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Sample records for postvitrectomy retinal detachment

  1. Retinal detachment

    PubMed Central

    2010-01-01

    Introduction Rhegmatogenous retinal detachment (RRD) is the most common form of retinal detachment, where a retinal "break" allows the ingress of fluid from the vitreous cavity to the subretinal space, resulting in retinal separation. It occurs in about 1 in 10,000 people a year. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent progression from retinal breaks or lattice degeneration to retinal detachment? What are the effects of different surgical interventions in people with rhegmatogenous retinal detachment? What are the effects of interventions to treat proliferative vitreoretinopathy occurring as a complication of retinal detachment or previous treatment for retinal detachment? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 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 21 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: corticosteroids, cryotherapy, daunorubicin, fluorouracil plus low molecular weight heparin, laser photocoagulation, pneumatic retinopexy, scleral buckling, short-acting or long-acting gas tamponade, silicone oil tamponade, and vitrectomy. PMID:21406128

  2. Retinal Detachment Vision Simulator

    MedlinePlus

    ... Retina Treatment Retinal Detachment Vision Simulator Retinal Detachment Vision Simulator Mar. 01, 2016 How does a detached or torn retina affect your vision? If a retinal tear is occurring, you may ...

  3. Retinal Detachment: Torn or Detached Retina Diagnosis

    MedlinePlus

    ... Eye Health / Eye Health A-Z Detached or Torn Retina Sections Retinal Detachment: What Is a Torn ... Retina Treatment Retinal Detachment Vision Simulator Retinal Detachment: Torn or Detached Retina Diagnosis Written by: Kierstan Boyd ...

  4. Retinal Detachment: Torn or Detached Retina Symptoms

    MedlinePlus

    ... Eye Health / Eye Health A-Z Detached or Torn Retina Sections Retinal Detachment: What Is a Torn ... Retina Treatment Retinal Detachment Vision Simulator Retinal Detachment: Torn or Detached Retina Symptoms Written by: Kierstan Boyd ...

  5. Retinal detachment

    MedlinePlus

    ... separate from the underlying tissues, much like a bubble under wallpaper. This is most often caused by ... small detachment, the doctor may place a gas bubble in the eye. This is called pneumatic retinopexy. ...

  6. Retinal detachment in pseudophakia.

    PubMed

    Galin, M A; Poole, T A; Obstbaum, S A

    1979-07-01

    In a series of cataract patients excluding myopic individuals, under age 60 years, and cases in which vitreous loss occurred, retinal detachment was no less frequent after intracapsular cataract extraction and Sputnik iris supported lenses than in controls. Both groups were followed up for a minimum of two years. The detachments predominantly occurred from retinal breaks in areas of the retina that looked normal preoperatively. PMID:464014

  7. The mechanics of retinal detachment

    NASA Astrophysics Data System (ADS)

    Chou, Tom; Siegel, Michael

    2013-03-01

    We present a model of the mechanical and fluid forces associated with exudative retinal detachments where the retinal photoreceptor cells separate typically from the underlying retinal pigment epithelium (RPE). By computing the total fluid volume flow arising from transretinal, vascular, and retinal pigment epithelium (RPE) pump currents, we determine the conditions under which the subretinal fluid pressure exceeds the maximum yield stress holding the retina and RPE together, giving rise to an irreversible, extended retinal delamination. We also investigate localized, blister-like retinal detachments by balancing mechanical tension in the retina with both the retina-RPE adhesion energy and the hydraulic pressure jump across the retina. For detachments induced by traction forces, we find a critical radius beyond which the blister is unstable to growth. Growth of a detached blister can also be driven by inflamed tissue within which e.g., the hydraulic conductivities of the retina or choroid increase, the RPE pumps fail, or the adhesion properties change. We determine the parameter regimes in which the blister either becomes unstable to growth, remains stable and finite-sized, or shrinks, allowing possible healing. This work supported by the Army Research Office through grant 58386MA

  8. Retinal Detachment: Torn or Detached Retina Treatment

    MedlinePlus

    ... of these procedures create a scar that helps seal the retina to the back of the eye. ... around the retinal tear. The scarring that results seals the retina to the underlying tissue, helping to ...

  9. Retinal detachment associated with atopic dermatitis.

    PubMed Central

    Takahashi, M; Suzuma, K; Inaba, I; Ogura, Y; Yoneda, K; Okamoto, H

    1996-01-01

    BACKGROUND: Retinal detachment associated with atopic dermatitis, one of the most common forms of dermatitis in Japan, has markedly increased in Japan in the past 10 years. To clarify pathogenic mechanisms of retinal detachment in such cases, we retrospectively studied clinical characteristics of retinal detachment associated with atopic dermatitis. METHODS: We examined the records of 80 patients (89 eyes) who had retinal detachment associated with atopic dermatitis. The patients were classified into three groups according to lens status: group A, eyes with clear lenses (40 eyes); group B, eyes with cataract (38 eyes), and group C, aphakic or pseudophakic eyes (11 eyes). RESULTS: No significant differences were noted in the ratio of males to females, age distribution, refractive error, or characteristic of retinal detachment among the three groups. The types of retinal breaks, however, were different in eyes with and without lens changes. While atrophic holes were dominant in group A, retinal dialysis was mainly seen in groups B and C. CONCLUSION: These findings suggested that anterior vitreoretinal traction may play an important role in the pathogenesis of retinal breaks in eyes with atopic cataract and that the same pathological process may affect the formation of cataract and tractional retinal breaks in patients with atopic dermatitis. PMID:8664234

  10. [Ocular hypertension after surgery for retinal detachment].

    PubMed

    Muşat, O; Cristescu, R; Coman, Corina; Asandi, R

    2012-01-01

    This papers presents a case of a patient with retinal detachement, 3 days ago operated (posterior vitrectomy internal tamponament with silicon oil 1000) who develop increased ocular pressure following silicon oil output in the anterior chamber.

  11. A mechanical model of retinal detachment

    NASA Astrophysics Data System (ADS)

    Chou, Tom; Siegel, Michael

    2012-08-01

    We present a model of the mechanical and fluid forces associated with exudative retinal detachments where the retinal photoreceptor cells separate, typically from the underlying retinal pigment epithelium (RPE). By computing the total fluid volume flow arising from transretinal, vascular and RPE pump currents, we determine the conditions under which the subretinal fluid pressure exceeds the maximum yield stress holding the retina and RPE together, giving rise to an irreversible, extended retinal delamination. We also investigate localized, blister-like retinal detachments by balancing mechanical tension in the retina with both the retina-RPE adhesion energy and the hydraulic pressure jump across the retina. For detachments induced by traction forces, we find a critical radius beyond which the blister is unstable to growth. Growth of a detached blister can also be driven by inflamed lesions in which the tissue has a higher choroidal hydraulic conductivity, has insufficient RPE pump activity, or has defective adhesion bonds. We determine the parameter regimes in which the blister either becomes unstable to growth, remains stable and finite-sized, or shrinks, allowing possible healing. The corresponding stable blister radius and shape are calculated. Our analysis provides a quantitative description of the physical mechanisms involved in exudative retinal detachments and can help guide the development of retinal reattachment protocols or preventative procedures.

  12. Evaluation and management of pediatric rhegmatogenous retinal detachment

    PubMed Central

    Wenick, Adam S.; Barañano, David E.

    2012-01-01

    Pediatric rhegmatogenous retinal detachments are rare, accounting for less than ten percent of all rhegmatogenous retinal detachments. While most retinal detachments in the adult population are related to posterior vitreous detachment, pediatric retinal detachment are often related to trauma or an underlying congenital abnormalities or genetic syndrome. The anatomy of pediatric eyes, the often late presentation of the disease, and the high incidence of bilateral pathology in children all pose significant challenges in the management of these patients. We discuss the epidemiology of pediatric rhegmatogenous retinal detachment, review the genetic syndromes associated with a high incidence of retinal detachment, and examine other common causes of retinal detachment in this age group. We then outline an approach to evaluation and management and describe the expected outcomes of repair of retinal detachment in the pediatric population. PMID:23961003

  13. [Retinal detachment with retinoschisis--case report].

    PubMed

    Cristescu, R; Muşat, O; Toma, Oana; Coma, Corina; Gabej, Ioana; Burcea, M

    2013-01-01

    We present the case of a 43 year old patient diagnosed with rhegmatogenous retinal detachment and retinoschizis, a rare case of disease association. Surgery is recommended and we practice 23 gauge vitrectomy, laser retinopexy, criopexy in the periphery and internal heavy oil tamponade. Postoperatory evolution was favorable.

  14. Retinoschisis transposition following a retinal detachment repair

    PubMed Central

    McVeigh, Katherine; Keller, Johannes; Haynes, Richard J.

    2015-01-01

    Objective: The authors have observed this phenomenon of translocation of the schisis cavity in a few previous cases and aim to report this unusual finding. Method: A patient with known superotemporal retinoschisis developed a distinctly separate inferotemporal retinal detachment in his left eye. This was repaired with a vitrectomy, cryotherapy and C2F6 tamponade under local anaesthetic. Following surgery, the retinoschisis was found in the inferonasal quadrant of the eye and remained stable as the gas dispersed. Result: We hypothesise that the tamponading agent compressed the viscous fluid within the area of schisis, displacing the area of schisis circumferentially. Conclusion: This case emphasises that as long as the retinal breaks are properly sealed, no intervention is required with the schisis during rhegmatogenous retinal detachment surgery.

  15. Central serous choroidopathy with bullous retinal detachment.

    PubMed

    Tsukahara, I; Uyama, M

    1978-05-16

    We report here a new type of secondary retinal detachment that has never been clearly defined. The characteristic features of the disease are: (1) prevalence in middle-aged males, (2) bilateral involvement, (3) frequent existence of prodromal lesions that over long periods resemble central serous retinopathy, (4) in the evolution stage, appearance of multiple yellowish white exudative flecks of one-half to one disc in diameter at or near the posterior pole of the fundus, (5) fluorescein studies revealing pronounced leakage of dye from the choroid into the subretinal space at the sites of exudates, (6) retinal detachment of various degrees with shifting subretinal fluid and without tears, (7) no evidence of intraocular inflammation, (8) no filling abnormalities seen in the choroidal fluorescence, (9) no response to medical therapy, including steroids and antibiotics, (10) photocoagulation to leakage sites leading to rapid resolution of retinal detachment; otherwise, spontaneous healing of detachment occurring within about 7-9 months, leaving fibroblastic macular scars and marked visual loss, and (11) no evidence of systemic findings that may be of etiologic significance. From this characteristic clinical picture, the idea of a new clinical entity must be considered. Our findings in 35 eyes from 18 Japanese patients are discussed.

  16. Fluorosilicone oil in the treatment of retinal detachment.

    PubMed Central

    Gremillion, C M; Peyman, G A; Liu, K R; Naguib, K S

    1990-01-01

    We evaluated the use of a heavier-than-water fluorinated silicone oil in the treatment of 30 selected cases of complicated retinal detachment from January 1988 to July 1989. Proliferative vitreoretinopathy grade C-2 or greater accounted for 19 cases, proliferative diabetic retinopathy with traction detachment for two cases, giant retinal tears five, ruptured globe with retinal detachment two, massive choroidal effusion with retinal detachment one, and acute retinal necrosis with retinal detachment one. Initial retinal reattachment was achieved in all cases. Complications included redetachment seven (23%), cataract six (75% of phakic patients), raised intraocular pressure four (13%), hypotony four (13%), keratopathy three (10%), uveitis-synechia formation three (10%), phthisis two (3%), choroidal haemorrhage one (3%), and vitreous haemorrhage one (3%). Postoperative visual acuities with at least six months' follow-up range from no light perception to 20/50, with seven patients (23%) 20/400 or better. Images PMID:2223698

  17. Fluorosilicone oil in the treatment of retinal detachment.

    PubMed

    Gremillion, C M; Peyman, G A; Liu, K R; Naguib, K S

    1990-11-01

    We evaluated the use of a heavier-than-water fluorinated silicone oil in the treatment of 30 selected cases of complicated retinal detachment from January 1988 to July 1989. Proliferative vitreoretinopathy grade C-2 or greater accounted for 19 cases, proliferative diabetic retinopathy with traction detachment for two cases, giant retinal tears five, ruptured globe with retinal detachment two, massive choroidal effusion with retinal detachment one, and acute retinal necrosis with retinal detachment one. Initial retinal reattachment was achieved in all cases. Complications included redetachment seven (23%), cataract six (75% of phakic patients), raised intraocular pressure four (13%), hypotony four (13%), keratopathy three (10%), uveitis-synechia formation three (10%), phthisis two (3%), choroidal haemorrhage one (3%), and vitreous haemorrhage one (3%). Postoperative visual acuities with at least six months' follow-up range from no light perception to 20/50, with seven patients (23%) 20/400 or better.

  18. Retinal Detachment due to CrossFit Training Injury.

    PubMed

    Joondeph, Stephanie A; Joondeph, Brian C

    2013-01-01

    The purpose of this paper is to describe a traumatic retinal detachment occurring as a result of CrossFit training using an elastic exercise band. The patient sustained an ocular injury from an elastic band during CrossFit training, resulting in a giant retinal dialysis and retinal detachment, which were successfully repaired. Trainers and athletes need to be aware of the potential for ocular injury from elastic exercise bands and take appropriate precautions.

  19. Retinal Detachment due to CrossFit Training Injury

    PubMed Central

    Joondeph, Stephanie A.; Joondeph, Brian C.

    2013-01-01

    The purpose of this paper is to describe a traumatic retinal detachment occurring as a result of CrossFit training using an elastic exercise band. The patient sustained an ocular injury from an elastic band during CrossFit training, resulting in a giant retinal dialysis and retinal detachment, which were successfully repaired. Trainers and athletes need to be aware of the potential for ocular injury from elastic exercise bands and take appropriate precautions. PMID:24106626

  20. Retinal Detachment due to CrossFit Training Injury.

    PubMed

    Joondeph, Stephanie A; Joondeph, Brian C

    2013-01-01

    The purpose of this paper is to describe a traumatic retinal detachment occurring as a result of CrossFit training using an elastic exercise band. The patient sustained an ocular injury from an elastic band during CrossFit training, resulting in a giant retinal dialysis and retinal detachment, which were successfully repaired. Trainers and athletes need to be aware of the potential for ocular injury from elastic exercise bands and take appropriate precautions. PMID:24106626

  1. An Unusual Case of Extensive Lattice Degeneration and Retinal Detachment

    PubMed Central

    Sarma, Saurabh Kumar; Basaiawmoit, Jennifer V.

    2016-01-01

    Lattice degeneration of the retina is not infrequently encountered on a dilated retinal examination and many of them do not need any intervention. We report a case of atypical lattice degeneration variant with peripheral retinal detachment. An asymptomatic 35-year-old lady with minimal refractive error was found to have extensive lattice degeneration, peripheral retinal detachment and fibrotic changes peripherally with elevation of retinal vessels on dilated retinal examination. There were also areas of white without pressure, chorioretinal scarring and retinal breaks. All the changes were limited to beyond the equator but were found to span 360 degrees. She was treated with barrage laser all around to prevent extension of the retinal detachment posteriorly. She remained stable till her latest follow-up two years after the barrage laser. This case is reported for its rarity with a discussion of the probable differential diagnoses. To the best of our knowledge, this is the first report of such findings in lattice degeneration.

  2. Advantages of diabetic tractional retinal detachment repair

    PubMed Central

    Sternfeld, Amir; Axer-Siegel, Ruth; Stiebel-Kalish, Hadas; Weinberger, Dov; Ehrlich, Rita

    2015-01-01

    Purpose To evaluate the outcomes and complications of patients with diabetic tractional retinal detachment (TRD) treated with pars plana vitrectomy (PPV). Patients and methods We retrospectively studied a case series of 24 eyes of 21 patients at a single tertiary, university-affiliated medical center. A review was carried out on patients who underwent PPV for the management of TRD due to proliferative diabetic retinopathy from October 2011 to November 2013. Preoperative and final visual outcomes, intraoperative and postoperative complications, and medical background were evaluated. Results A 23 G instrumentation was used in 23 eyes (95.8%), and a 25 G instrumentation in one (4.2%). Mean postoperative follow-up time was 13.3 months (4–30 months). Visual acuity significantly improved from logarithm of the minimum angle of resolution (LogMAR) 1.48 to LogMAR 1.05 (P<0.05). Visual acuity improved by ≥3 lines in 75% of patients. Intraoperative complications included iatrogenic retinal breaks in seven eyes (22.9%) and vitreal hemorrhage in nine eyes (37.5%). In two eyes, one sclerotomy was enlarged to 20 G (8.3%). Postoperative complications included reoperation in five eyes (20.8%) due to persistent subretinal fluid (n=3), vitreous hemorrhage (n=1), and dislocated intraocular lens (n=1). Thirteen patients (54.2%) had postoperative vitreous hemorrhage that cleared spontaneously, five patients (20.8%) required antiglaucoma medications for increased intraocular pressure, seven patients (29.2%) developed an epiretinal membrane, and two patients (8.3%) developed a macular hole. Conclusion Patients with diabetic TRD can benefit from PPV surgery. Intraoperative and postoperative complications can be attributed to the complexity of this disease. PMID:26604667

  3. Bilateral Simultaneous Rhegmatogenous Retinal Detachment following Laser in situ Keratomileusis

    PubMed Central

    Yumusak, Erhan; Ornek, Kemal; Ozkal, Fatma

    2016-01-01

    A 21-year-old woman developed simultaneous rhegmatogenous retinal detachment after laser in situ keratomileusis (LASIK) in both eyes. She underwent pars plana vitrectomy surgery combined with endolaser photocoagulation and silicone oil tamponade in the right eye. A week later, pneumatic retinopexy was done in the left eye. As the retinal tear did not seal, 360° scleral buckling surgery was performed and retina was attached. Bilateral simultaneous rhegmatogenous retinal detachment after LASIK for correction of myopia can be a serious complication. Patients should be informed about the possibility of this complication. PMID:27462264

  4. Bilateral Simultaneous Rhegmatogenous Retinal Detachment following Laser in situ Keratomileusis.

    PubMed

    Yumusak, Erhan; Ornek, Kemal; Ozkal, Fatma

    2016-01-01

    A 21-year-old woman developed simultaneous rhegmatogenous retinal detachment after laser in situ keratomileusis (LASIK) in both eyes. She underwent pars plana vitrectomy surgery combined with endolaser photocoagulation and silicone oil tamponade in the right eye. A week later, pneumatic retinopexy was done in the left eye. As the retinal tear did not seal, 360° scleral buckling surgery was performed and retina was attached. Bilateral simultaneous rhegmatogenous retinal detachment after LASIK for correction of myopia can be a serious complication. Patients should be informed about the possibility of this complication. PMID:27462264

  5. Risk factors of rhegmatogenous retinal detachment associated with choroidal detachment in Chinese patients

    PubMed Central

    Gu, Yong-Hao; Ke, Gen-Jie; Wang, Lin; Gu, Qi-Hong; Zhou, En-Liang; Pan, Hong-Biao; Wang, Shi-Ying

    2016-01-01

    AIM To comprehensively analyze the risk factors of rhegmatogenous retinal detachment (RRD) associated with choroidal detachment (CD). METHODS A total of 265 eyes of 265 consecutive cases of RRD were retrospectively analyzed. All patients had systemic and ophthalmologic examination. CD was diagnosed by indirect ophthalmoscopy, B-scan ultrasonography, and ultrasound biomicroscope (UBM). Each parameter was compared between patients of RRD and rhegmatogenous retinal detachment associated with choroidal detachment (RRDCD). Logistic regression analysis was used to determine the independent risk factors of CD. RESULTS There were 52 eyes (19.62%) with CD. Pseudophakia was more commonly seen in RRDCD (21.15% vs 6.10%, P=0.002). Intraocular pressure (IOP) was lower (8.60±3.62 vs 12.96±3.55, P<0.001), best-corrected visual acuity was worse [3.00 (2.00 to 3.00) vs 1.92 (1.22 to 3.00), P=0.001], and refractive error was more myopic [-4 (-9 to -2) vs -2 (-6 to 0), P=0.007] in RRDCD. Eyes with RRDCD had larger extent of retinal detachment (P=0.007). In RRDCD, 34.62% of eyes presented with multiple holes (P=0.044) and 25.00% with macular holes (P=0.012), compared with 20.66% and 14.08% in RRD. High myopia (P=0.039), low IOP (P=0.017), and larger extent of retinal detachment (P<0.001) were significant and independent risk factors for developing CD. CONCLUSION For CD in RRD, related factors include BCVA, IOP, lens status, refractive error, extent of retinal detachment, number of holes, and macular hole. Larger extent of retinal detachment, high myopia, and low IOP are significant and independent risk factors. PMID:27500106

  6. Bilateral Rhegmatogenous Retinal Detachment during External Beam Radiotherapy.

    PubMed

    Hidaka, Takako; Chuman, Hideki; Nao-I, Nobuhisa

    2016-01-01

    Herein, we report a case of nontraumatic bilateral rhegmatogenous retinal detachment (RRD) during external beam radiotherapy for nonocular tumor, presented as an observational case study in conjunction with a review of the relevant literature. A 65-year-old male was referred to our hospital due to bilateral RRD. He underwent a biopsy for a tumor of the left frontal lobe 4 months prior to presentation, and the tumor had been diagnosed as primary central nerve system B-cell type lymphoma. He received chemotherapy and external beam radiotherapy for 1 month. There were no traumatic episodes. Bilateral retinal detachment occurred during a series of radiotherapies. Simultaneous nontraumatic bilateral retinal detachment is rare. The effects of radiotherapy on ocular functionality, particularly in cases involving retinal adhesion and vitreous contraction, may include RRD. Thus, it is necessary to closely monitor the eyes of patients undergoing radiotherapy, particularly those undergoing surgery for retinal detachment and those with a history of photocoagulation for retinal tears, a relevant family history, or risk factors known to be associated with RRD. PMID:27462261

  7. An Unusual Case of Extensive Lattice Degeneration and Retinal Detachment

    PubMed Central

    Sarma, Saurabh Kumar; Basaiawmoit, Jennifer V.

