation from 10 to 40 mm Hg. The dAR analysis extracted the following parameters: baseline BF, average BF 10 seconds before IOP elevation; BFΔmax, maximum BF change from baseline BF; Tr, time from baseline BF to the BFΔmax; Kr, average descending BF rate. Results. Mean postlaser IOP was 20.2 ± 5.9 and 12.3 ± 2.6 mm Hg in EG and control eyes, respectively (P < 0.0001). Compared with prelaser values, baseline BF was higher in early EG, but lower in moderate to advanced EG (P = 0.01). Tr was increased and Kr was reduced in both stages (P < 0.01). BFΔmax was smaller in the early EG (P = 0.05) and remained low in the moderate to advanced EG (P = 0.15). No changes in the parameters were observed in control eyes. Conclusions. Chronic IOP elevation causes ONH autoregulation dysfunction in the early stage of EG, characterized by a disrupted BF response and delayed Tr, revealed by dAR analysis. PMID:24812551

  10. Static Blood Flow Autoregulation in the Optic Nerve Head in Normal and Experimental Glaucoma

    PubMed Central

    Wang, Lin; Burgoyne, Claude F.; Cull, Grant; Thompson, Simon; Fortune, Brad

    2014-01-01

    Purpose. To characterize the static blood flow autoregulation in the optic nerve head (ONH), and to investigate its role in hemodynamic changes in experimental glaucoma (EG). Methods. Unilateral elevation of intraocular pressure (IOP) was induced in 15 adult rhesus macaques by laser treatment to the trabecular meshwork. Prior to and after laser treatment, retinal nerve fiber layer thickness (RNFLT) was assessed, biweekly, by spectral-domain optical coherence tomography. Optic nerve head static autoregulation was assessed by determining the percentage blood flow (BF) change after the IOP was acutely increased from 10 to 30, 40, or 50 mm Hg manometrically, utilizing a laser speckle flowgraphy device. Results. Postlaser IOP (measured during average 7.7 ± 2.6 months) was 20.2 ± 5.9 mm Hg in EG eyes and 12.3 ± 2.6 mm Hg in control eyes (P < 0.0001). Retinal nerve fiber layer thickness was reduced by 33 ± 22% of the baseline values (P < 0.001) on average in EG eyes and by 0.4 ± 2.3% in control eyes (P > 0.05). The ONH BF remained at a constant level within a range of ocular perfusion pressure (OPP), 41 mm Hg and above. The autoregulation curves, created by all 723 tests in control and 352 tests in EG, were not significantly different (P = 0.71). Conclusions. Optic nerve head BF in normal nonhuman primate (NHP) eyes is effectively regulated within a range of OPP approximately 41 mm Hg and above. Chronic IOP elevation causes no remarkable change to the static autoregulation within the ONH of EG eyes. PMID:24436190

  11. β-III-Tubulin: a reliable marker for retinal ganglion cell labeling in experimental models of glaucoma

    PubMed Central

    Jiang, Shan-Ming; Zeng, Li-Ping; Zeng, Ji-Hong; Tang, Li; Chen, Xiao-Ming; Wei, Xin

    2015-01-01

    AIM To evaluate the reliability of β-III-Tubulin protein as a retinal ganglion cell (RGC) marker in the experimental glaucoma model. METHODS Glaucoma mouse models were established by injecting polystyrene microbeads into the anterior chamber of C57BL/6J mice, then their retinas were obtained 14d and 28d after the intraocular pressure (IOP) was elevated. Retinal flat mounts and sections were double-labeled by fluorogold (FG) and β-III-Tubulin antibody or single-labeled by β-III-Tubulin antibody, then RGCs were counted and compared respectively. RESULTS IOP of the injected eyes were elevated significantly and reached the peak at 22.8±0.7 mm Hg by day 14 after injection, then dropped to 11.3±0.7 mm Hg by day 28. RGC numbers counted by FG labeling and β-III-Tubulin antibody labeling were 64 807±4930 and 64614±5054 respectively in the control group, with no significant difference. By day 14, RGCs in the experimental group decreased significantly compared to the control group, but there was no significant difference between the FG labeling counting and the β-III-Tubulin antibody labeling counting either in the experimental group or in the control group. The result was similar by day 28, with further RGC loss. CONCLUSION Our result suggested that the β-III-Tubulin protein was not affected by IOP elevation and can be used as a reliable marker for RGC in experimental models of glaucoma. PMID:26309856

  12. Glaucoma (image)

    MedlinePlus

    Glaucoma is a condition of increased fluid pressure inside the eye. The increased pressure causes compression of ... nerve which can eventually lead to nerve damage. Glaucoma can cause partial vision loss, with blindness as ...

  13. Delivery of antifibroblast agents as adjuncts to filtration surgery. Part I--Periocular clearance of cobalt-57 bleomycin in experimental drug delivery: pilot study in the rabbit

    SciTech Connect

    Kay, J.S.; Litin, B.S.; Woolfenden, J.M.; Chvapil, M.; Herschler, J.

    1986-10-01

    Antitumor and antifibroblast agents show promise as adjuncts after glaucoma filtration surgery in reducing postoperative scarring and failure. We used nuclear imaging in rabbits to investigate periocular clearance of one such agent (/sup 57/Co-bleomycin). Sub-Tenon injection was compared to other delivery techniques. Our results showed that a collagen sponge and a silastic disc implant with a microhole prolonged drug delivery when compared to sub-Tenon injection alone or injection with a viscosity enhancing agent (0.5% sodium hyaluronate). We theorize that if an antifibroblast agent can be delivered in small and sustained amounts after filtration surgery, this may prolong bleb longevity and avoid unnecessary drug toxicity.

  14. Photopic negative response in diagnosis of glaucoma: an experimental study in glaucomatous rabbit model

    PubMed Central

    ElGohary, Amal A.; Elshazly, Laila Hassan M.

    2015-01-01

    AIM To determine whether the photopic negative response (PhNR) elicited by transient white flash on white background is characterizing for glaucoma model in rabbits. METHODS Glaucoma was induced in twelve rabbits by subconjunctival injection of 0.05 mL of betamethasone in right eyes (each 1 mL contain betamethasone dipropionate 5 mg and betamethasone sodium phosphate 2 mg).The intraocular pressure (IOP), electroretinogram (ERG) and visual evoked potential (VEP) were measured successively prior and on the 3, 7d, two weeks and four weeks postglaucoma induction. After four weeks, the animals were sacrificed and the globes were histopathologically examined. RESULTS The IOP increased significantly after one week (P=0.0001), then it gradually returned to the control level. In ERG examination, the means of a and b wave amplitude and latency were not affected significantly. PhNR amplitude decreased significantly within one week (P=0.0001), but its latency was not affected significantly (P=0.132). The means of VEP latency and amplitude were significantly affected after two weeks and four weeks of glaucoma induction (P=0.0001 and 0.02, respectively). The histopathologic examination of the globes showed reduced number of cells in the retinal ganglion cell layer with multiple vacuoles in the retinal nerve fibre layer.There was significant positive correlation between ganglion cell layer cells and PhNR amplitude (r=0.8, P=0.002). CONCLUSION The rise in IOP resulted in irreversible changes or incomplete recovery of VEP and PhNR amplitude. Both PhNR and VEP represented good additional tools in early diagnosis of glaucoma. PMID:26085991

  15. Efficacy and safety of memantine, an NMDA-type open-channel blocker, for reduction of retinal injury associated with experimental glaucoma in rat and monkey.

    PubMed

    Hare, W; WoldeMussie, E; Lai, R; Ton, H; Ruiz, G; Feldmann, B; Wijono, M; Chun, T; Wheeler, L

    2001-05-01

    Glutamatergic excitotoxicity has been implicated as a mechanism for injury in a variety of central nervous system pathologies, including glaucoma. Memantine, an NMDA-type glutamatergic open-channel blocker, has pharmacologic properties that make its efficacy greater under excitotoxic conditions, but lesser under normal conditions. Daily oral dosing for approximately 15 months with 4.0 mg/kg memantine in monkeys yielded plasma concentrations similar to those found in patients who received memantine treatment for Parkinson's disease. This same dose of memantine was not associated with any evidence of an effect on the normal function of the retina and central visual pathways, as indicated by measures of the electroretinogram (ERG) and visually-evoked cortical potential (VECP). Amplitude of the VECP response was reduced in eyes with experimentally induced glaucoma. When compared to vehicle-treated control animals, memantine-treated glaucoma eyes suffered significantly less reduction of VECP amplitude. Preliminary results in a rat model for experimental glaucoma also show that, when compared to control animals, systemic treatment with memantine (10 mg/kg/day) was associated with a significant reduction in glaucoma-induced loss of retinal ganglion cells. PMID:11377450

  16. Neuroprotection in Glaucoma

    PubMed Central

    Doozandeh, Azadeh; Yazdani, Shahin

    2016-01-01

    Glaucoma is a degenerative optic neuropathy characterized by retinal ganglion cell (RGC) loss and visual field defects. It is known that in some glaucoma patients, death of RGCs continues despite intraocular pressure (IOP) reduction. Neuroprotection in the field of glaucoma is defined as any treatment, independent of IOP reduction, which prevents RGC death. Glutamate antagonists, ginkgo biloba extract, neurotrophic factors, antioxidants, calcium channel blockers, brimonidine, glaucoma medications with blood regulatory effect and nitric oxide synthase inhibitors are among compounds with possible neuroprotective activity in preclinical studies. A few agents (such as brimonidine or memantine) with neuroprotective effects in experimental studies have advanced to clinical trials; however the results of clinical trials for these agents have not been conclusive. Nevertheless, lack of compelling clinical evidence has not prevented the off-label use of some of these compounds in glaucoma practice. Stem cell transplantation has been reported to halt experimental neurodegenerative disease processes in the absence of cell replacement. It has been hypothesized that transplantation of some types of stem cells activates multiple neuroprotective pathways via secretion of various factors. The advantage of this approach is a prolonged and targeted effect. Important concerns in this field include the secretion of unwanted harmful mediators, graft survival issues and tumorigenesis. Neuroprotection in glaucoma, pharmacologically or by stem cell transplantation, is an interesting subject waiting for broad and multidisciplinary collaborative studies to better clarify its role in clinical practice. PMID:27413504

  17. Neuroprotection in Glaucoma.

    PubMed

    Doozandeh, Azadeh; Yazdani, Shahin

    2016-01-01

    Glaucoma is a degenerative optic neuropathy characterized by retinal ganglion cell (RGC) loss and visual field defects. It is known that in some glaucoma patients, death of RGCs continues despite intraocular pressure (IOP) reduction. Neuroprotection in the field of glaucoma is defined as any treatment, independent of IOP reduction, which prevents RGC death. Glutamate antagonists, ginkgo biloba extract, neurotrophic factors, antioxidants, calcium channel blockers, brimonidine, glaucoma medications with blood regulatory effect and nitric oxide synthase inhibitors are among compounds with possible neuroprotective activity in preclinical studies. A few agents (such as brimonidine or memantine) with neuroprotective effects in experimental studies have advanced to clinical trials; however the results of clinical trials for these agents have not been conclusive. Nevertheless, lack of compelling clinical evidence has not prevented the off-label use of some of these compounds in glaucoma practice. Stem cell transplantation has been reported to halt experimental neurodegenerative disease processes in the absence of cell replacement. It has been hypothesized that transplantation of some types of stem cells activates multiple neuroprotective pathways via secretion of various factors. The advantage of this approach is a prolonged and targeted effect. Important concerns in this field include the secretion of unwanted harmful mediators, graft survival issues and tumorigenesis. Neuroprotection in glaucoma, pharmacologically or by stem cell transplantation, is an interesting subject waiting for broad and multidisciplinary collaborative studies to better clarify its role in clinical practice. PMID:27413504

  18. Elevated intraocular pressure decreases response sensitivity of inner retinal neurons in experimental glaucoma mice

    PubMed Central

    Pang, Ji-Jie; Frankfort, Benjamin J.; Gross, Ronald L.; Wu, Samuel M.

    2015-01-01

    Glaucoma is the second leading cause of blindness in the United States and the world, characterized by progressive degeneration of the optic nerve and retinal ganglion cells (RGCs). Glaucoma patients exhibit an early diffuse loss of retinal sensitivity followed by focal loss of RGCs in sectored patterns. Recent evidence has suggested that this early sensitivity loss may be associated with dysfunctions in the inner retina, but detailed cellular and synaptic mechanisms underlying such sensitivity changes are largely unknown. In this study, we use whole-cell voltage-clamp techniques to analyze light responses of individual bipolar cells (BCs), AII amacrine cells (AIIACs), and ON and sustained OFF alpha-ganglion cells (ONαGCs and sOFFαGCs) in dark-adapted mouse retinas with elevated intraocular pressure (IOP). We present evidence showing that elevated IOP suppresses the rod ON BC inputs to AIIACs, resulting in less sensitive AIIACs, which alter AIIAC inputs to ONαGCs via the AIIAC→cone ON BC→ONαGC pathway, resulting in lower ONαGC sensitivity. The altered AIIAC response also reduces sOFFαGC sensitivity via the AIIAC→sOFFαGC chemical synapses. These sensitivity decreases in αGCs and AIIACs were found in mice with elevated IOP for 3–7 wk, a stage when little RGC or optic nerve degeneration was observed. Our finding that elevated IOP alters neuronal function in the inner retina before irreversible structural damage occurs provides useful information for developing new diagnostic tools and treatments for glaucoma in human patients. PMID:25675503

  19. Virus-mediated EpoR76E Therapy Slows Optic Nerve Axonopathy in Experimental Glaucoma.

    PubMed

    Bond, Wesley S; Hines-Beard, Jessica; GoldenMerry, Y Paul L; Davis, Mara; Farooque, Alma; Sappington, Rebecca M; Calkins, David J; Rex, Tonia S

    2016-02-01

    Glaucoma, a common cause of blindness, is currently treated by intraocular pressure (IOP)-lowering interventions. However, this approach is insufficient to completely prevent vision loss. Here, we evaluate an IOP-independent gene therapy strategy using a modified erythropoietin, EPO-R76E, which has reduced erythropoietic function. We used two models of glaucoma, the murine microbead occlusion model and the DBA/2J mouse. Systemic recombinant adeno-associated virus-mediated gene delivery of EpoR76E (rAAV.EpoR76E) was performed concurrent with elevation of IOP. Axon structure and active anterograde transport were preserved in both models. Vision, as determined by the flash visual evoked potential, was preserved in the DBA/2J. These results show that systemic EpoR76E gene therapy protects retinal ganglion cells from glaucomatous degeneration in two different models. This suggests that EPO targets a component of the neurodegenerative pathway that is common to both models. The efficacy of rAAV.EpoR76E delivered at onset of IOP elevation supports clinical relevance of this treatment. PMID:26502777

  20. Longitudinal Detection of Optic Nerve Head Changes by Spectral Domain Optical Coherence Tomography in Early Experimental Glaucoma

    PubMed Central

    He, Lin; Yang, Hongli; Gardiner, Stuart K.; Williams, Galen; Hardin, Christy; Strouthidis, Nicholas G.; Fortune, Brad; Burgoyne, Claude F.

    2014-01-01

    Purpose. We determined if the detection of spectral-domain optical coherence tomography (SDOCT) optic nerve head (ONH) change precedes the detection of confocal scanning laser tomography (CSLT) ONH surface, SDOCT retinal nerve fiber layer (RNFL), scanning laser perimetry (SLP), and multifocal electroretinography (mfERG) change in eight experimental glaucoma (EG) eyes. Methods. Both eyes from eight monkeys were tested at least three times at baseline, and then every 2 weeks following laser-induced chronic unilateral IOP elevation. Event and trend-based definitions of onset in the control and EG eyes for 11 SDOCT neural and connective tissue, CSLT surface, SDOCT RNFL, SLP, and mfERG parameters were explored. The frequency and timing of onset for each parameter were compared using a logrank test. Results. Maximum post-laser IOP was 18 to 42 mm Hg in the EG eyes and 12 to 20 mm Hg in the control eyes. For event- and trend-based analyses, onsets were achieved earliest and most frequently within the ONH neural and connective tissues using SDOCT, and at the ONH surface using CSLT. SDOCT ONH neural and connective tissue parameter change preceded or coincided with CSLT ONH surface change in most EG eyes. The SDOCT and SLP measures of RNFL thickness, and mfERG measures of visual function demonstrated similar onset rates, but occurred later than SDOCT ONH and CSLT surface change, and in fewer eyes. Conclusions. SDOCT ONH change detection commonly precedes or coincides with CSLT ONH surface change detection, and consistently precedes RNFLT, SLP, and mfERG change detection in monkey experimental glaucoma. PMID:24255047

  1. The Connective Tissue Components of Optic Nerve Head Cupping in Monkey Experimental Glaucoma Part 1: Global Change

    PubMed Central

    Yang, Hongli; Ren, Ruojin; Lockwood, Howard; Williams, Galen; Libertiaux, Vincent; Downs, Crawford; Gardiner, Stuart K.; Burgoyne, Claude F.

    2015-01-01

    Purpose To characterize optic nerve head (ONH) connective tissue change within 21 monkey experimental glaucoma (EG) eyes, so as to identify its principal components. Methods Animals were imaged three to five times at baseline then every 2 weeks following chronic unilateral IOP elevation, and euthanized early through end-stage confocal scanning laser tomographic change. Optic nerve heads were serial-sectioned, three-dimensionally (3D) reconstructed, delineated, and quantified. Overall EG versus control eye differences were assessed by general estimating equations (GEE). Significant, animal-specific, EG eye change was required to exceed the maximum physiologic intereye differences in six healthy animals. Results Overall EG eye change was significant (P < 0.0026) and animal-specific EG eye change most frequent, for five phenomena (number of EG eyes and range of animal-specific change): posterior laminar deformation (21, −29 to −437 μm), laminar thickening (11, 20–73 μm) and thinning (3, −23 to −31 μm), scleral canal expansion (17, 20–139 μm), outward anterior (16, −16 to −124 μm) and posterior (17, −22 to −279 μm) laminar insertion migration, and peripapillary scleral bowing (11, 21–77 μm). Experimental glaucoma versus control eye laminar thickness differences were bimodal in behavior, being thickened in most EG eyes demonstrating the least deformation and less thickened or thinned in most EG eyes demonstrating the greatest deformation. Conclusions Our postmortem studies retrospectively identify five connective tissue components of ONH “cupping” in monkey EG which serve as targets for longitudinally staging and phenotyping ONH connective tissue alteration within all forms of monkey and human optic neuropathy. PMID:26641545

  2. Molecular Genetics in Glaucoma

    PubMed Central

    Liu, Yutao

    2015-01-01

    Glaucoma is a family of diseases whose pathology is defined by the progressive loss of retinal ganglion cells. Clinically, glaucoma presents as a distinctive optic neuropathy with associated visual field loss. Primary open-angle glaucoma (POAG), chronic angle closure glaucoma (ACG), and exfoliation glaucoma (XFG) are the most prevalent forms of glaucoma globally and are the most common causes of glaucoma-related blindness worldwide. A host of genetic and environmental factors contribute to glaucoma phenotypes. This review examines the current status of genetic investigations of POAG, ACG, XFG, including the less common forms of glaucoma primary congenital glaucoma (PCG), the developmental glaucomas, and pigment dispersion glaucoma. PMID:21871452

  3. Inflammatory glaucoma

    PubMed Central

    Bodh, Sonam A.; Kumar, Vasu; Raina, Usha K.; Ghosh, B.; Thakar, Meenakshi

    2011-01-01

    Glaucoma is seen in about 20% of the patients with uveitis. Anterior uveitis may be acute, subacute, or chronic. The mechanisms by which iridocyclitis leads to obstruction of aqueous outflow include acute, usually reversible forms (e.g., accumulation of inflammatory elements in the intertrabecular spaces, edema of the trabecular lamellae, or angle closure due to ciliary body swelling) and chronic forms (e.g., scar formation or membrane overgrowth in the anterior chamber angle). Careful history and follow-up helps distinguish steroid-induced glaucoma from uveitic glaucoma. Treatment of combined iridocyclitis and glaucoma involves steroidal and nonsteroidal antiinflammatory agents and antiglaucoma drugs. However, glaucoma drugs can often have an unpredictable effect on intraocular pressure (IOP) in the setting of uveitis. Surgical intervention is required in case of medical failure. Method of Literature Search: Literature on the Medline database was searched using the PubMed interface. PMID:21713239

  4. Glaucoma medications.

    PubMed

    Chae, Bora; Cakiner-Egilmez, Tulay; Desai, Manishi

    2013-01-01

    Glaucoma is a common eye condition that affects millions of individuals worldwide, making it the second-leading cause of blindness. Because glaucoma is associated with increased IOP level, the primary goal in treatment of glaucoma includes lowering IOP to prevent further progression of the disease. While various surgical interventions exist, medical therapy is currently the first line of treatment. Medical treatment of glaucoma includes topical beta-blockers, alpha-2 agonists, prostaglandins, parasympathomimetics and CAIs. Anti-glaucoma agents help reduce IOP by affecting the production of aqueous humor or increasing the outflow of aqueous through the trabecular or uveoscleral pathway. Choosing an appropriate medical regimen can be challenging and various factors such as efficacy, safety, cost and patient compliance must be considered. First-line treatment is often topical beta-blockers or prostaglandin analogs. However, beta-blocking agents can be associated with systemic side effects and need to be used cautiously in patients with serious concomitant cardiopulmonary disease. Alpha-2 agonists and parasympathomimetics are often considered second- or third-line treatment options but good adjunctive agents. Oral CAIs are often indicated for patients with elevated IOP in an acute setting or for patients resistant to other glaucoma medications and patients who are not good surgical candidates. PMID:23505792

  5. Colloid filtration in surface dense vegetation: Experimental results and theoretical predictions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding colloid and colloid-facilitated contaminant transport in overland flow through dense vegetation is essential to protect water quality for the environment. In previous studies, a single-stem efficiency theory for rigid and clean stem systems has been developed to predict colloid filtrat...

  6. The Complex Role of Neuroinflammation in Glaucoma

    PubMed Central

    Soto, Ileana; Howell, Gareth R.

    2014-01-01

    Glaucoma is a multifactorial neurodegenerative disorder affecting 80 million people worldwide. Loss of retinal ganglion cells and degeneration of their axons in the optic nerve are the major pathological hallmarks. Neuroinflammatory processes, inflammatory processes in the central nervous system, have been identified in human glaucoma and in experimental models of the disease. Furthermore, neuroinflammatory responses occur at early stages of experimental glaucoma, and inhibition of certain proinflammatory pathways appears neuroprotective. Here, we summarize the current understanding of neuroinflammation in the central nervous system, with emphasis on events at the optic nerve head during early stages of glaucoma. PMID:24993677

  7. Longitudinal Change Detected by Spectral Domain Optical Coherence Tomography in the Optic Nerve Head and Peripapillary Retina in Experimental Glaucoma

    PubMed Central

    Strouthidis, Nicholas G.; Fortune, Brad; Yang, Hongli; Sigal, Ian A.