    2016-01-01

    Lattice degeneration of the retina is not infrequently encountered on a dilated retinal examination and many of them do not need any intervention. We report a case of atypical lattice degeneration variant with peripheral retinal detachment. An asymptomatic 35-year-old lady with minimal refractive error was found to have extensive lattice degeneration, peripheral retinal detachment and fibrotic changes peripherally with elevation of retinal vessels on dilated retinal examination. There were also areas of white without pressure, chorioretinal scarring and retinal breaks. All the changes were limited to beyond the equator but were found to span 360 degrees. She was treated with barrage laser all around to prevent extension of the retinal detachment posteriorly. She remained stable till her latest follow-up two years after the barrage laser. This case is reported for its rarity with a discussion of the probable differential diagnoses. To the best of our knowledge, this is the first report of such findings in lattice degeneration. PMID:27630875

  8. Serous retinal detachment after trabeculectomy in angle recession glaucoma

    PubMed Central

    Roy, Avik Kumar; Padhy, Debananda

    2015-01-01

    An 18-year-old male with 360 degree angle recession after blunt trauma in his right eye developed uncontrolled intraocular pressure (IOP) despite four antiglaucoma medications (AGM) with advancing disc damage. He underwent trabeculectomy with intraoperative mitomycin-c (MMC) application. There was an intraoperative vitreous prolapse which was managed accordingly. On post-surgery day 1, he had shallow choroidal detachment superiorly with non-recordable IOP. This was deteriorated 1 week postoperatively as choroidal detachment proceeded to serous retinal detachment. He was started with systemic steroid in addition to topical route. The serous effusions subsided within 2 weeks time. At the last follow up at 3 months, he was enjoying good visual acuity, deep anterior chamber, diffuse bleb, an IOP in low teens off any AGM and attached retina. This case highlights the rare occurrence of serous retinal detachment after surgical management of angle recession glaucoma. PMID:27625959

  9. Serous retinal detachment after trabeculectomy in angle recession glaucoma

    PubMed Central

    Roy, Avik Kumar; Padhy, Debananda

    2015-01-01

    An 18-year-old male with 360 degree angle recession after blunt trauma in his right eye developed uncontrolled intraocular pressure (IOP) despite four antiglaucoma medications (AGM) with advancing disc damage. He underwent trabeculectomy with intraoperative mitomycin-c (MMC) application. There was an intraoperative vitreous prolapse which was managed accordingly. On post-surgery day 1, he had shallow choroidal detachment superiorly with non-recordable IOP. This was deteriorated 1 week postoperatively as choroidal detachment proceeded to serous retinal detachment. He was started with systemic steroid in addition to topical route. The serous effusions subsided within 2 weeks time. At the last follow up at 3 months, he was enjoying good visual acuity, deep anterior chamber, diffuse bleb, an IOP in low teens off any AGM and attached retina. This case highlights the rare occurrence of serous retinal detachment after surgical management of angle recession glaucoma.

  10. Astrocyte structural reactivity and plasticity in models of retinal detachment.

    PubMed

    Luna, Gabriel; Keeley, Patrick W; Reese, Benjamin E; Linberg, Kenneth A; Lewis, Geoffrey P; Fisher, Steven K

    2016-09-01

    Although retinal neurodegenerative conditions such as age-related macular degeneration, glaucoma, diabetic retinopathy, retinitis pigmentosa, and retinal detachment have different etiologies and pathological characteristics, they also have many responses in common at the cellular level, including neural and glial remodeling. Structural changes in Müller cells, the large radial glia of the retina in retinal disease and injury have been well described, that of the retinal astrocytes remains less so. Using modern imaging technology to describe the structural remodeling of retinal astrocytes after retinal detachment is the focus of this paper. We present both a review of critical literature as well as novel work focusing on the responses of astrocytes following rhegmatogenous and serous retinal detachment. The mouse presents a convenient model system in which to study astrocyte reactivity since the Mϋller cell response is muted in comparison to other species thereby allowing better visualization of the astrocytes. We also show data from rat, cat, squirrel, and human retina demonstrating similarities and differences across species. Our data from immunolabeling and dye-filling experiments demonstrate previously undescribed morphological characteristics of normal astrocytes and changes induced by detachment. Astrocytes not only upregulate GFAP, but structurally remodel, becoming increasingly irregular in appearance, and often penetrating deep into neural retina. Understanding these responses, their consequences, and what drives them may prove to be an important component in improving visual outcome in a variety of therapeutic situations. Our data further supports the concept that astrocytes are important players in the retina's overall response to injury and disease. PMID:27060374

  11. Astrocyte structural reactivity and plasticity in models of retinal detachment.

    PubMed

    Luna, Gabriel; Keeley, Patrick W; Reese, Benjamin E; Linberg, Kenneth A; Lewis, Geoffrey P; Fisher, Steven K

    2016-09-01

    Although retinal neurodegenerative conditions such as age-related macular degeneration, glaucoma, diabetic retinopathy, retinitis pigmentosa, and retinal detachment have different etiologies and pathological characteristics, they also have many responses in common at the cellular level, including neural and glial remodeling. Structural changes in Müller cells, the large radial glia of the retina in retinal disease and injury have been well described, that of the retinal astrocytes remains less so. Using modern imaging technology to describe the structural remodeling of retinal astrocytes after retinal detachment is the focus of this paper. We present both a review of critical literature as well as novel work focusing on the responses of astrocytes following rhegmatogenous and serous retinal detachment. The mouse presents a convenient model system in which to study astrocyte reactivity since the Mϋller cell response is muted in comparison to other species thereby allowing better visualization of the astrocytes. We also show data from rat, cat, squirrel, and human retina demonstrating similarities and differences across species. Our data from immunolabeling and dye-filling experiments demonstrate previously undescribed morphological characteristics of normal astrocytes and changes induced by detachment. Astrocytes not only upregulate GFAP, but structurally remodel, becoming increasingly irregular in appearance, and often penetrating deep into neural retina. Understanding these responses, their consequences, and what drives them may prove to be an important component in improving visual outcome in a variety of therapeutic situations. Our data further supports the concept that astrocytes are important players in the retina's overall response to injury and disease.

  12. Unilateral, recurrent exudative retinal detachment in association with pansinusitis

    PubMed Central

    Osman Saatci, Ali; Ozbek Soylemezoglu, Zeynep; Barut Selver, Ozlem; Cenk Ecevit, M.; Ada, Emel

    2012-01-01

    Aim: To report a patient with unilateral exudative retinal detachment due to pansinusitis. Methods: Case report. Results: A 65-year-old woman with a two-month history of blurred vision, red eye and lid swelling in her left eye was referred to us. Her best-corrected visual acuity was 20/20 in the right eye and 20/200 in the left. Conjunctival vessels were engorged in the OS. Funduscopy revealed a 360° exudative detachment in OS and computerized tomography (CT) imaging revealed pansinusitis. Systemic antibiotic treatment was employed and exudative detachment regressed. However, exudative detachment remitted as soon as antibiotic treatment ceased. Finally she underwent sinus surgery and decompression of the orbita. Her visual acuity improved to 20/100 just two days after the surgery, stabilized at 20/30 and no further recurrences occured during the follow-up of 10 months. Conclusion: Since exudative retinal detachment usually accompanies systemic inflammatory or neoplastic diseases, systemic screening and collaboration with other disciplines are mandatory. To the best of our knowledge, this is the first report of a case that developed exudative retinal detachment due to pansinusitis and only recovered after decompression surgery.

  13. Surgical treatment of retinal detachment in the choroidal colobomas.

    PubMed

    Corcostegui, B; Güell, J L; García-Arumí, J

    1992-01-01

    Seven eyes from seven patients with retinal detachment and choroidal coloboma (with or without optic disc involvement) were treated. The retinal break was always inside the colobomatous area, except in the cases with evidence of peripheral retinal breaks. In order to produce reattachment of the retina, vitrectomy procedures with removal of posterior hyaloid were used. Drainage of subretinal fluid was performed through the break in the area of the coloboma, with simultaneous fluid-air exchange. Previously undetected retinal breaks were identified by inspecting for the presence of schlieren in the colobomatous area during fluid-air exchange. A peripheral scleral buckle was then applied. Argon laser endophotocoagulation was performed, but when the coloboma involved the optic disc, red krypton endophotocoagulation was used. Retinal reattachment was achieved in all cases.

  14. Biostatistical analysis of pseudophakic and aphakic retinal detachments.

    PubMed

    Ramos, Meisy; Kruger, Erik F; Lashkari, Kameran

    2002-01-01

    Removal of the crystalline lens increases the risk of rhegmatogenous retinal detachment (RD) by creating changes in the ocular environment that predispose to development of retinal breaks. The evolution of cataract surgery from intracapsular cataract extraction (ICCE) to extracapsular cataract extraction (ECCE) and phacoemulsification has reduced the incidence of RD, while advances in vitreoretinal surgery have resulted in improved outcomes when retinal detachment does occur. The incidence of RD varies between 0.4-3.6% for ICCE and between 0.55-1.65% for ECCE. In eyes having undergone phacoemulsification the incidence is similar to those of ECCE and ranges between 0.75-1.65%. In this article the authors review the incidence and risk factors associated with pseudophakic and aphakic RD. The risk factors discussed include pre-operative risk factors such as age, status of the fellow eye and myopia, and surgical risk factors such as vitreous loss, posterior capsular integrity and Nd : YAG capsulotomy.

  15. Spectral domain optical coherence tomography imaging of subretinal bands associated with chronic retinal detachments

    PubMed Central

    Kothari, Nikisha; Kuriyan, Ajay E; Flynn, Harry W

    2016-01-01

    We report three patients with subretinal bands associated with retinal detachment in chronic retinal detachments who underwent successful retinal reattachment. Subretinal bands before and after surgery can be identified on clinical examination and spectral domain optical coherence tomography. Removal of subretinal bands is not mandatory to achieve retinal reattachment. PMID:27099457

  16. Regular silicone and fluorosilicone oil in the prevention of retinal detachment caused by experimental proliferative vitreoretinopathy.

    PubMed

    Alghadyan, A; Peyman, G A; Fizer, C; Tawakol, M; Liu, K R; Yue, B; Peace, J H

    1988-01-01

    The effect of both regular silicone and fluorosilicone in preventing retinal detachment caused by experimental proliferative vitreoretinopathy was studied in rabbit eyes which received 250,000 fibroblasts after vitrectomy and lensectomy. In the control group, 14 out of 20 eyes which received fibroblasts had retinal detachments with disorganization of internal structures. In eyes receiving fibroblast and regular silicone, 4 out of 20 eyes had shallow retinal detachment. In the eyes receiving fibroblasts and fluorosilicone, 5 of 28 eyes had shallow retinal detachment. Our findings indicate that both regular silicone and fluorosilicone were effective in preventing retinal detachments caused by experimental proliferative vitreoretinopathy. There was no statistical difference between the two silicone oils.

  17. Retinal Detachment in Down Syndrome: Characteristics and Surgical Outcomes

    PubMed Central

    AlAhmadi, Badr O.; Alsulaiman, Sulaiman M.; Arevalo, J. Fernando

    2016-01-01

    Purpose. To determine the functional and anatomic outcomes of rhegmatogenous retinal detachment (RRD) surgery in patients with Down syndrome. Methods. A retrospective chart review was performed of patients with Down syndrome who had undergone surgery for RRD at King Khalid Eye Specialist Hospital between 1995 and 2014. Results. A total of 245 patients with Down syndrome were evaluated during the study period. Eighteen eyes of 15 patients (6.1%) with RRD were identified. Three out of 15 patients (20%) presented with bilateral retinal detachment. All eyes presented with macula off retinal detachment. The retina was successfully reattached in 16/18 (88.8%) eyes after a mean follow-up of 48 months. The final postoperative visual acuity ranged from light perception to 20/125 (median: hand motion) (11/18 eyes). Conclusions. The anatomic success rate of retinal reattachment surgery in patients with Down syndrome is comparable to the general population. Patients with Down syndrome should undergo regular ophthalmic examinations for early diagnosis. Despite late diagnosis and the presence of proliferative vitreoretinopathy (PVR) in some patients, favorable anatomical outcomes can be achieved. PMID:27123341

  18. Retinal Detachment in Down Syndrome: Characteristics and Surgical Outcomes.

    PubMed

    AlAhmadi, Badr O; Alsulaiman, Sulaiman M; Arevalo, J Fernando

    2016-01-01

    Purpose. To determine the functional and anatomic outcomes of rhegmatogenous retinal detachment (RRD) surgery in patients with Down syndrome. Methods. A retrospective chart review was performed of patients with Down syndrome who had undergone surgery for RRD at King Khalid Eye Specialist Hospital between 1995 and 2014. Results. A total of 245 patients with Down syndrome were evaluated during the study period. Eighteen eyes of 15 patients (6.1%) with RRD were identified. Three out of 15 patients (20%) presented with bilateral retinal detachment. All eyes presented with macula off retinal detachment. The retina was successfully reattached in 16/18 (88.8%) eyes after a mean follow-up of 48 months. The final postoperative visual acuity ranged from light perception to 20/125 (median: hand motion) (11/18 eyes). Conclusions. The anatomic success rate of retinal reattachment surgery in patients with Down syndrome is comparable to the general population. Patients with Down syndrome should undergo regular ophthalmic examinations for early diagnosis. Despite late diagnosis and the presence of proliferative vitreoretinopathy (PVR) in some patients, favorable anatomical outcomes can be achieved. PMID:27123341

  19. Interventions for asymptomatic retinal breaks and lattice degeneration for preventing retinal detachment

    PubMed Central

    Wilkinson, Charles P

    2015-01-01

    Background Asymptomatic retinal breaks and lattice degeneration are visible lesions that are risk factors for later retinal detachment. Retinal detachments occur when fluid in the vitreous cavity passes through tears or holes in the retina and separates the retina from the underlying retinal pigment epithelium. Creation of an adhesion surrounding retinal breaks and lattice degeneration, with laser photocoagulation or cryotherapy, has been recommended as an effective means of preventing retinal detachment. This therapy is of value in the management of retinal tears associated with the symptoms of flashes and floaters and persistent vitreous traction upon the retina in the region of the retinal break, because such symptomatic retinal tears are associated with a high rate of progression to retinal detachment. Retinal tears and holes unassociated with acute symptoms and lattice degeneration are significantly less likely to be the sites of retinal breaks that are responsible for later retinal detachment. Nevertheless, treatment of these lesions frequently is recommended, in spite of the fact that the effectiveness of this therapy is unproven. Objectives The objective of this review was to assess the effectiveness and safety of techniques used to treat asymptomatic retinal breaks and lattice degeneration for the prevention of retinal detachment. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 2), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to February 2014), EMBASE (January 1980 to February 2014), PubMed (January 1948 to February 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in

  20. Retinal Detachment in Southwest Ethiopia: A Hospital Based Prospective Study

    PubMed Central

    Asaminew, Tsedeke; Gelaw, Yeshigeta; Bekele, Sisay; Solomon, Berhan

    2013-01-01

    Purpose The incidence of retinal detachment in Blacks is generally considered to be low though there are few supporting studies in Africa. This study, thus, aimed at describing the clinical profile of patients with retinal detachment in Southwest Ethiopia. Methods A hospital-based study was done on all consecutive retinal detachment patients who presented to Jimma University Hospital over six months period. A semi-structured questionnaire was used to collect patients’ sociodemographic characteristics and clinical history. Comprehensive anterior and posterior segment eye examinations were done and risk factors were sought for. Statistical tests were considered significant if P < 0.05. Results A total of 94 eyes of 80 patients (1.5%) had retinal detachment (RD) and about 69% of patients were symptomatic for over a month before presentation. The mean age was 41.4 years (SD ±16.5). Fourteen patients (17.5%) had bilateral RD. At presentation, 61 eyes (64.9%) were blind from RD and 11 (13.8%) patients were bilaterally blind from RD. Rhegmatogenous RD was seen in 55 eyes (58.5%) and tractional RD in 22 eyes (23.4%). The most common risk factors were ocular trauma (32 eyes, 34.0%), myopia (23 eyes, 24.5%), posterior uveitis (13 eyes, 13.8%) and diabetic retinopathy (9 eyes, 9.6%). Most retinal breaks (25 eyes, 43.1%) were superotemporal and horse-shoe tear was the most common (19 eyes, 20.2%). Macula was off in 77 eyes (81.9%) and 38 eyes (69.1% of RRD eyes) had grade C proliferative vitreoretinopathy (PVR). Macular status was significantly associated with PVR (P=0.011), and duration of symptoms (RR=1.25, 95%CI: 1.059-1.475, P=0.040). Conclusions A significant numbers of patients with ocular problem had retinal detachment, and nearly two third of the patients presented late. Trauma and myopia were the most important risk factors. People should be educated to improve their health seeking behavior and use eye safety precautions to prevent ocular trauma. PMID:24086614

  1. A rare case of traumatic posterior phacocele with retinal detachment

    PubMed Central

    Sindal, Manavi D; Mourya, Deepesh

    2016-01-01

    Dislocation of crystalline lens into the anterior subconjunctival or subtenon's space is a rare but known complication of blunt trauma. Dislocation into the posterior subtenon's space is even rarer and can be associated with a complication such as occult scleral tear and retinal detachment. We report a case of traumatic posterior subtenon's dislocation of crystalline lens after blunt trauma and its successful surgical management. PMID:26953031

  2. Rhegmatogenous retinal detachment with a pit of the optic nerve head.

    PubMed

    Traboulsi, E I; Pilkerton, A R

    1988-04-01

    A 56-year-old myope developed a retinal detachment of the macular area and the temporal quadrants in his left eye that harbored a temporally-located pit of the optic nerve head. Under anesthesia a small peripheral retinal break was identified, and the retina was reattached successfully using cryotherapy and a limited scleral buckling procedure. Peripheral retinal breaks should be searched for in myopic eyes with optic pits and retinal detachments involving peripheral retinal quadrants.

  3. Surgical management of retinal diseases: proliferative diabetic retinopathy and traction retinal detachment.

    PubMed

    Cruz-Iñigo, Yousef J; Acabá, Luis A; Berrocal, Maria H

    2014-01-01

    Current indications for pars plana vitrectomy in patients with proliferative diabetic retinopathy (PDR) include vitreous hemorrhage, tractional retinal detachment (TRD), combined tractional and rhegmatogenous retinal detachment (CTRRD), diabetic macular edema associated with posterior hyaloidal traction, and anterior segment neovascularization with media opacities. This chapter will review the indications, surgical objectives, adjunctive pharmacotherapy, microincision surgical techniques, and outcomes of diabetic vitrectomy for PDR, TRD, and CTRRD. With the availability of new microincision vitrectomy technology, wide-angle microscope viewing systems, and pharmacologic agents, vitrectomy can improve visual acuity and achieve long-term anatomic stability in eyes with severe complications from PDR.

  4. Mechanism of traumatic retinal detachment in blunt impact: a finite element study.

    PubMed

    Liu, Xiaoyu; Wang, Lizhen; Wang, Chao; Sun, Ganyun; Liu, Songyang; Fan, Yubo

    2013-04-26

    Retinal detachment typically occurs when the retina is pulled away from its normal position by blunt trauma. It has been estimated that traumatic retinal detachments account for 10-20% of all detachments. Understanding the mechanism of traumatic retinal detachment is helpful for ophthalmologists to make a more accurate diagnosis before the symptoms develop. A finite element eye model, validated through published data, was used to simulate traumatic retinal detachment. Retinal adhesive force was incorporated into the model using breakable bonded contact. Under BB impact, global deformation was divided into four stages: compression, decompression, overshooting and oscillation. Shockwave propagation in the retina produced high strain in the retina. For an impact speed of 50 m/s, the peak strain of 0.138 in ora serrata exceeded the specified threshold for retinal break. When the eye was decompressed, negative pressure occurred around and anterior to the equator, with a minimum of -663 kPa, leading to retinal detachment. The following relative inertia motions between the retina and its supporting tissue extended the detachment. In addition, the simulations of lower shear modulus of vitreous and increased retinal adhesive force also confirm that the extent of retinal detachment is determined by negative pressure and inertial motion. In conclusion, shockwave and negative pressure contribute to retinal detachment. Shockwave propagation in the retina leads to retinal break, while negative pressure and relative inertial motion could pull the retina away from the supporting tissue. The current work would help understand the basic mechanisms underlying blunt trauma.

  5. Injection of fluorosilicone oil and pars plana vitrectomy for complex retinal detachment.

    PubMed

    Peyman, G A; Smith, R T; Charles, H

    1987-08-01

    Pars plana vitrectomy can be combined with injection of fluorosilicone oil to treat complex retinal detachments. We describe three cases to illustrate the technique, which is adapted according to the type and location of the retinal breaks.

  6. Perfluorocarbon liquids in the management of complicated retinal detachments.

    PubMed

    Comaratta, M R; Chang, S

    1991-06-01

    Low viscosity perfluorocarbon liquids have unique physical properties making them ideal for the temporary tamponade, mechanical fixation, and manipulation of the retina. These substances are optically clear, have a specific gravity greater than that of water, and have interfacial tension properties similar to those of silicone oil. The temporary mechanical fixation of the retina by perfluorocarbon liquids facilitates the removal of epiretinal membranes and release of tractional forces. Intraoperative flattening of the retina under perfluorocarbon liquid eliminates the need for a posterior retinotomy. Perfluorocarbon liquids are being used intraoperatively for hydrokinetic manipulation of the retina during vitrectomy for complicated retinal detachments secondary to proliferative vitreoretinopathy, giant retinal tears, and trauma. Additional indications for the intraoperative utilization of perfluorocarbon liquids in vitreous surgery are discussed.

  7. Perfluorocarbon liquids in the management of complicated retinal detachments.

    PubMed

    Comaratta, M R; Chang, S

    1991-06-01

    Low viscosity perfluorocarbon liquids have unique physical properties making them ideal for the temporary tamponade, mechanical fixation, and manipulation of the retina. These substances are optically clear, have a specific gravity greater than that of water, and have interfacial tension properties similar to those of silicone oil. The temporary mechanical fixation of the retina by perfluorocarbon liquids facilitates the removal of epiretinal membranes and release of tractional forces. Intraoperative flattening of the retina under perfluorocarbon liquid eliminates the need for a posterior retinotomy. Perfluorocarbon liquids are being used intraoperatively for hydrokinetic manipulation of the retina during vitrectomy for complicated retinal detachments secondary to proliferative vitreoretinopathy, giant retinal tears, and trauma. Additional indications for the intraoperative utilization of perfluorocarbon liquids in vitreous surgery are discussed. PMID:10149295

  8. Reduction of corneal sensitivity after retinal detachment surgery.

    PubMed Central

    Gibson, R A

    1981-01-01

    Corneal sensitivity measurements were performed on both eyes of 57 patients after they were subjected to unilateral retinal detachment surgery, the unoperated eyes acting as controls. A marked decrease in corneal sensitivity was found in eyes that were treated with encircling bands, but no significant change of sensitivity could be detected in eyes in which localised radial or circumferential silicone sponge explants alone had been employed. It would appear that encirclement procedures lower the sensitivity of the cornea, and this may continue as a long-term effect. PMID:7295628

  9. Tamponade in the surgical management of retinal detachment

    PubMed Central

    Vaziri, Kamyar; Schwartz, Stephen G; Kishor, Krishna S; Flynn, Harry W

    2016-01-01

    Despite treatment advances, rhegmatogenous retinal detachment (RD) can have poor visual outcomes even with prompt and appropriate therapy. Pars plana vitrectomy is a leading management modality for the treatment of RD. This procedure is generally accompanied by the use of internal tamponade. Various gases and silicone oils may yield beneficial outcomes. Heavy silicone oils have been approved in some European nations but are not available in the USA. Different tamponade agents have unique benefits and risks, and choice of the agent should be individualized according to the characteristics of the patient and RD, as well as perioperative and postoperative factors. PMID:27041988

  10. Photoreceptor cell death and rescue in retinal detachment and degenerations

    PubMed Central

    Murakami, Yusuke; Notomi, Shoji; Hisatomi, Toshio; Nakazawa, Toru; Ishibashi, Tatsuro; Miller, Joan W.; Vavvas, Demetrios G.

    2013-01-01

    Photoreceptor cell death is the ultimate cause of vision loss in various retinal disorders, including retinal detachment (RD). Photoreceptor cell death has been thought to occur mainly through apoptosis, which is the most characterized form of programmed cell death. The caspase family of cysteine proteases plays a central role for inducing apoptosis, and in experimental models of RD, dying photoreceptor cells exhibit caspase activation; however, there is a paradox that caspase inhibition alone does not provide a sufficient protection against photoreceptor cell loss, suggesting that other mechanisms of cell death are involved. Recent accumulating evidence demonstrates that non-apoptotic forms of cell death, such as autophagy and necrosis, are also regulated by specific molecular machinery, such as those mediated by autophagy-related proteins and receptor-interacting protein kinases, respectively. Here we summarize the current knowledge of cell death signaling and its roles in photoreceptor cell death after RD and other retinal degenerative diseases. A body of studies indicate that not only apoptotic but also autophagic and necrotic signaling are involved in photoreceptor cell death, and that combined targeting of these pathways may be an effective neuroprotective strategy for retinal diseases associated with photoreceptor cell loss. PMID:23994436

  11. Management of inferior retinal breaks during pars plana vitrectomy for retinal detachment

    PubMed Central

    Tanner, V; Minihan, M; Williamson, T

    2001-01-01

    AIMS—To determine whether it is necessary to support inferior retinal breaks with a scleral explant during pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RD).
METHODS—A prospective study was carried out on nine eyes of nine consecutive patients undergoing PPV for primary RD with associated inferior retinal breaks and no significant proliferative vitreoretinopathy.
RESULTS—Eight eyes were successfully reattached with a single operation. No cases presented with redetachment because of failed closure of the original inferior breaks.
CONCLUSIONS—It is not necessary to support inferior retinal breaks with a scleral explant during PPV for primary RD repair in selected cases.

 PMID:11264142

  12. Rhegmatogenous retinal detachment: a reappraisal of its pathophysiology and treatment.

    PubMed

    Kuhn, Ferenc; Aylward, Bill

    2014-01-01

    This article represents a synthesis of an extensive literature review and the authors' decades-long personal experience with both scleral buckling (SB) and vitrectomy for rhegmatogenous retinal detachment (RD). Presenting a coherent understanding of the pathophysiology and treatment of RD, the authors confirm numerous findings described in earlier publications but also challenge certain long-standing dogmas. The key argument made here is that it is extremely rare for the chain of events leading to an RD to start with a retinal pathology. Rather, the initial pathology is syneresis of the vitreous, which then allows gel movement (intraocular currents). At the point of vitreoretinal adhesion, dynamic traction is exerted on the retina, which may be sufficient to tear it. If the tear is operculated and the dynamic traction overcomes the forces keeping the neuroretina and retinal pigment epithelium (RPE) together, the heretofore virtual subretinal space becomes accessible through the retinal tear. The intraocular currents allow the free (nonbound) intravitreal fluid to enter the subretinal space, and once the amount of the incoming fluid overwhelms the draining capacity of the RPE, an RD ensues. Detachment of the posterior cortical vitreous (PVD) is not a necessary prerequisite to RD development; furthermore, PVD cannot be diagnosed preoperatively with adequate certainty with current technology such as biomicroscopy, ultrasonography or optical coherence tomography. The surgeon should expect no or only partial (anomalous) PVD at the time of surgical repair in over half of eyes. The treatment's primary goal must thus be weakening (pneumatic retinopexy, SB) or eliminating (vitrectomy) this dynamic traction. If vitrectomy is employed, it must be a truly complete vitreous removal. This includes a surgically induced PVD if one is not present, close shaving at the periphery, and removing the vitreous immediately behind the lens. The vitrectomy is followed by the creation of a

  13. Scleral buckling surgery for rhegmatogenous retinal detachment with subretinal proliferation

    PubMed Central

    Ghasemi Falavarjani, K; Alemzadeh, S A; Modarres, M; Parvaresh, M M; Hashemi, M; Naseripour, M; Nazari Khanamiri, H; Askari, S

    2015-01-01

    Purpose To evaluate the outcome of scleral buckling surgery in patients with rhegmatogenous retinal detachment (RRD) with subretinal proliferation. Methods In this retrospective study, a chart review of all patients with RRD associated with subretinal proliferation who were primarily treated with scleral buckling procedure, from April 2007 to April 2014, was undertaken. Main outcome measures were anatomical retinal reattachment and visual acuity. Results Forty-four eyes of 43 patients including 24 males and 19 females with a mean age of 26.5±13.1 years were evaluated. Immediately after the surgery, retina was reattached in all eyes. However, five eyes (11.3%) needed additional surgery for retinal redetachment. Single surgery anatomical success rate was 88.7%. Four eyes (9.1%), needed pars plana vitrectomy for the treatment of redetachment associated with proliferative vitreoretinopathy and scleral buckle revision surgery was successfully performed in the other eye. Best corrected visual acuity improved from 1.5±0.9 logMAR before surgery to 1.1±0.7 logMAR after surgery (P<0.001). An improvement in BCVA of >2 lines was found in 23 eyes (52.2%) and worsening of best corrected visual acuity of >2 lines was observed in 2 eyes (4.5%). Conclusions Scleral buckling surgery is highly successful in eyes with RRD associated with subretinal proliferation. PMID:25613841

  14. Success Rates of Vitrectomy in Treatment of Rhegmatogenous Retinal Detachment

    PubMed Central

    Ono, Kozue; Kinoshita, Hirofumi; Uematsu, Masafumi; Tsuiki, Eiko; Fujikawa, Azusa; Kitaoka, Takashi

    2016-01-01

    Aim. To investigate the anatomical success rates of pars plana vitrectomy (PPV) after primary rhegmatogenous retinal detachment (RRD). Methods. This retrospective study was conducted between December 2008 and October 2014 at Nagasaki University Hospital. The preoperative data recorded included the lens status, location of the retinal tear, whether a tear was visualized, presence of multiple tears, macula status, presence of peripheral lattice retinal degeneration, and best-corrected visual acuity (BCVA). The primary outcome measures were anatomical (primary and final) and functional success (visual acuity better than 6/60). Results. This study evaluated 422 eyes of 411 patients with a mean age of 57.7 ± 11.2 years. The single-operation reattachment rate (primary anatomical success) was 89.8%. The final anatomical success rate was 100% after 2–6 operations (mean = 3.14 ± 1.03). Functional success rate after the primary reattachment operation was 96.7%, while it was 97.2% at the end of the follow-up. Multiple logistic regression analysis of the possible risk factors for the primary anatomical failure showed a significant relation with the 25 G instruments (P = 0.002) and the presence of multiple tears (P = 0.01). Conclusion. The primary anatomical success of PPV for primary uncomplicated RRD was 89.8% and the final anatomical success rate was 100%. PMID:27478632

  15. Retrospective Review of Ocular Point-of-Care Ultrasound for Detection of Retinal Detachment

    PubMed Central

    Jacobsen, Bradley; Lahham, Sari; Lahham, Shadi; Patel, Amy; Spann, Sophia; Fox, John C.

    2016-01-01

    Introduction Retinal detachment is an ocular emergency that commonly presents to the emergency department (ED). Ophthalmologists are able to accurately make this diagnosis with a dilated fundoscopic exam, scleral depression or ophthalmic ultrasound when a view to the retina is obstructed. Emergency physicians (EPs) are not trained to examine the peripheral retina, and thus ophthalmic ultrasound can be used to aid in diagnosis. We assessed the accuracy of ocular point-of-care ultrasound (POCUS) in diagnosing retinal detachment. Methods We retrospectively reviewed charts of ED patients with suspected retinal detachment who underwent ocular POCUS between July 2012 and May 2015. Charts were reviewed for patients presenting to the ED with ocular complaints and clinical concern for retinal detachment. We compared ocular POCUS performed by EPs against the criterion reference of the consulting ophthalmologist’s diagnosis. Results We enrolled a total of 109 patients. Of the 34 patients diagnosed with retinal detachment by the ophthalmologists, 31 were correctly identified as having retinal detachment by the EP using ocular POCUS. Of the 75 patients who did not have retinal detachment, 72 were ruled out by ocular POCUS by the EP. This resulted in a POCUS sensitivity of 91% (95% CI [76–98]) and specificity of 96% (95% CI [89–99]). Conclusion This retrospective study suggests that ocular POCUS performed by EPs can aid in the diagnosis of retinal detachment in ED. PMID:26973752

  16. Scleral buckling biomaterials and implants for retinal detachment surgery.

    PubMed

    Baino, Francesco

    2010-11-01

    Scleral buckling is a widely used surgical procedure that aims at repairing retinal detachments. Many materials and procedural techniques have been variously proposed and tested in an attempt to find the best combination for providing optimal results to the patient. This review highlights the evolution of scleral buckling implants and chronicles the main advances that have been made in such a context. Specifically, the limitations of the materials and implants fallen in disuse, as well as the advantages of currently adopted devices are critically examined and discussed. Future directions for the research are considered, underlining in particular the great potential carried by the development of accurate mathematical models for describing the postoperative evolution of buckled eye. These analytical models, supported by a comprehensive data set provided by advanced techniques of medical investigations, may become useful tools for helping surgeons to choose, and to design if necessary, the best buckling material and configuration to be used in each specific clinical case.

  17. Macula-Sparing Rhegmatogenous Retinal Detachment: Is Emergent Surgery Necessary?

    PubMed Central

    Mahmoudi, Sasan; Almony, Arghavan

    2016-01-01

    The status of the macula is a significant factor in determining final visual outcomes in rhegmatogenous retinal detachment (RRD) and should be considered in the timing of surgical repair. Several studies have shown that macula-involving RRDs attain similar visual and anatomic outcomes when surgery is performed within seven days as compared to emergent surgery (within 24 hours). In contrast, surgery prior to macular detachment in macula-sparing RRDs generally yields the best visual outcomes. In the case of macula-sparing RRDs, it is not clear how long the macula may remain attached, therefore, standard practice dictates emergent surgery. Timing of presentation, examination findings, case complexity, co-existing medical conditions, surgeon expertise, and timing and quality of access to operating facilities and staff, however, should all be considered in determining whether a macula-sparing RRD requires immediate intervention or if equivalent visual and possibly better overall outcomes can be achieved with scheduled surgery within an appropriate time frame. PMID:27195093

  18. Massive Bilateral Serous Retinal Detachment in a Case of Hypertensive Chorioretinopathy

    PubMed Central

    Villalba-Pinto, Luis; Hernández-Ortega, M. Ángeles; de los Mozos, F. Javier Lavid; Pascual-Camps, Isabel; Dolz-Marco, Rosa; Arevalo, J. Fernando; Gallego-Pinazo, Roberto

    2014-01-01

    Introduction Systemic high blood pressure is related to a variety of retinal manifestations. We present an atypical case of hypertensive chorioretinopathy with massive bilateral serous retinal detachment. Case Report A 26-year-old male with a genitourinary malformation and secondary grade IV chronic kidney failure as well as high blood pressure complained of acute vision loss. Dilated fundus examination evidenced a bilateral serous retinal detachment with macular involvement. The patient was unresponsive to oral antihypertensive therapy and dialysis treatment. The serous retinal detachment progressively decreased after the restoration of dialysis and antihypertensive therapy. The final visual acuity was 0.50 in both eyes. Discussion In cases of serous macular detachment, it is mandatory to rule out different systemic and ocular diseases. The presence of uncontrolled high blood pressure may produce aggressive bilateral retinal changes, thus hypertension must be under early and strict control in order to improve the visual outcomes. PMID:25120474

  19. Traumatic retinal detachment--the difficulty and importance of correct diagnosis.

    PubMed

    Hoogewoud, Florence; Chronopoulos, Argyrios; Varga, Zsolt; Souteyrand, Georges; Thumann, Gabriele; Schutz, James S

    2016-01-01

    Accurate characterization of a retinal detachment as traumatic is often difficult, but is important because it may instigate a careful search for occult coexistent traumatic pathology, affect the prognosis and the treatment of both eyes, influence insurance coverage benefits and medical-legal determinations, and is essential for epidemiologic studies. We review the epidemiology and pathophysiology of traumatic retinal detachment, common obstacles to correct diagnosis, diagnostic guidelines, and outline categories of traumatic causal relationships. Because there is no generally accepted definition of traumatic retinal detachment, we offer a practical one. Categorization as traumatic should be based on the particular history and physical examination rather than epidemiologic criteria.

  20. Fibulin 2, a Tyrosine O-Sulfated Protein, Is Up-regulated Following Retinal Detachment*

    PubMed Central

    Kanan, Yogita; Brobst, Daniel; Han, Zongchao; Naash, Muna I.; Al-Ubaidi, Muayyad R.

    2014-01-01

    Retinal detachment is the physical separation of the retina from the retinal pigment epithelium. It occurs during aging, trauma, or during a variety of retinal disorders such as age-related macular degeneration, diabetic retinopathy, retinopathy of prematurity, or as a complication following cataract surgery. This report investigates the role of fibulin 2, an extracellular component, in retinal detachment. A major mechanism for detachment resolution is enhancement of cellular adhesion between the retina and the retinal pigment epithelium and prevention of its cellular migration. This report shows that fibulin 2 is mainly present in the retinal pigment epithelium, Bruch membrane, choriocapillary, and to a lesser degree in the retina. In vitro studies revealed the presence of two isoforms for fibulin 2. The small isoform is located inside the cell, and the large isoform is present inside and outside the cells. Furthermore, fibulin 2 is post-translationally modified by tyrosine sulfation, and the sulfated isoform is present outside the cell, whereas the unsulfated pool is internally located. Interestingly, sulfated fibulin 2 significantly reduced the rate of cellular growth and migration. Finally, levels of fibulin 2 dramatically increased in the retinal pigment epithelium following retinal detachment, suggesting a direct role for fibulin 2 in the re-attachment of the retina to the retinal pigment epithelium. Understanding the role of fibulin 2 in enhancing retinal attachment is likely to help improve the current therapies or allow the development of new strategies for the treatment of this sight-threatening condition. PMID:24692557

  1. [Rhegmatogenous retinal detachment in a patient with previous penetrating keratoplasty (clinical case)].

    PubMed

    Burcea, M; Muşat, O; Gheorghe, Andreea; Mahdi, Labib; Colta, Diana; Cernat, Corina; Mansour, Agajani

    2014-01-01

    We present the case of a 54 year old patient diagnosed with rhegmatogenous retinal detachment and perforating keratoplasty. Surgery is recommended and we performed posterior vitrectomy, endolaser, and internal heavy oil tamponade. The post-operative course was favorable.

  2. Atypical Presentation of Ocular Toxoplasmosis: A Case Report of Exudative Retinal Detachment and Choroidal Ischemia.

    PubMed

    Al-Zahrani, Yahya A; Al-Dhibi, Hassan A; Al-Abdullah, Abdulelah A

    2016-01-01

    A 24-year-old healthy male presented with a chief complaint of blurred vision in the right eye for 1-week. Fundus examination indicated right exudative retinal detachment and choroidal ischemia. The patient responded well to anti-toxoplasmosis medications and steroids. Exudative retinal detachment and choroidal ischemia are atypical presentations of ocular toxoplasmosis. However, both conditions responded well to anti.parasitic therapy with steroid. PMID:26957857

  3. Atypical Presentation of Ocular Toxoplasmosis: A Case Report of Exudative Retinal Detachment and Choroidal Ischemia

    PubMed Central

    Al-Zahrani, Yahya A.; Al-Dhibi, Hassan A.; Al-Abdullah, Abdulelah A.