    2011-01-01

    Purpose. To investigate whether longitudinal changes deep within the optic nerve head (ONH) are detectable by spectral domain optical coherence tomography (SDOCT) in experimental glaucoma (EG) and whether these changes are detectable at the onset of Heidelberg Retina Tomography (HRT; Heidelberg Engineering, Heidelberg, Germany)–defined surface topography depression. Methods. Longitudinal SDOCT imaging (Spectralis; Heidelberg Engineering) was performed in both eyes of nine rhesus macaques every 1 to 3 weeks. One eye of each underwent trabecular laser-induced IOP elevation. Four masked operators delineated internal limiting membrane (ILM), retinal nerve fiber layer (RNFL), Bruch's membrane/retinal pigment epithelium (BM/RPE), neural canal opening (NCO), and anterior lamina cribrosa surface (ALCS) by using custom software. Longitudinal changes were assessed and compared between the EG and control (nonlasered) eyes at the onset of HRT-detected surface depression (follow-up 1; [FU1]) and at the most recent image (follow-up 2; [FU2]). Results. Mean IOP in EG eyes was 7.1 to 24.6 mm Hg at FU1 and 13.5 to 31.9 mm Hg at FU2. In control eyes, the mean IOP was 7.2 to 12.6 mm Hg (FU1) and 8.9 to 16.0 mm Hg (FU2). At FU1, neuroretinal rim decreased and ALCS depth increased significantly (paired t-test, P < 0.01); no change in RNFL thickness was detected. At FU2, however, significant prelaminar tissue thinning, posterior displacement of NCO, and RNFL thinning were observed. Conclusions. Longitudinal SDOCT imaging can detect deep ONH changes in EG eyes, the earliest of which are present at the onset of HRT-detected ONH surface height depression. These parameters represent realistic targets for SDOCT detection of glaucomatous progression in human subjects. PMID:21217108

  8. Glaucoma, Open-Angle

    MedlinePlus

    ... Prevalent Cases of Glaucoma (in thousands) by Age, Gender, and Race/Ethnicity Because of their longer life ... Prevalent Cases of Glaucoma (in thousands) by Age, Gender, and Race/Ethnicity Projections for Glaucoma (2010-2030- ...

  9. 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. ...

  10. [Glaucoma medications, preservatives and the ocular surface.

    PubMed

    Aptel, F; Labbé, A; Baudouin, C; Bron, A; Lachkar, Y; Sellem, E; Renard, J-P; Nordmann, J-P; Rouland, J-F; Denis, P

    2014-10-14

    Several clinical and experimental studies have demonstrated that ocular surface disease is common in glaucoma patients receiving chronic glaucoma drops, and that the preservatives in these drops play a major role in the occurrence of ocular surface disease. These ocular surface changes may induce both symptoms reported by the patients and anterior segment clinical signs, and should be systematically assessed by history and exam in all glaucoma patients. In these patients with ocular surface disease, reducing the amount of preservatives administered to the eye should be strived for, rather than adding additional eye drops to alleviate or mask the side effects of the glaucoma drops. PMID:25440185

  11. Neuroprotection in glaucoma

    PubMed Central

    Vasudevan, Sushil K; Gupta, Viney; Crowston, Jonathan G

    2011-01-01

    Glaucoma is a neurodegenerative disease characterized by loss of retinal ganglion cells and their axons. Recent evidence suggests that intraocular pressure (IOP) is only one of the many risk factors for this disease. Current treatment options for this disease have been limited to the reduction of IOP; however, it is clear now that the disease progression continues in many patients despite effective lowering of IOP. In the search for newer modalities in treating this disease, much data have emerged from experimental research the world over, suggesting various pathological processes involved in this disease and newer possible strategies to treat it. This review article looks into the current understanding of the pathophysiology of glaucoma, the importance of neuroprotection, the various possible pharmacological approaches for neuroprotection and evidence of current available medications. PMID:21150020

  12. Experimental Glaucoma Causes Optic Nerve Head Neural Rim Tissue Compression: A Potentially Important Mechanism of Axon Injury

    PubMed Central

    Fortune, Brad; Reynaud, Juan; Hardin, Christy; Wang, Lin; Sigal, Ian A.; Burgoyne, Claude F.

    2016-01-01

    Purpose We tested the hypothesis that experimental glaucoma (EG) results in greater thinning of the optic nerve head (ONH) neural rim tissue than the peripapillary retinal nerve fiber layer (RNFL) tissue. Methods Longitudinal spectral-domain optical coherence tomography (SDOCT) imaging of the ONH and peripapillary RNFL was performed every other week under manometric IOP control (10 mm Hg) in 51 nonhuman primates (NHP) during baseline and after induction of unilateral EG. The ONH parameter minimum rim area (MRA) was derived from 80 radial B-scans centered on the ONH; RNFL cross-sectional area (RNFLA) from a peripapillary circular B-scan with 12° diameter. Results In control eyes, MRA was 1.00 ± 0.19 mm2 at baseline and 1.00 ± 0.19 mm2 at the final session (P = 0.77), while RNFLA was 0.95 ± 0.09 and 0.95 ± 0.10 mm2, respectively (P = 0.96). In EG eyes, MRA decreased from 1.00 ± 0.19 mm2 at baseline to 0.63 ± 0.21 mm2 at the final session (P < 0.0001), while RNFLA decreased from 0.95 ± 0.09 to 0.74 ± 0.19 mm2, respectively (P < 0.0001). Thus, MRA decreased by 36.4 ± 20.6% in EG eyes, significantly more than the decrease in RNFLA (21.7 ± 19.4%, P < 0.0001). Other significant changes in EG eyes included increased Bruch's membrane opening (BMO) nonplanarity (P < 0.05), decreased BMO aspect ratio (P < 0.0001), and decreased MRA angle (P < 0.001). Bruch's membrane opening area did not change from baseline in either control or EG eyes (P = 0.27, P = 0.15, respectively). Conclusions Optic nerve head neural rim tissue thinning exceeded peripapillary RNFL thinning in NHP EG. These results support the hypothesis that axon bundles are compressed transversely within the ONH rim along with glaucomatous deformation of connective tissues. PMID:27564522

  13. Experimental and Numerical Investigations on Flue Gas Purification during Hot Gas Filtration

    SciTech Connect

    Thulfaut, C.; Renz, U.

    2002-09-19

    The aim of the actual investigations is to integrate the catalytic reduction of carbon monoxide and particularly nitric oxides into the hot gas filtration process with ceramic filter elements of fluidized bed combustors which mainly represent an important N2O-source. According to Klein (Klein 1994) worldwide approx. 260 coal-fired power plants with fluidized bed combustors in the power range > 50 MWel existed in 1994, to which approx. 1% of the global coal dissipation corresponds. These emitted dinitrogen oxide with 70 kt/a, however, 20% of the entire N2O amounts from stationary firing plants. After Kleins calculations an increase of coal-fired fluidized bed combustors only by 10% triples the N2O emission.

  14. Filtration of triazine herbicides by polymer-clay sorbents: coupling an experimental mechanistic approach with empirical modeling.

    PubMed

    Gardi, Ido; Nir, Shlomo; Mishael, Yael G

    2015-03-01

    Triazine herbicides detected in surface and groundwater pose environmental and health risks. Removal of triazine herbicides (simazine, atrazine and terbuthylazine) by polymer-clay composites was studied and modeled. Their binding by a poly 4-vinyl pyridine co styrene-montmorillonite (HPVP-CoS-MMT) composite was especially high due to specific interactions between the herbicides and polymer, mainly hydrogen bonds and π-π stacking. The binding kinetics to the composite was in the order of simazine > atrazine > terbuthylazine, which was in accord with their equilibrium Langmuir binding coefficients; 44,000, 17,500 and 16,500 M(-1), respectively, which correlated with herbicide accessibility to form specific interaction with the polymer. Simazine binding kinetics to the composite was significantly faster than to granulated activated carbon (GAC), reaching 93% vs 38% of the maximal adsorption within 10 min, respectively. Herbicide filtration by composite columns was adequately fitted by a model which considers convection and employs Langmuir formalism for kinetics of adsorption/desorption. Filtration of simazine (10 μg L(-1)) by composite columns (40 cm long, which included 26 g composite mixed with sand 1:40 (weight ratio)), was well predicted by the model with nearly 120 L purified, i.e., effluent concentrations were below regulation limit (3 μg L(-1)). Effluent concentrations from GAC columns exceeded the limit after filtering 5 L. Experimental results and model predictions suggest that while GAC has a high capacity for simazine binding, the composite has higher affinity towards the herbicide and its adsorption is faster, which yields more efficient filtration by composite columns. PMID:25506764

  15. Simultaneous Complement Response via Lectin Pathway in Retina and Optic Nerve in an Experimental Autoimmune Glaucoma Model

    PubMed Central

    Reinehr, Sabrina; Reinhard, Jacqueline; Gandej, Marcel; Kuehn, Sandra; Noristani, Rozina; Faissner, Andreas; Burkhard Dick, H.; Joachim, Stephanie C.

    2016-01-01

    Glaucoma is a multifactorial disease and especially mechanisms occurring independently from an elevated intraocular pressure (IOP) are still unknown. Likely, the immune system contributes to the glaucoma pathogenesis. Previously, IgG antibody depositions and retinal ganglion cell (RGC) loss were found in an IOP-independent autoimmune glaucoma model. Therefore, we investigated the possible participation of the complement system in this model. Here, rats were immunized with bovine optic nerve homogenate antigen (ONA), while controls (Co) received sodium chloride (n = 5–6/group). After 14 days, RGC density was quantified on flatmounts. No changes in the number of RGCs could be observed at this point in time. Longitudinal optic nerve sections were stained against the myelin basic protein (MBP). We could note few signs of degeneration processes. In order to detect distinct complement components, retinas and optic nerves were labeled with complement markers at 3, 7, 14, and 28 days and analyzed. Significantly more C3 and MAC depositions were found in retinas and optic nerves of the ONA group. These were already present at day 7, before RGC loss and demyelination occurred. Additionally, an upregulation of C3 protein was noted via Western Blot at this time. After 14 days, quantitative real-time PCR revealed significantly more C3 mRNA in the ONA retinas. An upregulation of the lectin pathway-associated mannose-serine-protease-2 (MASP2) was observed in the retinas as well as in the optic nerves of the ONA group after 7 days. Significantly more MASP2 in retinas could also be observed via Western Blot analyses at this point in time. No effect was noted in regard to C1q. Therefore, we assume that the immunization led to an activation of the complement system via the lectin pathway in retinas and optic nerves at an early stage in this glaucoma model. This activation seems to be an early response, which then triggers degeneration. These findings can help to develop novel

  16. Mice with an induced mutation in collagen 8A2 develop larger eyes and are resistant to retinal ganglion cell damage in an experimental glaucoma model

    PubMed Central

    Steinhart, Matthew R.; Cone, Frances E.; Nguyen, Cathy; Nguyen, Thao D.; Pease, Mary E.; Puk, Oliver; Graw, Jochen; Oglesby, Ericka N.

    2012-01-01

    positive integral IOP exposure). Conclusions The Aca23 mutation in collagen 8α2 is the first gene defect found to alter susceptibility to experimental glaucoma, reducing RGC loss possibly due to differences in mechanical behavior of the sclera. Detailed study of the specific changes in scleral connective tissue composition and responses to chronic IOP elevation in this strain could produce new therapeutic targets for RGC neuroprotection. PMID:22701298

  17. Filtration Fundamentals.

    ERIC Educational Resources Information Center

    Ward, Ken; Hunsaker, Scot

    1997-01-01

    Examines how choice of commercial swimming-pool filtration systems is driven by the project-specific needs of the pools. Also highlighted are definitions of specific terms used when discussing filtration systems. Questions that pool designers can answer to make filtration-system purchasing decisions are listed. (GR)

  18. Water Filtration

    ERIC Educational Resources Information Center

    Jacobsen, Erica K.

    2004-01-01

    A water filtration column is devised by students using a two-liter plastic bottle containing gravel, sand, and activated charcoal, to test the filtration potential of the column. Results indicate that the filtration column eliminates many of the contaminating materials, but does not kill bacteria.

  19. Minimally invasive glaucoma surgery: current status and future prospects

    PubMed Central

    Richter, Grace M; Coleman, Anne L

    2016-01-01

    Minimally invasive glaucoma surgery aims to provide a medication-sparing, conjunctival-sparing, ab interno approach to intraocular pressure reduction for patients with mild-to-moderate glaucoma that is safer than traditional incisional glaucoma surgery. The current approaches include: increasing trabecular outflow (Trabectome, iStent, Hydrus stent, gonioscopy-assisted transluminal trabeculotomy, excimer laser trabeculotomy); suprachoroidal shunts (Cypass micro-stent); reducing aqueous production (endocyclophotocoagulation); and subconjunctival filtration (XEN gel stent). The data on each surgical procedure for each of these approaches are reviewed in this article, patient selection pearls learned to date are discussed, and expectations for the future are examined. PMID:26869753

  20. Glaucoma in Asian Populations

    MedlinePlus

    ... Us Donate In This Section Glaucoma In Asian Populations email Send this article to a friend by ... an even more serious problem as the world population and longevity increases. The other major glaucoma type ...

  1. Screening for Glaucoma

    MedlinePlus

    ... enough evidence to determine the potential benefits and harms of glaucoma screening for adults who do not ... Glaucoma is a group of diseases that can harm the eye’s optic nerve. The optic nerve carries ...

  2. EXPERIMENTAL STUDIES ON THE ETIOLOGY OF TYPHUS FEVER : IV. IMMUNIZING AND TOXIC AGENTS FOUND OCCASIONALLY IN FILTRATES OF TYPHUS-INFECTED TISSUES.

    PubMed

    Olitsky, P K

    1922-03-31

    In the filtrates of typhus-infected tissues of guinea pigs can be occasionally found a substance which produces in these animals thermic reactions, lesions characteristic of experimental typhus, and, still less frequently, immunity to later injections of active virus. The general indications are that this substance is not a living organism. PMID:19868620

  3. Glaucoma Research Foundation

    MedlinePlus

    ... second leading cause of blindness. How Glaucoma Affects Sight Facts and Statistics Request a Free Glaucoma Booklet Vision Loss Progression healthy advanced Tips for Glaucoma Care We've worked with patients, researchers, and eye care professionals to bring you the most helpful ...

  4. Experimental investigation of the formaldehyde removal mechanisms in a dynamic botanical filtration system for indoor air purification.

    PubMed

    Wang, Zhiqiang; Pei, Jingjing; Zhang, Jensen S

    2014-09-15

    Botanical filtration has been proved to be effective for indoor gas pollutant removal. To understand the roles of different transport, storage and removal mechanism by a dynamic botanical air filter, a series of experimental investigations were designed and conducted in this paper. Golden Pothos (Epipremnum aureum) plants was selected for test, and its original soil or activated/pebbles root bed was used in different test cases. It was found that flowing air through the root bed with microbes dynamically was essential to obtain meaningful formaldehyde removal efficiency. For static potted plant as normally place in rooms, the clean air delivery rate (CADR), which is often used to quantify the air cleaning ability of portable air cleaners, was only ∼ 5.1m(3)/h per m(2) bed, while when dynamically with air flow through the bed, the CADR increased to ∼ 233 m(3)/h per m(2) bed. The calculated CADR due to microbial activity is ∼ 108 m(3)/h per m(2) bed. Moisture in the root bed also played an important role, both for maintaining a favorable living condition for microbes and for absorbing water-soluble compounds such as formaldehyde. The role of the plant was to introduce and maintain a favorable microbe community which effectively degraded the volatile organic compounds adsorbed or absorbed by the root bed. The presence of the plant increased the removal efficiency by a factor of two based on the results from the bench-scale root bed experiments. PMID:25164387

  5. Genetic bases for glaucoma.

    PubMed

    Fuse, Nobuo

    2010-05-01

    Glaucoma is the leading cause of visual impairment and blindness throughout the world. Primary open angle glaucoma (POAG; MIM 137760) is the main type of glaucoma in most populations, and more than 20 genetic loci for POAG have been reported. Only three causative genes have been identified in these loci, viz. myocilin (MYOC), optineurin (OPTN), and WD repeat domain 36 (WDR36). However, mutations in these genes account for only a small percentage of the patients with POAG. Some of these glaucoma cases have a Mendelian inheritance pattern, and a considerable fraction of the cases result from a large number of variants in several genes each contributing small effects. Glaucoma is considered to be a common disease such as diabetes mellitus, coronary disease, Crohn disease, and several( )common cancers. The main technological approaches used to identify the genes associated with glaucoma are the candidate gene approach, linkage analysis, case-control association study, and genome-wide association study. Association studies have found about 27 genes related to POAG, but the glaucoma-causing effects of these genes need to be investigated in more detail. The current trend is to use case-control association studies or genome-wide association studies to map the genes associated with glaucoma. Such studies are expected to greatly advance our understanding of the genetic basis of glaucoma, and to provide information on the effectiveness of glaucoma therapy. This review gives an overview on the genetic aspects of glaucoma. PMID:20431268

  6. Pediatric Glaucoma: Pharmacotherapeutic Options.

    PubMed

    Samant, Monica; Medsinge, Anagha; Nischal, Ken K

    2016-06-01

    Childhood glaucoma is a major therapeutic challenge for pediatric ophthalmologists and glaucoma specialists worldwide. Management depends on the etiology and age at presentation. A variety of drugs are available for the control of intraocular pressure in children; however, none of these drugs have been licensed by the regulatory agencies for use in children. Furthermore, evidence gained from randomized controlled trials in the pediatric population is sparse, and little is known regarding the use of newer anti-glaucoma preparations. This evidence-based review aims to discuss the available pharmacotherapeutic options for glaucoma in children. Topical adrenoceptor blockers, topical and systemic carbonic anhydrase inhibitors, prostaglandin (PG) analogs, adrenoceptor agonists, parasympathomimetics, and combined preparations are available for use in children, but usually as an off-label indication. Therefore, it is important to recognize that serious side effects have been reported, even with topical drops, and measures to reduce systemic absorption should be taken. Most drugs have been shown to have comparable ocular hypotensive effects, with the lowest occurrence of systemic side effects with PG analogs. Whereas a newly introduced prostaglandin analog, tafluprost, and some other preservative-free preparations have shown promising results in adult glaucoma patients, no pediatric reports are available as yet. Future studies may describe their role in treating pediatric glaucoma. This review also shares some suggested treatment pathways for primary congenital glaucoma (PCG), juvenile open angle glaucoma (JOAG), developmental glaucoma, aphakic/pseudophakic glaucoma, and uveitic glaucoma. PMID:27093864

  7. The Scarborough Glaucoma Survey

    PubMed Central

    Shenken, Ellis; Glas, S.

    1966-01-01

    A glaucoma screening survey was carried out in Scarborough, Ontario, to detect previously unsuspected cases of the disease. General practitioners were employed to perform Schiotz tonometry. Suspected cases were further tested with applanation tonometry and tonography with water drinking. Of the 17,968 persons examined, 999 had a family history of glaucoma. Forty-one of these had obvious clinical glaucoma. The use of Schiotz tonometry plus applanation tonometry in individuals with a positive family history uncovered 463 suspected of having glaucoma. Tonography with water drinking revealed 348 persons with abnormal findings. Of this number, 228 had clinical glaucoma and 120 preclinical glaucoma. Mass screening by tonometry was found to be valuable in detecting glaucoma in the early stages. In most instances, blindness from this disease can be prevented by early diagnosis. ImagesFig. 1Fig. 2Fig. 3 PMID:5912178

  8. Microglia in mouse retina contralateral to experimental glaucoma exhibit multiple signs of activation in all retinal layers

    PubMed Central

    2014-01-01

    Background Glaucomatous optic neuropathy, a leading cause of blindness, can progress despite control of intraocular pressure - currently the main risk factor and target for treatment. Glaucoma progression shares mechanisms with neurodegenerative disease, including microglia activation. In the present model of ocular hypertension (OHT), we have recently described morphological signs of retinal microglia activation and MHC-II upregulation in both the untreated contralateral eyes and OHT eyes. By using immunostaining, we sought to analyze and quantify additional signs of microglia activation and differences depending on the retinal layer. Methods Two groups of adult Swiss mice were used: age-matched control (naïve, n = 12), and lasered (n = 12). In the lasered animals, both OHT eyes and contralateral eyes were analyzed. Retinal whole-mounts were immunostained with antibodies against Iba-1, MHC-II, CD68, CD86, and Ym1. The Iba-1+ cell number in the plexiform layers (PL) and the photoreceptor outer segment (OS), Iba-1+ arbor area in the PL, and area of the retina occupied by Iba-1+ cells in the nerve fiber layer-ganglion cell layer (NFL-GCL) were quantified. Results The main findings in contralateral eyes and OHT eyes were: i) ameboid microglia in the NFL-GCL and OS; ii) the retraction of processes in all retinal layers; iii) a higher level of branching in PL and in the OS; iv) soma displacement to the nearest cell layers in the PL and OS; v) the reorientation of processes in the OS; vi) MHC-II upregulation in all retinal layers; vii) increased CD68 immunostaining; and viii) CD86 immunolabeling in ameboid cells. In comparison with the control group, a significant increase in the microglial number in the PL, OS, and in the area occupied by Iba-1+ cells in the NFL-GCL, and significant reduction of the arbor area in the PL. In addition, rounded Iba-1+ CD86+ cells in the NFL-GCL, OS and Ym1+ cells, and rod-like microglia in the NFL-GCL were restricted to OHT eyes

  9. 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? Written by: David Turbert , contributing ...

  10. [Late postcontusion secondary glaucoma].

    PubMed

    Chiseliţă, D; Vancea, P; Filiman, O; Brănişteanu, D; Bredetean, M; Poiata, I

    1995-01-01

    The investigation of 33 patients with late postcontusional glaucoma subjected to surgery and followed up for 25 +/- 8.24 months has revealed: the interval accident-surgery is shorter in the close-angle combined forms; the essential mechanisms responsible for glaucoma occurrence are: the alteration of trabecular meshwork (for open-angle glaucoma) and pupillary block (for close angle glaucoma); simple cases required antiglaucoma surgery (trabeculectomy, peripheral iridectomy) and the mixed ones required combined (trabeculectomy, lens extraction, lens implant) or sequential surgeries (antiglaucoma surgery, vitrectomy etc); the glaucomatous process was stopped in 83.4% of the open-angle glaucoma cases and progressed in 23.5% of the close-angle glaucoma cases; the functional improvements post antiglaucoma surgery combined with removal of opacities are lessened by the higher frequency of severe per- and post-operative complication. PMID:7654676

  11. Experimental study on filtration and continuous regeneration of a particulate filter system for heavy-duty diesel engines.

    PubMed

    Tang, Tao; Zhang, Jun; Cao, Dongxiao; Shuai, Shijin; Zhao, Yanguang

    2014-12-01

    This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst (DOC) and a catalyzed diesel particulate filter (CDPF). Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number (SPN) was close to 100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration. PMID:25499491

  12. Traumatic Glaucoma in Children

    PubMed Central

    Kaur, Savleen; Singh Pandav, Surinder

    2014-01-01

    ABSTRACT Young patients are more prone to ocular trauma but most of the published studies describe complicated cataract as a result of trauma with its treatment modality. As a result, little is known about the different causes, common presenting signs and symptoms, visual outcomes, and most frequent management modalities of traumatic glaucoma in children. This review aims to study the demographical profile, presentation, management and outcome of traumatic glaucoma in children as well as the various factors associated with advanced glaucomatous changes. How to cite this article: Kaur S, Kaushik S, Pandav SS. Traumatic Glaucoma in Children. J Curr Glaucoma Pract 2014; 8(2):58-62. PMID:26997810

  13. Glaucoma: diagnosis and management.

    PubMed Central

    Infeld, D. A.; O'Shea, J. G.