    2016-01-01

    A 24-year-old healthy male presented with a chief complaint of blurred vision in the right eye for 1-week. Fundus examination indicated right exudative retinal detachment and choroidal ischemia. The patient responded well to anti-toxoplasmosis medications and steroids. Exudative retinal detachment and choroidal ischemia are atypical presentations of ocular toxoplasmosis. However, both conditions responded well to anti.parasitic therapy with steroid. PMID:26957857

  4. Scleral Buckling for Rhegmatogenous Retinal Detachment Associated with Pars Planitis

    PubMed Central

    Ahn, Jae Kyoun

    2016-01-01

    Purpose. To evaluate the surgical outcome of scleral buckling (SB) in rhegmatogenous retinal detachment (RRD) patients associated with pars planitis. Methods. Retrospective review of RRD patients (32 eyes of pars planitis RRD and 180 eyes of primary RRD) who underwent SB. We compared primary and final anatomical success rates and visual outcomes between two groups. Results. Primary and final anatomical success were achieved in 25 (78.1%) and 31 (96.8%) eyes in the pars planitis RRD group and in 167 eyes (92.7%) and 176 eyes (97.7%) in primary RRD group, respectively. Both groups showed significant visual improvement (p < 0.001) and there were no significant differences in final visual acuity. Pars planitis RRD group was associated with higher rate of postoperative proliferative vitreoretinopathy (PVR) development (12.5% versus 2.8%, p = 0.031). Pars planitis and high myopia were significant preoperative risk factors and pseudophakia was borderline risk for primary anatomical failure after adjusting for various clinical factors. Conclusions. Pars planitis associated RRD showed inferior primary anatomical outcome after SB due to postoperative PVR development. However, final anatomical and visual outcomes were favorable. RRD cases associated with pars planitis, high myopia, and pseudophakia might benefit from different surgical approaches, such as combined vitrectomy and SB. PMID:27688907

  5. Visual Recovery after Primary Retinal Detachment Surgery: Biofeedback Rehabilitative Strategy

    PubMed Central

    Vingolo, Enzo M.; Fragiotta, Serena; Domanico, Daniela; Limoli, Paolo G.; Nebbioso, Marcella; Spadea, Leopoldo

    2016-01-01

    Purpose. To evaluate possible speeding up recovery time after retinal detachment (RD) surgery using biofeedback strategy. Methods. A total of 52 eyes were selected. After surgery, patients were divided into two groups: group A, including patients submitted to biofeedback with MP-1 strategy; group B, patients who received common care strategy. Biofeedback strategy was started 15 days after the suspension of cycloplegic eye drops in buckling procedure or after silicone oil removal in the vitrectomized eyes. Controls were scheduled at baseline and 6, 12, and 18 weeks. Results. At baseline, there was no significant difference in BCVA between groups (P = 0.4230). At the end of biofeedback treatment (WK 6) BCVA of group A was significantly better (P < 0.001) than group B and BCVA was still better in group A than group B at WK 12 (P = 0.028) and at WK 18 (P = 0.041). Conclusions. Visual recovery after RD surgery is still unclear, and it does not depend on entity of the RD. Our data demonstrate that in biofeedback group there was a significant recovery in visual performances that still remains evident after 3 months from the baseline. PMID:26998353

  6. Scleral Buckling for Rhegmatogenous Retinal Detachment Associated with Pars Planitis.

    PubMed

    Kim, Yong-Kyu; Yoon, Wontae; Ahn, Jae Kyoun; Park, Sung Pyo

    2016-01-01

    Purpose. To evaluate the surgical outcome of scleral buckling (SB) in rhegmatogenous retinal detachment (RRD) patients associated with pars planitis. Methods. Retrospective review of RRD patients (32 eyes of pars planitis RRD and 180 eyes of primary RRD) who underwent SB. We compared primary and final anatomical success rates and visual outcomes between two groups. Results. Primary and final anatomical success were achieved in 25 (78.1%) and 31 (96.8%) eyes in the pars planitis RRD group and in 167 eyes (92.7%) and 176 eyes (97.7%) in primary RRD group, respectively. Both groups showed significant visual improvement (p < 0.001) and there were no significant differences in final visual acuity. Pars planitis RRD group was associated with higher rate of postoperative proliferative vitreoretinopathy (PVR) development (12.5% versus 2.8%, p = 0.031). Pars planitis and high myopia were significant preoperative risk factors and pseudophakia was borderline risk for primary anatomical failure after adjusting for various clinical factors. Conclusions. Pars planitis associated RRD showed inferior primary anatomical outcome after SB due to postoperative PVR development. However, final anatomical and visual outcomes were favorable. RRD cases associated with pars planitis, high myopia, and pseudophakia might benefit from different surgical approaches, such as combined vitrectomy and SB. PMID:27688907

  7. Scleral Buckling for Rhegmatogenous Retinal Detachment Associated with Pars Planitis

    PubMed Central

    Ahn, Jae Kyoun

    2016-01-01

    Purpose. To evaluate the surgical outcome of scleral buckling (SB) in rhegmatogenous retinal detachment (RRD) patients associated with pars planitis. Methods. Retrospective review of RRD patients (32 eyes of pars planitis RRD and 180 eyes of primary RRD) who underwent SB. We compared primary and final anatomical success rates and visual outcomes between two groups. Results. Primary and final anatomical success were achieved in 25 (78.1%) and 31 (96.8%) eyes in the pars planitis RRD group and in 167 eyes (92.7%) and 176 eyes (97.7%) in primary RRD group, respectively. Both groups showed significant visual improvement (p < 0.001) and there were no significant differences in final visual acuity. Pars planitis RRD group was associated with higher rate of postoperative proliferative vitreoretinopathy (PVR) development (12.5% versus 2.8%, p = 0.031). Pars planitis and high myopia were significant preoperative risk factors and pseudophakia was borderline risk for primary anatomical failure after adjusting for various clinical factors. Conclusions. Pars planitis associated RRD showed inferior primary anatomical outcome after SB due to postoperative PVR development. However, final anatomical and visual outcomes were favorable. RRD cases associated with pars planitis, high myopia, and pseudophakia might benefit from different surgical approaches, such as combined vitrectomy and SB.

  8. Preludes to retinal detachment in the aphakic eye.

    PubMed

    Osterlin, S

    1977-01-01

    The author reviews the characteristic differences in primary rhegmatogenous retina detachment occurring in phakic eyes and in aphakic eyes. The preoperative findings in aphakic detachment are explained on the basis of two factors: surgical trauma during cataract extraction and postoperative changes in the macromolecular compostion of the vitreous.

  9. Repair of retinal detachment associated with proliferative vitreoretinopathy using perfluoroperhydrophenanthrene (Vitreon). Vitreon Study Group.

    PubMed

    Carroll, B F; Peyman, G A; Mehta, N J; Millsap, C M; Greve, M D; Dunlap, W A; Lee, K J; Ma, P E

    1994-04-01

    A total of 140 consecutive patients underwent repair of retinal detachment associated with grade C2 to D3 proliferative vitreoretinopathy with perfluoroperhydrophenanthrene (Vitreon) as an intraoperative hydrokinetic tool. In seven patients the Vitreon was left in the eye for extended tamponade. Intraoperative reattachment was obtained in 98% of patients. At the final follow-up examination (mean 7 months) 84% of retinas remained attached, and 92% of patients had stable or improved visual acuity. Vitreon was found to be safe and effective in the repair of complicated retinal detachments. No complications were directly related to Vitreon when used intraoperatively or when left in the eye for extended tamponade.

  10. Repair of retinal detachment associated with proliferative vitreoretinopathy using perfluoroperhydrophenanthrene (Vitreon). Vitreon Study Group.

    PubMed

    Carroll, B F; Peyman, G A; Mehta, N J; Millsap, C M; Greve, M D; Dunlap, W A; Lee, K J; Ma, P E

    1994-04-01

    A total of 140 consecutive patients underwent repair of retinal detachment associated with grade C2 to D3 proliferative vitreoretinopathy with perfluoroperhydrophenanthrene (Vitreon) as an intraoperative hydrokinetic tool. In seven patients the Vitreon was left in the eye for extended tamponade. Intraoperative reattachment was obtained in 98% of patients. At the final follow-up examination (mean 7 months) 84% of retinas remained attached, and 92% of patients had stable or improved visual acuity. Vitreon was found to be safe and effective in the repair of complicated retinal detachments. No complications were directly related to Vitreon when used intraoperatively or when left in the eye for extended tamponade. PMID:8069756

  11. Retinal detachment as a complication of neodymium: yttrium aluminum garnet laser cyclophotocoagulation.

    PubMed

    Geyer, O; Neudorfer, M; Lazar, M

    1993-05-01

    We report a traction retinal detachment that developed within one month of transscleral neodymium: yttrium aluminum garnet (Nd:YAG) laser cyclophotocoagulation, a previously unreported complication of the new cyclodestructive procedure. A 17-year-old boy was referred to our department with uncontrolled aphakic glaucoma OD after having undergone cyclocryotherapy twice. Three treatments with transscleral Nd:YAG cyclophotocoagulation were done over nine months to lower his intraocular pressure. Hypotony and traction retinal detachment occurred after the third laser treatment and was managed successfully by vitrectomy with a fluid-gas exchange. Thus, the possibility of this additional complication should be remembered when doing transscleral Nd:YAG cyclophotocoagulation. PMID:8517586

  12. Macrophage- and RIP3-dependent inflammasome activation exacerbates retinal detachment-induced photoreceptor cell death

    PubMed Central

    Kataoka, K; Matsumoto, H; Kaneko, H; Notomi, S; Takeuchi, K; Sweigard, J H; Atik, A; Murakami, Y; Connor, K M; Terasaki, H; Miller, J W; Vavvas, D G

    2015-01-01

    Detachment of photoreceptors from the retinal pigment epithelium is seen in various retinal disorders, resulting in photoreceptor death and subsequent vision loss. Cell death results in the release of endogenous molecules that activate molecular platforms containing caspase-1, termed inflammasomes. Inflammasome activation in retinal diseases has been reported in some cases to be protective and in others to be detrimental, causing neuronal cell death. Moreover, the cellular source of inflammasomes in retinal disorders is not clear. Here, we demonstrate that patients with photoreceptor injury by retinal detachment (RD) have increased levels of cleaved IL-1β, an end product of inflammasome activation. In an animal model of RD, photoreceptor cell death led to activation of endogenous inflammasomes, and this activation was diminished by Rip3 deletion. The major source of Il1b expression was found to be infiltrating macrophages in the subretinal space, rather than dying photoreceptors. Inflammasome inhibition attenuated photoreceptor death after RD. Our data implicate the infiltrating macrophages as a source of damaging inflammasomes after photoreceptor detachment in a RIP3-dependent manner and suggest a novel therapeutic target for treatment of retinal diseases. PMID:25906154

  13. Exudative retinal detachment following strabismus surgery in Sturge-Weber syndrome.

    PubMed

    Kim, Yu Cheol; Lee, Se Yeop; Kim, Kwang Soo

    2015-06-01

    A 15-year-old boy with Sturge-Weber syndrome underwent strabismus surgery (oculus sinister [OS]) for the treatment of exotropia. The patient's visual acuity (OS) decreased to hand motion 10 days after the surgery. One month after the surgery, the patient's visual acuity decreased to light perception, and a fundus examination showed total exudative retinal detachment (OS). PMID:26265655

  14. Controversy over the etiology and therapy of retinal detachment: the struggles of Jules Gonin.

    PubMed

    Gloor, Balder P; Marmor, Michael F

    2013-01-01

    Retinal tears were recognized as soon as ophthalmoscopy became available. They were initially considered to be secondary events, from choroidal exudation and pressure behind the detached retina. This led von Graefe and others to recommend cuts in the retina to drain subretinal fluid into the vitreous cavity. De Wecker (1875, 1879) and Leber (1882) first proposed that intrinsic tears within the retina are the cause of retinal detachment, but they faced extreme and long lasting opposition for this view. Surgical results at this time were uniformly disastrous, and therapeutic nihilism still prevailed when Dufour and Gonin became convinced around 1904-1906 that the retinal tear was indeed the origin of the detachment. It took ten years, however, before Gonin figured out how to close tears by exact placement of heat coagulation ("thermopuncture") and provide therapeutic evidence for his beliefs. When he first presented his results in 1921, colleagues jeered at him, especially Deutschmann and Sourdille who, like the other ophthalmic surgeons, denied the role of the tear (and still made "therapeutic" incisions through the detached retina). Recognition of Gonin's approach finally came at the International Congresses in Amsterdam 1928 and in Madrid in 1933. Sourdille modified his approach when his son Gabriel convinced him to change after 1930, but Deutschmann stuck to his horrific procedure until his death in 1935. Then a new generation of retinal surgeons took over, with subsequent discussion focused on finding the best methods to close the tears. PMID:23257154

  15. Exudative retinal detachment following strabismus surgery in Sturge–Weber syndrome

    PubMed Central

    Kim, Yu Cheol; Lee, Se Yeop; Kim, Kwang Soo

    2015-01-01

    A 15-year-old boy with Sturge–Weber syndrome underwent strabismus surgery (oculus sinister [OS]) for the treatment of exotropia. The patient's visual acuity (OS) decreased to hand motion 10 days after the surgery. One month after the surgery, the patient's visual acuity decreased to light perception, and a fundus examination showed total exudative retinal detachment (OS). PMID:26265655

  16. Combined silicone and fluorosilicone oil tamponade (double filling) in the management of complicated retinal detachment.

    PubMed

    Bottoni, F; Arpa, P; Vinciguerra, P; Zenoni, S; De Molfetta, V

    1992-01-01

    We evaluated the use of simultaneous double filling with polydimethylsiloxane (PDMS) and fluorosilicone (FSiO) in the repair of complicated retinal detachment in 12 selected cases. Initial retinal reattachment was achieved in all cases. Proliferative vitreoretinopathy (PVR) recurred in 10 patients (83%), 6 of which showed partial retinal detachment. Inferior and superior postoperative residual free spaces were abolished by this procedure, but a new residual fluid space was created, lying horizontally between the bubbles and expanding in a triangular shape nasally to the optic disk and temporally to the macula. Overall, 9 of 10 eyes with postoperative PVR had proliferation involving these areas. These findings support the concept that 'compartmentalization' is of major importance in determining postoperative cell proliferation.

  17. RETINOPATHY OF PREMATURITY: INVOLUTION, FACTORS PREDISPOSING TO RETINAL DETACHMENT, AND EXPECTED UTILITY OF PREEMPTIVE SURGICAL REINTERVENTION

    PubMed Central

    Coats, David K

    2005-01-01

    Purpose To characterize involution of retinopathy of prematurity (ROP) following treatment at threshold, to identify findings during involution that portend development of retinal detachment, and to assess the potential utility of preemptive vitrectomy for eyes with high-risk features. Methods The probability of ROP involution and of retinal detachment evolution over time was analyzed in 262 treated eyes of 138 infants in a retrospective observational non–case controlled series. Expected utility of preemptive reintervention in eyes with high-risk features was evaluated using decision analysis. Modifications were devised to enhance classification of advanced ROP. Results ROP fully involuted in approximately 80% of eyes within 28 days of treatment. Vitreous organization meeting the study’s clinically important definition was associated with a 31-fold (5.37 to 183.63; P < .0001) and a 13-fold (2.97 to 58.59; P < .0001) increase in the odds for retinal detachment for right and left eyes, respectively. Vitreous hemorrhage defined as clinically important was associated with a 38-fold (2.69 to 551.19; P = .007) and a 15-fold (1.65 to 144.12; P = .02) increase in the odds for retinal detachment for right and left eyes, respectively. As modeled, an expected utility of 0.85 was calculated for preemptive vitrectomy compared with 0.79 for deferred vitrectomy for eyes with clinically important vitreous organization. Conclusions Acute-phase ROP involuted quickly in most eyes. Vitreous organization and vitreous hemorrhage were predictive of eyes that developed a retinal detachment. Decision analysis suggests that preemptive vitrectomy for eyes with vitreous organization meeting specific criteria is not likely to be worse than deferred vitrectomy, and it could be advantageous in some scenarios. PMID:17057808

  18. [Perfluorodecalin as a hydrokinetic substance in complicated retinal detachment].

    PubMed

    Greber, H

    1991-01-01

    Perfluorodecalin is a clear colourless fluid with high specific gravity. It is immiscible with gas, blood, water, or any other fluid used in vitrectomy. The low viscosity permits easy injection and removal with microsurgical equipment. The high weight displaces subretinal fluid anteriorly through retinal breaks back into the vitreous space. Posterior retinotomies can be avoided. A large bubble of perfluorodecalin in the vitreous cavity stabilizes the retina mechanically during dissection and peeling of epiretinal membranes. Before the procedure is ended the fluid must be completely removed from the eye and replaced by BSS, air, gas, or silicon oil. We present the surgical technique and preliminary results.

  19. [Perfluorodecalin as a hydrokinetic substance in complicated retinal detachment].

    PubMed

    Greber, H

    1991-01-01

    Perfluorodecalin is a clear colourless fluid with high specific gravity. It is immiscible with gas, blood, water, or any other fluid used in vitrectomy. The low viscosity permits easy injection and removal with microsurgical equipment. The high weight displaces subretinal fluid anteriorly through retinal breaks back into the vitreous space. Posterior retinotomies can be avoided. A large bubble of perfluorodecalin in the vitreous cavity stabilizes the retina mechanically during dissection and peeling of epiretinal membranes. Before the procedure is ended the fluid must be completely removed from the eye and replaced by BSS, air, gas, or silicon oil. We present the surgical technique and preliminary results. PMID:1786919

  20. Long-term surgical outcomes of retinal detachment in patients with Stickler syndrome

    PubMed Central

    Reddy, Devasis N; Yonekawa, Yoshihiro; Thomas, Benjamin J; Nudleman, Eric D; Williams, George A

    2016-01-01

    Purpose The aim of the study was to present the long-term anatomical and visual outcomes of retinal detachment repair in patients with Stickler syndrome. Patients and methods This study is a retrospective, interventional, consecutive case series of patients with Stickler syndrome undergoing retinal reattachment surgery from 2009 to 2014 at the Associated Retinal Consultants, William Beaumont Hospital. Results Sixteen eyes from 13 patients were identified. Patients underwent a mean of 3.1 surgical interventions (range: 1–13) with a mean postoperative follow-up of 94 months (range: 5–313 months). Twelve eyes (75%) developed proliferative vitreoretinopathy. Retinal reattachment was achieved in 100% of eyes, with ten eyes (63%) requiring silicone oil tamponade at final follow-up. Mean preoperative visual acuity (VA) was 20/914, which improved to 20/796 at final follow-up (P=0.81). There was a significant correlation between presenting and final VA (P<0.001), and patients with poorer presenting VA were more likely to require silicone oil tamponade at final follow-up (P=0.04). Conclusion Repair of retinal detachment in patients with Stickler syndrome often requires multiple surgeries, and visual outcomes are variable. Presenting VA is significantly predictive of long-term VA outcomes. PMID:27574392

  1. Occult retinal detachment after mild traumatic brain injury: case report and literature review.

    PubMed

    Bedgood, Alysia; Rand, Scott E; Major, James

    2015-01-01

    Concussions, or mild traumatic brain injuries (mTBI), are on the forefront of sports medicine. There is a spectrum of symptoms associated with mTBI, some of which include blurriness, double vision, and light sensitivity. Further evaluation for nonconcussion-related causes is warranted if vision changes do not improve concurrently with other symptoms. Keeping in mind other less obvious injuries, including retinal detachment, is important when performing an initial evaluation or follow-up of an mTBI.

  2. Serous retinal detachment following panretinal photocoagulation (PRP) using Pattern Scan Laser (PASCAL) photocoagulator

    PubMed Central

    Azar, Georges; Wolff, Benjamin; Cornut, Pierre-Loïc; Mauget-Faÿsse, Martine

    2012-01-01

    Objective: To report a case of serous retinal detachment after Pattern Scan Laser (PASCAL) treatment in a diabetic woman. Methods: A 34-year-old diabetic woman presented with florid diabetic retinopathy after a miscarriage during the 20th week of pregnancy. Her Best Corrected Visual Acuity (BCVA) was 20/40 right eye (OD) and 20/30 left eye (OS). Fundus exam showed multiple microaneurysms, large blot hemorrhages and venous dilation both eyes (OU). Fundus fluorescein angiography (FFA) revealed large areas of capillary nonperfusion and panretinal neovascularisation in all quadrants OU. Macular Spectral-Domain Optical Coherence Tomography scan (SD-OCT) did not show any foveal thickening. Panretinal photocoagulation (PRP) was immediately performed OU during the same day. Results: Two days after PASCAL treatment, her BCVA decreased to 20/80 OU and worsened to Count Fingers (CF) during the following days. Fundus exam revealed an extensive serous retinal detachment confirmed on SD-OCT. 2 sub-conjunctival injections of 0.1 ml Betamethasone were done OU. One month later, BCVA improved to 20/30 and SD-OCT confirmed regression of retinal detachment. Conclusions: PASCAL is considered to be a safe treatment, but one has to be aware of its potential side effects. It has to be used with caution in pregnant women.

  3. Postoperative Recovery of Visual Function after Macula-Off Rhegmatogenous Retinal Detachment

    PubMed Central

    van de Put, Mathijs A. J.; Croonen, Danna; Nolte, Ilja M.; Japing, Wouter J.; Hooymans, Johanna M. M.; Los, Leonoor I.