    1998-01-01

    Glaucoma is the third most prevalent cause of global blindness, accounting for over 5 million blind. It is common in Western Countries; the estimated prevalence of primary open angle glaucoma rises from a total prevalence of 1.1% to approximately 3% of our population as it ages. Ethnicity affects both the risk of developing glaucoma and the outcome. It is an expensive disease both to detect and to treat. Recent scientific advances include elucidation of the genetic mechanism behind the disease and the study of haemodynamic and biochemical co-factors in the development of glaucomatous optic neuropathy, particularly in relation to the pathogenesis of normal tension glaucoma. Several new types of topical medication have recently been developed for use in glaucoma; both the impact of these therapies and their cost effectiveness remain to be evaluated. There are widely differing regimes which effectively treat glaucoma; some ophthalmologists prefer early surgical intervention whilst others reserve surgery for relatively advanced disease. All methods of current treatment rely on the reduction of intra-ocular pressure; as yet there is no medication which has been definitively proven to be either neuroprotective or to influence favourably optic nerve perfusion. Despite this, most sufferers of glaucoma are able to lead lives of quality. Increased community awareness of glaucoma, and earlier detection of the condition, will doubtless result in decreased morbidity due to glaucoma. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:10320884

  14. The Suprachoroidal Route in Glaucoma Surgery

    PubMed Central

    Shaarawy, Tarek

    2016-01-01

    ABSTRACT Glaucoma surgeries targeting the uveoscleral drainage pathways have been drawing more attention lately. Among all the available techniques, procedures focusing on the supra-choroidal space seem particularly promising, by making use of a presumably efficient and secure outflow route and avoiding subconjunctival filtration blebs. The purpose of this review is to assess the efficacy and the security of the different suprachoroidal drainage implants, namely the CyPass Micro-Stent, the iStent Supra, the SOLX Gold Shunt, the Aquashunt, and the STARflo Glaucoma Implant. Most clinical studies seem to currently point toward the direction that there are actual benefits in suprachoroidal surgeries by avoiding bleb-related complications. Nevertheless, even suprachoroidal implants may be subject to scarring and failure. More data are still needed, especially concerning long-term effects, although the approach does seem appealing. How to cite this article: Gigon A, Shaarawy T. The Suprachoroidal Route in Glaucoma Surgery. J Curr Glaucoma Pract 2016;10(1): 13-20. PMID:27231415

  15. Corneal thickness in glaucoma.

    PubMed

    De Cevallos, E; Dohlman, C H; Reinhart, W J

    1976-02-01

    The central corneal stromal thickness of patients with open angle glaucoma, secondary glaucoma (the majority aphakic), or a history of unilateral acute angle closure glaucoma were measured and compared with the stromal thickness of a group of normal patients. In open angle glaucoma, there was a small but significant increase in the average stromal thickness. This thickness increase was, in all likelihood, due to an abnormal function of the endothelium in this disease since the level of the intraocular pressure did not seem to be a factor. There was no correlation between stromal thickness and duration of the glaucoma or type of anti-glaucomatous medication. Most cases of secondary glaucome, controlled medically or not, had markedly increased corneal thickness, again, most likely, due to endothelial damage rather than to level of intraocular pressure. After an angle closure attack, permanent damage to the cornea was found to be rare. PMID:1247273

  16. [Vascular factors in glaucoma].

    PubMed

    Mottet, B; Aptel, F; Geiser, M; Romanet, J P; Chiquet, C

    2015-12-01

    The exact pathophysiology of glaucoma is not fully understood. Understanding of the vascular pathophysiology of glaucoma requires: knowing the techniques for measuring ocular blood flow and characterizing the topography of vascular disease and the mechanisms involved in this neuropathy. A decreased mean ocular perfusion pressure and a loss of vascular autoregulation are implicated in glaucomatous disease. Early decrease in ocular blood flow has been identified in primary open-angle glaucoma and normal pressure glaucoma, contributing to the progression of optic neuropathy. The vascular damage associated with glaucoma is present in various vascular territories within the eye (from the ophthalmic artery to the retina) and is characterized by a decrease in basal blood flow associated with a dysfunction of vasoregulation. PMID:26597554

  17. Animal Models of Glaucoma

    PubMed Central

    A. Bouhenni, Rachida; Dunmire, Jeffrey; Sewell, Abby; Edward, Deepak P.

    2012-01-01

    Glaucoma is a heterogeneous group of disorders that progressively lead to blindness due to loss of retinal ganglion cells and damage to the optic nerve. It is a leading cause of blindness and visual impairment worldwide. Although research in the field of glaucoma is substantial, the pathophysiologic mechanisms causing the disease are not completely understood. A wide variety of animal models have been used to study glaucoma. These include monkeys, dogs, cats, rodents, and several other species. Although these models have provided valuable information about the disease, there is still no ideal model for studying glaucoma due to its complexity. In this paper we present a summary of most of the animal models that have been developed and used for the study of the different types of glaucoma, the strengths and limitations associated with each species use, and some potential criteria to develop a suitable model. PMID:22665989

  18. 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. PMID:26693592

  19. Filtration by eyelashes

    NASA Astrophysics Data System (ADS)

    Vistarakula, Krishna; Bergin, Mike; Hu, David

    2010-11-01

    Nearly every mammalian and avian eye is rimmed with lashes. We investigate experimentally the ability of lashes to reduce airborne particle deposition in the eye. We hypothesize that there is an optimum eyelash length that maximizes both filtration ability and extent of peripheral vision. This hypothesis is tested using a dual approach. Using preserved heads from 36 species of animals at the American Museum of Natural History, we determine the relationship between eye size and eyelash geometry (length and spacing). We test the filtration efficacy of these geometries by deploying outdoor manikins and measuring particle deposition rate as a function of eyelash length.

  20. Primary lens extraction for glaucoma management: A review article

    PubMed Central

    Eid, Tarek M.

    2011-01-01

    Recently, primary lens extraction alone gained more acceptance as an alternative surgical approach for glaucoma management. This view was supported by the advances in phacoemulsification and intraocular lenses with greater safety and visual recovery, in addition to a substantial reduction of intraocular pressure and deepening of the anterior chamber and filtration angle. The decrease in IOP after cataract surgery in primary open-angle glaucoma (POAG) is mild, less predictable, related to baseline levels, and may return to presurgical values after an initial period of reduction. Therefore, the IOP-lowering effect of primary cataract extraction in POAG may be insufficient to achieve adequate IOP control. The IOP reduction after lens extraction is consistently greater in eyes with primary angle closure glaucoma (PACG) than in eyes with POAG. Primary lens extraction in acute PACG eliminates, or at least, reduces the risk of recurrence of acute attacks and deepens the anterior chamber and widens the angle which reduces the risk of progression of peripheral anterior synechiae and development of chronic PACG. Primary lens extraction may be more preferable to glaucoma incisional surgery in mild to moderate PACG eyes with appositional angle closure. The decision to do lens extraction as a primary treatment for glaucoma should be individualized based upon several factors other than the effect on IOP. These factors include patients’ characteristics, surgeons’ skills and preferences, status of glaucoma control, type of cataract and intraocular lens implanted, and potential harm of laser treatment for late capsular opacification and fibrosis. PMID:23960947

  1. Structural and Functional Abnormalities of Retinal Ganglion Cells Measured In Vivo at the Onset of Optic Nerve Head Surface Change in Experimental Glaucoma

    PubMed Central

    Fortune, Brad; Burgoyne, Claude F.; Cull, Grant A.; Reynaud, Juan; Wang, Lin

    2012-01-01

    Purpose. To compare peripapillary retinal nerve fiber layer thickness (RNFLT), RNFL retardance, and retinal function at the onset of optic nerve head (ONH) surface topography change in experimental glaucoma (EG). Methods. Thirty-three rhesus macaques had three or more weekly baseline measurements in both eyes of ONH surface topography, peripapillary RNFLT, RNFL retardance, and multifocal electroretinography (mfERG). Laser photocoagulation was then applied to the trabecular meshwork of one eye to induce chronic elevation of IOP and weekly recordings continued alternating between ONH surface topography and RNFLT during one week and RNFL retardance and mfERG the next week. Data were pooled for the group at the onset of ONH surface topography change in each EG eye, which was defined as the first date when either the mean position of the disc (MPD) fell below the 95% confidence limit of each eye's individual baseline range and/or when the topographic change analysis (TCA) map was subjectively judged as having demonstrated change, whichever came first. Analysis of variance with post hoc tests corrected for multiple comparisons were used to assess parameter changes. Results. At onset of ONH surface topography change, there was no significant difference for RNFLT versus baseline or fellow control eyes. RNFL retardance and mfERG were significantly reduced in the recordings just prior (median of 9 days) to ONH onset (P < 0.01) and had progressed significantly (P < 0.001) an average of 17 days later (median of 7 days after ONH onset). RNFLT did not exhibit significant thinning until 15 days after onset of ONH surface topography change (P < 0.001). Conclusions. These results support the hypothesis that during the course of glaucomatous neurodegeneration, axonal cytoskeletal and retinal ganglion cell functional abnormalities exist before thinning of peripapillary RNFL axon bundles begins. PMID:22589428

  2. Anterior and Posterior Optic Nerve Head Blood Flow in Nonhuman Primate Experimental Glaucoma Model Measured by Laser Speckle Imaging Technique and Microsphere Method

    PubMed Central

    Wang, Lin; Cull, Grant A.; Piper, Chelsea; Burgoyne, Claude F.; Fortune, Brad

    2012-01-01

    Purpose. To characterize optic nerve head (ONH) blood flow (BF) changes in nonhuman primate experimental glaucoma (EG) using laser speckle flowgraphy (LSFG) and the microsphere method and to evaluate the correlation between the two methods. Methods. EG was induced in one eye each of 9 rhesus macaques by laser treatment to the trabecular meshwork. Prior to lasering and following onset of intraocular pressure (IOP) elevation, retinal never fiber layer thickness (RNFLT) and ONH BF were measured biweekly by spectral-domain optical coherence tomography and LSFG, respectively, until RNFLT loss was approximately 40% in the EG eye. Final BF was measured by LSFG and by the microsphere method in the anterior ONH (MS-BFANT), posterior ONH (MS-BFPOST), and peripapillary retina (MS-BFPP). Results. Baseline RNFLT and LSFG-BF showed no difference between the two eyes (P = 0.69 and P = 0.43, respectively, paired t-test). Mean (±SD) IOP was 30 ± 6 mm Hg in EG eyes and 13 ± 2 mm Hg in control eyes (P < 0.001). EG eye RNFLT and LSFG-BF were reduced by 42 ± 16% (P < 0.0001) and 22 ± 13% (P = 0.003), respectively, at the final time point. EG eye MS-BFANT, MS-BFPOST, and MS-BFPP were reduced by 41 ± 17% (P < 0.001), 22 ± 34% (P = 0.06), and 30 ± 12% (P = 0.001), respectively, compared with the control eyes. Interocular ONH LSFG-BF differences significantly correlated to that measured by the microsphere method (R2 = 0.87, P < 0.001). Conclusions. Chronic IOP elevation causes significant ONH BF decreases in the EG model. The high correlation between the BF reduction measured by LSFG and the microsphere method provides evidence that the LSFG is capable of assaying BF for a critical deep ONH region. PMID:23169886

  3. Three experimental glaucoma models in rats: comparison of the effects of intraocular pressure elevation on retinal ganglion cell size and death.

    PubMed

    Urcola, J Haritz; Hernández, María; Vecino, Elena

    2006-08-01

    Glaucoma is a chronic and progressive optic nerve neuropathy involving the death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is considered to be the major risk factor associated with the development of this neuropathy. The objective of the present study was to compare the effects on RGC survival of three different experimental methods to induce chronic elevation of IOP in rats. These methods were: (i) injections of latex microspheres into the eye anterior chamber; (ii) injections into the anterior chamber of a mixture of microspheres plus hydroxypropylmethylcellulose (HPM) and (iii) cauterization of three episcleral veins. The IOP of right (control) and left (glaucomatous) eyes was measured with an applanation tonometer in awake animals. Thirteen to 30 weeks later, RGCs were retrogradely labeled with 3% fluorogold. Subsequently, we analyzed the density of RGCs, as well as the major axis length and area of RGC soma resulting from the application of each method. A significant increase in IOP was found following application of each of the three methods. Cell death was evident in the glaucomatous eyes as compared to controls. However, no statistical differences were found between the extent of cell death associated with each of the three methods. IOP increase also induced a significant increase in the size of the soma of the remaining RGCs. In conclusion, the three methods used to increase IOP induce a similar degree of RGC death. Moreover, the extent of cell death was similar when the retinas were maintained under conditions of elevated IOP for 24 weeks in comparison to 13 weeks. PMID:16682027

  4. 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 ...

  5. Facts about Glaucoma

    MedlinePlus

    ... remain blurred for several hours. Tonometry is the measurement of pressure inside the eye by using an ... the eye to detect glaucoma. Pachymetry is the measurement of the thickness of your cornea. Your eye ...

  6. Daily Life with Glaucoma

    MedlinePlus

    ... Close Send Thanks for emailing that article! Tweet Free Booklet You can also find the information in ... are not reflected on our website. Get Our Free Newsletter Subscribe Doctors Order booklets about glaucoma for ...

  7. African Americans and Glaucoma

    MedlinePlus

    ... Close Send Thanks for emailing that article! Tweet Free Booklet You can also find the information in ... are not reflected on our website. Get Our Free Newsletter Subscribe Doctors Order booklets about glaucoma for ...

  8. Five Common Glaucoma Tests

    MedlinePlus

    ... Close Send Thanks for emailing that article! Tweet Free Booklet You can also find the information in ... are not reflected on our website. Get Our Free Newsletter Subscribe Doctors Order booklets about glaucoma for ...

  9. Coping with Glaucoma

    MedlinePlus Videos and Cool Tools

    ... comprehensive eye examination performed by a qualified eye care professional such as an opthalmologistor optometrist. The exam ... at-risk individuals -- that's the recommendation of eye care professionals, and that's the way to stop glaucoma ...

  10. What Is Glaucoma?

    MedlinePlus

    ... Glaucoma is a disease that damages your eye's optic nerve. It usually happens when fluid builds up ... increases the pressure in your eye, damaging the optic nerve. It is estimated that three million Americans ...

  11. The best of the best: a review of select glaucoma case reports published in 2014

    PubMed Central

    Hoguet, Ambika; Pasquale, Louis R.

    2015-01-01

    This review article summarizes four key case reports published in the field of glaucoma in the year 2014. The first article describes successful early drainage of delayed suprachoroidal hemorrhage in 7 patients who underwent glaucoma surgery. The second describes the use of a corneal patch graft to repair leaking or hypotonous blebs in patients who underwent glaucoma filtration surgery. The third article describes methods to reduce complications when implanting posterior chamber phakic intraocular lenses. The last article describes the clinical course and treatment of a patient in whom oseltamivir use resulted in bilateral acute angle closure. PMID:27330473

  12. Premium IOLs in Glaucoma

    PubMed Central

    Bhartiya, Shibal; Sharma, Anuj

    2013-01-01

    ABSTRACT Advanced technology or premium intraocular lenses have been developed to meet the patient expectations of perfect distance and near vision without the need for spectacles. Careful patient selection is critical when implanting these implants. This brief review focusses mainly on multifocal and toric IOLs and their application and limitations in patients with glaucoma. How to cite this article: Ichhpujani P, Bhartiya S, Sharma A. Premium IOLs in Glaucoma. J Current Glau Prac 2013;7(2): 54-57. PMID:26997783

  13. Glaucoma in developing countries

    PubMed Central

    Thomas, Ravi

    2012-01-01

    Objective: To describe the background and strategy required for the prevention of blindness from glaucoma in developing countries. Materials and Methods: Extrapolation of existing data and experience in eye care delivery and teaching models in an unequally developed country (India) are used to make recommendations. Results: Parameters like population attributable risk percentage indicate that glaucoma is a public health problem but lack of simple diagnostic techniques and therapeutic interventions are barriers to any effective plan. Case detection rather than population-based screening is the recommended strategy for detection. Population awareness of the disease is low and most patients attending eye clinics do not receive a routine comprehensive eye examination that is required to detect glaucoma (and other potentially blinding eye diseases). Such a routine is not taught or practiced by the majority of training institutions either. Angle closure can be detected clinically and relatively simple interventions (including well performed cataract surgery) can prevent blindness from this condition. The strategy for open angle glaucoma should focus on those with established functional loss. Outcomes of this proposed strategy are not yet available. Conclusions: Glaucoma cannot be managed in isolation. The objective should be to detect and manage all potential causes of blindness and prevention of blindness from glaucoma should be integrated into existing programs. The original pyramidal model of eye care delivery incorporates this principle and provides an initial starting point. The routine of comprehensive eye examination in every clinic and its teaching (and use) in residency programs is mandatory for the detection and management of potentially preventable blinding pathology from any cause, including glaucoma. Programs for detection of glaucoma should not be initiated unless adequate facilities for diagnosis and surgical intervention are in place and their monitoring

  14. Onset and Progression of Peripapillary Retinal Nerve Fiber Layer (RNFL) Retardance Changes Occur Earlier Than RNFL Thickness Changes in Experimental Glaucoma

    PubMed Central

    Fortune, Brad; Burgoyne, Claude F.; Cull, Grant; Reynaud, Juan; Wang, Lin

    2013-01-01

    Purpose. Longitudinal measurements of peripapillary RNFL thickness and retardance were compared in terms of time to reach onset of damage and time to reach a specific progression endpoint. Methods. A total of 41 rhesus macaques with unilateral experimental glaucoma (EG) each had three or more weekly baseline measurements in both eyes of peripapillary RNFL thickness (RNFLT) and retardance. Laser photocoagulation was then applied to the trabecular meshwork of one eye to induce chronic elevation of intraocular pressure and weekly imaging continued. Pairwise differences between baseline observations were sampled by bootstrapping to determine the 95% confidence limits of each measurement's repeatability. The first two sequential measurements below the lower confidence limit defined the endpoint for each parameter. Segmented linear and exponential decay functions were fit to each RNFL-versus-time series to determine the time to damage onset. Results. In all, 29 (71%) of the EG eyes reached endpoint by RNFL retardance and 25 (61%) reached endpoint by RNFLT. In total, 33 (80%) reached endpoint by at least one of the RNFL parameters and 21 (51%) reached endpoint by both RNFL parameters. Of the 33 EG eyes reaching any endpoint, a larger proportion reached endpoint first by retardance (n = 26, 79%) than did by RNFLT (n = 7, 21%; P = 0.002). Survival analysis indicated a shorter time to reach endpoint by retardance than by RNFLT (P < 0.001). Of the 21 EG eyes that reached endpoint by both measures, the median duration to endpoint was 120 days for retardance and 223 days for RNFLT (P = 0.003, Wilcoxon test). The time to onset was faster for retardance than that for RNFLT based on either segmented fits (by 31 days; P = 0.008, average R2 = 0.89) or exponential fits (by 102 days; P = 0.01, average R2 = 0.89). Conclusions. The onset of progressive loss of RNFL retardance occurs earlier than the onset of RNFL thinning. Endpoints of progressive loss from baseline also occurred more

  15. [Glaucoma in children and adolescents: diagnosis and therapeutic difficulties].

    PubMed

    Nordmann, J-P

    2009-03-01

    The management of glaucoma in young patients has made considerable progress over the recent years. Its treatment is essentially surgical, mainly filtration procedure. Use of antimetabolites combined with filtration is highly recommended. Medical treatment has a limited place, but should not be neglected. The number of topical pressure-lowering treatments permits a large therapeutic choice, but their clinical efficacy and tolerability should be assessed on an individual patient's basis. These topically applied treatments have not been tested in sufficient, adequate, clinical studies to guarantee their efficacy and safety in children and adolescents. Consequently, their approved labelling indicates "not recommended for use in these patients", which means that they are prescribed outside of their granted marketing authorization. Therefore, such clinical studies appear particularly needed. Indications of cyclodestruction or drainage implants has to be confined to refractory glaucoma and complicated cases. PMID:19515330

  16. New Tool to Predict Glaucoma

    MedlinePlus

    ... News About Us Donate In This Section A New Tool to Predict Glaucoma email Send this article ... determine if a patient has glaucoma. Recently, a new tool has become available to eye care specialists ...

  17. Improving Glaucoma Detection and Management

    ClinicalTrials.gov

    2015-12-09

    Glaucoma; Glaucoma Suspect; Diabetic Retinopathy; Ocular Hypertension; Cataract; Branch Retinal Vein Occlusion; Branch Retinal Arterial Occlusion; Central Retinal Vein Occlusion; Central Retinal Artery Occlusion; Epi-retinal Membrane; Macular Degeneration; Drusen; Loss of Vision

  18. Diabetes and Your Eyesight (Glaucoma)

    MedlinePlus

    ... without the eye disease. Neovascular glaucoma, a rare type of glaucoma, is always associated with other abnormalities, diabetes being the most common. In some cases of diabetic retinopathy, blood vessels on the retina are damaged. ...

  19. Single half-wavelength ultrasonic particle filter: Predictions of the transfer matrix multilayer resonator model and experimental filtration results

    NASA Astrophysics Data System (ADS)

    Hawkes, Jeremy J.; Coakley, W. Terence; Gröschl, Martin; Benes, Ewald; Armstrong, Sian; Tasker, Paul J.; Nowotny, Helmut

    2002-03-01

    The quantitative performance of a ``single half-wavelength'' acoustic resonator operated at frequencies around 3 MHz as a continuous flow microparticle filter has been investigated. Standing wave acoustic radiation pressure on suspended particles (5-μm latex) drives them towards the center of the half-wavelength separation channel. Clarified suspending phase from the region closest to the filter wall is drawn away through a downstream outlet. The filtration efficiency of the device was established from continuous turbidity measurements at the filter outlet. The frequency dependence of the acoustic energy density in the aqueous particle suspension layer of the filter system was obtained by application of the transfer matrix model [H. Nowotny and E. Benes, J. Acoust. Soc. Am. 82, 513-521 (1987)]. Both the measured clearances and the calculated energy density distributions showed a maximum at the fundamental of the piezoceramic transducer and a second, significantly larger, maximum at another system's resonance not coinciding with any of the transducer or empty chamber resonances. The calculated frequency of this principal energy density maximum was in excellent agreement with the optimal clearance frequency for the four tested channel widths. The high-resolution measurements of filter performance provide, for the first time, direct verification of the matrix model predictions of the frequency dependence of acoustic energy density in the water layer.

  20. Snoring and Glaucoma

    PubMed Central

    Wang, Ya Xing; Xu, Liang; Li, Jian Jun; Yang, Hua; Zhang, Ya Qin; Jonas, Jost B.

    2014-01-01

    Purpose To examine a potential association between snoring and glaucoma in a population-based setting. Methods The population-based Beijing Eye Study 2011 included 3468 subjects with an age of 50+ years. The participants underwent a detailed ophthalmic examination. Glaucoma was determined according to the ophthalmoscopic appearance of the optic nerve head. Snoring assessed in an interview was graded into “severe snoring”, “moderate snoring”, and “no snoring”. Results Data on snoring and glaucoma were available for 3146 subjects. Snoring was reported for 1787 (66.8%) subjects, with moderate snoring reported for 1384 (44.0%) subjects and severe snoring for 403 (12.8%) subjects. In multivariate analysis, prevalence of severe snoring was significantly associated with male gender (P = 0.002; regression coefficient B: 0.36; Odds ratio (OR): 1.44 (95% confidence interval (CI): 1.14, 1.81)), higher body mass index (P<0.001; B: 0.12; OR: 1.13 (95%CI: 1.09, 1.16)), higher systolic blood pressure (P<0.001; B: 0.01; OR: 1.01 (95%CI: 1.005, 1.02)), younger age (P = 0.007; B: −0.018; OR: 0.98 (95%CI: 0.97, 0.995)), and higher cognitive function (P = 0.03; B: 0.04; OR: 1.04 (95%CI: 1.004, 1.08)), however it was not significantly associated with the prevalence of open-angle glaucoma (P = 0.10; B: −0.63; OR: 0.53 (95%CI: 0.25, 1.12)). Prevalence of severe snoring was neither significantly associated with the prevalence of angle-closure glaucoma (P = 0.65), retinal vein occlusions (P = 0.24), neuroretinal rim area (P = 0.19), retinal nerve fiber layer thickness (P = 0.16) nor vertical cup/disc ratio (P = 0.64). Conclusions Severe snoring was not significantly associated with the prevalence of open-angle glaucoma, angle-closure glaucoma or retinal vein occlusions after adjustment for age, gender, body mass index, systolic blood pressure and cognitive function score. Our population-based study did not reveal that snoring was a risk

  1. Exciting Directions in Glaucoma

    PubMed Central

    Rasmussen, Carol A; Kaufman, Paul L

    2014-01-01

    Glaucoma is a complex, life-long disease that requires an individualized, multifaceted approach to treatment. Most patients will be started on topical ocular hypotensive eyedrop therapy and over time, multiple classes of drugs will be needed to control their intraocular pressure (IOP). The search for drugs with novel mechanisms of action, to treat those who do not achieve adequate IOP control with, or become refractory to, current therapeutics, is ongoing, as is the search for more efficient, targeted drug delivery methods. Gene transfer and stem cell applications for glaucoma therapeutics are moving forward. Advances in imaging technologies improve our understanding of glaucoma pathophysiology and enable more refined patient evaluation and monitoring, improving patient outcomes. PMID:25433744

  2. Update on congenital glaucoma

    PubMed Central

    Mandal, Anil K; Chakrabarti, Debasis

    2011-01-01

    Congenital glaucoma is a global problem and poses a diagnostic and therapeutic challenge to the ophthalmologist. A detailed evaluation under general anesthesia is advisable to establish the diagnosis and plan for management. Medical therapy has a limited role and surgery remains the primary therapeutic modality. While goniotomy or trabeculotomy ab externo is valuable in the management of congenital glaucoma, primary combined trabeculotomy–trabeculectomy offers the best hope of success in advanced cases. Trabeculectomy with antifibrotic agent and glaucoma drainage devices has a role in the management of refractory cases, and cyclodestructive procedures should be reserved for patients where these procedures have failed. Early diagnosis, prompt therapeutic intervention and proper refractive correction are keys to success. Management of residual vision and visual rehabilitation should be an integral part of the management of children with low vision and lifelong follow-up is a must. PMID:21150027

  3. [Consensus on neovascular glaucoma].

    PubMed

    Hamard, P; Baudouin, C

    2000-03-01

    Neovascular glaucoma is a dreadful pathology with a rapid spontaneous evolution responsible for painful and blind eye. The main cause is an anterior neovascular proliferation following a broad retinal ischemia. Early diagnosis and treatment are required in order to maintain a good visual status and a satisfactory IOP control with medical, surgical or cylodestructive procedures. In any case, the treatment of the retinal ischemia has to be performed. One must keep in mind that the most efficient way to avoid the incidence of neovascular glaucoma is a strict control of clinical situations potentially responsible for retinal ischemia, namely VRO in elderly patients and diabetic retinopathy in younger patients. PMID:10740059

  4. [Contrast sensitivity in glaucoma].

    PubMed

    Bartos, D

    1989-05-01

    Author reports on results of the contrast sensitivity examinations using the Cambridge low-contrast lattice test supplied by Clement Clarke International LTD, in patients with open-angle glaucoma and ocular hypertension. In glaucoma patients there was observed statistically significant decrease of the contrast sensitivity. In patients with ocular hypertension decrease of the contrast sensitivity was in patients affected by corresponding changes of the visual field and of the optical disc. The main advantages of the Cambridge low-contrast lattice test were simplicity, rapidity and precision of its performance. PMID:2743444

  5. A New Safety Concern for Glaucoma Treatment Demonstrated by Mass Spectrometry Imaging of Benzalkonium Chloride Distribution in the Eye, an Experimental Study in Rabbits

    PubMed Central

    Brignole-Baudouin, Françoise; Desbenoit, Nicolas; Hamm, Gregory; Liang, Hong; Both, Jean-Pierre; Brunelle, Alain; Fournier, Isabelle; Guerineau, Vincent; Legouffe, Raphael; Stauber, Jonathan; Touboul, David; Wisztorski, Maxence; Salzet, Michel; Laprevote, Olivier; Baudouin, Christophe

    2012-01-01

    We investigated in a rabbit model, the eye distribution of topically instilled benzalkonium_(BAK) chloride a commonly used preservative in eye drops using mass spectrometry imaging. Three groups of three New Zealand rabbits each were used: a control one without instillation, one receiving 0.01%BAK twice a day for 5 months and one with 0.2%BAK one drop a day for 1 month. After sacrifice, eyes were embedded and frozen in tragacanth gum. Serial cryosections were alternately deposited on glass slides for histological (hematoxylin-eosin staining) and immunohistological controls (CD45, RLA-DR and vimentin for inflammatory cell infiltration as well as vimentin for Müller glial cell activation) and ITO or stainless steel plates for MSI experiments using Matrix-assisted laser desorption ionization time-of-flight. The MSI results were confirmed by a round-robin study on several adjacent sections conducted in two different laboratories using different sample preparation methods, mass spectrometers and data analysis softwares. BAK was shown to penetrate healthy eyes even after a short duration and was not only detected on the ocular surface structures, but also in deeper tissues, especially in sensitive areas involved in glaucoma pathophysiology, such as the trabecular meshwork and the optic nerve areas, as confirmed by images with histological stainings. CD45-, RLA-DR- and vimentin-positive cells increased in treated eyes. Vimentin was found only in the inner layer of retina in normal eyes and increased in all retinal layers in treated eyes, confirming an activation response to a cell stress. This ocular toxicological study confirms the presence of BAK preservative in ocular surface structures as well as in deeper structures involved in glaucoma disease. The inflammatory cell infiltration and Müller glial cell activation confirmed the deleterious effect of BAK. Although these results were obtained in animals, they highlight the importance of the safety-first principle for

  6. Relating Retinal Ganglion Cell Function and Retinal Nerve Fiber Layer (RNFL) Retardance to Progressive Loss of RNFL Thickness and Optic Nerve Axons in Experimental Glaucoma

    PubMed Central

    Fortune, Brad; Cull, Grant; Reynaud, Juan; Wang, Lin; Burgoyne, Claude F.

    2015-01-01

    Purpose. To relate changes in retinal function and retinal nerve fiber layer (RNFL) retardance to loss of RNFL thickness and optic nerve axon counts in a nonhuman primate (NHP) model of experimental glaucoma (EG). Methods. Bilateral longitudinal measurements of peripapillary RNFL thickness (spectral-domain optical coherence tomography, SDOCT; Spectralis), retardance (GDxVCC), and multifocal electroretinography (mfERG; VERIS) were performed in 39 NHP at baseline (BL; median, 5 recordings; range, 3–10) and weekly after induction of unilateral EG by laser photocoagulation of the trabecular meshwork. Multifocal ERG responses were high-pass filtered (>75 Hz) to measure high- and low-frequency component (HFC and LFC) amplitudes, including LFC features N1, P1, and N2. High-frequency component amplitudes are known to specifically reflect retinal ganglion cell (RGC) function. Complete (100%) axon counts of orbital optic nerves were obtained in 31/39 NHP. Results. Postlaser follow-up was 10.4 ± 7.9 months; mean and peak IOP were 18 ± 5 and 41 ± 11 mm Hg in EG eyes, 11 ± 2 and 18 ± 6 mm Hg in control (CTL) eyes. At the final available time point, RNFL thickness had decreased from BL by 14 ± 14%, retardance by 20 ± 11%, and the mfERG HFC by 30 ± 17% (P < 0.0001 each). Longitudinal changes in retardance and HFC were linearly related to RNFL thickness change (R2 = 0.51, P < 0.0001 and R2 = 0.22, P = 0.002, respectively); LFC N2 was weakly related but N1 or P2 (N1: R2 = 0.07, P = 0.11; P1: R2 = 0.04, P = 0.24; N2: R2 = 0.13, P = 0.02). At zero change from BL for RNFL thickness (Y-intercept), retardance was reduced by 11% (95% confidence interval [CI]: −15.3% to −6.8%) and HFC by 21.5% (95% CI: −28.7% to −14.3%). Relative loss of RNFL thickness, retardance, and HFC (EG:CTL) were each related to axon loss (R2 = 0.66, P < 0.0001; R2 = 0.42, P < 0.0001; R2 = 0.42, P < 0.0001, respectively), but only retardance and HFC were significantly reduced at zero relative axon

  7. Final report for Grant No. DOE/DE-FG02-98ER14909: Experimental and modeling studies of nanometer aerosol filtration

    SciTech Connect

    Pui, David Y.H.; Chen, Da-Ren

    2002-12-10

    The primary objective is to perform a fundamental study of filtration of nanoparticles, and to obtain filtration knowledge necessary to design particle collection devices/systems for nanoparticle processing and for preventing nanoparticle emissions into the environment. The research covered a wide area relevant to nanoparticle filtration, under these main topics: (1) nanoparticle filtration and molecular dynamics simulation, (2) nanoparticle virtual impactor, (3) particle transport under low pressure, and (4) development of a high-throughput nanoparticle generator. A number of novel tools and numerical models have been developed under the DOE support.

  8. OCT Imaging in Glaucoma

    NASA Astrophysics Data System (ADS)

    Nevins, Jessica E.; Wollstein, Gadi; Schuman, Joel S.

    The precise micron scale quantification of ocular structures provided by OCT turn this technology to be a valuable tool in clinical evaluation of glaucoma patients. This chapter describes the clinical utility of OCT from choosing the scan pattern and scan location to the interpretation of the test outcome.

  9. Pharmacotherapy of Glaucoma

    PubMed Central

    Schmidl, Doreen; Garhöfer, Gerhard; Popa-Cherecheanu, Alina

    2015-01-01

    Abstract Glaucoma is a group of diseases involving the optic nerve and associated structures, which is characterized by progressive visual field loss and typical changes of the optic nerve head (ONH). The only known treatment of the disease is reduction of intraocular pressure (IOP), which has been shown to reduce glaucoma progression in a variety of large-scale clinical trials. Nowadays, a relatively wide array of topical antiglaucoma drugs is available, including prostaglandin analogues, carbonic anhydrase inhibitors, beta-receptor antagonists, adrenergic agonists, and parasympathomimetics. In clinical routine, this allows for individualized treatment taking risk factors, efficacy, and safety into account. A major challenge is related to adherence to therapy. Sustained release devices may help minimize this problem but are not yet available for clinical routine use. Another hope arises from non-IOP-related treatment concepts. In recent years, much knowledge has been gained regarding the molecular mechanisms that underlie the disease process in glaucoma. This also strengthens the hope that glaucoma therapy beyond IOP lowering will become available. Implementing this concept with clinical trials remains, however, a challenge. PMID:25587905

  10. 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 ...

  11. Genetics Home Reference: early-onset glaucoma

    MedlinePlus

    ... Glaucoma Genetic Testing Registry (2 links) Glaucoma, congenital Primary open angle glaucoma juvenile onset 1 ClinicalTrials.gov (1 link) ClinicalTrials.gov Scientific articles on PubMed (1 link) PubMed OMIM (2 links) ...

  12. Glaucoma: Symptoms, Diagnosis, Treatment and Latest Research

    MedlinePlus

    ... of this page please turn Javascript on. Feature: Glaucoma Glaucoma: Symptoms, Diagnosis, Treatment and Latest Research Past Issues / Fall 2009 Table of Contents Symptoms and Diagnosis Glaucoma can develop in one or both eyes. Often ...

  13. Mouse models of retinal ganglion cell death and glaucoma

    PubMed Central

    McKinnon, Stuart J.; Schlamp, Cassandra L.; Nickells, Robert W.

    2011-01-01

    Once considered too difficult to use for glaucoma studies, mice are now becoming a powerful tool in the research of the molecular and pathological events associated with this disease. Often adapting technologies first developed in rats, ganglion cell death in mice can be induced using acute models and chronic models of experimental glaucoma. Similarly, elevated IOP has been reported in transgenic animals carrying defects in targeted genes. Also, one group of mice, from the DBA/2 line of inbred animals, develops a spontaneous optic neuropathy with many features of human glaucoma that is associated with IOP elevation caused by an anterior chamber pigmentary disease. The advent of mice for glaucoma research is already having a significant impact on our understanding of this disease, principally because of the access to genetic manipulation technology and genetics already well established for these animals. PMID:19105954

  14. Evaluation of post-treatment filter, Part I: Experimental study of DMMP and DIMP filtration at high temperature and high dew point using activated carbon. Final report, November 1994-September 1995

    SciTech Connect

    Mahle, J.J.; Buettner, L.C.; Mauer, S.

    1996-08-01

    A series of experimental results are reported for breakthrough of the agent simulants DMMP and DIMP on coconut carbon. This adsorbent is used in filters for the Chemical Demiliterization program. The conditions were appropriate for a post treatment stack gas filter. Results indicate that high capacity and long filtration times are achievable under moderate humidity conditions up to 180 degrees F.

  15. 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

  16. Nonwoven filtration mat production by electrospinning method

    NASA Astrophysics Data System (ADS)

    Lackowski, M.; Krupa, A.; Jaworek, A.

    2011-06-01

    The filtration of nanoparticles and submicron particles is an important problem in industry and health protection. One of the methods which can be used to solve this problem is to use nonwoven nanofibrous filters. The process of producing filtration mats of different thickness by electrospinning is presented in the paper. The experimental results on filtration properties of nanofibrous filter mat, including the efficiency of removal of cigarette smoke particles from a gas are also presented.

  17. The management of complicated glaucoma

    PubMed Central

    Clement, C I; Goldberg, Ivan

    2011-01-01

    Complicated glaucomas present considerable diagnostic and management challenges. Response to treatment can be unpredictable or reduced compared with other glaucomas. However, target intraocular pressure and preservation of vision may be achieved with selected medical, laser and surgical treatment. The evidence for such treatment is expanding and consequently affords clinicians a better understanding of established and novel techniques. Herein we review the mechanisms involved in the development of complicated glaucoma and the current evidence supporting its management. PMID:21150026

  18. [Angle-closure chronic glaucoma].

    PubMed

    Lachkar, Y

    2003-10-01

    The incidence of chronic angle closure glaucoma is considerably greater than the incidence of the acute type. This type of glaucoma may mimic primary open angle glaucoma with visual field deterioration, optic nerve alteration and intraocular pressure elevation with a quiet painless eye. Its diagnosis is based on indentation gonioscopy showing peripheral anterior synechiae. The mechanisms of angle closure are the pupillary block, the plateau iris configuration and the creeping form. The treatment of chronic angle closure glaucoma is based on laser peripheral iridotomy. PMID:14646832

  19. Endothelin, Astrocytes and Glaucoma

    PubMed Central

    Prasanna, Ganesh; Krishnamoorthy, Raghu; Yorio, Thomas

    2010-01-01

    It has become increasingly clear that astrocytes may play an important role in the genesis of glaucoma. Astrogliosis occurs in response to ocular stress or the presence of noxious stimuli. Agents that appear to stimulate reactive gliosis are becoming increasingly clear. One class of agents that is emerging is the endothelins (ETs; specifically, ET-1). In this review we examine the interactions of ET-1 with astrocytes and provide examples where ET-1 appears to contribute to activation of astrocytes and play a role in the neurodegenerative effects that accompany such reactivation resulting in astrogliosis. These actions are presented in the context of glaucoma although information is also presented with respect to ET-1's role in the central nervous system and brain. While much has been learned with respect to ET-1/astrocyte interactions, there are still a number of questions concerning the potential therapeutic implications of these findings. Hopefully this review will stimulate others to examine this potential. PMID:20849847

  20. [Glaucoma in dogs and cats. Review and retrospective evaluation of 421 patients. I. Pathobiological background, classification and breed predisposition].

    PubMed

    Boevé, M H; Stades, F C

    1985-03-15

    Glaucoma is diagnosed frequently in dogs and cats. A review of case records at the University of Utrecht Small Animal Clinic revealed that during a 4-year period glaucoma accounted for 8.6% of all ophthalmological diagnoses. Glaucoma is defined as an increased intraocular pressure, which sooner or later leads to loss of function of the eye. Primary and secondary types can be distinguished. In primary glaucoma an increased intraocular pressure exists in the absence of other primary eye disorders. By gonioscopy a discrimination can be made between open and narrow or closed anterior chamber angle forms of primary glaucoma. This requires a clear distinction between the definitions of chamber angle and filtration angle. In the Netherlands primary glaucoma is seen especially in the American Cocker Spaniel, Bouvier and Basset breeds. In secondary glaucoma an increased intraocular pressure occurs as a consequence of another primary eye disorder. Dislocation of the lens is the main cause for secondary glaucoma. Several-mainly small-terrier breeds are predisposed to this entity. PMID:3873120

  1. Glomerular filtration rate

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/007305.htm Glomerular filtration rate To use the sharing features on this page, please enable JavaScript. Glomerular filtration rate (GFR) is a test used to check ...

  2. Neurodegeneration and Neuroprotection in Glaucoma.

    PubMed

    Gauthier, Angela C; Liu, Ji

    2016-03-01

    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

  3. 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.

  4. Juvenile glaucoma linked to GLCIA in a Panamanian family.

    PubMed Central

    Lichter, P R; Richards, J E; Boehnke, M; Othman, M; Cameron, B D; Stringham, H M; Downs, C A; Lewis, S B; Boyd, B F

    1996-01-01

    PURPOSE: To carry out clinical and genetic characterization of juvenile-onset primary open-angle glaucoma (POAG) inherited as an autosomal dominant trait in a Panamanian family. METHODS: Twenty-two members of a six-generation Panamanian family underwent an ophthalmologic evaluation. Blood samples were collected from 20 of these individuals for preparation of DNA for use in screening of microsatellite repeat genetic markers via polymerase chain reaction. RESULTS: Eleven living family members covering 4 generations were diagnosed as affected with open-angle glaucoma of primarily juvenile onset. Four of 6 other at-risk individuals examined and enrolled were characterized as unaffected and two as indeterminate. Two additional individuals were not included in this study because they were too young to characterize or to provide a blood sample. Three spouses of affected family members were also examined and found not to have glaucoma. Of clinical importance was the finding of markedly elevated intraocular pressure (IOP) in 2 affected brothers, both of whom were advised to have urgent filtration surgery; the finding of elevated IOP in the only seeing eye of the mother of these brothers, causing us to advise her to pursue more aggressive treatment; and the finding of early signs of glaucoma in a previously undiagnosed 9-year-old family member. Linkage analysis using selected microsatellite repeat markers in the 1q21-q31 region revealed strong evidence for linkage to the GLC1A gene with a maximum lod score of 3.75 for marker D1S431 at a recombination fraction of 0.00. CONCLUSIONS: The most likely interpretation of our data is that a mutation in the GLC1A gene is responsible for juvenile-onset POAG in this Panamanian family, thus expanding the countries of origin where this gene has been found to exist. The numbers of families with GLC1A glaucoma now reported from only a few centers worldwide raise questions about whether this disease may be more common than once thought

  5. 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

  6. Mitochondria-Targeted Antioxidant SS-31 is a Potential Novel Ophthalmic Medication for Neuroprotection in Glaucoma.

    PubMed

    Pang, Yu; Wang, Chao; Yu, Ling

    2015-01-01

    Glaucoma is the second leading cause of irreversible blindness and a neurodegenerative disease with a complex pathogenesis. Increasing evidence suggests that oxidative stress and mitochondrial dysfunction have crucial roles in most neurodegenerative diseases such as glaucoma. The conventional clinical treatment for glaucoma is lowering the intraocular pressure (IOP). Some patients have normal IOP, whereas other patients appear to obtain adequate control of IOP after filtration surgery or medication. However, these patients still experience progressive visual field loss. Vision field loss in glaucoma is attributed to retinal ganglion cell (RGC) apoptosis. Many recent researches demonstrated that the link between mitochondrial dysfunction and oxidative stress was a major cause of RGCs apoptosis. How oxidative stress leads to RGCs apoptosis in glaucoma is unclear but may involve the neurotoxic effects of oxidative stress-induced mitochondrial dysfunction and/or damage from reactive oxygen species (ROS). Investigations are needed concerning the mitochondria as effective targets for potential therapeutic interventions to maintain mitochondrial function and reduce oxidative stress, and thereby delay or stop RGC loss and prolong visual function. The mitochondria-targeted antioxidant Szeto-Schiller (SS) peptide is a candidate molecule. Szeto-Schiller-31 (H-D-Arg-Dmt-Lys-Phe-NH2) is an attractive mitochondria-targeted antioxidant that can protect the mitochondria and RGCs against oxidative damage. Therefore, we suggest SS-31 as a novel neuroprotective ophthalmic drug for protecting RGCs in glaucoma. PMID:27350953

  7. Mitochondria-Targeted Antioxidant SS-31 is a Potential Novel Ophthalmic Medication for Neuroprotection in Glaucoma

    PubMed Central

    PANG, Yu; WANG, Chao; YU, Ling

    2015-01-01

    Glaucoma is the second leading cause of irreversible blindness and a neurodegenerative disease with a complex pathogenesis. Increasing evidence suggests that oxidative stress and mitochondrial dysfunction have crucial roles in most neurodegenerative diseases such as glaucoma. The conventional clinical treatment for glaucoma is lowering the intraocular pressure (IOP). Some patients have normal IOP, whereas other patients appear to obtain adequate control of IOP after filtration surgery or medication. However, these patients still experience progressive visual field loss. Vision field loss in glaucoma is attributed to retinal ganglion cell (RGC) apoptosis. Many recent researches demonstrated that the link between mitochondrial dysfunction and oxidative stress was a major cause of RGCs apoptosis. How oxidative stress leads to RGCs apoptosis in glaucoma is unclear but may involve the neurotoxic effects of oxidative stress-induced mitochondrial dysfunction and/or damage from reactive oxygen species (ROS). Investigations are needed concerning the mitochondria as effective targets for potential therapeutic interventions to maintain mitochondrial function and reduce oxidative stress, and thereby delay or stop RGC loss and prolong visual function. The mitochondria-targeted antioxidant Szeto-Schiller (SS) peptide is a candidate molecule. Szeto-Schiller-31 (H-D-Arg-Dmt-Lys-Phe-NH2) is an attractive mitochondria-targeted antioxidant that can protect the mitochondria and RGCs against oxidative damage. Therefore, we suggest SS-31 as a novel neuroprotective ophthalmic drug for protecting RGCs in glaucoma. PMID:27350953

  8. Lifestyle, Nutrition and Glaucoma

    PubMed Central

    Pasquale, Louis R.; Kang, Jae Hee

    2009-01-01

    The only proven strategy to prevent primary open-angle glaucoma (POAG) is the use of ocular hypotensive therapy among people diagnosed with ocular hypertension. In this review, various modifiable lifestyle factors, such as exercise, diet and cigarette smoking, that may influence intraocular pressure and that have been studied in relation to the risk of developing POAG are discussed. Epidemiologic studies on lifestyle factors are few, and the current evidence suggests that there are no environmental factors that are clearly associated with POAG; however, a few factors merit further study. This review also outlines future directions for research into the primary prevention of POAG. PMID:19680048

  9. Rotary filtration system

    DOEpatents

    Herman, David T.; Maxwell, David N.