    2014-01-01

    Purpose To determine which factors affect the recovery of visual function in macula off rhegmatogenous retinal detachment (RRD). Methods In a prospective study of forty-five patients with a primary macula-off RRD of 24 hours to 6 weeks duration, the height of the macular detachment was determined by ultrasonography. At 12 months postoperatively, best corrected visual acuity (BCVA), contrast acuity, and color confusion indexes (CCI) were obtained. Results Macular detachment was present for 2–32 (median 7) days before repair. A shorter duration of macular detachment was correlated with a better CCI saturé (p = 0.0026) and lower LogMAR BCVA (better Snellen visual acuity)(p = 0.012). Also, a smaller height of macular detachment was correlated with a lower LogMAR BCVA (p = 0.0034). A younger age and lower pre-operative LogMAR BCVA at presentation were both correlated with better postoperative contrast acuity in the total group (age: p = 1.7×10−4 and pre-operative LogMAR BCVA: p = 0.0034). Conclusion Functional recovery after macula-off RRD is affected by the duration and the height of the macular detachment. Recovery of contrast acuity is also affected by age and BCVA at presentation. Meeting presentation ARVO annual meeting 2013, May 7, Seattle, Washington, United States of America. Trial registration: trialregister.nl NTR839 PMID:24927502

  4. Impact of Duration of Macula off Rhegmatogenous Retinal Detachment on Visual Outcome

    PubMed Central

    Khanzada, Mahtab Alam; Wahab, Shahid; Hargun, Lakhani Das

    2014-01-01

    Objective: To assess impact of duration of macular detachment on visual outcome after scleral buckling for retinal detachment with macula off. Methods: Prospective, descriptive case series was conducted at Ophthalmology Department Dow University of Health Sciences, Civil Hospital Karachi and Al Noor Eye Clinic Karachi from May 2012 to June 2013. Five groups were made according to period of macular detachment. Best corrected Visual acuity (BCVA) was main outcome measure. P value < 0.001 was considered significant. Results: Mean duration of macula off was 17.0±4.0 (SD) days. Mean pre-operative VA in patients with immediate, early, intermediate, delayed or late group were 2/60, 2/60, Counting figure (CF) 3 meters (m), CF2 m and Hand Movement (HM) respectively. Only 48.48% patients of those repaired within 7 to15 days had significantly better (P < 0.001) BCVA (6/9-6/18) than the other groups. Only 19.35% patients of intermediate group achieved BCVA 6/18-6/24 (P < 0.001) which was comparatively better than the delayed and late group. Conclusions: Scleral buckle surgery for macular-off Rhegmatogenous Retinal Detachment has good post-operative visual outcomes if repaired within two weeks. PMID:24948972

  5. Rhegmatogenous retinal detachments associated to Stickler syndrome in a tertiary eye care center in Saudi Arabia

    PubMed Central

    Alshahrani, Saeed T; Ghazi, Nicola G; Al-Rashaed, Saba

    2016-01-01

    Purpose To investigate the clinical findings and outcomes of rhegmatogenous retinal detachment (RRD) in Stickler syndrome on affected and fellow eyes that underwent prophylactic retinopexy. Patients and methods Chart review of 70 eyes (62 patients). Incidence of RRD, postoperative visual acuity, and risk factors were evaluated. Results Twenty-two patients (35%) had RRD in the fellow eye, 37% of the eyes had cataract, 93% had macular detachment, 50% had proliferative vitreoretinopathy, and 41% had posterior vitreous detachment. Success rates were: 60% of patients after scleral buckling; 57.1% after pars plana vitrectomy; and 75% after combined scleral buckling and pars plana vitrectomy. Sixty-one (93.8%) of patients had successful surgery (including second surgery). Silicone oil tamponade was significantly associated with final anatomic outcome, with a protective odds ratio of 0.11 (P=0.027). Visual acuity improved in 54% of eyes and decreased in 5%. Statistically significant associations were present for eyes with final visual acuity ≥20/200, and total retinal detachment (P<0.001); preoperative cataract (P=0.023); and proliferative vitreoretinopathy (P<0.001). RRD developed in 16/44 eyes despite laser prophylaxis. Conclusion Prophylactic retinopexy was not beneficial for Stickler syndrome patients. Success of primary surgery for RRD remains low. The primary surgery should be vitrectomy combined with scleral buckling and silicone oil tamponade. PMID:26730175

  6. Evaluation of Intravitreal Ranibizumab on the Surgical Outcome for Diabetic Retinopathy With Tractional Retinal Detachment

    PubMed Central

    Dong, Feng; Yu, Chenying; Ding, Haiyuan; Shen, Liping; Lou, Dinghua

    2016-01-01

    Abstract This study aims to investigate intravitreal injection of Ranibizumab on the surgical outcome for diabetic patients who had tractional retinal detachment but did not receive any preoperative retinal photocoagulation. Ninety-seven patients (97 eyes) who had diabetic retinopathy with tractional retinal detachment were enrolled to receive 23-G pars plana vitrectomy (PPV). They were assigned to an experimental group (Group I, n = 47 eyes) and a control group (Group II, n = 50 eyes). The patients in Group I were given 1 injection of intravitreal Ranibizumab (Lucentis 0.5 mg/0.05 mL) 1 week before surgery, whereas those in Group II went down to surgery directly. Follow-ups were performed for 6 months to 3 years (16 ± 6 months), and indicators observed included postoperative best-corrected visual acuity, complications, and retinal thickness in the macula measured by optical coherence tomography. In Group I, BCVA improved from logMAR 1.92 ± 0.49 to logMAR 0.81 ± 0.39 following surgery, whereas in Group II, BCVA improved from logMAR 1.91 ± 0.49 to logMAR 0.85 ± 0.41. There was significant postoperative gain in vision, but there was no significant difference between the 2 groups at postoperative follow-up visits. The mean duration of vitrectomy in Group I and Group II was (40 ± 7) minutes and (53 ± 9) minutes, respectively, with significant difference. Iatrogenic breaks were noted in 5 eyes (11%) in the experimental group and 17 eyes (34%) in the control group; the difference was significant. The retinal thickness in the macula measured by OCT was (256 ± 44) μm and (299 ± 84) μm in Group I and Group II respectively with significant difference. Besides, there were significantly more eyes in Group II that required silicone oil tamponade and postoperative retinal photocoagulation. 23-G PPV combined with intravitreal tamponade and panretinal photocoagulation still remains an effective regimen for the

  7. Changes of cone electroretinograms to colour flash stimuli after successful retinal detachment surgery

    PubMed Central

    Hayashi, M; Yamamoto, S

    2001-01-01

    AIM—To examine the changes in the short wavelength (S) and mixed long (L) and middle (M) wavelength sensitive cone (L,M-cone) electroretinograms (ERGs) after successful retinal detachment surgery.
METHODS—Cone ERGs elicited by different colour flashes were recorded from 19 eyes with unilateral rhegmatogenous retinal detachment treated successfully by conventional buckling surgery. Ganzfeld colour flashes on a bright white background were used to elicit S-cone and L,M-cone ERGs. The ratio (operated eye/fellow eye) of the S-cone b-wave elicited by a 450 nm stimulus and the ratio (operated eye/fellow eye) of the L,M-cone b-wave elicited by a 633 nm stimulus were evaluated preoperatively and 1, 3, and 6 months after surgery.
RESULTS—Preoperatively, no significant difference was observed between the ratio of the S-cone ERG amplitudes and the ratio of the L,M-cone ERG amplitudes. Postoperatively, the ratio of the L,M-cone ERGs increased significantly over the preoperative value (p=0.001) but the ratio of the S-cone ERG did not improve. There were significant differences between the ratios of the S-cone and the L,M-cone ERGs at 1, 3, and 6 months after surgery. The postoperative recovery of the S-cone ERG was significantly greater in eyes treated within 4 weeks after the onset of the detachment than in eyes treated later than 4 weeks.
CONCLUSIONS—These results indicate that the impairment of the L,M-cone system caused by retinal detachment may be reversible. However, the S-cone system may have more profound permanent damage.

 PMID:11264128

  8. Shape Change of the Vitreous Chamber Influences Retinal Detachment and Reattachment Processes: Is Mechanical Stress during Eye Rotations a Factor?

    PubMed Central

    Meskauskas, Julia; Repetto, Rodolfo; Siggers, Jennifer H.

    2012-01-01

    Purpose. We aim to understand how mechanical causation influences retinal detachment and reattachment processes. In particular, myopes suffer retinal detachment more frequently than emmetropes, and following a retinal detachment, scleral buckling promotes retinal reattachment. We test the hypothesis that stresses arising from saccadic eye rotations are involved in the processes, and that the alteration in the stress due to the change in the vitreous chamber geometry is sufficient to explain the phenomena. Methods. The vitreous chamber of the eye has an approximately spherical shape and it is filled with vitreous humor. We developed a mathematical model, treating the vitreous chamber in emmetropic and myopic eyes as a spheroid and in eyes subjected to scleral buckling as a sphere with a circumferential indentation. We assume that the eye performs prescribed small-amplitude, periodic, torsional rotations and we solve semi-analytically for the fluid pressure, velocity, and stress distributions. Results. The shape of the vitreous chamber has a large effect on the retinal stress. The vitreous and the retina of a highly myopic eye continuously experience shear stresses significantly higher than those of an emmetropic eye. An eye fitted with a scleral buckle experiences large stress levels localized around the buckle. Conclusions. Our results provide a mechanical explanation for the more frequent occurrence of posterior vitreous detachment and retinal detachment in myopic eyes. To understand how the stress distribution in a buckled eye facilitates reattachment, an additional model of the details of the reattachment process should be coupled to this model. PMID:22899755

  9. Hypoxia inducible factor 1α contributes to regulation of autophagy in retinal detachment

    PubMed Central

    Shelby, Shameka J.; Angadi, Pavan S.; Zheng, Qiong-Duon; Yao, Jingyu; Jia, Lin; Zacks, David N.

    2015-01-01

    Photoreceptor (PR) cells receive oxygen and nutritional support from the underlying retinal pigment epithelium (RPE). Retinal detachment results in PR hypoxia and their time-dependent death. Detachment also activates autophagy within the PR, which serves to reduce the rate of PR apoptosis. In this study, we test the hypothesis that autophagy activation in the PR results, at least in part, from the detachment-induced activation of hypoxia-inducible factors (HIF). Retina-RPE separation was created in Brown-Norway rats and C57BL/6J mice by injection of 1% hyaluronic acid into the subretinal space. Retinas were harvested and assayed for HIF protein levels. Cultured 661W photoreceptor cells were subjected to hypoxic conditions and assayed for induction of HIF and autophagy. The requirement of HIF-1α and HIF-2α in regulating photoreceptor autophagy was tested using siRNA in vitro and in vivo. We observed increased levels of HIF-1α and HIF-2α within 1 day post-detachment, as well as increased levels of BNIP3, a downstream target of HIF-1α that contributes to autophagy activation. Exposing 661W cells to hypoxia resulted in increased HIF-1α and HIF-2α levels and increase in conversion of LC3-I to LC3-II. Silencing of HIF-1α, but not HIF-2α, reduced the hypoxia-induced increase in LC3-II formation and increased cell death in 661W cells. Silencing of HIF-1α in rat retinas prevented the detachment-induced increase in BNIP3 and LC3-II, resulting in increased PR cell death. Our data support the hypothesis that HIF-1α, but not HIF-2α, serves as an early response signal to induce autophagy and reduce photoreceptor cell death. PMID:26093278

  10. N-Acetylcysteine Suppresses Retinal Detachment in an Experimental Model of Proliferative Vitreoretinopathy

    PubMed Central

    Lei, Hetian; Velez, Gisela; Cui, Jing; Samad, Arif; Maberley, David; Matsubara, Joanne; Kazlauskas, Andrius

    2010-01-01

    Proliferative vitreoretinopathy (PVR) is a complication that develops in 5% to 10% of patients who undergo surgery to correct a detached retina. The only treatment option for PVR is surgical intervention, which has a limited success rate that diminishes in patients with recurring PVR. Our recent studies revealed that antioxidants prevented intracellular signaling events that were essential for experimental PVR. The purpose of this study was to test whether N-acetyl-cysteine (NAC), an antioxidant used in a variety of clinical settings, was capable of protecting rabbits from PVR. Vitreous-driven activation of PDGFRα and cellular responses intrinsic to PVR (contraction of collagen gels and cell proliferation) were blocked by concentrations of NAC that were well below the maximum tolerated dose. Furthermore, intravitreal injection of NAC effectively protected rabbits from developing retinal detachment, which is the sight-robbing phase of PVR. Finally, these observations with an animal model appear relevant to clinical PVR because NAC prevented human PVR vitreous-induced contraction of primary RPE cells derived from a human PVR membrane. Our observations demonstrate that antioxidants significantly inhibited experimental PVR, and suggest that antioxidants have the potential to function as a PVR prophylactic in patients undergoing retinal surgery to repair a detached retina. PMID:20489144

  11. Corneal Complications During and After Vitrectomy for Retinal Detachment in Photorefractive Keratectomy Treated Eyes

    PubMed Central

    Tosi, Gian Marco; Baiocchi, Stefano; Balestrazzi, Angelo; Martone, Gianluca; Marigliani, Davide; Neri, Giovanni; Caporossi, Tomaso

    2015-01-01

    Abstract To evaluate the occurrence of late-onset corneal haze (LOCH) after vitrectomy for rhegmatogenous retinal detachment (RRD) in photorefractive keratectomy (PRK)-treated eyes. This observational cohort study comprised 13 eyes of 13 patients who underwent vitrectomy for RRD and who had been subjected to PRK years earlier. The occurrence of LOCH was evaluated together with all the preoperative, intraoperative, and postoperative factors that could affect final corneal status. LOCH developed in 2 eyes. Both patients had undergone PRK for high myopia—one 3 years and the other 9 years prior to RRD. Both patients presented with RRD due to giant retinal tear and were subjected to scleral buckle, 20-gauge vitrectomy, and silicone oil tamponade. Three months after vitrectomy and 1 month after silicone oil removal they both developed LOCH. During vitreoretinal surgery neither of the 2 patients needed mechanical epithelial debridement. Intraoperative epithelial debridement was performed in 2 of the other patients of the series, who had undergone previous PRK for high myopia and had clear corneas at presentation; in 1 of them this manoeuvre hampered intraoperative visualization. Follow-up after retinal detachment surgery ranged from 6 to 156 months (mean, 37.5 months). Subepithelial corneal scarring may be reactivated many years after PRK. In our series this happened after vitrectomy. PMID:26683931

  12. Drainage of subretinal fluidduring scleral buckling surgery for rhegmatogenous retinal detachment

    PubMed Central

    MALAGOLA, R.; PANNARALE, L.; TORTORELLA, P.; ARRICO, L.

    2015-01-01

    Background and objective The purpose of the study is to compare the drainage of subretinal fluid (SRF) in a scleral pocket (SP) with incision parallel to the limbus to drainage through a simple radial scleral thinning (ST), during scleral buckling surgery for rhegmatogenous retinal detachment (RRD). Patients and methods Retrospective cohort study of one hundred sixty-nine consecutive buckling surgery for RRD, where a drainage puncture was performed through SP in eighty-five cases and through previous radial ST in eighty-four cases. Results PT shows significant lower complication rate. The incidence of retinal incarceration or formation of a retinal hole at the first drainage site is lower in PT group (p=0.0285). During surgery choroidal detachment have been observed in a higher percentage of cases in the SP group (p=0.0379). At the end of the surgery a certain amount of SRF behind the buckling was significant in ST group (p=0.0026). Conclusion The SP drainage technique appears to be a useful, effective and safe method to drain SRF. PMID:26188754

  13. [Evaluation of the macula which was not involved in retinal detachment after surgical treatment of retinal detachment using scleral indentation. Summary of a doctoral thesis].

    PubMed

    Boduch-Cieślińska, K

    1992-10-01

    The goal of the study was the evaluation of the influence of the nowadays most frequently used surgical methods in cases of retinal detachment on the macula not involved in the detachment. The study takes into account surgical interventions which have the same indications and principles of action. They are based on an extra-scleral indentation--temporary or permanent one--by means of a Lincoff-Kreissig balloon and a meridional silicone sponge implant. The examinations comprised 54 patients. They were divided into 2 groups: 1st group (24 patients) was treated by cryopexy and a Lincoff-Kreissig balloon, the 2nd group (30 patients) by cryopexy and a meridional silicone sponge implant. In all the patients of both groups the retina reattached. During the 5-years observation of patients of the 1st group no macular changes were detected; one did not observe metamorphopsia or disturbances of the color vision. In the 2nd group instead 17 patients claimed metamorphopsia, 20 patients showed disturbances of the color vision and angiography changes involving the macular region (13 patients). PMID:1306534

  14. Late corneal scarring after retinal detachment surgery 42 months after photorefractive keratectomy.

    PubMed

    Tosi, Gian Marco; Baiocchi, Stefano; Caporossi, Tomaso

    2004-05-01

    A 42-year-old man had uneventful bilateral nonsimultaneous photorefractive keratectomy (PRK) for severe myopia. Thirty-nine months after the procedure, the patient presented with a retinal detachment (RD) in the right eye. Cerclage, vitrectomy, endolaser, and intravitreal silicone oil tamponade were performed, and the RD was successfully repaired. Three months after vitrectomy and 42 months after PRK, the patient complained of visual impairment in the right eye and photophobia. On slitlamp examination, marked reticular scarring of the central anterior cornea was observed. The occurrence of late-onset corneal haze highlights the need for special attention to patients who have vitrectomy after PRK.

  15. Biocompatibility of a Synthetic Biopolymer for the Treatment of Rhegmatogenous Retinal Detachment

    PubMed Central

    Sarfare, Shanta; Dacquay, Yann; Askari, Syed; Nusinowitz, Steven; Hubschman, Jean-Pierre

    2015-01-01

    Objective The aim of this study is to evaluate the retinal safety and toxicity of a novel synthetic biopolymer to be used as a patch to treat rhegmatogenous retinal detachment. Methods Thirty one adult wild type albino mice were divided in 2 groups. In Group A (n=9) 0.2 μl balanced salt solution (BSS) and in Group B (n=22), 0.2 μl biopolymer was injected in the subretinal space. Trans-scleral subretinal injection was performed in one eye and the fellow eye was used as control. In both groups, in vivo color fundus photography, electroretinogram (ERG), spectral domain optical coherence tomography (SD-OCT) were performed before injection and at days 7 and 14 post-intervention. Histological analysis was performed following euthanization at days 1, 7 and 21 post-injection. Results The biopolymer was visualized in the subretinal space in vivo by SD-OCT and post-life by histology up to 1 week after the injection. There were no significant differences in ERG parameters between the two groups at 1 and 2 weeks post-injection. Minimal inflammatory response and loss of photoreceptor cells was only observed in the immediate proximity of the site of scleral perforation, which was similar in both groups. Overall integrity of the outer, inner retina and retinal pigment epithelial (RPE) layers was unaffected by the presence of the biopolymer in the subretinal space. Conclusions Functional and histological evaluation suggests that the synthetic biopolymer is non-inflammatory and non-toxic to the eye. It may represent a safe therapeutic agent in the future, for the treatment of rhegmatogenous retinal detachment. PMID:26744635

  16. Topical difluprednate for treatment of serous retinal detachment and panuveitis associated with Vogt-Koyanagi-Harada disease

    PubMed Central

    Lu, Stacey; Taban, Mehran

    2016-01-01

    Summary Patients with bilateral serous retinal detachments and panuveitis related to Vogt-Koyanagi-Harada disease are commonly managed with oral corticosteroids, immunosuppressive agents, and/or intravitreal injections. We present the case of a 56-year-old Hispanic man with Harada disease whose bilateral serous retinal detachments and panuveitis were treated with topical corticosteroid difluprednate alone. Functional and anatomical recoveries were assessed by fluorescein angiograms and optical coherence tomography studies over a period of 9 months. The patient’s serous retinal detachments resolved, and his vision and panuveitis improved dramatically over a period of 2 weeks, after which he was placed on a drop taper and maintenance therapy for the remainder of the 9 months. PMID:27582676

  17. Topical difluprednate for treatment of serous retinal detachment and panuveitis associated with Vogt-Koyanagi-Harada disease.