    2011-04-19

    A rotary filtration apparatus for filtering a feed fluid into permeate is provided. The rotary filtration apparatus includes a container that has a feed fluid inlet. A shaft is at least partially disposed in the container and has a passageway for the transport of permeate. A disk stack made of a plurality of filtration disks is mounted onto the shaft so that rotation of the shaft causes rotation of the filtration disks. The filtration disks may be made of steel components and may be welded together. The shaft may penetrate a filtering section of the container at a single location. The rotary filtration apparatus may also incorporate a bellows seal to prevent leakage along the shaft, and an around the shaft union rotary joint to allow for removal of permeate. Various components of the rotary filtration apparatus may be removed as a single assembly.

  10. ITP Filtrate Benzene Removal Alternatives

    SciTech Connect

    Dworjanyn, L.O.

    1993-05-21

    Existing ITP filtrate hold tanks may provide sufficient capacity and residence time to strip dissolved benzene from the incoming filtrate using nitrogen sparging in the bottom of the old tanks. This is based on equilibrium supported by late Wash test data using aged washed slurry. Theoretical considerations indicate that benzene stripping will be more difficult from the ITP unwashed high salt filtrates due to reduced mass transfer. Therefore experimental sparging data is needed to quantify the theoretical effects.Foaming limits which dictate allowable sparging rate will also have to be established. Sparging in the hold tanks will require installation of sintered metal spargers, and possibly stirrers and foam monitoring/disengagement equipment. The most critical sparging needs are at the start of the precipitation/concentration cycle, when the filtrate flux rate is the highest,and at the end of wash cycle where Henry`s equilibrium constant falls off,requiring more gas to sparge the dissolved benzene. With adequate recycle (for proper distribution) or sparging in the old tanks, the 30 inch column could be used for the complete ITP process. A courser packing would reduce back pressure while enabling benzene stripping. The Late Wash Tests indicate adequate benzene stripping even at reduced gas flow. This will require experimental verification under ITP conditions. Using the 30 in. column vs 18 in. during the wash cycle will enhance stripping without need for additional sparging provided the minimum flow requirements are met.

  11. 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 ...

  12. Pediatric genetic diseases causing glaucoma

    PubMed Central

    Ichhpujani, Parul; Singh, Rohan B.

    2014-01-01

    Glaucomatous optic neuropathy may be considered as an endpoint of multiple systemic factors. Genetic conditions commonly causing glaucoma in children and adolescents include Axenfeld-Reiger syndrome, aniridia, Marfan syndrome, Weill-Marchessani syndrome, Sturge-Weber syndrome, Rubinstein-Taybi syndrome, nevus of Ota, congenital rubella and neurofibromatosis type 1. In the recent years, with the advancements in genetic research our understanding of the fundamental causes of glaucoma associated with inherited disorders has improved. In addition to intraocular pressure reduction, it is important for the clinician to be familiar with the multiple systemic associations with glaucoma, to re-evaluate treatment frequently, and to target the underlying disease process, if present.

  13. In vitro experiment of the pressure regulating valve for a glaucoma implant

    NASA Astrophysics Data System (ADS)

    Bae, Byunghoon; Kee, Hongseok; Kim, Seonho; Lee, Yeon; Sim, Taeseok; Kim, Yongkweon; Park, Kyihwan

    2003-09-01

    Glaucoma is an eye disease which is caused by abnormal high intraocular pressure (IOP) in the eye. If the condition of the patient becomes serious, the use of an implant device is recommended, which decreases the IOP compulsory. Active implants for glaucoma implants are capable of controlling the IOP actively and coping with the personal differences of patients. However, the conventional active valves for the glaucoma implant are not convenient for the patient and feasibility is not shown for the glaucoma treatment. In this paper, we propose, analyze, fabricate and experiment on the pressure regulating valve for the active implant. Based on the analysis, we carry out optimal design of the proposed valve. The in vitro experiments are performed extensively both using and not using a rabbit in open- and closed-loop pressure control. The various experimental results verify the possibility of the proposed valve for a glaucoma implant.

  14. Managing advanced unilateral pseudoexfoliative glaucoma.

    PubMed

    Marques, André

    2014-01-01

    The only proven therapy for glaucoma is intraocular pressure (IOP) reduction, which can be accomplished by different means. Each should be properly discussed with patients in order to best preserve visual function and quality of life. We report a case of unilateral pseudoexfoliative glaucoma, treated for years with triple topical IOP-lowering drugs. The patient presented with advanced optic neuropathy and important ocular side effects secondary to the treatment. Having discussed his options and prognosis, laser trabeculoplasty was performed while maintaining the remaining therapy considering the advanced stage of glaucoma. His IOP was effectively reduced and no progression was noted after 1-year follow-up. Although medical therapy is the mainstream in glaucoma management, its side effects should not be ignored, especially in unilateral cases. Surgery might have been a better solution, but we chose to perform laser trabeculoplasty, an effective and safer alternative, considering the unlikely but serious risk of the "wipe-out phenomenon" in this case. PMID:24850557

  15. Implants for draining neovascular glaucoma.

    PubMed Central

    Molteno, A C; Van Rooyen, M M; Bartholomew, R S

    1977-01-01

    The implant design, surgical technique, and pharmacological methods of controlling bleb fibrosis, used to treat neovascular glaucoma, are described, together with the results of 14 operations performed on 12 eyes. Images PMID:843508

  16. Does Your Child Have Glaucoma?

    MedlinePlus

    ... Involved News About Us Donate In This Section Does Your Child Have Glaucoma? email Send this article ... for in children under the age of two: Does your child have unusually large eyes? Is there ...

  17. Feline Glaucoma – A Comprehensive Review

    PubMed Central

    McLellan, Gillian J; Miller, Paul E

    2012-01-01

    Cats with glaucoma typically present late in the course of disease. It is likely that glaucoma in cats is under-diagnosed due to its insidious onset and gradual progression, as well as limitations of some commonly used tonometers in this species. Treatment of glaucoma in feline patients presents a clinical challenge, particularly as glaucoma is often secondary to other disease processes in cats. In this review, we consider the clinical features, patho-physiology and classification of the feline glaucomas and provide current evidence to direct selection of appropriate treatment strategies for feline glaucoma patients. PMID:21923820

  18. [Current trends in neovascular glaucoma treatment].

    PubMed

    Vancea, P P; Abu-Taleb, A

    2005-01-01

    Neovascular glaucoma is divided in three clinical stages: rubeosis iridis, secondary open-angle glaucoma, and synechia of the angle-closure glaucoma. 36% of neovascular glaucomas occurs after central retinal vein occlusion, 32% after diabetic proliferative retinopathy, and 13% occurs after carotid artery obstructive. The key of success in the treatment of neovascular glaucoma is the early and rightly diagnosis, the treatment is aimed mainly at relieving pain, as the prognosis for maintaining visual function is extremely poor. The most important surgical procedures are trabeculectomy, artificial drainage shunts and cyclo-distraction by trans-scleral diode laser. This essay presents a synthesis of modern principle data concerning neovascular glaucoma. PMID:16607783

  19. [Screening in open angle glaucoma].

    PubMed

    Mocanu, Carmen; Mocanu, Andrei

    2012-01-01

    Primary open angle glaucoma (POAG) represents the second cause of mondial cecity, after retinal diabetes complications, with extremely severe implications in quality of life. Screening testing for glaucoma is justified, because only the diagnosis in very incipient stage will preserve the visual function; any treatment will not assure the reversibility of pre-existent optic nerve lesions. Screening of glaucoma, will take into a consideration the costs, the time of investigation, the adverse effects, and the sensitivity and specificity of tests; the last parameter also will strongly influence the positive predictive value. An ideal screening identifies all subjects that present the disease (sensitivity) and will exclude all healthy subjects (specificity). In this moment, in Dolj district, the diagnosis is based on active diagnosis of new cases of glaucoma on the high risk level population, therefore in a 210000 habitants. 4723 patients with glaucoma are diagnosed, screened and follow-up on medical cabinets and on Center of Glaucoma, which coordinates their activity. To better monitored patients, automatized programs with acquisition and storage for different types of medical imaging facilities had become indispensable to any routine practice. PMID:23755511

  20. Glaucoma: Screening Can Save Your Sight!

    MedlinePlus

    ... People with glaucoma see the world through a tunnel. Glaucoma is a group of diseases that can ... diagnosis is important. Studies have shown that early detection and treatment are the best way to control ...

  1. Dry Eyes and Glaucoma: Double Trouble

    MedlinePlus

    ... Size Small Text Medium Text Large Text Contrast Dark on Light Light on Dark Donate Search Menu Donate What is Glaucoma? Care ... Low Vision Resources Medication Guide Resources on the Web » See All Articles Help the Cause Glaucoma affects ...

  2. 7. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT (#1773), LOOKING NORTHEAST, SHOWING PUMP NO. 1 AND METERING EQUIPMENT - Presidio Water Treatment Plant, Filtration Plant, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA

  3. 8. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT (#1773), LOOKING SOUTHWEST, SHOWING MEZZANINE WITH FILTER TANKS AT REAR - Presidio Water Treatment Plant, Filtration Plant, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA

  4. WATER FILTRATION AT DULUTH

    EPA Science Inventory

    After partial completion of the Lakewood Filtration Plant at Duluth, studies were begun with funding provided by the demonstration grant. Research covered a variety of topics and was done with a 10 gpm pilot plant located at the filtration plant, with the full scale plant operati...

  5. Normal-tension glaucoma (Low-tension glaucoma)

    PubMed Central

    Anderson, Douglas R

    2011-01-01

    Glaucoma is now considered an abnormal physiology in the optic nerve head that interacts with the level of intraocular pressure (IOP), with the degree and rate of damage depending on the IOP and presumably the degree of abnormal physiology. Diagnosis of normal-tension glaucoma (NTG), defined as glaucoma without a clearly abnormal IOP, depends on recognizing symptoms and signs associated with optic nerve vulnerability, in addition to absence of other explanations for disc abnormality and visual field loss. Among the findings are a halo or crescent of absence of retinal pigment epithelium around the disc, bilateral pre-chiasmal visual field defects, splinter hemorrhages at the disc margin, vascular dysregulation (low blood pressure, cold hands and feet, migraine headache with aura, and the like), or a family history of glaucoma. Possibly relevant, is a history of hemodynamic crisis, arterial obstructive disease, or sleep apnea. Neurological evaluation with imaging is needed only for atypical cases or ones that progress unexpectedly. Management follows the same principle of other chronic glaucomas, to lower the IOP by a substantial amount, enough to prevent disabling visual loss. However, many NTG cases are non-progressive. Therefore, it may often be wisein mild cases to determine whether the case is progressive and the rate of progression before deciding on how aggressivene to be with therapy. Efforts at neuroprotection and improvement in blood flow have not yet been shown effective. PMID:21150042

  6. Provider Education about Glaucoma and Glaucoma Medications during Videotaped Medical Visits.

    PubMed

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

    2014-01-01

    Objective. The purpose of this study was to examine how patient, physician, and situational factors are associated with the extent to which providers educate patients about glaucoma and glaucoma medications, and which patient and provider characteristics are associated with whether providers educate patients about glaucoma and glaucoma medications. Methods. Patients with glaucoma who were newly prescribed or on glaucoma medications were recruited and a cross-sectional study was conducted at six ophthalmology clinics. Patients' visits were videotape recorded and patients were interviewed after visits. Generalized estimating equations were used to analyze the data. Results. Two hundred and seventy-nine patients participated. Providers were significantly more likely to educate patients about glaucoma and glaucoma medications if they were newly prescribed glaucoma medications. Providers were significantly less likely to educate African American patients about glaucoma. Providers were significantly less likely to educate patients of lower health literacy about glaucoma medications. Conclusion. Eye care providers did not always educate patients about glaucoma or glaucoma medications. Practice Implications. Providers should consider educating more patients about what glaucoma is and how it is treated so that glaucoma patients can better understand their disease. Even if a patient has already been educated once, it is important to reinforce what has been taught before. PMID:24868450

  7. Aqueous shunts for glaucoma

    PubMed Central

    Minckler, Don; Vedula, Satyanarayana S; Li, Tianjing; Mathew, Milan; Ayyala, Ramesh; Francis, Brian

    2014-01-01

    Background Aqueous shunts are employed for intraocular pressure (IOP) control in primary and secondary glaucomas that fail medical, laser, and other surgical therapies. Objectives This review compares aqueous shunts for IOP control and safety. Search strategy We searched CENTRAL, MEDLINE, PubMed, EMBASE, NRR in January 2006, LILACS to February 2004 and reference lists of included trials. Selection criteria We included all randomized and quasi-randomized trials in which one arm of the study involved shunts. Data collection and analysis Two authors independently extracted data for included studies and a third adjudicated discrepancies. We contacted investigators for missing information. We used fixed-effect models and summarized continuous outcomes using mean differences. Main results We included fifteen trials with a total of 1153 participants with mixed diagnoses. Five studies reported details sufficient to verify the method of randomization but only two had adequate allocation concealment. Data collection and follow-up times were variable. Meta-analysis of two trials comparing Ahmed implant with trabeculectomy found trabeculectomy resulted in lower mean IOPs 11 to 13 months later (mean difference 3.81 mm Hg, 95% CI 1.94 to 5.69 mm Hg). Meta-analysis of two trials comparing double-plate Molteno implant with the Schocket shunt was not done due to substantial heterogeneity. One study comparing ridged with standard double-plate Molteno implants found no clinically significant differences in outcome. Two trials investigating the effectiveness of adjunctive mitomycin (MMC) with the Molteno and Ahmed implants found no evidence of benefit with MMC. Two trials that investigated surgical technique variations with the Ahmed found no benefit with partial tube ligation or excision of Tenon's capsule. One study concluded there were outcome advantages with a double versus a single-plate Molteno implant and one trial comparing the 350 mm2 and 500 mm2 Baerveldt shunts found no

  8. Neuroinflammation in advanced canine glaucoma

    PubMed Central

    Jiang, Bing; Harper, Matthew M.; Kecova, Helga; Adamus, Grazyna; Kardon, Randy H.; Grozdanic, Sinisa D.

    2010-01-01

    Purpose The pathophysiological events that occur in advanced glaucoma are not well characterized. The principal purpose of this study is to characterize the gene expression changes that occur in advanced glaucoma. Methods Retinal RNA was obtained from canine eyes with advanced glaucoma as well as from healthy eyes. Global gene expression patterns were determined using oligonucleotide microarrays and confirmed by real-time PCR. The presence of tumor necrosis factor (TNF) and its receptors was evaluated by immunolabeling. Finally, we evaluated the presence of serum autoantibodies directed against retinal epitopes using western blot analyses. Results We identified over 500 genes with statistically significant changes in expression level in the glaucomatous retina. Decreased expression levels were detected for large number of functional groups, including synapse and synaptic transmission, cell adhesion, and calcium metabolism. Many of the molecules with decreased expression levels have been previously shown to be components of retinal ganglion cells. Genes with elevated expression in glaucoma are largely associated with inflammation, such as antigen presentation, protein degradation, and innate immunity. In contrast, expression of many other pro-inflammatory genes, such as interferons or interleukins, was not detected at abnormal levels. Conclusions This study characterizes the molecular events that occur in the canine retina with advanced glaucoma. Our data suggest that in the dog this stage of the disease is accompanied by pronounced retinal neuroinflammation. PMID:21042562

  9. Ex-PRESS glaucoma filter: an MRI compatible metallic orbital foreign body imaged at 1.5 and 3 T

    PubMed Central

    Mabray, M.C.; Uzelac, A.; Talbott, J.F.; Lin, S.C.; Gean, A.D.

    2015-01-01

    AIM To report on the MRI compatibility of the Ex-PRESS glaucoma filtration device, a tiny metallic implant placed into the anterior chamber of the eye that is much smaller than traditional glaucoma shunts, and to educate the radiology community regarding its appearance. MATERIALS AND METHODS Seven patients with Ex-PRESS glaucoma filtration devices were identified that had undergone MRI at San Francisco General Hospital/University of California San Francisco Medical Center by searching and cross-referencing the radiology reporting system and the electronic medical record. MRI images were reviewed for artefact interfering with interpretation. Ophthalmology examinations were reviewed for evidence of complications. RESULTS Eighteen individual MRI examinations were performed during 12 unique MRI events on these 7 patients. 13/18 individual MRI examinations and 7/12 MRI events were performed at 3 T with the others performed at 1.5 T. Mean time from Ex-PRESS implantation to MRI was 17.5 months. Mean time from MRI to first ophthalmology examination was 1.1 months and from MRI to latest ophthalmology examination was 6.6 months. Susceptibility artefact did not interfere with image interpretation and no complications related to MRI were encountered. CONCLUSION The Ex-PRESS glaucoma filtration device appears to be safe for MRI at 1.5 and 3 T and does not produce significant susceptibility artefact to affect diagnostic interpretation adversely. PMID:25735675

  10. Risk Factors for Glaucoma Needing More Attention

    PubMed Central

    Coleman, Anne L; Kodjebacheva, Gergana

    2009-01-01

    Glaucoma is defined as a chronic progressive optic neuropathy, for which elevated intraocular pressure (IOP) is the only modifiable risk factor. Emerging research indicates that modifiable factors besides IOP may be associated with the presence of glaucoma. In this review, we discuss the role of modifiable determinants, specifically socioeconomic status, nutritional intake, body mass index and obesity, exercise, smoking, and sleep apnea, in the presence of glaucoma. Preliminary studies suggest that associations may exist between these non-inherent factors and glaucoma although research had significant limitations. The mechanisms of influence are unknown or understudied. Research needs to incorporate the broader behavioral and social factors that may affect glaucoma status. PMID:19816585

  11. Clinical Management of Malignant Glaucoma

    PubMed Central

    Foreman-Larkin, Julie; Netland, Peter A.; Salim, Sarwat

    2015-01-01

    Malignant glaucoma remains one of the most challenging complications of ocular surgery. Although it has been reported to occur spontaneously or after any ophthalmic procedure, it is most commonly encountered after glaucoma surgery in eyes with prior chronic angle closure. The clinical diagnosis is made in the setting of a patent peripheral iridotomy and axial flattening of the anterior chamber. Intraocular pressure is usually elevated, but it may be normal in some cases. Although the exact etiology of this condition is not fully understood, several mechanisms have been proposed and it is thought to result from posterior misdirection of aqueous humor into or behind the vitreous. This review discusses pathophysiology, differential diagnosis, imaging modalities, and current treatment strategies for this rare form of secondary glaucoma. PMID:26819754

  12. Differential Gene Expression in Glaucoma

    PubMed Central

    Jakobs, Tatjana C.

    2014-01-01

    In glaucoma, regardless of its etiology, retinal ganglion cells degenerate and eventually die. Although age and elevated intraocular pressure (IOP) are the main risk factors, there are still many mysteries in the pathogenesis of glaucoma. The advent of genome-wide microarray expression screening together with the availability of animal models of the disease has allowed analysis of differential gene expression in all parts of the eye in glaucoma. This review will outline the findings of recent genome-wide expression studies and discuss their commonalities and differences. A common finding was the differential regulation of genes involved in inflammation and immunity, including the complement system and the cytokines transforming growth factor β (TGFβ) and tumor necrosis factor α (TNFα). Other genes of interest have roles in the extracellular matrix, cell–matrix interactions and adhesion, the cell cycle, and the endothelin system. PMID:24985133

  13. Pseudophakic pupillary-block glaucoma.

    PubMed Central

    Werner, D.; Kaback, M.

    1977-01-01

    Four cases of iris-supported pseudophakic pupillary-block glaucoma were presented. Pupillary-block glaucoma is the first postoperative complication seen following the implantation of an intraocular lens, and in our series occurred at an incidence of 3-8%. A short review was made of pupillary-block glaucoma with all types of intraocular lenses, with emphasis on the iris-supported lens. The role of inflammation, haemorrhage, and vitreous and lens material in obstructing aqueous flow at the pupil and peripheral iridectomy site was emphasised. Pitfalls in the diagnosis and management of this condition were reviewed. Methods of prevention and treatment were reviewed with emphasis on early mydriasis, along with carbonic anhydrase inhibitors and hyperosmotic agents as a primary medical treatment. Iridectomy, laser iridotomy, or transfixation of the iris was mentioned as a surgical treatment. PMID:871462

  14. A retrospective survey of childhood glaucoma prevalence according to Childhood Glaucoma Research Network classification

    PubMed Central

    Hoguet, Ambika; Grajewski, Alana; Hodapp, Elizabeth; Chang, Ta Chen Peter

    2016-01-01

    Purpose: To evaluate the Childhood Glaucoma Research Network (CGRN) classification system and describe the prevalence of each subtype according to this classification. Materials and Methods: Retrospectively, the medical records of 205 consecutive childhood glaucoma and glaucoma suspect patients at an urban tertiary care center were reviewed. The initial diagnosis and new diagnosis according to CGRN classification were recorded. Results: All patients fit one of the seven categories of the new classification. Seventy-one percent of diagnoses were changed upon reclassification. Twenty-three percent of patients had primary glaucoma (juvenile open-angle glaucoma and primary congenital glaucoma [PCG]); 36% had secondary glaucoma (glaucoma associated with nonacquired ocular anomalies; glaucoma associated with nonacquired systemic disease or syndrome; glaucoma associated with acquired condition; and glaucoma following cataract surgery); and 39% were glaucoma suspect. Of the patients diagnosed with glaucoma, PCG was the most common diagnosis, seen in 32% of patients. Conclusion: The CGRN classification provides a useful method of classifying childhood glaucoma. PMID:27050345

  15. Pathophysiology of glaucoma in uveitis.

    PubMed

    Ritch, R

    1981-09-01

    Glaucoma secondary to uveitis may occur by any one or by a combination of several different pathophysiological mechanisms. These include acute angle-closure due to iris bombé caused by posterior synechiae; chronic angle-closure due to peripheral anterior synechiae; and open angle glaucoma due to obstruction and/or inflammation of the trabecular meshwork. Secretory hypotony may mask impairment of outflow, while steroids used to treat the uveitis may further complicate the situation by causing a rise in intraocular pressure. Careful delineation of the pathophysiology involved is the cornerstone of successful management. PMID:6963820

  16. Water sample filtration unit

    USGS Publications Warehouse

    Skougstad, M.W.; Scarbro, G.F., Jr.

    1968-01-01

    A readily portable, all plastic, pressure filtration unit is described which greatly facilitates rapid micropore membrane field filtration of up to several liters of water with a minimum risk of inorganic chemical alteration or contamination of the sample. The unit accommodates standard 10.2-cm. (4-inch) diameter filters. The storage and carrying case serves as a convenient filter stand for both field and laboratory use.

  17. Water Filtration Products

    NASA Technical Reports Server (NTRS)

    1986-01-01

    American Water Corporation manufactures water filtration products which incorporate technology originally developed for manned space operations. The formula involves granular activated charcoal and other ingredients, and removes substances by catalytic reactions, mechanical filtration, and absorption. Details are proprietary. A NASA literature search contributed to development of the compound. The technology is being extended to a deodorizing compound called Biofresh which traps gas and moisture inside the unit. Further applications are anticipated.