    PubMed

    Lu, Stacey; Taban, Mehran

    2016-01-01

    Patients with bilateral serous retinal detachments and panuveitis related to Vogt-Koyanagi-Harada disease are commonly managed with oral corticosteroids, immunosuppressive agents, and/or intravitreal injections. We present the case of a 56-year-old Hispanic man with Harada disease whose bilateral serous retinal detachments and panuveitis were treated with topical corticosteroid difluprednate alone. Functional and anatomical recoveries were assessed by fluorescein angiograms and optical coherence tomography studies over a period of 9 months. The patient's serous retinal detachments resolved, and his vision and panuveitis improved dramatically over a period of 2 weeks, after which he was placed on a drop taper and maintenance therapy for the remainder of the 9 months. PMID:27582676

  18. Predictive factors for postoperative visual function of primary chronic rhegmatogenous retinal detachment after scleral buckling

    PubMed Central

    Fang, Wei; Li, Jiu-Ke; Jin, Xiao-Hong; Dai, Yuan-Min; Li, Yu-Min

    2016-01-01

    AIM To evaluate predictive factors for postoperative visual function of primary chronic rhegmatgenous retinal detachment (RRD) after sclera buckling (SB). METHODS Totally 48 patients (51 eyes) with primary chronic RRD were included in this prospective interventional clinical cases study, which underwent SB alone from June 2008 to December 2014. Age, sex, symptoms duration, detached extension, retinal hole position, size, type, fovea on/off, proliferative vitreoretinopathy (PVR), posterior vitreous detachment (PVD), baseline best corrected visual acuity (BCVA), operative duration, follow up duration, final BCVA were measured. Pearson correlation analysis, Spearman correlation analysis and multivariate linear stepwise regression were used to confirm predictive factors for better final visual acuity. Student's t-test, Wilcoxon two-sample test, Chi-square test and logistic stepwise regression were used to confirm predictive factors for better vision improvement. RESULTS Baseline BCVA was 0.8313±0.6911 logMAR and final BCVA was 0.4761±0.4956 logMAR. Primary surgical success rate was 92.16% (47/51). Correlation analyses revealed shorter symptoms duration (r=0.3850, P=0.0053), less detached area (r=0.5489, P<0.0001), fovea (r=0.4605, P=0.0007), no PVR (r=0.3138, P=0.0250), better baseline BCVA (r=0.7291, P<0.0001), shorter operative duration (r=0.3233, P=0.0207) and longer follow up (r=-0.3358, P=0.0160) were related with better final BCVA, while independent predictive factors were better baseline BCVA [partial R-square (PR2)=0.5316, P<0.0001], shorter symptoms duration (PR2=0.0609, P=0.0101), longer follow up duration (PR2=0.0278, P=0.0477) and shorter operative duration (PR2=0.0338, P=0.0350). Patients with vision improvement took up 49.02% (25/51). Univariate and multivariate analyses both revealed predictive factors for better vision improvement were better baseline vision [odds ratio (OR) =50.369, P=0.0041] and longer follow up duration (OR=1.144, P=0

  19. Retinal detachment post-phacoemulsification in Bichons Frises: A retrospective study of 54 dogs

    PubMed Central

    Pryor, Silvia G.; Bentley, Ellison; McLellan, Gillian J; Giuliano, Elizabeth A; Albaugh, Rachel A; Rankin, Amy J; Labelle, Amber L; Buhr, Kevin A

    2015-01-01

    Objective To compare rates of retinal detachment (RD) post phacoemulsification in American Bichons Frises with and without prophylactic retinopexy. Procedures Medical records of 54 Bichons Frises undergoing phacoemulsification with or without prophylactic retinopexy between 2003–2013 in one or both eyes were reviewed from five Midwestern university veterinary teaching hospitals. Inclusion criteria were pre-operative ERG, at least 6 months of follow up post phacoemulsification, and absence of pre-existing RD as determined by ophthalmic examination and/or ultrasound. Statistical analyses used chi-squared and Wilcoxon rank-sum tests and Wilson confidence intervals with the p value <0.05 considered significant. Results Phacoemulsification was performed without retinopexy in 79 eyes (42 dogs, non-PR group) and with prophylactic retinopexy in 23 eyes (12 dogs, PR group). Incidence of diabetes mellitus was 10/42 and 3/12 in the non-PR and the PR groups respectively (p=0.93). Intraocular lens implantation was performed in 40/42 non-PR dogs and 11/12 PR dogs, (p=0.63, 73/79 versus 21/23 eyes). At final re-examination, RD occurred in 4/79 eyes without retinopexy, compared to 0/23 RD in the retinopexy group. There was no statistically significant difference in RD rates between the two groups (p=0.27) Conclusions These data provide no statistical evidence to support prophylactic retinopexy in Bichon Frises. Due to the low rate of retinal detachment following phacoemulsification without prophylactic retinopexy, the procedure appears to offer limited benefit to offset cost, procedural risk and risk of extended or repeated anesthesia in Bichons Frises. PMID:26429670

  20. High frequency of latent Chlamydia trachomatis infection in patients with rhegmatogenous retinal detachment

    PubMed Central

    Boiko, Ernest V.; Pozniak, Alexei L.; Maltsev, Dmitrii S.; Suetov, Alexei A.; Nuralova, Irina V.

    2016-01-01

    AIM To determine the frequency of detection of ocular and extraocular Chlamydia trachomatis (CT) infection in non-high myopes with rhegmatogenous retinal detachment (RRD). METHODS This was a single-center, nonrandomized, prospective, case-control study. One hundred and four patients were divided into a study group with RRD (n=63) and a control group with traumatic retinal detachment (n=41). Samples of subretinal fluid (SFR), conjunctival, urethral/cervical swabs, and blood were collected. The frequency of detection of CT infection in SRF samples was determined by polymerase chain reaction (PCR), direct fluorescence assay (DFA) and cell culture, whereas that in conjunctival swabs was determined by PCR and DFA, and those in urethral/cervical swabs and blood were determined by DFA. Yates Chi-square test (with Bonferroni correction) and two-tailed Student's t-test were used for statistical analysis. RESULTS SRF CT infection was detected more frequently in the study group (50.8%-71.4%) than in the control group (9.8%-12.2%) by all the methods used (P<0.01). The frequency of detection of conjunctival CT infection by DFA was higher in the RRD patients compared with the controls (81.0% vs 24.4%, P=0.004). The PCR detected conjunctival CT infection more often in the study group than in the controls (46.0% vs 9.8%, P=0.007). The DFA detected CT in blood specimens almost as frequently as in urogenital specimens, for the RRD patients (61.2% vs 63.5%) and the controls (7.3% vs 9.8%). CONCLUSION CT infection is detected with high frequency in non-high myopes with RRD. PMID:27366689

  1. Five Year Nationwide Incidence of Rhegmatogenous Retinal Detachment Requiring Surgery in Korea

    PubMed Central

    Park, Sang Jun; Choi, Nam-Kyoung; Park, Kyu Hyung; Woo, Se Joon

    2013-01-01

    Purpose To define the incidence and demographic characteristics of rhegmatogenous retinal detachment (RRD) requiring surgery in Korea. Design Nationwide population-based retrospective study. Methods Patients who underwent surgery for RRD from 2007 to 2011 were retrospectively identified using the diagnostic code for RRD and the surgical codes for retinal detachment surgeries in the national claim database. The average incidence rate of RRD during the 5-year period was estimated using the population data of the 2010 Census in Korea. Results A total of 24,928 surgically treated RRD cases were identified. The average incidence of surgery requiring RRD was 10.39 cases per 100,000 person-years [95% confidence interval (CI), 10.26–10.52). The incidence in men (11.32 cases per 100,000 person-years; 95% CI: 11.13–11.51) was significantly higher than that in women (9.47 cases per 100,000 person-years; 95% CI: 9.29–9.64) (p<0.001). The incidence of surgery requiring RRD showed a bimodal distribution across age groups, with one peak (28.55 cases per 100,000 person-years; 95% CI: 27.46–29.67) representing patients between 65 and 69 years of age and the second peak (approximately 8.5 per 100,000 person-years) representing patients between 20 and 29 years of age. The male-to-female ratio was approximately 1.0 for the peak-incidence age groups, whereas the ratio was higher for the other age groups. Conclusions The incidence of RRD in the Korean population was similar to that reported previously, with the peak incidence being lower than that in the Caucasian population. The age-specific RRD incidence pattern in Korea followed a bimodal distribution. PMID:24236173

  2. Congenital Bilateral Retinal Detachment in Two Siblings with Osteoporosis-Pseudoglioma Syndrome.

    PubMed

    Welinder, Lotte G; Robitaille, Johane M; Rupps, Rosemarie; Boerkoel, Cornelius F; Lyons, Christopher J

    2015-01-01

    The birth of a bilaterally blind child is catastrophic for families and a challenging diagnostic and management problem for ophthalmologists. Early identification of the underlying cause and its genetic basis helps initiate possible treatment, delineate prognosis, and identify risks for future pregnancies. In some cases, an early diagnosis can also influence the treatment of other family members. We report two sisters with bilateral retinal detachment and retro-lental masses from birth with no detectable NDP or FZD4 mutations. They were born to parents without detectable retinal anomalies. At 1 year of age, the elder sister had low impact bone fractures, and further evaluation identified severe osteopenia and multiple spinal compression fractures. Molecular testing identified biallelic lipoprotein receptor-related protein 5 (LRP5) mutations (NM_002335.3:c. [889dupA]; [2827 + 1G > A]) confirming a diagnosis of osteoporosis-pseudoglioma (OPPG) syndrome. After this diagnosis, the father and mother were found to have low bone mass and the father started on therapy. We conclude that early detection of LRP5 mutations is important for initiation of treatment of reduced bone density in the patients and their carrier relatives. PMID:25945592

  3. Outcome of rhegmatogenous retinal detachment repair: Experience of a tertiary center in Oman

    PubMed Central

    Al-Hinai, Ahmed S.; Al-Abri, Mohamed S.

    2013-01-01

    Aim: To study the outcome of repair of rhegmatogenous retinal detachment (RRD) in a tertiary center. Materials and Methods: Review of electronic medical records within a period of 29 months of consecutive patients who underwent surgical repair for RRD in Sultan Qaboos University Hospital (SQUH). Results: We included 33 consecutive patients (36 eyes). Males constituted 70% of them. The average age was 47 years. Seven eyes out of the 36 had macula-on RRD at presentation. The primary success rate with a single procedure was 86%. However, redetachment occurred in five eyes (14%). Visual acuity was either same as preoperative or better in 81% of the eyes. Giant retinal tear was found in three eyes (8%). The average follow-up period for all patients was 10.25 months (range: 3-25 months). Conclusion: Rhegmatogenous RD is not uncommon disorder. It occurs more frequently in males. However, it has a good prognosis if an intervention was performed in early stages. PMID:24379553

  4. Surgical outcomes of 25-gauge pars plana vitrectomy for diabetic tractional retinal detachment

    PubMed Central

    Dikopf, M S; Patel, K H; Setlur, V J; Lim, J I

    2015-01-01

    Purpose To evaluate the outcomes and complications of 25-gauge (G) pars plana vitrectomy (PPV) for repair of diabetic tractional retinal detachment (TRD). Methods Retrospective review of consecutive, single-surgeon 25-G PPV cases between July 2007 and July 2014. Seventy eyes from 55 patients were operated on for diabetic TRD; all eyes were tamponaded with sulfur hexafluoride, octofluoropropane, silicone oil, or balanced salt solution. Mean age at surgery was 47.7 years (range 23–76 years), and mean length of follow-up was 713 days (range 90–2368 days; median 671 days). Primary outcomes included best-corrected visual acuity (BCVA), intraocular pressure (IOP), anatomic success, redetachment, and endophthalmitis. Results Preoperatively, 49 eyes (70%) had a concurrent rhegmatogenous component (8 of which also had proliferative vitreoretinopathy (PVR)). Mean BCVA improved from logarithm of the minimal angle of resolution 1.59 (20/800, SD 0.88) to 0.68 postoperatively (20/100, 0.77), P-value<0.001. Mean IOP increased from 15.9 to 20 mm Hg 1 day after surgery. Elevated postoperative IOP (≥22 mm Hg) occurred in 25 eyes, and low IOP (≤5 mm Hg) occurred in 2 eyes. Primary reattachment was achieved in 63 eyes (90%), and final anatomical success occurred in 69 eyes (99%). There were no cases of endophthalmitis. Conclusions Twenty-five-G PPV repair was safe and effective in the repair of diabetic TRD, including eyes with a combined rhegmatogenous detachment or PVR. Gas, silicone oil, and balanced salt solution tamponading agents all proved to be efficacious in this surgical population. PMID:26183284

  5. Diffuse choroidal hemangioma associated with exudative retinal detachment in a Sturge-Weber syndrome case: photodynamic therapy and intravitreous bevacizumab.

    PubMed

    Anaya-Pava, Edwin J; Saenz-Bocanegra, Carlos H; Flores-Trejo, Alejandro; Castro-Santana, Norma A

    2015-03-01

    We report the case of a young female patient with a diffuse choroidal hemangioma (DCH) and glaucoma as part of Sturge-Weber syndrome (SWS) and symptomatic retinal detachment that was treated successfully with photodynamic therapy (PDT) and intravitreal bevacizumab (IVB). The patient was treated with a single session of PDT, a 689-nm laser was used to deliver 50J/cm(2) with a maximum spot size of 6400μm, for 166s. IVB was administered 3 days later. The exudative retinal detachment (ERD), macular edema and visual acuity improved one week after treatment. The patient was followed for 18 months with no recurrence of ERD, and her visual acuity was preserved. PDT followed by IVB may be an effective treatment option for visual deterioration due to ERD in patients with DCHs, as are found in SWS. PMID:25560419

  6. Comparison of scleral buckling using wide-angle viewing systems and indirect ophthalmoscope for rhegmatogenous retinal detachment

    PubMed Central

    Li, Xiu-Juan; Yang, Xiao-Peng; Lyu, Xiao-Bei

    2016-01-01

    AIM To compare the effects of scleral buckling using wide-angle viewing systems (WAVS) with that using indirect ophthalmoscope for the treatment of rhegmatogenous retinal detachment. METHODS The study was a retrospective analyses of the medical records of 94 eyes (94 patients) with rhegmatogenous retinal detachment. Among them, 47 eyes underwent scleral buckling using WAVS with endoilluminator (Group W), and 47 eyes underwent scleral buckling using indirect ophthalmoscope (Group I). Surgical durations, primary success rate, best-corrected visual acuities (BCVA), delayed subretinal fluid absorptions and surgical complications were compared between the two groups. RESULTS At baseline, there were no statistical differences between the two groups in patient's age (P=0.997), gender (P=0.853), symptom duration (P=0.216), BCVA (P=0.389), refractive error (P=0.167), intraocular pressure (P=0.595), the number of retinal breaks (P=0.832), the extent of retinal detachment (P=0.246), subretinal demarcation line (P=0.801), and macular detachment (P=0.811). The follow-up period was 12mo. The surgical durations in Group W (with or without encircling buckling) were significant shorter than those in Group I (P<0.001 respectively). The primary success rate was 94.27% in Group W, which was similar to that in Group I (92.38%, P = 0.931). The BCVA in Group W was better than that in Group I (P<0.001) at 1-month follow-up visit. However, there were no significant differences between the two groups at 3-month (P=0.221), 6-month (P=0.674), and 12-month (P=0.363) follow-up visits respectively. Delayed subretinal fluid absorptions were more common in Group I than in Group W at 1-month (P=0.045) follow-up visit, but there were no significant differences between the two groups at 3-month (P=0.111), 6-month (P=1.000) and 12-month follow-up visits respectively. CONCLUSION Scleral buckling using WAVS can be an alternative choose for rhegmatogenous retinal detachment. PMID:27672597

  7. Comparison of scleral buckling using wide-angle viewing systems and indirect ophthalmoscope for rhegmatogenous retinal detachment

    PubMed Central

    Li, Xiu-Juan; Yang, Xiao-Peng; Lyu, Xiao-Bei

    2016-01-01

    AIM To compare the effects of scleral buckling using wide-angle viewing systems (WAVS) with that using indirect ophthalmoscope for the treatment of rhegmatogenous retinal detachment. METHODS The study was a retrospective analyses of the medical records of 94 eyes (94 patients) with rhegmatogenous retinal detachment. Among them, 47 eyes underwent scleral buckling using WAVS with endoilluminator (Group W), and 47 eyes underwent scleral buckling using indirect ophthalmoscope (Group I). Surgical durations, primary success rate, best-corrected visual acuities (BCVA), delayed subretinal fluid absorptions and surgical complications were compared between the two groups. RESULTS At baseline, there were no statistical differences between the two groups in patient's age (P=0.997), gender (P=0.853), symptom duration (P=0.216), BCVA (P=0.389), refractive error (P=0.167), intraocular pressure (P=0.595), the number of retinal breaks (P=0.832), the extent of retinal detachment (P=0.246), subretinal demarcation line (P=0.801), and macular detachment (P=0.811). The follow-up period was 12mo. The surgical durations in Group W (with or without encircling buckling) were significant shorter than those in Group I (P<0.001 respectively). The primary success rate was 94.27% in Group W, which was similar to that in Group I (92.38%, P = 0.931). The BCVA in Group W was better than that in Group I (P<0.001) at 1-month follow-up visit. However, there were no significant differences between the two groups at 3-month (P=0.221), 6-month (P=0.674), and 12-month (P=0.363) follow-up visits respectively. Delayed subretinal fluid absorptions were more common in Group I than in Group W at 1-month (P=0.045) follow-up visit, but there were no significant differences between the two groups at 3-month (P=0.111), 6-month (P=1.000) and 12-month follow-up visits respectively. CONCLUSION Scleral buckling using WAVS can be an alternative choose for rhegmatogenous retinal detachment.

  8. Using optical coherence tomography to evaluate macular changes after surgical management for rhegmatogenous retinal detachment.

    PubMed

    Cheng, Kai-Chun; Cheng, Kai-Yuan; Cheng, Kai-Hung; Chen, Kuo-Jen; Chen, Chia-Hui; Wu, Wen-Chuan

    2016-05-01

    Incomplete visual recovery, color vision defects, or persistent metamorphopsia may persist even after successful surgery for rhegmatogenous retinal detachment (RRD), especially in cases of RD with macula off, suggesting microstructural macular damage that standard fundus biomicroscopy could not detect. We compared spectral-domain optical coherence tomography imaging with preoperative and postoperative visual acuity to evaluate the relationship between morphological changes in the outer retina and visual outcome after successful repair of RRD with macula on or off. We enrolled 43 patients (43 eyes) with successful repair of RRD and a minimum 6-month follow up after surgery in this retrospective research. Patients accepted spectral-domain optical coherence tomography postoperatively and visual acuity examination preoperatively and postoperatively. The mean age of the patients was 48.74 ± 12.68 years (range: 16-77 years). The mean visual acuity (logarithm of minimal angle of resolution) before surgery was 0.87 ± 0.70. Disrupted ellipsoid zone was noted in one of 11 eyes in the macula-on group (9.1%) and 19 of 32 eyes in the macula-off group (59.4%). Disrupted external limiting membrane (ELM) was noted in no eye in the macula-on group (0%) and 11 of 32 eyes in the macula-off group (34.4%). The macula-off group was associated with better postoperative visual gains than the macula-on group (p = 0.013). Patients with integrity of the ellipsoid zone and ELM were associated with significant visual improvement than patients with disruption of the ellipsoid zone or ELM. PMID:27316583

  9. Point-of-care ultrasonography of the orbit for detection of retinal detachment in a patient with hemolysis, elevated liver enzymes, and low platelet count syndrome

    PubMed Central

    Shrestha, Gentle Sunder; Rajbhandari, Shayuja; Dhungel, Shashwat; Sharma, Nutan; Poudel, Nimesh; Manandhar, Dhiraj N.

    2016-01-01

    Retinal detachment is a rare, but well-known cause of visual impairment in patients with hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. With supportive care, patients usually improve, with complete recovery of vision. Bedside ultrasonography of the orbit can be helpful for early detection of retinal detachment in these patients. Here, we present a case of HELLP syndrome presenting with severe visual symptoms. Retinal detachment was detected with point-of-care ocular sonography, which was confirmed with ophthalmoscopic examination. The patient was reassured of the favorable prognosis. Early initiation of aggressive supportive care was followed by progressive improvement of vision, which correlated with sonographic evidence of resolution of detachment. Her vision recovered completely in 2 weeks. PMID:27688632

  10. Point-of-care ultrasonography of the orbit for detection of retinal detachment in a patient with hemolysis, elevated liver enzymes, and low platelet count syndrome.

    PubMed

    Shrestha, Gentle Sunder; Rajbhandari, Shayuja; Dhungel, Shashwat; Sharma, Nutan; Poudel, Nimesh; Manandhar, Dhiraj N

    2016-09-01

    Retinal detachment is a rare, but well-known cause of visual impairment in patients with hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. With supportive care, patients usually improve, with complete recovery of vision. Bedside ultrasonography of the orbit can be helpful for early detection of retinal detachment in these patients. Here, we present a case of HELLP syndrome presenting with severe visual symptoms. Retinal detachment was detected with point-of-care ocular sonography, which was confirmed with ophthalmoscopic examination. The patient was reassured of the favorable prognosis. Early initiation of aggressive supportive care was followed by progressive improvement of vision, which correlated with sonographic evidence of resolution of detachment. Her vision recovered completely in 2 weeks. PMID:27688632

  11. Minimally invasive curved-micro-drainer (CMD) capable of innocuous drainage of subretinal fluid for the treatment of retinal detachment.