  18. Hot gas filtration technical issues

    SciTech Connect

    Pontius, D.H.

    1995-11-01

    The primary objective of this research has been to provide an understanding of factors pertinent to the development of an effective filtration system for removing particles from high-temperature, high-pressure gas streams in advanced power generation systems under development by the Department of Energy. Information used to define the filtration system issues was compiled from the Morgantown Energy Technology Center (METC) Contractors Conferences, specific tasks assigned to Southern Research Institute, meetings with METC personnel and contractors, and other conferences and workshops organized by METC. Initial research and pilot scale installations have shown that there are some potential problem areas. Thick ash deposits have formed, bridging from passive surfaces to the filter material and between filter candles. A great number of ceramic filters have broken in various experimental and demonstration devices, especially during long-term testing. This paper reviews particulate characteristics (effects on filtration processes, conventional fly ash, gasifier char, PFBC ash, and detailed studies of PFBC ash) and ceramic filter materials (general issues, thermal stress, clay-bonded SiC filter materials, and monolithic ceramic materials).

  19. COMPARISONS OF VARIOUS FILTRATION MEDIA

    EPA Science Inventory

    The report reviews use of filtering materials in diatomaceous earth (DE) filtration, slow sand filtration, and coagulation-rapid rate filtration. For DE filtration, increased effluent clarity (lower turbidity) is generally attained at the expense of increased rates of head loss i...

  20. Managing advanced unilateral pseudoexfoliative glaucoma

    PubMed Central

    Marques, André

    2014-01-01

    The only proven therapy for glaucoma is intraocular pressure (IOP) reduction, which can be accomplished by different means. Each should be properly discussed with patients in order to best preserve visual function and quality of life. We report a case of unilateral pseudoexfoliative glaucoma, treated for years with triple topical IOP-lowering drugs. The patient presented with advanced optic neuropathy and important ocular side effects secondary to the treatment. Having discussed his options and prognosis, laser trabeculoplasty was performed while maintaining the remaining therapy considering the advanced stage of glaucoma. His IOP was effectively reduced and no progression was noted after 1-year follow-up. Although medical therapy is the mainstream in glaucoma management, its side effects should not be ignored, especially in unilateral cases. Surgery might have been a better solution, but we chose to perform laser trabeculoplasty, an effective and safer alternative, considering the unlikely but serious risk of the “wipe-out phenomenon” in this case. PMID:24850557

  1. Peripapillary Retinoschisis in Glaucoma Patients

    PubMed Central

    Bayraktar, Serife; Cebeci, Zafer; Kabaalioglu, Melis; Ciloglu, Serife; Kir, Nur; Izgi, Belgin

    2016-01-01

    Purpose. To investigate peripapillary retinoschisis and its effect on retinal nerve fiber layer (RNFL) thickness measurements by using spectral-domain optical coherence tomography (SD-OCT) in glaucomatous eyes. Methods. Circumpapillary RNFL (cpRNFL) B-scan images of 940 glaucoma patients (Group 1) and 801 glaucoma-suspect patients (Group 2) obtained by SD-OCT were reviewed. The structural and clinical characteristics of the retinoschisis were investigated. The RNFL thickness measurements taken at the time of retinoschisis diagnosis and at the follow-up visits were also compared. Results. Twenty-nine retinoschisis areas were found in 26 of the 940 glaucoma patients (3.1%) in Group 1 and seven areas were found in 801 patients (0.87%) in Group 2. In glaucomatous eyes, the retinoschisis was attached to the optic disc and overlapped with the RNFL defect. At the time of retinoschisis, the RNFL thickness was statistically greater in the inferior temporal quadrant when compared with the follow-up scans (p < 0.001). No macular involvement or retinal detachment was observed. Conclusion. The present study investigated 33 peripapillary retinoschisis patients. Increase in RNFL thickness measurements was observed at the time of retinoschisis. It is important to examine the cpRNFL B-scan images of glaucoma patients so that the RNFL thickness is not overestimated. PMID:27069674

  2. SQSTM1 Mutations and Glaucoma

    PubMed Central

    Scheetz, Todd E.; Roos, Ben R.; Solivan-Timpe, Frances; Miller, Kathy; DeLuca, Adam P.; Stone, Edwin M.; Kwon, Young H.; Alward, Wallace L. M.; Wang, Kai; Fingert, John H.

    2016-01-01

    Glaucoma is the most common cause of irreversible blindness worldwide. One subset of glaucoma, normal tension glaucoma (NTG) occurs in the absence of high intraocular pressure. Mutations in two genes, optineurin (OPTN) and TANK binding kinase 1 (TBK1), cause familial NTG and have known roles in the catabolic cellular process autophagy. TKB1 encodes a kinase that phosphorylates OPTN, an autophagy receptor, which ultimately activates autophagy. The sequestosome (SQSTM1) gene also encodes an autophagy receptor and also is a target of TBK1 phosphorylation. Consequently, we hypothesized that mutations in SQSTM1 may also cause NTG. We tested this hypothesis by searching for glaucoma-causing mutations in a cohort of NTG patients (n = 308) and matched controls (n = 157) using Sanger sequencing. An additional 1098 population control samples were also analyzed using whole exome sequencing. A total of 17 non-synonymous mutations were detected which were not significantly skewed between cases and controls when analyzed separately, or as a group (p > 0.05). These data suggest that SQSTM1 mutations are not a common cause of NTG. PMID:27275741

  3. Prevention of Blindness: Chronic Glaucoma

    ERIC Educational Resources Information Center

    Richardson, Kenneth T.

    1970-01-01

    An evaluation of present screening procedures for chronic open-angle glaucoma includes suggestions for improvement: greater distribution of screening and education, conversion from monophasic to multiphasic screen, and examination of visual fields, optic nerve, and medical history in addition to the tonometry currently done. (KW)

  4. Glaucoma and optic nerve repair.

    PubMed

    Diekmann, Heike; Fischer, Dietmar

    2013-08-01

    Glaucoma is a leading cause of irreversible blindness worldwide and causes progressive visual impairment attributable to the dysfunction and death of retinal ganglion cells (RGCs). Progression of visual field damage is slow and typically painless. Thus, glaucoma is often diagnosed after a substantial percentage of RGCs has been damaged. To date, clinical interventions are mainly restricted to the reduction of intraocular pressure (IOP), one of the major risk factors for this disease. However, the lowering of IOP is often insufficient to halt or reverse the progress of visual loss, underlining the need for the development of alternative treatment strategies. Several lines of evidence suggest that axonal damage of RGCs occurs primary at the optic nerve head, where axons appear to be most vulnerable. Axonal injury leads to the functional loss of RGCs and subsequently induces the death of the neurons. However, the detailed molecular mechanism(s) underlying IOP-induced optic nerve injury remain poorly understood. Moreover, whether glaucoma pathophysiology is primarily axonal, glial, or vascular remains unclear. Therefore, protective strategies to prevent further axonal and subsequent soma degeneration are of great importance to limit the progression of sight loss. In addition, strategies that stimulate injured RGCs to regenerate and reconnect axons with their central targets are necessary for functional restoration. The present review provides an overview of the context of glaucoma pathogenesis and surveys recent findings regarding potential strategies for axonal regeneration of RGCs and optic nerve repair, focusing on the role of cytokines and their downstream signaling pathways. PMID:23512141

  5. Optical Coherence Tomography in Glaucoma

    NASA Astrophysics Data System (ADS)

    Berisha, Fatmire; Hoffmann, Esther M.; Pfeiffer, Norbert

    Retinal nerve fiber layer (RNFL) thinning and optic nerve head cupping are key diagnostic features of glaucomatous optic neuropathy. The higher resolution of the recently introduced SD-OCT offers enhanced visualization and improved segmentation of the retinal layers, providing a higher accuracy in identification of subtle changes of the optic disc and RNFL thinning associated with glaucoma.

  6. [Surgical indications in coexisting cataracts and glaucoma].

    PubMed

    Collignon-Brach, J D; Ravet, O; Robe-Collignon, N

    2000-01-01

    Cataract surgery in glaucoma patients remains a controversial subjects. Indication of surgery depends on a lot of clinical parameters: diagnosis, state, evolution of glaucoma as well as compliance with medical treatment--surgical procedures of cataract and glaucoma--sites of the surgery--use of antifibrosis agents and surgeon's experience. As cataract extraction alone decreases the intraocular pressure in open angle glaucoma and mainly in uncomplicated closed angle glaucoma and trabeculectomy alone reduces the intraocular pressure more than combined surgery with less complications we recommended the following surgical options: Cataract extraction alone in patients with controlled open angle glaucoma and in patients with closed angle glaucoma. A two step procedure: filtering surgery followed by cataract extraction in patients with poorly controlled open angle glaucoma or mixed closed angle glaucoma. Ambulatory surgery and topical anesthesia permit a two stages surgery with less inconveniences. A combined procedure in patients with a chronic closed angle glaucoma where filtering procedure alone is associated with important complications. Actually, the best surgical cataract procedure is phacoemulsification with a small supero-corneal incision and implantation of a foldable intraocular lens. The best filtering procedure remains trabeculectomy, or the new non penetrating trabecular surgery for experimented surgeons, in the superior quadrant. In the future new surgical procedures and new safe and non toxic pharmacologic drugs which modulate wound healing could be found in order to increase the efficacity and indications of combined surgery. PMID:11262885

  7. Corneal hysteresis and its relevance to glaucoma

    PubMed Central

    Deol, Madhvi; Taylor, David A.; Radcliffe, Nathan M.

    2015-01-01

    Purpose of review Glaucoma is a leading cause of irreversible blindness worldwide. It is estimated that roughly 60.5 million people had glaucoma in 2010 and that this number is increasing. Many patients continue to lose vision despite apparent disease control according to traditional risk factors. The purpose of this review is to discuss the recent findings with regard to corneal hysteresis, a variable that is thought to be associated with the risk and progression of glaucoma. Recent findings Low corneal hysteresis is associated with optic nerve and visual field damage in glaucoma and the risk of structural and functional glaucoma progression. In addition, hysteresis may enhance intraocular pressure (IOP) interpretation: low corneal hysteresis is associated with a larger magnitude of IOP reduction following various glaucoma therapies. Corneal hysteresis is dynamic and may increase in eyes after IOP-lowering interventions are implemented. Summary It is widely accepted that central corneal thickness is a predictive factor for the risk of glaucoma progression. Recent evidence shows that corneal hysteresis also provides valuable information for several aspects of glaucoma management. In fact, corneal hysteresis may be more strongly associated with glaucoma presence, risk of progression, and effectiveness of glaucoma treatments than central corneal thickness. PMID:25611166

  8. One Year of Glaucoma Research in Review: 2012 to 2013

    PubMed Central

    Kim, Charles; Demetriades, Anna M.; Radcliffe, Nathan M.

    2014-01-01

    Purpose The objective of this study was to provide the practicing clinical ophthalmologist with an update of pertinent glaucoma literature published from 2012 to 2013. Design Literature review. Methods The authors conducted a 1-year (July 1, 2012, to September 30, 2013) English-language glaucoma literature search on PubMed using the following terms: glaucoma, automated perimetry, optic nerve imaging, optical coherence tomography, glaucoma structure and function, intraocular pressure, central corneal thickness, glaucoma medical therapy, neuroprotection, glaucoma laser treatment, secondary glaucoma, glaucoma surgery, and miscellaneous topics in glaucoma. Results Of 2659 articles on glaucoma published during our time frame, this review selected original and review articles that reflect novel aspects and updates in the field of glaucoma, while excluding letters to the editor, unpublished works, and abstracts. Preference was given to human research. Conclusions This review focuses on literature that is applicable to ophthalmologists in practice and also highlights studies that may enhance the diagnosis and management of glaucoma. PMID:25177529

  9. Waste water filtration enhancement

    SciTech Connect

    Martin, H.L.

    1989-01-01

    Removal of submicron particles from process solutions and waste water is now economically achievable using a new Tyvek{reg sign} media in conventional filtration equipment. This new product greatly enhances filtration and allows use of the much improved filter aids and polymers which were recently developed. It has reduced operating costs and ensures a clean effluent discharge to the environment. This significant technical development is especially important to those who discharge to a small stream with low 7Q10 flow and must soon routinely pass the Toxicity tests that are being required by many States for NPDES permit renewal. The Savannah River Plant produces special nuclear materials for the US Government. Aluminum forming and metal finishing operations in M-Area, that manufacture fuel and target assemblies for the nuclear reactors, discharge to a waste water treatment facility using BAT hydroxide precipitation and filtration. The new Tyvek{reg sign} media and filter aids have achieved 55% less solids in the filtrate discharged to Tims Branch Creek, 15% less hazardous waste (dry filter cake), 150%-370% more filtration capacity, 74% lower materials purchase cost, 10% lower total M-Area manufacturing cost, and have improved safety. Performance with the improved polymers is now being evaluated.

  10. Diabetes Mellitus as a Risk Factor in Glaucoma's Physiopathology and Surgical Survival Time: A Literature Review.

    PubMed

    Costa, Lívio; Cunha, João Paulo; Amado, Duarte; Pinto, Luís Abegão; Ferreira, Joana

    2015-01-01

    Glaucoma is a multifactorial condition under serious influence of many risk factors. The role of diabetes mellitus (DM) in glaucoma etiology or progression remains inconclusive. Although, the diabetic patients have different healing mechanism comparing to the general population and it has a possible-negative role on surgical outcomes. This review article attempts to analyze the association of both diseases, glaucoma and DM, before and after the surgery. The epidemiological studies, based mainly in population prevalence analyzes, have shown opposite outcomes in time and even in the most recent articles also the association remains inconclusive. On the contrary, the experimental models based on animal induced chronic hyperglycemia have shown an important association of both diseases, explained by common neurodegenerative mechanisms. Diabetic patients have a different wound healing process in the eye viz-a-viz other organs. The healing process is more and it results in lower surgical survival time, higher intraocular pressure (IOP) levels and, therefore, these patients usually need more medication to lower the IOP. Both randomized and nonrandomized retrospective and experimental molecular studies have shown the association between DM and glaucoma. Further studies are needed to get better explanations about outcomes on more recent surgical procedures and with the exponential use of antifibrotics. How to cite this article: Costa L, Cunha JP, Amado D, Pinto LA, Ferreira J. Diabetes Mellitus as a Risk Factor in Glaucoma's Physiopathology and Surgical Survival Time: A Literature Review. J Curr Glaucoma Pract 2015;9(3):81-85. PMID:26997842

  11. Microfluidic colloid filtration

    NASA Astrophysics Data System (ADS)

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-03-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” - often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level.

  12. Microfluidic colloid filtration

    PubMed Central

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-01-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” – often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level. PMID:26927706

  13. Microfluidic colloid filtration.

    PubMed

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J C; Wessling, Matthias

    2016-01-01

    Filtration of natural and colloidal matter is an essential process in today's water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a "cake layer" - often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level. PMID:26927706

  14. CENTRIFUGAL MEMBRANE FILTRATION

    SciTech Connect

    Daniel J. Stepan; Bradley G. Stevens; Melanie D. Hetland

    1999-10-01

    The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc).

  15. Non-steroidal drug-induced glaucoma

    PubMed Central

    Razeghinejad, M R; Pro, M J; Katz, L J

    2011-01-01

    Numerous systemically used drugs are involved in drug-induced glaucoma. Most reported cases of non-steroidal drug-induced glaucoma are closed-angle glaucoma (CAG). Indeed, many routinely used drugs that have sympathomimetic or parasympatholytic properties can cause pupillary block CAG in individuals with narrow iridocorneal angle. The resulting acute glaucoma occurs much more commonly unilaterally and only rarely bilaterally. CAG secondary to sulfa drugs is a bilateral non-pupillary block type and is due to forward movement of iris–lens diaphragm, which occurs in individuals with narrow or open iridocorneal angle. A few agents, including antineoplastics, may induce open-angle glaucoma. In conclusion, the majority of cases with glaucoma secondary to non-steroidal medications are of the pupillary block closed-angle type and preventable if the at-risk patients are recognized and treated prophylactically. PMID:21637303

  16. Magnetic-seeding filtration

    SciTech Connect

    Depaoli, D.

    1996-10-01

    This task will investigate the capabilities of magnetic-seeding filtration for the enhanced removal of magnetic and nonmagnetic particulates from liquids. This technology appies to a wide range of liquid wastes, including groundwater, process waters, and tank supernatant. Magnetic-seeding filtration can be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal-size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes.

  17. Optic disc morphology in pigmentary glaucoma

    PubMed Central

    Jonas, J.; Dichtl, A.; Budde, W.; Lang, P.

    1998-01-01

    AIM—To evaluate the morphology of the optic nerve head in eyes with pigmentary glaucoma.
METHODS—Colour stereo optic disc photographs of 62 patients with pigmentary glaucoma and 566 patients with primary open angle glaucoma were morphometrically evaluated. By prestudy selection, mean visual field defect and neuroretinal rim area were not significantly different between the two groups (p=0.89 and p=0.45).
RESULTS—The pigmentary glaucoma group did not vary significantly (p >0.10) from the primary open angle glaucoma group in size and shape of the optic disc, configuration of neuroretinal rim, depth of optic cup, area of alpha zone of parapapillary atrophy, diameter of retinal vessels at the disc border, and frequency of disc haemorrhages and localised retinal nerve fibre layer defects. The beta zone of parapapillary atrophy was slightly, but not statistically significantly (p=0.06), smaller in the pigmentary glaucoma group. The mean maximal intraocular pressure and mean intraocular pressure amplitude were significantly (p<0.001) higher in the pigmentary glaucoma group.
CONCLUSIONS—In contrast with the characteristic morphology of the anterior segment and despite significantly higher intraocular pressure peaks and a larger pressure amplitude, eyes with pigmentary glaucoma compared with eyes with primary open angle glaucoma do not show a pathognomonic morphology of the optic disc and retinal nerve fibre layer. The slightly smaller beta zone of parapapillary atrophy may correspond to higher intraocular pressure in pigmentary glaucoma.

 Keywords: optic disc morphology; pigmentary glaucoma; secondary open angle glaucoma PMID:9828769

  18. NOVELTIES IN MEDICAL TREATMENT OF GLAUCOMA.

    PubMed

    Cornel, Stefan; Mihaela, Timaru Cristina; Adriana, Iliescu Daniela; Mehdi, Batras; Algerino, De Simone

    2015-01-01

    The purpose of this study is to review the current medical treatment and the new and better alternatives for patients with glaucoma. Glaucoma refers to a group of related eye disorders that have in common an optic neuropathy associated with visual function loss. It is one of the leading causes of irreversible blindness worldwide. Glaucoma can damage vision gradually so it may not be noticed until the disease is at an advanced stage. Early diagnosis and treatment can minimize or prevent optic nerve damage and limit glaucoma-related vision loss. Nowadays, research continues for the improvement of current medical treatment. PMID:26978866

  19. Water Treatment Technology - Filtration.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on filtration provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purposes of sedimentation basins and flocculation…

  20. [Chronic closed-angle glaucoma].

    PubMed

    Valtot, F

    2004-06-01

    Five times more frequent than the acute form, chronic closed-angle glaucoma often goes unrecognized for a long time, resulting in considerable visual field deficiencies, even in loss of the eye. It is sometimes confused with chronic glaucoma and treated as such, which is inadequate to halt the progression of the disease. Only gonioscopy can diagnose it. If doubt persists, UBM (ultrasound biomicroscopy) can detect goniosynechiae, a malposition of the ciliary body or of the lens, or the existence of iridociliary cysts. Nine times out of ten, pupillary block initiates the process and an iridotomy should always be done to remediate it, even if this procedure alone does not always suffice to solve the problem. PMID:15319750

  1. An adaptive threshold based image processing technique for improved glaucoma detection and classification.

    PubMed

    Issac, Ashish; Partha Sarathi, M; Dutta, Malay Kishore

    2015-11-01

    Glaucoma is an optic neuropathy which is one of the main causes of permanent blindness worldwide. This paper presents an automatic image processing based method for detection of glaucoma from the digital fundus images. In this proposed work, the discriminatory parameters of glaucoma infection, such as cup to disc ratio (CDR), neuro retinal rim (NRR) area and blood vessels in different regions of the optic disc has been used as features and fed as inputs to learning algorithms for glaucoma diagnosis. These features which have discriminatory changes with the occurrence of glaucoma are strategically used for training the classifiers to improve the accuracy of identification. The segmentation of optic disc and cup based on adaptive threshold of the pixel intensities lying in the optic nerve head region. Unlike existing methods the proposed algorithm is based on an adaptive threshold that uses local features from the fundus image for segmentation of optic cup and optic disc making it invariant to the quality of the image and noise content which may find wider acceptability. The experimental results indicate that such features are more significant in comparison to the statistical or textural features as considered in existing works. The proposed work achieves an accuracy of 94.11% with a sensitivity of 100%. A comparison of the proposed work with the existing methods indicates that the proposed approach has improved accuracy of classification glaucoma from a digital fundus which may be considered clinically significant. PMID:26321351

  2. Detecting Glaucoma Using Automated Pupillography

    PubMed Central

    Tatham, Andrew J.; Meira-Freitas, Daniel; Weinreb, Robert N.; Zangwill, Linda M.; Medeiros, Felipe A.

    2014-01-01

    Objective To evaluate the ability of a binocular automated pupillograph to discriminate healthy subjects from those with glaucoma. Design Cross-sectional observational study. Participants Both eyes of 116 subjects, including 66 patients with glaucoma in at least 1 eye and 50 healthy subjects from the Diagnostic Innovations in Glaucoma Study. Eyes were classified as glaucomatous by repeatable abnormal standard automated perimetry (SAP) or progressive glaucomatous changes on stereophotographs. Methods All subjects underwent automated pupillography using the RAPDx pupillograph (Konan Medical USA, Inc., Irvine, CA). Main Outcome Measures Receiver operating characteristic (ROC) curves were constructed to assess the diagnostic ability of pupil response parameters to white, red, green, yellow, and blue full-field and regional stimuli. A ROC regression model was used to investigate the influence of disease severity and asymmetry on diagnostic ability. Results The largest area under the ROC curve (AUC) for any single parameter was 0.75. Disease asymmetry (P < 0.001), but not disease severity (P = 0.058), had a significant effect on diagnostic ability. At the sample mean age (60.9 years), AUCs for arbitrary values of intereye difference in SAP mean deviation (MD) of 0, 5, 10, and 15 dB were 0.58, 0.71, 0.82, and 0.90, respectively. The mean intereye difference in MD was 2.2±3.1 dB. The best combination of parameters had an AUC of 0.85; however, the cross-validated bias-corrected AUC for these parameters was only 0.74. Conclusions Although the pupillograph had a good ability to detect glaucoma in the presence of asymmetric disease, it performed poorly in those with symmetric disease. PMID:24485921

  3. Chronic open-angle glaucoma

    PubMed Central

    Adatia, Feisal A.; Damji, Karim F.