    PubMed

    Ma, Yonghao; Lee, ChangYeol; Li, Cheng Guo; You, Yong Sung; Sung, Ho Lee; Jung, Hyungil

    2016-08-01

    Retinal detachment is a serious vision threatening disease. Current consensus for the treatment of retinal detachment is to reattach the retina onto the choroid layer by drainage of accumulated subretinal fluid. Although several surgical methods have been developed, no satisfactory visual outcome has been obtained without surgical complications such as unintended puncture and hemorrhage of the retina and choroid tissue. In this study, we developed a novel Curved-Micro-Drainer (CMD) for the innocuous drainage of subretinal fluid. It is a curved structure with a 15° beveled tip that is 5 mm in length, with an 80 μm inner diameter and a 100 μm outer diameter. This high inner-to-outer diameter ratio of CMD with a 100 μm outer diameter allows efficient drainage of highly viscous subretinal fluid in a minimally invasive manner. In addition, the curved structure precisely matches the spherical ocular structure, which facilitates the CMD insertion into the subretinal space without choroid tissue damage. We demonstrate that the optimized CMD allows for the innocuous drainage of the viscous subretinal fluid from the porcine eye, whereas the traditional hypodermic needle (31-gauge) induces severe retinal and choroid damage. CMD can overcome a critical safety issue and is a potential alternative to conventional surgical interventions for the innocuous drainage of subretinal fluid. PMID:27412289

  12. Long-term follow-up of vitrectomy, with or without 360° encircling buckle, for rhegmatogenous retinal detachment due to inferior retinal breaks

    PubMed Central

    Ghoraba, Hamouda Hamdy; Zaky, Adel Galal; Ellakwa, Amin Faisal

    2016-01-01

    Objective The aim of this study was to report and compare the anatomic and functional results of primary vitrectomy with and without 360° encircling scleral buckle (SB) for the treatment of rhegmatogenous retinal detachment (RRD) due to inferior retinal break(s). Background A variety of options, including SB, pars plana vitrectomy (PPV) with or without SB, and pneumatic retinopexy have been described as methods to repair RRDs. The use of additional SB with vitrectomy for RRD associated with inferior breaks has been a recent controversy after the introduction of transconjunctival cannula systems. Patients and methods A retrospective, interventional, comparative case study was performed. In this study, we reviewed 105 consecutive patients who underwent vitrectomy for primary RRD with inferior retinal break(s) at the vitreoretinal center, performed by a single surgeon. Ninety four patients (94 eyes) were followed up for at least 4 months after silicon oil removal (SOR), and were analyzed. They were divided into two groups: group I included 50 patients who underwent PPV alone + silicon oil (SO); and group II included 44 patients who underwent PPV with 360° SB + SO. The essential parameters were single-operation success rate (SOSR) before SOR, incidence of retinal redetachment after SOR, and final visual acuity. Results SOSR was obtained in 89 eyes (47 [94%] in group I and 42 [95.5%] in group II). From overall 59 phakic retinal detachments (RDs), SOSR was obtained in 56 eyes (30 in group I [93.8%] and 26 in group II [96.3%]) while from overall 35 aphakic or pseudophakic RDs, SOSR was obtained in 33 eyes (17 in group I [94.4%] and 16 in group II [94.1%]). Retinal redetachments after SOR occurred in three patients in group I and two patients in group II. Visual acuity improvement was greater in group I than in group II before SOR. Conclusion Both surgical procedures had similar reattachment rates. The addition of 360° SB to PPV + SO might not have additional benefits

  13. Optical Coherence Tomography Follow-up of an Unusual Case of Old Rhegmatogenous Retinal Detachment With a Hemorrhagic Macrocyst at the Macula.

    PubMed

    Tripathy, Koushik; Bypareddy, Ravi; Chawla, Rohan; Kumawat, Babulal

    2015-01-01

    A 32-year-old female presented with visual acuity of hand movement close to face, an old inferior rhegmatogenous retinal detachment (RRD), and a large hemorrhagic macular macrocyst (HMM) in the right eye. After 2 weeks of successful vitreoretinal surgery, the HMM started decreasing in height and resolved by 3 months. On optical coherence tomography, a zone of hyperreflectivity in the outer retinal layers was evident on resolution of the cyst. At final follow-up, the visual acuity improved to 1/60 only. Though HMM resolved completely after retinal reattachment, alteration and thickening of microarchitecture of the outer retinal layers ensued. PMID:26599252

  14. Application Of Laser Coagulation In Retinal Detachment And Open - Angle Glaucoma, On The Basis Of Own Experiments

    NASA Astrophysics Data System (ADS)

    Palacz, Olgierd; Karczewicz, Danuta; Owczarska, Wieslawa; Sylwestrzak, Zofia

    1987-10-01

    The first part of the paper presents the results of laser ¬Â¢hotocoaculation treatment involving: 141 patients with retinal detachment , 20 with holes in the macula, and 33 with holes at the eye fundus periphery. At estimating the results, the apposition of retina and the observation time have been taken into account. The second part contains the results of observation of 21 patients, in whom, in 26 eyes laser trabeculoplasty was performed. Normalization of intraocular pressure has been obtained in 76.9% of cases. The outflow coefficient after trabeculoplasty has increased in 57.6% of cases.

  15. Retinal Pigment Epithelium Atrophy 1 (rpea1): A New Mouse Model With Retinal Detachment Caused by a Disruption of Protein Kinase C, θ

    PubMed Central

    Ji, Xiaojie; Liu, Ye; Hurd, Ron; Wang, Jieping; Fitzmaurice, Bernie; Nishina, Patsy M.; Chang, Bo

    2016-01-01

    Purpose Retinal detachments (RDs), a separation of the light-sensitive tissue of the retina from its supporting layers in the posterior eye, isolate retinal cells from their normal supply of nourishment and can lead to their deterioration and death. We identified a new, spontaneous murine model of exudative retinal detachment, nm3342 (new mutant 3342, also referred to as rpea1: retinal pigment epithelium atrophy 1), which we characterize herein. Methods The chromosomal position for the recessive nm3342 mutation was determined by DNA pooling, and the causative mutation was discovered by comparison of whole exome sequences of mutant and wild-type controls. The effects of the mutation were examined in longitudinal studies by clinical evaluation, electroretinography (ERG), light microscopy, and marker and Western blot analyses. Results New mutant 3342, nm3342, also referred to as rpea1, causes an early-onset, complete RD on the ABJ/LeJ strain background, and central exudative RD and late-onset RPE atrophy on the C57BL/6J background. The ERG responses were normal at 2 months of age but deteriorate as mice age, concomitant with progressive pan-retinal photoreceptor loss. Genetic analysis localized rpea1 to mouse chromosome 2. By high-throughput sequencing of a whole exome capture library of an rpea1/rpea1 mutant and subsequent sequence analysis, a splice donor site mutation in the Prkcq (protein kinase C, θ) gene, was identified, leading to a skipping of exon 6, frame shift and premature termination. Homozygotes with a Prkcq-targeted null allele (Prkcqtm1Litt) have similar retinal phenotypes as homozygous rpea1 mice. We determined that the PKCθ protein is abundant in the lateral surfaces of RPE cells and colocalizes with both tight and adherens junction proteins. Phalloidin-stained RPE whole mounts showed abnormal RPE cell morphology with aberrant actin ring formation. Conclusions The homozygous Prkcqrpea1 and the null Prkcqtm1Litt mutants are reliable novel mouse

  16. Change in refraction after lens-sparing vitrectomy for rhegmatogenous retinal detachment and epiretinal membrane

    PubMed Central

    Iwase, Takeshi; Yamamoto, Kentaro; Yanagida, Kosei; Kobayashi, Misato; Ra, Eimei; Murotani, Kenta; Terasaki, Hiroko

    2016-01-01

    Abstract The aim of this study was to compare changes in refraction following lens-sparing vitrectomy between patients with rhegmatogenous retinal detachment (RRD) and epiretinal membrane (ERM) and to investigate factors associated with the change in refraction. We reviewed medical records of 49 eyes of 49 patients with RRD (53.6 ± 7.8 years, mean ± standard deviation) and 24 eyes of 24 patients with ERM (50.9 ± 15.7 years) who underwent lens-sparing vitrectomy. Spherical equivalent refractive power was evaluated before and up to 18 months after surgery. The relationship between the change in refraction and several parameters was evaluated. A significant progressive myopic shift in refractive power was observed after vitrectomy in operated RRD and ERM eyes (P < 0.001, P = 0.016, respectively), with no significant difference in fellow eyes. The refraction values observed at ≥3 and ≥12 months following vitrectomy were significantly different as compared with those observed at baseline in the RRD group (P < 0.001) and the ERM group (P < 0.05), respectively. The change in refraction between the RRD and ERM groups was significant (P = 0.030). The multiple linear regression analysis showed that only age was significantly correlated with the change in refraction in RRD (P = 0.018) and ERM (P < 0.001) groups. The change in refraction was significantly and positively correlated with age in RRD (r = −0.461, P = 0.001) and ERM (r = −0.687, P < 0.001) groups. Following lens-sparing vitrectomy, cataract surgery was performed on 30 eyes after 0.89 ± 0.26 years in the RRD group and on 10 eyes after 1.11 ± 0.14 years in the ERM group; there was a significant difference in time to cataract surgery between the groups (P = 0.007). Kaplan–Meier survival analysis demonstrated that there was a significant difference in the rate of cataract surgeries between the RRD and ERM groups (P = 0

  17. Change in refraction after lens-sparing vitrectomy for rhegmatogenous retinal detachment and epiretinal membrane.

    PubMed

    Iwase, Takeshi; Yamamoto, Kentaro; Yanagida, Kosei; Kobayashi, Misato; Ra, Eimei; Murotani, Kenta; Terasaki, Hiroko

    2016-08-01

    The aim of this study was to compare changes in refraction following lens-sparing vitrectomy between patients with rhegmatogenous retinal detachment (RRD) and epiretinal membrane (ERM) and to investigate factors associated with the change in refraction.We reviewed medical records of 49 eyes of 49 patients with RRD (53.6 ± 7.8 years, mean ± standard deviation) and 24 eyes of 24 patients with ERM (50.9 ± 15.7 years) who underwent lens-sparing vitrectomy. Spherical equivalent refractive power was evaluated before and up to 18 months after surgery. The relationship between the change in refraction and several parameters was evaluated.A significant progressive myopic shift in refractive power was observed after vitrectomy in operated RRD and ERM eyes (P < 0.001, P = 0.016, respectively), with no significant difference in fellow eyes. The refraction values observed at ≥3 and ≥12 months following vitrectomy were significantly different as compared with those observed at baseline in the RRD group (P < 0.001) and the ERM group (P < 0.05), respectively. The change in refraction between the RRD and ERM groups was significant (P = 0.030). The multiple linear regression analysis showed that only age was significantly correlated with the change in refraction in RRD (P = 0.018) and ERM (P < 0.001) groups. The change in refraction was significantly and positively correlated with age in RRD (r = -0.461, P = 0.001) and ERM (r = -0.687, P < 0.001) groups. Following lens-sparing vitrectomy, cataract surgery was performed on 30 eyes after 0.89 ± 0.26 years in the RRD group and on 10 eyes after 1.11 ± 0.14 years in the ERM group; there was a significant difference in time to cataract surgery between the groups (P = 0.007). Kaplan-Meier survival analysis demonstrated that there was a significant difference in the rate of cataract surgeries between the RRD and ERM groups (P = 0.022).Following lens

  18. Change in refraction after lens-sparing vitrectomy for rhegmatogenous retinal detachment and epiretinal membrane.

    PubMed

    Iwase, Takeshi; Yamamoto, Kentaro; Yanagida, Kosei; Kobayashi, Misato; Ra, Eimei; Murotani, Kenta; Terasaki, Hiroko

    2016-08-01

    The aim of this study was to compare changes in refraction following lens-sparing vitrectomy between patients with rhegmatogenous retinal detachment (RRD) and epiretinal membrane (ERM) and to investigate factors associated with the change in refraction.We reviewed medical records of 49 eyes of 49 patients with RRD (53.6 ± 7.8 years, mean ± standard deviation) and 24 eyes of 24 patients with ERM (50.9 ± 15.7 years) who underwent lens-sparing vitrectomy. Spherical equivalent refractive power was evaluated before and up to 18 months after surgery. The relationship between the change in refraction and several parameters was evaluated.A significant progressive myopic shift in refractive power was observed after vitrectomy in operated RRD and ERM eyes (P < 0.001, P = 0.016, respectively), with no significant difference in fellow eyes. The refraction values observed at ≥3 and ≥12 months following vitrectomy were significantly different as compared with those observed at baseline in the RRD group (P < 0.001) and the ERM group (P < 0.05), respectively. The change in refraction between the RRD and ERM groups was significant (P = 0.030). The multiple linear regression analysis showed that only age was significantly correlated with the change in refraction in RRD (P = 0.018) and ERM (P < 0.001) groups. The change in refraction was significantly and positively correlated with age in RRD (r = -0.461, P = 0.001) and ERM (r = -0.687, P < 0.001) groups. Following lens-sparing vitrectomy, cataract surgery was performed on 30 eyes after 0.89 ± 0.26 years in the RRD group and on 10 eyes after 1.11 ± 0.14 years in the ERM group; there was a significant difference in time to cataract surgery between the groups (P = 0.007). Kaplan-Meier survival analysis demonstrated that there was a significant difference in the rate of cataract surgeries between the RRD and ERM groups (P = 0.022).Following lens

  19. Quality assessment of cataract surgery in Denmark - risk of retinal detachment and postoperative endophthalmitis.

    PubMed

    Bjerrum, Søren Solborg

    2015-03-01

    The main purpose of this thesis was to examine whether the Danish National Patient Registry (NPR) could be used to monitor and assess the quality of cataract surgery in Denmark by studying the risks of two serious postoperative complications following cataract surgery - retinal detachment (RD) and postoperative endophthalmitis (PE). The thesis consists of four retrospective studies. In the first study (paper I), we used data from the NPR in the calendar period 2000-2010 to investigate the risk of pseudophakic retinal detachment (PRD) using the fellow non-operated eyes of the patients as reference. The study showed that over a 10-year study period, the risk of PRD was increased by a factor of 4.2 irrespective of sex and age. The risk of PRD was highest in the first part of the postoperative period and then gradually decreased but remained statistically significantly higher than the risk of RD in non-operated fellow eyes up to 10 years after cataract surgery. The epidemiology of RD in the non-operated fellow eyes was different from the epidemiology of RD in the background population as young men had the highest risk of RD in the non-operated fellow eyes. This means that the absolute risk of PRD was highest for young men because they had a higher risk of RD before they underwent cataract surgery. In the second study (paper II), we used data from the NPR and reviewed patient charts to assess the risk of PE after cataract surgery performed in public eye departments and private hospitals/clinics in the study period 2002-2010. The overall risk of PE among the seven public eye departments was 0.36 per 1000 registered cataract operations, and the PE risk among the departments was homogeneous. The overall risk of PE among the 28 private hospitals/clinics was 0.73 per 1000 registered cataract operations, and the risk among the private hospitals/clinics was heterogeneous. Most private hospitals/clinics had a risk of PE that was lower than or similar to the risk of PE after

  20. Anatomical and functional outcomes after Densiron 68 heavy silicone oil tamponade for complicated retinal detachment in Chinese eyes

    PubMed Central

    Liu, Fang; Li, Hui; Feng, Le; Wang, Fang

    2014-01-01

    AIM To evaluate the safety and efficacy of Densiron 68 heavy silicone oil (HSO) tamponade for complicated retinal detachment (RD) in Chinese eyes. METHODS Twenty-one eyes of 21 patients with complicated RD were included in this retrospective study. All patients underwent pars plana vitrectomy with an internal tamponade using Densiron 68 HSO. Anatomical and functional results and complications were evaluated, including retinal status, visual acuity (VA), intraocular pressure (IOP), intraocular inflammation, lens opacity, and HSO emulsification. RESULTS All the patients were followed up for 3mo to 1y (5.8±1.16mo). Retinal reattachment was achieved in 19 of 21 patients (90.5%). VA improved in 18 of 21 patients (85.7%), from 1.93 logMAR (±0.48) to 1.52 logMAR (±0.45) (P=0.001). Postoperative complications included early dispersion of HSO in 7 eyes (38.8%), cataract in 10 of 18 phakic eyes (55.5%), moderate postoperative inflammation reaction in 10 eyes (47.6%), and elevated IOP in 5 eyes (23.8%), all of which were controlled by medication or by surgery. CONCLUSION High anatomical and functional success rates can be achieved with primary vitrectomy for complicated RD by using Densiron 68 HSO; however, it should not be ignored that Densiron 68 HSO can cause some complications in the eye. PMID:24967193

  1. Perfluoro-n-octane as a temporary intraocular tamponade in a staged approach to manage complex retinal detachments

    PubMed Central

    Barthelmes, Daniel; Chandra, Jay

    2015-01-01

    Purpose To evaluate outcomes in patients with complex retinal detachments (RD) with proliferative vitreoretinopathy (PVR) requiring retinectomy using a staged approach utilizing perfluoro-n-octane (PFO) as a short-term postoperative intraocular tamponade. Methods Retrospective analysis. Patients who underwent 23G pars plana vitrectomy for the management of complicated RD where PFO was used as a primary temporary intraocular tamponade. Only eyes with PVR in rhegmatogenous RD or eyes with penetrating injuries or globe ruptures (ocular trauma) and subsequent RD with PVR were included. Analysis of 17 eyes of 17 consecutive patients with a minimum follow-up of 12 months during a period of 5 years. The primary outcome measure was the reattachment rate after at least 12 months of follow-up after the PFO removal. Secondary outcome measures were changes in visual acuity, complications due to PFO use, and necessity for further surgeries. Results Eight eyes with prior penetrating injuries or globe rupture and nine eyes with rhegmatogenous pathology were included. All eyes had PFO as temporary tamponade for 14 days (median), which was replaced by silicon oil. Sixteen eyes (94%) had complete and one eye partial reattachment. No redetachments occurred. All eyes retained or improved visual acuity. On average, only 2.5 procedures, including silicon oil removal, were performed. Two eyes had long-term intraocular pressure of 5 mmHg and no eye had intraocular pressure of ≥21 mmHg. No long-term inflammation was observed. Conclusion PFO seems to be beneficial in a staged approach to repair complex detachments when used as short-term tamponade. A median period of 14 days allowed for both sufficient retinal support plus a reduction in side effects seen in long-term endotamponades. PMID:25784785

  2. Preoperative peribulbar block in patients undergoing retinal detachment surgery under general anesthesia: a randomized double-blind study.

    PubMed

    Morel, Jérôme; Pascal, Jean; Charier, David; De Pasquale, Véronique; Gain, Philippe; Auboyer, Christian; Molliex, Serge

    2006-04-01

    Retinal detachment surgery is frequently associated with significant postoperative pain and emesis in adults. In this randomized, double-blind, controlled study we sought to demonstrate that 1% ropivacaine peribulbar (PB) block in conjunction with general anesthesia (GA) improves operative conditions and postoperative analgesia compared with GA combined with subcutaneous normal saline injection into the inferior eyelid. Thirty-one patients were included in each group. Anesthesia was performed with target-controlled infusion propofol and continuous remifentanil infusion adjusted to maintain bispectral index values between 40 and 50. Postoperative analgesia included fixed-dose IV infusion of propacetamol and IV injection of nefopam via a patient-controlled analgesia device. Tramadol was infused IV as rescue medication. Demographic data were comparable between the groups and bispectral index values were maintained at the objective target. In the PB group, fewer patients presented an oculocardiac reflex (6 versus 17; P < 0.01); bleeding interfering with the surgical field was reduced (1 versus 11 patients; P < 0.01); mean time to first nefopam request was longer (148 +/- 99 versus 46 +/- 58 min; P < 0.01); mean nefopam consumption was diminished during the first 6 h after tracheal extubation (18.9 +/- 13.9 versus 28.5 +/- 14.7 mg; P < 0.05); immediate postoperative pain scores were lower; and fewer patients required rescue medication (5 versus 23; P < 0.01). The two groups were similar with respect to the incidence of postoperative nausea and vomiting. Overall, PB block combined with GA improved operating conditions and postoperative analgesia in retinal detachment surgery. PMID:16551903

  3. Integrating Scleral Buckling, Transscleral Drainage of Subretinal Fluid, Intravitreal Anti-Vascular Endothelial Growth Factor, and Laser Photocoagulation in Stage 3B Coats' Total Retinal Detachment.

    PubMed

    Huang, Ying-Chen; Lai, Chi-Chun; Wu, Wei-Chi

    2016-09-01

    The integration of quadruple therapy in a 13-year-old boy with stage 3B Coats' disease achieved retinal reattachment and visual improvement. Scleral buckling might play a role in retinal detachment in Coats' disease, although it has previously been considered insignificant. Instead of performing vitrectomy and internal drainage with a drainage hole in the retina, less-invasive procedures that do not require retinotomy appear to be beneficial in cases of advanced Coats' disease. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:865-868.]. PMID:27631484

  4. Comparison of retinal detachment surgery outcome among patients undergoing pars plana vitrectomy with and without relaxing retinotomy.