    2005-01-01

    INTRODUCTION Chronic open-angle glaucoma (COAG) is a leading cause of irreversible blindness worldwide, including in Canada. It presents a challenge in diagnosis, as disease often progresses without symptoms; an estimated 50% of cases are undetected. SOURCES OF INFORMATION MEDLINE searches, reference lists of articles, and expert knowledge from one of the authors (K.F.D.), a glaucoma specialist, were used. MAIN MESSAGE A casefinding approach using early referral to optometrists and ophthalmologists for early detection of COAG is helpful for patients with risk factors such as age above 50, a positive family history, black race, and myopia. Moderate evidence for referral also exists for the following risk factors: hypertension, type 2 diabetes mellitus, hypothyroidism, and sleep apnea. Treatment with intraocular pressure–lowering medication can arrest or slow the course of the disease, permitting patients to retain good visual function. Family physicians should be aware that some intraocular pressure–lowering medications, particularly topical beta-blockers, can pose iatrogenic harm to patients and result in or exacerbate such conditions as asthma, cardiovascular disturbances, depression, and sexual dysfunction. CONCLUSION Appropriate referral patterns and an understanding of common as well as serious side effects of glaucoma medications are important in optimizing management of patients at risk of developing, or who have, COAG. PMID:16190176

  4. Update on Normal Tension Glaucoma

    PubMed Central

    Mallick, Jyotiranjan; Devi, Lily; Malik, Pradeep K.; Mallick, Jogamaya

    2016-01-01

    Normal tension glaucoma (NTG) is labelled when typical glaucomatous disc changes, visual field defects and open anterior chamber angles are associated with intraocular pressure (IOP) constantly below 21 mmHg. Chronic low vascular perfusion, Raynaud's phenomenon, migraine, nocturnal systemic hypotension and over-treated systemic hypertension are the main causes of normal tension glaucoma. Goldmann applanation tonometry, gonioscopy, slit lamp biomicroscopy, optical coherence tomography and visual field analysis are the main tools of investigation for the diagnosis of NTG. Management follows the same principles of treatment for other chronic glaucomas: To reduce IOP by a substantial amount, sufficient to prevent disabling visual loss. Treatment is generally aimed to lower IOP by 30% from pre-existing levels to 12-14 mmHg. Betaxolol, brimonidine, prostaglandin analogues, trabeculectomy (in refractory cases), systemic calcium channel blockers (such as nifedipine) and 24-hour monitoring of blood pressure are considered in the management of NTG. The present review summarises risk factors, causes, pathogenesis, diagnosis and management of NTG. PMID:27413503

  5. Corneal decompensation following filtering surgery with the Ex-PRESS® mini glaucoma shunt device

    PubMed Central

    Tojo, Naoki; Hayashi, Atsushi; Miyakoshi, Akio

    2015-01-01

    Purpose To report a case of corneal decompensation due to the Ex-PRESS® mini glaucoma shunt device (Ex-PRESS). Patient and methods A 75-year-old man had pseudoexfoliation glaucoma in his right eye. He underwent filtration surgery with Ex-PRESS. His intraocular pressure was 7 mmHg after 9 months. Results We observed partial decompensation of the corneal endothelium adjacent to the filtering bleb. Specular microscopy revealed a marked decrease in the endothelial cell density at the center of the cornea. Conclusion Anterior segment optical coherence tomography is very useful for evaluating corneal edema and the position of Ex-PRESS. It is important to follow up with an examination of the corneal endothelial cells. PMID:25834385

  6. Glaucoma - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Hindi (हिन्दी) Japanese (日本語) Korean (한국어) Portuguese (português) Russian (Русский) Somali (af Soomaali) Spanish (español) Vietnamese ( ... 한국어 (Korean) Bilingual PDF Health Information Translations Portuguese (português) Glaucoma Glaucoma - português (Portuguese) Bilingual PDF Health Information ...

  7. A Surgical Approach to Pediatric Glaucoma

    PubMed Central

    Khan, Arif O

    2015-01-01

    Glaucoma in children differs from adult-onset disease and typically requires surgical intervention. However, affected children exhibit a spectrum of disease severity and prospective data guiding the choice of operation are lacking. This article reviews common procedures and a surgical approach to pediatric glaucoma. PMID:26069523

  8. Melanocytic glaucoma in a cairn terrier.

    PubMed

    Hanselman, Beth A

    2002-04-01

    Melanocytic glaucoma, previously known as pigmentary glaucoma, is characterized by diffuse intraocular infiltration of heavily pigmented melanocytes. This unusual ocular disorder has been documented only in the cairn terrier and is considered familial. Treatment strategies are based on evidence that the condition is slowly progressive but not neoplastic. PMID:11963666

  9. Melanocytic glaucoma in a cairn terrier

    PubMed Central

    Hanselman, Beth A.

    2002-01-01

    Melanocytic glaucoma, previously known as pigmentary glaucoma, is characterized by diffuse intraocular infiltration of heavily pigmented melanocytes. This unusual ocular disorder has been documented only in the cairn terrier and is considered familial. Treatment strategies are based on evidence that the condition is slowly progressive but not neoplastic. PMID:11963666

  10. Liquid filtration simulation

    SciTech Connect

    Corey, I.; Bergman, W.

    1996-06-01

    We have a developed a computer code that simulates 3-D filtration of suspended particles in fluids in realistic filter structures. This code, being the most advanced filtration simulation package developed to date, provides LLNL and DOE with new capabilities to address problems in cleaning liquid wastes, medical fluid cleaning, and recycling liquids. The code is an integrated system of commercially available and LLNL-developed software; the most critical are the computational fluid dynamics (CFD) solver and the particle transport program. For the CFD solver, we used a commercial package based on Navier-Stokes equations and a LLNL-developed package based on Boltzman-lattice gas equations. For the particle transport program, we developed a cod based on the 3-D Langevin equation of motion and the DLVO theory of electrical interactions. A number of additional supporting packages were purchased or developed to integrate the simulation tasks and to provide visualization output.

  11. [Toward a high quality glaucoma care].

    PubMed

    Kashiwagi, Kenji

    2012-03-01

    The following studies were performed to solve current problems in glaucoma care and to pursue quality glaucoma care. Using a scanning peripheral anterior chamber depth analyzer that we developed, we: 1) conducted cross-sectional screening for eyes with angle closure; 2) examined longitudinal changes in anterior chamber depth and occurrence rates of primary angle closure in local senior residents; 3) investigated the significance of the anterior chamber and the angle of eyes with open angle glaucoma; and 4) looked into possible applications of anterior chamber depth and the angle in routine examinations. We investigated the effects of retinal glial cells and optic nerve astrocytes on retinal ganglion cell (RGC) survival and neurite growth using a culture system. We also identified candidate genies of retinal glial cells and optic nerve astrocytes affecting RGC survival and neurite growth using microarray and siRNA systems. SRC, a membrane-associated 60-kDa tyrosine kinase, is reported to be involved in neuron death and neurite growth. We developed two types of gene-targeted mice in which we modified the status of SRC phosphorylation. We compared RGC survival and neurite growth by conducting in vivo and in vitro experiments. Adherence is currently a very important issue in the field of glaucoma. We developed a nm thick and composed of 21.5 chitosan-sodium alginate pairs. IOP reduction and its duration, as well as adverse effects, were investigated. In addition, we established and evaluated a support system for glaucoma care in an effort to promote participation of glaucoma patients in glaucoma care using information and communication technology. This system improved the literacy of glaucoma patients as well as glaucoma medical therapy. At the same time, in order to ably provide glaucoma care given the increase in the number of glaucoma patients and the shortage of glaucoma specialists, a tele-medicine system for ophthalmology was developed, in which ophthalmologists

  12. Managed care and the impact of glaucoma.

    PubMed

    Reeder, Claiborne E; Franklin, Meg; Bramley, Thomas J

    2008-02-01

    Changes in the healthcare system, population demographics, and treatment alternatives have contributed to an emerging awareness of glaucoma among managed care organizations. Early diagnosis and treatment are essential to thwarting the personal and economic consequences of end-stage glaucoma. Despite recognition of the need for early intervention and therapy, the literature suggests a great need still exists for improvements in lowering intraocular pressure, managing appropriate follow-up, and improving adherence to current glaucoma medication regimens. As the elderly population continues to increase, these issues will intensify and present further problems for the healthcare system. The purpose of this introductory manuscript is to highlight the literature on the clinical and economic impact of glaucoma and its importance to the managed care community. The remainder of the supplement will focus on the current management of glaucoma and the potential role of neuroprotection in this patient population. PMID:18284314

  13. Recent advances in pharmacotherapy of glaucoma

    PubMed Central

    Gupta, S. K.; Niranjan D., Galpalli; Agrawal, S. S.; Srivastava, Sushma; Saxena, Rohit

    2008-01-01

    Glaucoma is a slow progressive degeneration of the retinal ganglion cells (RGCs) and the optic nerve axons, leading to irreversible blindness if left undiagnosed and untreated. Although increased intraocular pressure is a major risk factor of glaucoma, other factors include increased glutamate levels, alterations in nitric oxide (NO) metabolism, vascular alterations and oxidative damage caused by reactive oxygen species. Glaucoma is the second leading cause of blindness globally, accounting for 12.3% of the total blindness. Glaucoma has been broadly classified as primary or secondary open-angle or angle-closure glaucoma. The primary goal in management of glaucoma is to prevent the risk factor, especially elevated intraocular pressure (IOP), using medications, laser therapy or conventional surgery. The first-line treatment of glaucoma usually begins with the use of a topical selective or nonselective blocker or a prostaglandin analog. Second-line drugs of choice include alpha-agonists and topical carbonic anhydrase inhibitors. Cholinergic agonists are considered third-line treatment options. When a single therapy is not sufficient to lower the IOP, a combination therapy is indicated. To enhance the patient compliance, drug delivery systems like electronic devices, ocular inserts, tansdermal and mechanical drug delivery systems have been developed. Use of viscoelastic agents in ophthalmic formulations, emulsions and soluble ophthalmic drug inserts (SODI) enhance patience compliance and ocular drug delivery in patients in long-term glaucoma therapy. For patients who do not respond to antiglaucoma medications, laser trabeculoplasty and incisional surgery are recommended. Several nutrients and botanicals hold promise for the treatment of glaucoma, but most studies are preliminary, and larger, controlled studies are required. Future directions for the development of a novel therapy glaucoma may target glutamate inhibition, NMDA receptor blockade, exogenously applied

  14. Quadrant Field Pupillometry Detects Melanopsin Dysfunction in Glaucoma Suspects and Early Glaucoma.

    PubMed

    Adhikari, Prakash; Zele, Andrew J; Thomas, Ravi; Feigl, Beatrix

    2016-01-01

    It is difficult to detect visual function deficits in patients at risk for glaucoma (glaucoma suspects) and at early disease stages with conventional ophthalmic tests such as perimetry. To this end, we introduce a novel quadrant field measure of the melanopsin retinal ganglion cell mediated pupil light response corresponding with typical glaucomatous arcuate visual field defects. The melanopsin-mediated post-illumination pupil response (PIPR) was measured in 46 patients with different stages of glaucoma including glaucoma suspects and compared to a healthy group of 21 participants with no disease. We demonstrate that the superonasal quadrant PIPR differentiated glaucoma suspects and early glaucoma patients from controls with fair (AUC = 0.74) and excellent (AUC = 0.94) diagnostic accuracy, respectively. The superonasal PIPR provides a linear functional correlate of structural retinal nerve fibre thinning in glaucoma suspects and early glaucoma patients. This first report that quadrant PIPR stimulation detects melanopsin dysfunction in patients with early glaucoma and at pre-perimetric stages may have future implications in treatment decisions of glaucoma suspects. PMID:27622679

  15. [The denominations cataract and glaucoma].

    PubMed

    Tornquist, R

    1997-01-01

    Since ancient times a grey or white pupil in an nearly blind eye was thought to be caused by a mucous substance in front of the lens. It was called "hypochysis" or "hypochyma" in Greece and "suffusio" in Rome. Later the term "cataract" (=waterfall) was the most popular denomination. A surgical method was tried very early with usually good effect, when with a thin needle, introduced into the eye, the opaque material was removed from the pupillary area. In the middle of the 17th century more careful investigations showed that there was no membrane in front of the lens, but the lens itself was opaque. The final proof was delivered when an extraction of the lens was performed with good effect. In ancient times incurable blindness, which was called glaucoma, was thought to be located to the lens, which probably had a very important role in the seeing process. The name (of Greek orgin) is translated "green" or "blue-green", which was sometimes notified to be the color of the lens, seen through the pupil, in these cases. A period of great confusion followed when the removal of this very important part of the eye did not lead to blindness but rather an improved vision. As there were significant difficulties in identifying the specific color of the pupil the name glaucoma seemed to be very inadequate. In the beginning of the 19th century a disease entity (which is to-day called acute closed-angle glaucoma) seemed to eventually fullfill the demand of a greenlooking pupil. The most characteristic symptoms are pain and a high intraocular pressure causing a corneal edema and a change of the blackness of the pupil to hazy grey (and maybe a little green?). PMID:11625470

  16. Treatment of glaucoma with high intensity focused ultrasound.

    PubMed

    Aptel, Florent; Lafon, Cyril

    2015-05-01

    Glaucoma is a common disease mainly due to an increase in pressure inside the eye, leading to a progressive destruction of the optic nerve, potentially to blindness. Intraocular pressure (IOP) is the result of a balance between production of liquid that fills the eye--aqueous humour--and its resorption. All treatments for glaucoma aim to reduce IOP and can therefore have two mechanisms of action: reducing aqueous humour production by the partial destruction or medical inhibition of the ciliary body--the anatomical structure responsible for production of aqueous humour--or facilitating the evacuation of aqueous humour from the eye. Several physical methods can be used to destroy the ciliary body, e.g. laser, cryotherapy, microwave. All these methods have two major drawbacks: they are non-selective for the organ to be treated and they have an unpredictable dose–effect relationship. High intensity focused ultrasound (HIFU) can be used to coagulate the ciliary body and avoid these drawbacks. A commercially available device was marketed in the 1980s, but later abandoned, essentially for technical reasons. A smaller circular device using miniaturised transducers was recently developed and proposed for clinical practice. Experimental studies have shown selective coagulation necrosis of the treated ciliary body. The first three clinical trials in humans have shown that this device was well tolerated and allowed a significant, predictable and sustained reduction of IOP. The aim of this contribution is to present a summary of the work concerning the use of HIFU to treat glaucoma. PMID:25524084

  17. Clinical findings following Ahmed Glaucoma Valve™ implantation in pediatric glaucoma

    PubMed Central

    Pirouzian, Amir; Demer, Joseph L

    2008-01-01

    Purpose To describe clinical findings after Ahmed valve drainage implantation in children. Design All records in one practice were reviewed to identify and describe clinical findings in all children who had undergone Ahmed Glaucoma Valve™ S2 model insertion for uncontrolled primary or secondary glaucoma. Results A total of 6 patients were identified, ranging in age from 2–15 years. Mean follow-up time averaged from 2–5 years from the time of tube insertion. Three patients exhibited pupillary peaking towards the tube of the valve. All patients required additional surgery or additional medications to control intraocular pressure. Lenticular opacification near the tube site developed in one patient. Gradual tube extrusion was also noted in another two patients. Conclusion Multiple clinical events follow the Ahmed valve insertion in children. Pupillary irregularity is the most commonly noted event in this series. To avoid or reduce the risk of this complication, additional or modification of surgical procedures could be considered. The mechanism of such occurrence will further be discussed. PMID:19668395

  18. Sympathectomy for glaucoma: Its rise and fall (1898-1910).

    PubMed

    Feibel, Robert M

    2015-01-01

    The influence of the sympathetic nervous system upon intraocular pressure (IOP) has been a subject of great interest since 1727, when the first experimental ocular sympathetic paralysis was produced in dogs. By the middle of the 19th century, it was known that excision of the superior cervical sympathetic ganglion lowered, and that electrical stimulation of the sympathetic nerve trunk raised IOP in various animals. From these observations, it was thought that excision of this ganglion could replace or supplement the available operations for glaucoma of which iridectomy was the most popular. Iridectomy was acknowledged to be of great value in acute and subacute glaucoma, but less useful in chronic glaucoma. Iridectomy, however, was associated with major surgical complications and long-term failure, so that there was considerable appeal of an extraocular operation that avoided the risks of intraocular surgery. Beginning in 1898, cervical sympathectomy became a widely performed operation around the world, with most surgeons enthusiastic about its results, at least initially, and many publications from 1898 to 1905 claimed excellent results for various types of glaucoma. Opponents of the procedure emphasized that the effect on IOP was transient, and that the published reports of successful results were poorly documented. The popularity of sympathectomy gradually diminished and by 1910 it was abandoned. I discuss the reasons why cervical sympathectomy received such initial enthusiasm but was then questioned and discarded. These included bias from the surgeons promoting this surgery; the placebo effect; short follow-up; inaccurate, subjective, and variable measures of the surgical results; and the development of more effective procedures such as filtering surgery and cyclodialysis. PMID:25907524

  19. Structural basis for misfolding in myocilin-associated glaucoma.

    PubMed

    Donegan, Rebecca K; Hill, Shannon E; Freeman, Dana M; Nguyen, Elaine; Orwig, Susan D; Turnage, Katherine C; Lieberman, Raquel L

    2015-04-15

    Olfactomedin (OLF) domain-containing proteins play roles in fundamental cellular processes and have been implicated in disorders ranging from glaucoma, cancers and inflammatory bowel disorder, to attention deficit disorder and childhood obesity. We solved crystal structures of the OLF domain of myocilin (myoc-OLF), the best studied such domain to date. Mutations in myoc-OLF are causative in the autosomal dominant inherited form of the prevalent ocular disorder glaucoma. The structures reveal a new addition to the small family of five-bladed β-propellers. Propellers are most well known for their ability to act as hubs for protein-protein interactions, a function that seems most likely for myoc-OLF, but they can also act as enzymes. A calcium ion, sodium ion and glycerol molecule were identified within a central hydrophilic cavity that is accessible via movements of surface loop residues. By mapping familial glaucoma-associated lesions onto the myoc-OLF structure, three regions sensitive to aggregation have been identified, with direct applicability to differentiating between neutral and disease-causing non-synonymous mutations documented in the human population worldwide. Evolutionary analysis mapped onto the myoc-OLF structure reveals conserved and divergent regions for possible overlapping and distinctive functional protein-protein or protein-ligand interactions across the broader OLF domain family. While deciphering the specific normal biological functions, ligands and binding partners for OLF domains will likely continue to be a challenging long-term experimental pursuit, atomic detail structural knowledge of myoc-OLF is a valuable guide for understanding the implications of glaucoma-associated mutations and will help focus future studies of this biomedically important domain family. PMID:25524706

  20. [Trabeculectomy in the treatment of congenital glaucoma. Apropos of 74 cases].

    PubMed

    Sekkat, A; Hannane, A; Maillard, P; Lamdaouar, N

    1984-01-01

    The authors report the results obtained in 74 cases, or 105 eyes, with congenital glaucoma operated on by trabeculectomy. Three different trabeculectomy procedures were used: closing the scleral flap with two sutures; placing a silastic passing in bridge under the flap; and tightly suturing the scleral flap. The last mentioned method gave the best results. This was related to intervention during the first phase of the disease and minimizing damage to the cornea. It is derived from this study that the mechanism of action of a trabeculectomy is more an "opening" of the paths of physiological drainage than filtration via the sub-conjunctival space. PMID:6381581

  1. Depth perception deficits in glaucoma suspects

    PubMed Central

    Gupta, N; Krishnadev, N; Hamstra, S J; Yücel, Y H

    2006-01-01

    Aim To investigate depth perception in glaucoma suspects compared to glaucoma patients and controls. Methods Glaucoma suspects (n = 16), patients (n = 18), and normal age matched controls (n = 19) aged 40–65 years were prospectively evaluated for depth perception deficits using the Frisby test. Stereoacuity was measured by stereothreshold in seconds of arc for each group. Results Glaucoma suspects showed significantly increased mean stereothreshold compared to age matched normals (144.1 (SE 35.2) v 26.6 (3.7) seconds of arc; p = 0.0004). The mean stereothreshold in glaucoma patients was also increased compared to age matched normals 148.1 (33.8) v 26.6 (3.7) seconds of arc; p = 0.0004). Conclusions Glaucoma suspects show depth perception deficits. The impaired stereovision in glaucoma suspects suggests that binocular interactions can be disrupted in the presence of normal visual fields by standard achromatic automated perimetry. PMID:16672326

  2. Cellular stress response, redox status, and vitagenes in glaucoma: a systemic oxidant disorder linked to Alzheimer’s disease

    PubMed Central

    Trovato Salinaro, Angela; Cornelius, Carolin; Koverech, Guido; Koverech, Angela; Scuto, Maria; Lodato, Francesca; Fronte, Vincenzo; Muccilli, Vera; Reibaldi, Michele; Longo, Antonio; Uva, Maurizio G.; Calabrese, Vittorio

    2014-01-01

    Amyloid deposits, constituted of amyloid beta (Aβ) aggregates, are a characteristic feature of several neurodegenerative diseases, such as Alzheimer’s, mild cognitive impairment and Parkinson’s disease. They also have been recently implicated in the pathogenesis of retinal damage, as well as age-related macular degeneration and glaucoma. Glaucoma is a progressive optic neuropathy characterized by gradual degeneration of neuronal tissue due to retinal ganglion cell loss, associated to visual field loss over time resulting in irreversible blindness. Accumulation of Aβ characterizes glaucoma as a protein misfolding disease, suggesting a pathogenic role for oxidative stress in the pathogenesis of retinal degenerative damage associated to glaucoma. There is a growing body of evidence demonstrating a link between Alzheimer’s disease and glaucoma. Further, several heat shock proteins (HSPs) members have been implicated both in neurodegenerative diseases and glaucomatous apoptosis. To maintain redox homeostasis vitagenes, as integrated mechanisms, operate actively to preserve cell survival under condition of stress. Vitagenes encode for sirtuin, thioredoxin and HSPs. The present study was designed to investigate cellular stress response mechanisms in the blood of patients with glaucoma, compared to control subjects. Levels of vitagenes HSP-72, heme oxygenase-1, as well as F2-isoprostanes were significantly higher in the blood of patients with glaucoma than in controls. Furthermore, in the same experimental group increased expression of Trx and sirtuin 1 were measured. Our results sustain the importance of redox homeostasis disruption in the pathogenesis of glaucoma and highlights the opportunity that new therapies that prevents neurodegeneration through non-immunomodulatory mechanisms might be synergistically associated with current glaucoma therapies, thus unraveling important targets for novel cytoprotective strategies. PMID:24936186

  3. Dynamic optical filtration

    NASA Technical Reports Server (NTRS)

    Chretien, Jean-Loup (Inventor); Lu, Edward T. (Inventor)

    2005-01-01

    A dynamic optical filtration system and method effectively blocks bright light sources without impairing view of the remainder of the scene. A sensor measures light intensity and position so that selected cells of a shading matrix may interrupt the view of the bright light source by a receptor. A beamsplitter may be used so that the sensor may be located away from the receptor. The shading matrix may also be replaced by a digital micromirror device, which selectively sends image data to the receptor.

  4. Dynamic Optical Filtration

    NASA Technical Reports Server (NTRS)

    Chretien, Jean-Loup (Inventor); Lu, Edward T. (Inventor)

    2005-01-01

    A dynamic optical filtration system and method effectively blocks bright light sources without impairing view of the remainder of the scene. A sensor measures light intensity and position so that selected cells of a shading matrix may interrupt the view of the bright light source by a receptor. A beamsplitter may be used so that the sensor may be located away from the receptor. The shading matrix may also be replaced by a digital micromirror device, which selectively sends image data to the receptor.

  5. Management of complications in glaucoma surgery

    PubMed Central

    Vijaya, Lingam; Manish, Panday; Ronnie, George; Shantha, B

    2011-01-01

    Surgical option for glaucoma is considered when other modalities are not working out to keep the intraocular pressure under control. Since the surgical procedures for glaucoma disrupt the integrity of the globe, they are known to produce various complications. Some of those complications can be vision-threatening. To minimize the morbidity, it is very important that one should know how to prevent them, recognize them and treat them. The objective of this article is to provide insight into some of those complications that will help the ophthalmologists in treating glaucoma patients in their clinical practice. PMID:21150025

  6. 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.

  7. Repositioning of glaucoma tubes into the pars plana for refractory malignant glaucoma: a case report

    PubMed Central

    2013-01-01

    Introduction Malignant glaucoma occurs when the intraocular pressure elevates in the setting of a shallow anterior chamber and patent iridectomy. We describe a case in which malignant glaucoma that was refractory to conventional treatment and complete vitrectomy was successfully managed by rerouting the glaucoma tubes into the pars plana. Case presentation A 47-year-old Latino man had a history of neovascular glaucoma and subsequent peripheral anterior synechiae. He was status post-two glaucoma drainage devices. He developed pupillary block. Laser iridotomy was performed without complications. He subsequently developed malignant glaucoma that was refractory to yttrium aluminum garnet capsulohyaloidotomy of the anterior hyaloid. He underwent pars plana vitrectomy with successful control of his intraocular pressure. After 2 weeks, the malignant glaucoma recurred. He underwent repositioning of the tubes into the pars plana with successful control of his intraocular pressure. Conclusion In rare cases of malignant glaucoma refractive to yttrium aluminum garnet hyaloidotomy and vitrectomy, placement of glaucoma drainage devices is a reasonable alternative. PMID:23577950

  8. Magnetic-seeding filtration

    SciTech Connect

    DePaoli, D.W.; Tsouris, C.; Yiacoumi, Sotira

    1997-10-01

    Magnetic-seeding filtration is a technology under development for the enhanced removal of magnetic and non-magnetic particulates from liquids. This process involves the addition of a small amount of magnetic seed particles (such as naturally occurring iron oxide) to a waste suspension, followed by treatment with a magnetic filter. Non-magnetic and weakly magnetic particles are made to undergo nonhomogeneous flocculation with the seed particles, forming flocs of high magnetic susceptibility that are readily removed by a conventional high-gradient magnetic filter. This technology is applicable to a wide range of liquid wastes, including groundwater, process waters, and tank supernatants. Magnetic-seeding filtration may be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes. Waste stream characteristics for which the technology may be applicable include (1) particle sizes ranging from relatively coarse (several microns) to colloidal particles, (2) high or low radiation levels, (3) broad-ranging flow rates, (4) low to moderate solids concentration, (5) cases requiring high decontamination factors, and (6) aqueous or non-aqueous liquids. At this point, the technology is at the bench-scale stage of development; laboratory studies and fundamental modeling are currently being employed to determine the capabilities of the process.

  9. Design parameters for rotating cylindrical filtration

    NASA Technical Reports Server (NTRS)

    Schwille, John A.; Mitra, Deepanjan; Lueptow, Richard M.

    2002-01-01

    Rotating cylindrical filtration displays significantly reduced plugging of filter pores and build-up of a cake layer, but the number and range of parameters that can be adjusted complicates the design of these devices. Twelve individual parameters were investigated experimentally by measuring the build-up of particles on the rotating cylindrical filter after a fixed time of operation. The build-up of particles on the filter depends on the rotational speed, the radial filtrate flow, the particle size and the gap width. Other parameters, such as suspension concentration and total flow rate are less important. Of the four mechanisms present in rotating filters to reduce pore plugging and cake build-up, axial shear, rotational shear, centrifugal sedimentation and vortical motion, the evidence suggests rotational shear is the dominant mechanism, although the other mechanisms still play minor roles. The ratio of the shear force acting parallel to the filter surface on a particle to the Stokes drag acting normal to the filter surface on the particle due to the difference between particle motion and filtrate flow can be used as a non-dimensional parameter that predicts the degree of particle build-up on the filter surface for a wide variety of filtration conditions. c2002 Elsevier Science B.V. All rights reserved.

  10. Improving patient outcomes following glaucoma surgery: state of the art and future perspectives

    PubMed Central

    Van Bergen, Tine; Van de Velde, Sarah; Vandewalle, Evelien; Moons, Lieve; Stalmans, Ingeborg

    2014-01-01

    Of all the treatments currently used to lower intraocular pressure in glaucoma patients, filtration surgery is known to be the most effective. However, in a significant percentage of cases, the constructed channel closes due to excessive scar formation, resulting in surgical failure. The process of postoperative wound healing is characterized by the coagulative and inflammatory phase, followed by the proliferative and repair phase, and finally the remodeling phase. Perioperative antimitotic agents, such as mitomycin C and 5-fluorouracil, are known to modulate the process of wound healing and to improve surgical outcome, but they carry a risk of vision-threatening complications. New alternative strategies to prevent filtration failure, such as inhibition of transforming growth factor-β, vascular endothelial growth factor, and placental growth factor, have shown promising results in the improvement of surgical success. However, it remains necessary to broaden the therapeutic approach by focusing on combined therapies and on extended drug delivery. PMID:24833892

  11. Design, Fabrication, and In Vitro Testing of an Anti-biofouling Glaucoma Micro-shunt.

    PubMed

    Harake, Ryan S; Ding, Yuzhe; Brown, J David; Pan, Tingrui

    2015-10-01

    Glaucoma, one of the leading causes of irreversible blindness, is a progressive neurodegenerative disease. Chronic elevated intraocular pressure (IOP), a prime risk factor for glaucoma, can be treated by aqueous shunts, implantable devices, which reduce IOP in glaucoma patients by providing alternative aqueous outflow pathways. Although initially effective at delaying glaucoma progression, contemporary aqueous shunts often lead to numerous complications and only 50% of implanted devices remain functional after 5 years. In this work, we introduce a novel micro-device which provides an innovative platform for IOP reduction in glaucoma patients. The device design features an array of parallel micro-channels to provide precision aqueous outflow resistance control. Additionally, the device's microfluidic channels are composed of a unique combination of polyethylene glycol materials in order to provide enhanced biocompatibility and resistance to problematic channel clogging from biofouling of aqueous proteins. The microfabrication process employed to produce the devices results in additional advantages such as enhanced device uniformity and increased manufacturing throughput. Surface characterization experimental results show the device's surfaces exhibit significantly less non-specific protein adsorption compared to traditional implant materials. Results of in vitro flow experiments verify the device's ability to provide aqueous resistance control, continuous long-term stability through 10-day protein flow testing, and safety from risk of infection due to bacterial ingression. PMID:25821113

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

    SciTech Connect

    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 peculiar 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.

  13. Glaucoma eye drops adverse skin reactions.

    PubMed

    Cantisani, Carmen; Ambrifi, Marina; Frascani, Federica; Fazia, Gilda; Paolino, Giovanni; Lisi, Roberto; Calvieri, Stefano

    2014-01-01

    The term "Glaucoma" is used to describe a number of diseases of the eye characterized by a particular form of optic nerve damage that is often associated with high intraocular pressure (IOP). The open-angle glaucoma is the most common form that is also referred to as chronic glaucoma. This is described as an optic neuropathy with multifactorial nature in which there is a loss of characteristics of the optic nerve fibers. Therapeutic options for the treatment of this disease are different, you can take advantage of eye drops, laser therapy and conventional surgery or more combined treatments. Medicated eye drops are the most common way to treat glaucoma. Although eye drops are widely used, adverse reactions are not frequently observed and described. In particular, the adverse skin reactions are not frequently described in the literature, but often seen in dermatologic clinic, we reported their skin reactions and possible alternative treatments described in literature and their patent applications. PMID:25487259

  14. 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

  15. Management of exfoliative glaucoma: challenges and solutions

    PubMed Central

    Holló, Gábor; Katsanos, Andreas; Konstas, Anastasios GP

    2015-01-01

    Exfoliative glaucoma is the most common type of secondary open-angle glaucoma worldwide. It is characterized by high intraocular pressure (IOP) and worse 24-hour IOP characteristics. In order to minimize progression, treatment of exfoliative glaucoma has to provide a low long-term mean IOP and good 24-hour IOP control. To achieve these goals, fixed-dose combination eye drops, argon and selective laser trabeculoplasty, and various forms of surgery (trabeculectomy, deep sclerectomy, viscocanalostomy, ab interno trabeculotomy, trabecular aspiration, and cataract surgery) all need to be considered during the long-term management of the disease. Since exfoliative glaucoma is a disease of the elderly, and is frequently associated with systemic vascular disease, interdisciplinary consultations are of great clinical importance. These management aspects and the current medical, laser, and surgical results are covered in this review, with a special focus on the needs of the general ophthalmologist. PMID:26045655

  16. Management of exfoliative glaucoma: challenges and solutions.

    PubMed

    Holló, Gábor; Katsanos, Andreas; Konstas, Anastasios Gp

    2015-01-01

    Exfoliative glaucoma is the most common type of secondary open-angle glaucoma worldwide. It is characterized by high intraocular pressure (IOP) and worse 24-hour IOP characteristics. In order to minimize progression, treatment of exfoliative glaucoma has to provide a low long-term mean IOP and good 24-hour IOP control. To achieve these goals, fixed-dose combination eye drops, argon and selective laser trabeculoplasty, and various forms of surgery (trabeculectomy, deep sclerectomy, viscocanalostomy, ab interno trabeculotomy, trabecular aspiration, and cataract surgery) all need to be considered during the long-term management of the disease. Since exfoliative glaucoma is a disease of the elderly, and is frequently associated with systemic vascular disease, interdisciplinary consultations are of great clinical importance. These management aspects and the current medical, laser, and surgical results are covered in this review, with a special focus on the needs of the general ophthalmologist. PMID:26045655

  17. Surgical consequences in coexisting cataract and glaucoma.

    PubMed

    Blumenthal, M; Glovinsky, Y

    1995-04-01

    Of the three classical approaches to surgery for coexisting cataract and glaucoma, last year's publications dealt with the surgical consequences of combined cataract and glaucoma operations only. When used in combined cataract and glaucoma surgery, a small-incision extracapsular cataract extraction (ECCE) with phacoemulsification (PHACO) was found to be only slightly superior to the standard manual ECCE in terms of postoperative intraocular pressure (IOP) control. Injections of 5-fluorouracil postoperatively did not improve IOP control in PHACO-ECCE-trabeculectomy or manual ECCE-trabeculectomy. A preliminary uncontrolled report suggests, however, that intraoperative mitomycin C application in PHACO-ECCE-trabeculectomy may result in excellent postoperative IOP control without antiglaucomatous medications, and with no significant mitomycin C-related complications. Controlled studies on mitomycin C application in small-incision cataract and glaucoma surgery are needed to assess its long-term effect on IOP and astigmatism. PMID:10150852

  18. CENTRIFUGAL MEMBRANE FILTRATION

    SciTech Connect

    William A. Greene; Patricia A. Kirk; Richard Hayes; Joshua Riley

    2005-10-28

    SpinTek Membrane Systems, Inc., the developer of a centrifugal membrane filtration technology, has engineered and developed a system for use within the U.S. Department of Energy (DOE) Environmental Management (EM) Program. The technology uses supported microporous membranes rotating at high rpm, under pressure, to separate suspended and colloidal solids from liquid streams, yielding a solids-free permeate stream and a highly concentrated solids stream. This is a crosscutting technology that falls under the Efficient Separations and Processing Crosscutting Program, with potential application to tank wastes, contaminated groundwater, landfill leachate, and secondary liquid waste streams from other remediation processes, including decontamination and decommissioning systems. SpinTek II High Shear Rotary Membrane Filtration System is a unique compact crossflow membrane system that has large, demonstrable advantages in performance and cost compared to currently available systems: (1) High fluid shear prevents membrane fouling even with very high solids content; hazardous and radioactive components can be concentrated to the consistency of a pasty slurry without fouling. (2) Induced turbulence and shear across the membrane increases membrane flux by a factor of ten over existing systems and allows operation on fluids not otherwise treatable. (3) Innovative ceramic membrane and mechanical sealing technology eliminates compatibility problems with aggressive DOE waste streams. (4) System design allows rapid, simple disassembly for inspection or complete decontamination. (5) Produces colloidal- and suspended-solids-free filtrate without the addition of chemicals. The first phase of this project (PRDA maturity stage 5) completed the physical scale-up of the SpinTek unit and verified successful scale-up with surrogate materials. Given successful scale-up and DOE concurrence, the second phase of this project (PRDA maturity stage 6) will provide for the installation and

  19. Quantitative Mapping of Collagen Fiber Orientation in Non-glaucoma and Glaucoma Posterior Human Sclerae

    PubMed Central

    Pijanka, Jacek K.; Coudrillier, Baptiste; Ziegler, Kimberly; Sorensen, Thomas; Meek, Keith M.; Nguyen, Thao D.; Quigley, Harry A.; Boote, Craig

    2012-01-01

    Purpose. The posterior sclera has a major biomechanical influence on the optic nerve head, and may therefore be important in glaucoma. Scleral material properties are influenced significantly by collagen fiber architecture. Here we quantitatively map fiber orientation in non-glaucoma and glaucoma posterior human sclerae. Methods. Wide-angle x-ray scattering quantified fiber orientation at 0.5-mm intervals across seven non-glaucoma post-mortem human sclerae, and five sclerae with glaucoma history and confirmed axon loss. Multiphoton microscopy provided semiquantitative depth-profiling in the peripapillary sclera. Results. Midposterior fiber orientation was either uniaxial (one preferred direction) or biaxial (two directions). The peripapillary sclera was characterized by a ring of fibers located mainly in the mid-/outer stromal depth and encompassing ∼50% of the total tissue thickness. Fiber anisotropy was 37% higher in the peripapillary sclera compared with midposterior, varied up to 4-fold with position around the scleral canal, and was consistently lowest in the superior-nasal quadrant. Mean fiber anisotropy was significantly lower in the superior-temporal (P < 0.01) and inferior-nasal (P < 0.05) peripapillary scleral quadrants in glaucoma compared with non-glaucoma eyes. Conclusions. The collagen fiber architecture of the posterior human sclera is highly anisotropic and inhomogeneous. Regional differences in peripapillary fiber anisotropy between non-glaucoma and glaucoma eyes may represent adaptive changes in response to elevated IOP and/or glaucoma, or baseline structural properties that associate with predisposition to glaucomatous axon damage. Quantitative fiber orientation data will benefit numerical eye models aimed at predicting the sclera's influence on nerve head biomechanics, and thereby its possible role in glaucoma. PMID:22786908

  20. Acquired color vision loss and a possible mechanism of ganglion cell death in glaucoma.

    PubMed Central

    Nork, T M

    2000-01-01

    PURPOSE: First, to study the cellular mechanisms of acquired color vision loss in retinal detachment and diabetic retinopathy. Second, to learn why, in glaucoma, the type of color vision deficit that is observed is more characteristic of a retinal injury than it is of an optic neuropathy. Third, to test a hypothesis of photoreceptor-induced, ganglion cell death in glaucoma. METHODS: Various histologic techniques were employed to distinguish the L/M-cones (long/medium wavelength-sensitive cones, or red/green sensitive cones) from the S-cones (short wavelength-sensitive cones, or blue sensitive cones) in humans and monkeys with retinal detachment, humans with diabetic retinopathy, and both humans and monkeys with glaucoma. To test if the photoreceptors were contributing to ganglion cell death, laser photocoagulation was used in a experimental model of glaucoma to focally eliminate the photoreceptors. As a control, optic nerve transection was done following retinal laser photocoagulation in one animal. RESULTS: Selective and widespread loss of the S-cones was found in retinal detachment as well as diabetic retinopathy. By contrast, in human as well as experimental glaucoma, marked swelling of the L/M-cones was the predominant histopathologic feature. Retinal laser photocoagulation followed by experimental glaucoma resulted in selective protection of ganglion cells overlying the laser spots. This was not seen with retinal laser photocoagulation by optic nerve transection. CONCLUSIONS: In retinal detachment and diabetic retinopathy, acquired tritan-like color vision loss could be caused, or contributed to, by selective loss of the S-cones. Both L- and M-cones are affected in glaucoma, which is also consistent with a tritan-like deficit. Although not a therapeutic option, protection of ganglion cells by retinal laser in experimental glaucoma is consistent with an hypothesis of anterograde, photoreceptor-induced, ganglion cell death. Images FIGURE 1 FIGURE 2 FIGURE 3

  1. Noninvasive glaucoma procedures: current options and future innovations.

    PubMed

    Abdelrahman, Ahmed M

    2015-01-01

    Noninvasive glaucoma procedures (NIGPs) represent a new dawn in the management of glaucoma. They try to fill the gap between the shortcoming of invasive glaucoma surgeries and antiglaucoma medications. NIGPs were introduced as an adjunct or alternative treatments for glaucoma. Some of these procedures have shown good efficacy with few serious complications. Hence, they are now used as both primary and adjunctive therapy for glaucoma. The most common NIGPS involve laser and ultrasound technologies. Currently, the portfolio of NIGPs includes argon laser trabeculoplasty, selective laser trabeculoplasty, and micropulse diode laser trabeculoplasty. More recent innovations include therapeutic ultrasound for glaucoma, ultrasonic circular cyclocoagulation, and deep wave trabeculoplasty. PMID:25624667

  2. Noninvasive Glaucoma Procedures: Current Options and Future Innovations

    PubMed Central

    Abdelrahman, Ahmed M.

    2015-01-01

    Noninvasive glaucoma procedures (NIGPs) represent a new dawn in the management of glaucoma. They try to fill the gap between the shortcoming of invasive glaucoma surgeries and antiglaucoma medications. NIGPs were introduced as an adjunct or alternative treatments for glaucoma. Some of these procedures have shown good efficacy with few serious complications. Hence, they are now used as both primary and adjunctive therapy for glaucoma. The most common NIGPS involve laser and ultrasound technologies. Currently, the portfolio of NIGPs includes argon laser trabeculoplasty, selective laser trabeculoplasty, and micropulse diode laser trabeculoplasty. More recent innovations include therapeutic ultrasound for glaucoma, ultrasonic circular cyclocoagulation, and deep wave trabeculoplasty. PMID:25624667

  3. Simulation of Anomalous Oil Filtration in a Porous Bed

    NASA Astrophysics Data System (ADS)

    Kelbaliev, G. I.; Rzaev, Ab. G.; Rasulov, S. R.; Guseinova, L. V.

    2015-03-01

    The problems of modeling the processes of filtration of anomalous structurized oils with coagulation structures present in a porous bed are considered. An equation for the filtration of Bingham fluids in a carrier bed that accounts for the dependence of the filtration rate on the pressure gradient and shear stress has been derived. Models for calculating the effective viscosity and mobility of oil depending on the change of the pressure gradient in the bed and of the concentration of particles in it have been developed. A comparison of these models with the experimental data available in the literature for various wells yielded satisfactory results.

  4. Evaluating glaucoma damage: emerging imaging technologies

    PubMed Central

    Kostanyan, Tigran; Wollstein, Gadi; Schuman, Joel S

    2015-01-01

    The use of ocular imaging tools to estimate structural and functional damage in glaucoma has become a common clinical practice and a substantial focus of vision research. The evolution of the imaging technologies through increased scanning speed, penetration depth, image registration and development of multimodal devices has the potential to detect the pathology more reliably and in earlier stages. This review is focused on new ocular imaging modalities used for glaucoma diagnosis. PMID:27087829

  5. Transscleral photodisruption for the treatment of glaucoma

    NASA Astrophysics Data System (ADS)

    Sacks, Zachary S.; Loesel, Frieder H.; Durfee, Charles G., III; Kurtz, Ron M.; Juhasz, Tibor; Mourou, Gerard A.

    1999-03-01

    To evaluate transscleral glaucoma surgery techniques using ultrashort pulsed lasers, we attempted to produce photodisruption on the inner surface of the sclera without damaging the overlying tissue. We identified two methods, using pulses centered at 1700 nm and a transparency inducing drug, to produce the spatial and temporal confinement of the pulse necessary to produce photodisruption in the highly scattering sclera. When fully developed these concepts may help address the longstanding limitations of current glaucoma surgical techniques.

  6. Electroconvulsive therapy in a patient with glaucoma.

    PubMed

    Amritwar, Ameya; Karia, Sagar; De Sousa, Avinash; Sonavane, Sushma

    2016-01-01

    There is little information on the use of electroconvulsive therapy (ECT) in the presence of glaucoma. An elderly man with known severe depression underwent surgery for cataract and glaucoma in the left eye. His depression worsened in the postoperative period and he required two sessions of ECT within 2 months of the surgery. There were no ophthalmic complications or adverse events associated with ECT and he responded well to treatment. PMID:27586212

  7. Microscope-integrated optical coherence tomography for image-aided positioning of glaucoma surgery.

    PubMed

    Li, Xiqi; Wei, Ling; Dong, Xuechuan; Huang, Ping; Zhang, Chun; He, Yi; Shi, Guohua; Zhang, Yudong

    2015-07-01

    Most glaucoma surgeries involve creating new aqueous outflow pathways with the use of a small surgical instrument. This article reported a microscope-integrated, real-time, high-speed, swept-source optical coherence tomography system (SS-OCT) with a 1310-nm light source for glaucoma surgery. A special mechanism was designed to produce an adjustable system suitable for use in surgery. A two-graphic processing unit architecture was used to speed up the data processing and real-time volumetric rendering. The position of the surgical instrument can be monitored and measured using the microscope and a grid-inserted image of the SS-OCT. Finally, experiments were simulated to assess the effectiveness of this integrated system. Experimental results show that this system is a suitable positioning tool for glaucoma surgery. PMID:26160346

  8. Microscope-integrated optical coherence tomography for image-aided positioning of glaucoma surgery

    NASA Astrophysics Data System (ADS)

    Li, Xiqi; Wei, Ling; Dong, Xuechuan; Huang, Ping; Zhang, Chun; He, Yi; Shi, Guohua; Zhang, Yudong

    2015-07-01

    Most glaucoma surgeries involve creating new aqueous outflow pathways with the use of a small surgical instrument. This article reported a microscope-integrated, real-time, high-speed, swept-source optical coherence tomography system (SS-OCT) with a 1310-nm light source for glaucoma surgery. A special mechanism was designed to produce an adjustable system suitable for use in surgery. A two-graphic processing unit architecture was used to speed up the data processing and real-time volumetric rendering. The position of the surgical instrument can be monitored and measured using the microscope and a grid-inserted image of the SS-OCT. Finally, experiments were simulated to assess the effectiveness of this integrated system. Experimental results show that this system is a suitable positioning tool for glaucoma surgery.

  9. MICROBIOLOGY AND DRINKING WATER FILTRATION

    EPA Science Inventory

    Concerns about waterborne viruses and protozoan cysts developed in the third quarter of the twentieth century, and filtration research for microorganism control in the 1960's through 1980's has reflected these concerns. The chapter briefly reviews historical filtration research f...

  10. A PERSPECTIVE OF RIVERBANK FILTRATION

    EPA Science Inventory

    Riverbank filtration is a process in which pumping of wells located along riverbanks induce a portion of the river water to flow toward the pumping wells. The process has many similarities to the slow sand filtration process. River water contaminants are attenuated due to a combi...