    PubMed

    Frenkel, Tal; Moisseiev, Elad; Neudorfer, Meira; Loewenstein, Anat; Barak, Adiel

    2015-06-01

    The purpose of this four year retrospective study was to compare the anatomical and functional outcomes of complicated retinal detachment (RD) surgery by pars plana vitrectomy (PPV) with and without retinotomy. The main outcome measures were primary anatomical success (defined as retinal re-attachment at the final follow-up after a single operation, with or without silicone in situ), final anatomical success, final best-corrected visual acuity (BCVA) and postoperative complications. Baseline characteristics did not differ between the groups, although there was a borderline significant trend for the retinotomy group to be associated with worse pre-surgical ocular pathology. With a mean follow-up of 18 (± 7.8) months, primary anatomical success was achieved in 76.7% (33 of 43) of the retinotomy group eyes vs. 67.8% (40 of 59) of the eyes in the group without retinotomy. Final anatomical success rates for the retinotomy group and no retinotomy group were 100 and 93.2% respectively. The final BCVA was 1.57 LogMAR with retinotomy and 1.38 without retinotomy, an improvement in both groups. The incidence of postoperative complications was similar in the two groups, while the frequency of macular holes was higher in the retinotomy group. A similar degree of improvement in BCVA following both surgeries indicates their similar efficacy and justifies their performance even in complicated eyes in order to improve the patients' quality of life. With neither approach superior to the other, the choice of method should be left to the surgeon. PMID:25142375

  5. Clinical outcomes of 23-gauge vitrectomy may be better than 20-gauge vitrectomy for retinal detachment repair

    PubMed Central

    Jiang, Ya-Qin

    2015-01-01

    Objective This study compared the clinical outcomes between 23-gauge (23-G) vitrectomy and 20-gauge (20-G) vitrectomy for the repair of retinal detachment (RD). Methods A retrospective comparative analysis of 135 RD patients was conducted between January, 2013 and September, 2014 in the Ophthalmology Department of the Affiliated Hospital of Weifang Medical College. The clinical outcomes of RD patients who underwent 23-G vitrectomy (n = 65) and 20-G vitrectomy (n = 70) were compared. A logistic regression analysis was used for prognostic factors in RD patients. A meta-analysis was performed using the comprehensive Meta-Analysis version 2.0 software. Results Baseline characteristics of RD patients between the 23-G group and the 20-G group were not significantly different (all p>0.05). The postoperative wound closure time was obviously shorter, and postoperative intraocular pressure (IOP; mmHg) and the incidence of macular holes (MH) were evidently lower in the 23-G group than in the 20-G group (all p<0.05). However, no statistical significances in the postoperative retinal reattachment rate or visual acuity improvement in the logarithm of the minimum angle of resolution (logMAR) were detected between the 23-G group and the 20-G group (both p>0.05). The meta-analysis further confirmed a shorter postoperative wound closure time, as well as a lower postoperative IOP and incidence of MH in the 23-G group than in the 20-G group (all p<0.05), while neither the postoperative retinal reattachment rate nor the visual acuity improvement in the logMAR showed statistical significance (all p>0.05). Conclusions Our retrospective comparative study of RD surgery using 20-G or 23-G techniques revealed a shorter postoperative wound closure time, as well as a lower postoperative IOP and incidence of MH in the 23-G group than in the 20-G group, confirming the superiority of 23-G vitrectomy over 20-G vitrectomy. This study provided a better option of 23-G vitrectomy for clinically

  6. Computational Simulation of Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment: On the Effect of the Band Size on the Myopization

    PubMed Central

    Lanchares, Elena; del Buey, María A.; Cristóbal, José A.; Ascaso, Francisco J.

    2016-01-01

    A finite element model (FE) of the eye including cornea, sclera, crystalline lens, and ciliary body was created to analyze the influence of the silicone encircling bandwidth and the tightness degree on the myopia induced by scleral buckling (SB) procedure for rhegmatogenous retinal detachment. Intraocular pressure (IOP) was applied to the reference geometry of the FE model and then SB surgery was simulated with encircling bandwidths of 1, 2, and 2.5 mm. Different levels of tightening and three values of IOP were applied. The anterior segment resulted as unaffected by the surgery. The highest value of Cauchy stress appeared in the surroundings of the implant, whereas no increment of stress was observed either in anterior segment or in the optic nerve head. The initial IOP did not appear to play any role in the induced myopia. The wider the band, the greater the induced myopia: 0.44, 0.88, and 1.07 diopters (D) for the 1, 2, and 2.5 mm bandwidth, respectively. Therefore, patients become more myopic with a wider encircling element. The proposed simulations allow determining the effect of the bandwidth or the tightness degree on the axial lengthening, thus predicting the myopic increment caused by the encircling surgery. PMID:27413542

  7. Computational Simulation of Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment: On the Effect of the Band Size on the Myopization.

    PubMed

    Lanchares, Elena; Del Buey, María A; Cristóbal, José A; Calvo, Begoña; Ascaso, Francisco J; Malvè, Mauro

    2016-01-01

    A finite element model (FE) of the eye including cornea, sclera, crystalline lens, and ciliary body was created to analyze the influence of the silicone encircling bandwidth and the tightness degree on the myopia induced by scleral buckling (SB) procedure for rhegmatogenous retinal detachment. Intraocular pressure (IOP) was applied to the reference geometry of the FE model and then SB surgery was simulated with encircling bandwidths of 1, 2, and 2.5 mm. Different levels of tightening and three values of IOP were applied. The anterior segment resulted as unaffected by the surgery. The highest value of Cauchy stress appeared in the surroundings of the implant, whereas no increment of stress was observed either in anterior segment or in the optic nerve head. The initial IOP did not appear to play any role in the induced myopia. The wider the band, the greater the induced myopia: 0.44, 0.88, and 1.07 diopters (D) for the 1, 2, and 2.5 mm bandwidth, respectively. Therefore, patients become more myopic with a wider encircling element. The proposed simulations allow determining the effect of the bandwidth or the tightness degree on the axial lengthening, thus predicting the myopic increment caused by the encircling surgery.

  8. Computational Simulation of Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment: On the Effect of the Band Size on the Myopization.

    PubMed

    Lanchares, Elena; Del Buey, María A; Cristóbal, José A; Calvo, Begoña; Ascaso, Francisco J; Malvè, Mauro

    2016-01-01

    A finite element model (FE) of the eye including cornea, sclera, crystalline lens, and ciliary body was created to analyze the influence of the silicone encircling bandwidth and the tightness degree on the myopia induced by scleral buckling (SB) procedure for rhegmatogenous retinal detachment. Intraocular pressure (IOP) was applied to the reference geometry of the FE model and then SB surgery was simulated with encircling bandwidths of 1, 2, and 2.5 mm. Different levels of tightening and three values of IOP were applied. The anterior segment resulted as unaffected by the surgery. The highest value of Cauchy stress appeared in the surroundings of the implant, whereas no increment of stress was observed either in anterior segment or in the optic nerve head. The initial IOP did not appear to play any role in the induced myopia. The wider the band, the greater the induced myopia: 0.44, 0.88, and 1.07 diopters (D) for the 1, 2, and 2.5 mm bandwidth, respectively. Therefore, patients become more myopic with a wider encircling element. The proposed simulations allow determining the effect of the bandwidth or the tightness degree on the axial lengthening, thus predicting the myopic increment caused by the encircling surgery. PMID:27413542

  9. Combined Tractional and Rhegmatogenous Retinal Detachment in Proliferative Diabetic Retinopathy in the Anti-VEGF Era

    PubMed Central

    Hsieh, Yi-Ting; Yang, Chung-May

    2014-01-01

    Purpose. To investigate the clinical features, surgical outcomes, and prognostic factors of combined rhegmatogenous and tractional detachment (combined RD) in proliferative diabetic retinopathy (PDR) in recent years. Methods. Medical records of PDR and combined RD treated with vitrectomy from 2008 to 2013 were retrospectively reviewed. Results. A total of 57 eyes from 49 patients were included. Nine eyes had received panretinal photocoagulation (PRP) and 7 eyes had intravitreal bevacizumab (IVB) within 3 months before RD developed. Thirty-eight eyes (66.7%) had ≧3 sites of broad adhesion of fibrovascular proliferation (FVP). Thirty-three eyes (57.9%) showed active FVP. Thirty-four eyes (59.6%) had extent of RD involving 3 or 4 quadrants. The primary reattachment rate was 93.0%, and the final visual acuity (VA) improved by more than 3 lines in 80.7% of eyes. Neovascular glaucoma occurred in 4 eyes postoperatively. Poor preoperative VA, severe vitreoretinal adhesion, and broad extent of RD had significant correlation with poor visual outcomes. Conclusion. PRP or IVB might play a role in provoking combined RD. The anatomical and functional success rates of surgery were high. Poor preoperative VA and severe proliferations predicted poor visual outcomes. PMID:25061523

  10. Associations Between Retinal Pigment Epithelium and Drusen Volume Changes During the Lifecycle of Large Drusenoid Pigment Epithelial Detachments

    PubMed Central

    Balaratnasingam, Chandrakumar; Yannuzzi, Lawrence A.; Curcio, Christine A.; Morgan, William H.; Querques, Giuseppe; Capuano, Vittorio; Souied, Eric; Jung, Jesse; Freund, K. Bailey

    2016-01-01

    Purpose Drusenoid pigment epithelial detachments (PEDs) are a defined path to atrophy in age-related macular degeneration (AMD). We analyzed the relationships between retinal pigment epithelium (RPE) and drusen volume changes during the PED lifecycle, using spectral-domain optical coherence tomography (SD-OCT). Methods Twenty-one cases of drusenoid PED tracked using SD-OCT through periods of growth and collapse were evaluated. Volumetric calculations and piece-wise linear regression analysis were used to determine the breakpoint between growth and collapse. Spectral-domain OCT scans were independently evaluated for the appearance of intraretinal hyperreflective foci, acquired vitelliform lesions (AVLs), and disruptions to the RPE+basal lamina band. Timing of these events with respect to the breakpoint was statistically evaluated. Morphometric characteristics of drusenoid PEDs were correlated with rate of PED collapse and final visual acuity. Results Mean age of subjects was 75.3 years and mean period of follow up was 4.1 years (median 4.5 years; range, 0.6–6.6 years). The lifecycle of drusenoid PEDs was asymmetric, in that the rate of collapse (0.199 mm3/month) is significantly faster (P < 0.001) than the rate of growth (0.022 mm3/month). Appearance of intraretinal hyperreflective foci and AVLs preceded the breakpoint (both P < 0.001). The timing of disruptions to the RPE+basal lamina band did not differ from the breakpoint (P = 0.510). Maximal height, volume, and diameter of drusenoid PEDs were inversely correlated with final visual acuity (all P < 0.001) and positively correlated with the rate of PED collapse (all P < 0.001). Conclusions Spectral-domain OCT signatures, plausibly attributable to anteriorly migrated RPE and disintegration of the RPE layer, precede or occur simultaneously with changes in volume of drusenoid PED during the lifecycle of this lesion. PMID:27760262

  11. Valved versus nonvalved cannula small-gauge pars plana vitrectomy for repair of retinal detachments with Grade C proliferative vitreoretinopathy

    PubMed Central

    Oellers, Patrick; Stinnett, Sandra; Hahn, Paul

    2016-01-01

    Purpose Valved cannulas are a recent addition to small-gauge pars plana vitrectomy (PPV) and provide stable intraocular fluidics. The goal of this study was to compare outcomes and postoperative complication rates of valved vs nonvalved cannula small-gauge PPV for repair of retinal detachments (RDs) complicated by Grade C proliferative vitreoretinopathy (PVR). Methods A retrospective chart review of 364 consecutive eyes with either valved or nonvalved cannula PPV for RD repair was performed. The primary outcomes were single surgery and final anatomic success and change in best-corrected visual acuity for repair of RDs complicated by Grade C PVR. Results We identified 36 eyes in the valved group and 31 eyes in the nonvalved group with Grade C PVR RD. The single surgery success was 83% vs 77% (P=0.555) and the final anatomic success was 94% vs 87% (P=0.404) in the valved vs nonvalved eyes, respectively. The mean final visual acuity gain was −0.36 logarithm of the minimum angle of resolution (logMAR; approximate Early Treatment Diabetes Retinopathy Study [ETDRS] score =17 letters) in valved eyes vs −0.33 logMAR (approximate ETDRS score =16 letters) in nonvalved eyes (P=0.81). Postoperative complication rates including postoperative day 1 hypotony, hypertony, and anterior chamber fibrin formation; postoperative retention of intraocular or subretinal perfluorocarbon liquid; and subsequent epiretinal membrane peel were not statistically different between groups. Conclusion Valved cannula PPV yields equivalent visual acuity and anatomic outcomes without increased postoperative complication rates compared to traditional nonvalved cannula PPV for Grade C PVR-associated RD repair. PMID:27313445

  12. Hybrid microincision vitrectomy surgery combined with 20-gauge silicone cannulas for use with 20-gauge horizontal scissors in diabetic tractional retinal detachment

    PubMed Central

    Yamada, Keiko; Maeno, Takatoshi; Yamada, Mitsunori

    2013-01-01

    Purpose To verify the utility and preliminary safety of a 20-gauge silicone cannula for use with 20-gauge horizontal scissors delamination during microincision vitrectomy surgery (MIVS). Methods Thirty-eight eyes in 35 consecutive patients with diabetic tractional retinal detachment, who underwent MIVS between April 2010 and March 2012 and were followed for 3–24 months, were retrospectively assessed using a chart review. Twenty-gauge scissors delamination through a silicone cannula, with an additional 20-gauge port as a hybrid, was primarily selected when treating thick and rigid fibrovascular membranes, including fluctuating vessels over the detached retina near the macula. The main outcome measures included the proportion of patients treated with this hybrid method, the postoperative visual acuity, and the incidence of complications. Results Compared with the 26 eyes treated with MIVS only, 12 eyes (32%) required a hybrid technique with the use of 20-gauge instruments through a silicone cannula in addition to MIVS. Two patients underwent additional surgery. Temporary silicone oil tamponade was performed in one case of retinotomy and one case of schizophrenia. The mean visual acuity (logarithm of the minimum angle of resolution [logMAR]) improved from 1.43 ± 0.85 to 0.72 ± 0.47 at the last follow-up visit. No patients exhibited worsening of their visual acuity postoperatively. No sclerotomy-related complications were recorded during the intraoperative or postoperative periods. Conclusion Hybrid MIVS combined with a 20-gauge silicone cannula for use with 20-gauge horizontal scissors in diabetic tractional retinal detachment eyes is useful and safe due to the reduced risk of sclerotomy-related retinal breaks. This procedure is a reasonable option when performing complex surgery for diabetic vitrectomy. PMID:23946642

  13. Nine genes that may contribute to partial trisomy (6)(p22→pter) and unique presentation of persistent hyperplastic primary vitreous with retinal detachment.

    PubMed

    Su, Pen-Hua; Lee, Inn-Chi; Yang, Shun-Fa; Ng, Yan-Yan; Liu, Chan-Sheng; Chen, Jia-Yuh

    2012-04-01

    We report on a newborn girl with facial anomalies, a congenital heart defect, severe pre- and postnatal growth retardation, feeding problems, and persistent hyperplastic primary vitreous. Cytogenetic analysis by high resolution GTG banding showed extra chromosomal material on the short arm of one chromosome 1 of the patient, but neither parent. SKY and CGH analysis demonstrated that the patient had a de novo 46,XX, der(1)t(1;6)(p36.3; p22). Compared with previously reported cases of partial trisomy 6p22 syndrome, this patient exhibited a unique condition for this syndrome: persistent hyperplastic primary vitreous (PHPV) with retinal detachment. The human genome database was searched for candidate genes and we propose the following nine genes located in the 6p22→6pter region for their potential contribution to the phenotype of partial trisomy 6p22→pter and persistent hyperplastic primary vitreous (PHPV) with retinal detachment: Forkhead box Q1 (FOXQ1), FOXF2, FOXC1, NRN1, EDN1, ATXN1, DEK oncogene, E2F3, and NRNS1. PMID:22407547

  14. Comparison of the Inverted Internal Limiting Membrane Flap Technique and the Internal Limiting Membrane Peeling for Macular Hole with Retinal Detachment

    PubMed Central

    Matsumura, Takehiro; Takamura, Yoshihiro; Tomomatsu, Takeshi; Arimura, Shogo; Gozawa, Makoto; Kobori, Akira; Inatani, Masaru

    2016-01-01

    Purpose To evaluate the efficacy of the inverted internal limiting membrane (ILM) flap technique in vitrectomy for macular hole (MH) with retinal detachment (RD) compared with vitrectomy using ILM peeling. Methods A retrospective case series study was performed. Twenty-two eyes of 22 patients who underwent vitrectomy for MH with RD and followed-up more than 12 months after the surgery were included in this study. We retrospectively reviewed the medical records of patients who underwent vitrectomy with inverted ILM flap technique or vitrectomy with ILM peeling. Ten patients who had been treated vitrectomy with inverted ILM flap technique, and 12 patients who had been treated vitrectomy with ILM peeling were analyzed. We evaluated changes in best-corrected visual acuity (BCVA) before and after surgery, closing rates of MH, and retinal reattachment rates and compared between both groups. Results MH was closed and RD was reattached postoperatively in 9 eyes (90%) in the inverted ILM flap group. In the ILM peeling group, the MH was closed in 4 eyes (33.3%) and the retinas were reattached in 6 eyes (50%) after surgery. Significant improvement in BCVA after surgery (P = 0.0017) was only found in the inverted ILM flap group. Conclusions Higher rates of closed MH and retinal reattachment, and small but significant improvement in BCVA were found in the inverted ILM flap group. Based on our data, the inverted ILM flap technique may be useful in vitrectomy for MH with RD. PMID:27764184

  15. Risk of Tractional Retinal Detachment Following Intravitreal Bevacizumab Along with Subretinal Fluid Drainage and Cryotherapy for Stage 3B Coats’ Disease

    PubMed Central

    Bhat, Vishalakshi; D’Souza, Palmeera; Shah, Parag K.; Narendran, V.

    2016-01-01

    Purpose: To review the surgical outcomes of intravitreal bevacizumab (IVB) along with subretinal fluid drainage with cryotherapy in patients with stage 3B Coats’ disease. Materials and Methods: A retrospective study of seven cases of stage 3B Coats’ disease, who underwent subretinal fluid drainage with cryopexy, from May 2011 to March 2014. Five eyes received additional IVB at the end of surgery. Green laser therapy was performed on telangiectatic vessels postoperatively. Results: The mean age was 34 months (range, 10-84 months). Mean follow-up was 19 months. Six patients (85.7%) had an attached retina at final follow-up. Three out of four patients (75%) that received IVB developed tractional retinal detachments (TRDs). Two eyes that did not receive bevacizumab did not develop any traction. None progressed to neovascular glaucoma or phthisis bulbi. Conclusion: Simultaneous injection of bevacizumab along with subretinal drainage and cryotherapy for advanced Coats’ disease could not avoid TRD. PMID:27162454

  16. Retinal Disorders

    MedlinePlus

    ... be serious enough to cause blindness. Examples are Macular degeneration - a disease that destroys your sharp, central vision Diabetic eye disease Retinal detachment - a medical emergency, when the retina is ... children. Macular pucker - scar tissue on the macula Macular hole - ...

  17. F6H8 as an Intraoperative Tool and F6H8/Silicone Oil as a Postoperative Tamponade in Inferior Retinal Detachment with Inferior PVR

    PubMed Central

    Tosi, Gian Marco; Bacci, Tommaso; Romeo, Napoleone; Balestrazzi, Angelo; Martone, Gianluca; Caporossi, Tomaso

    2014-01-01

    Purpose. To evaluate the effectiveness and safety of perfluorohexyloctane (F6H8) for intraoperative flattening of the retina and of F6H8/silicone oil (SO) 1000 cSt as a postoperative tamponade for inferior retinal detachment with inferior proliferative vitreoretinopathy. Methods. This is a retrospective review of 22 patients who underwent pars plana vitrectomy using F6H8 as an intraoperative tool to flatten the retina. At the end of the surgery a direct partial exchange between F6H8 and SO 1000 cSt was performed, tamponing the eye with different ratios of F6H8/SO (70/30, 60/40, 50/50, 40/30, and 30/70). Anatomical and functional results and complications were evaluated over the follow-up period (mean 22.63 months). Results. F6H8 was efficacious for intraoperative flattening of the retina. Twenty-one of the 22 patients achieved a complete retinal reattachment. Postoperative visual acuity (VA) ranged from light perception to 20/70, with 72% of patients obtaining VA better than 20/400. No emulsification/inflammation was observed whatever the ratio of F6H8/SO used. With higher ratios of F6H8/SO (70/30 and 60/40) cloudiness of the tamponade was observed. A transparent mixture was present with all the other ratios. Conclusions. The surgical technique adopted is very simple and safe. The optimal F6H8/SO ratio seems to be between 50/50 and 30/70. PMID:24672710

  18. Disruption of murine Adamtsl4 results in zonular fiber detachment from the lens and in retinal pigment epithelium dedifferentiation.

    PubMed

    Collin, Gayle B; Hubmacher, Dirk; Charette, Jeremy R; Hicks, Wanda L; Stone, Lisa; Yu, Minzhong; Naggert, Jürgen K; Krebs, Mark P; Peachey, Neal S; Apte, Suneel S; Nishina, Patsy M

    2015-12-15

    Human gene mutations have revealed that a significant number of ADAMTS (a disintegrin-like and metalloproteinase (reprolysin type) with thrombospondin type 1 motifs) proteins are necessary for normal ocular development and eye function. Mutations in human ADAMTSL4, encoding an ADAMTS-like protein which has been implicated in fibrillin microfibril biogenesis, cause ectopia lentis (EL) and EL et pupillae. Here, we report the first ADAMTSL4 mouse model, tvrm267, bearing a nonsense mutation in Adamtsl4. Homozygous Adamtsl4(tvrm267) mice recapitulate the EL phenotype observed in humans, and our analysis strongly suggests that ADAMTSL4 is required for stable anchorage of zonule fibers to the lens capsule. Unexpectedly, homozygous Adamtsl4(tvrm267) mice exhibit focal retinal pigment epithelium (RPE) defects primarily in the inferior eye. RPE dedifferentiation was indicated by reduced pigmentation, altered cellular morphology and a reduction in RPE-specific transcripts. Finally, as with a subset of patients with ADAMTSL4 mutations, increased axial length, relative to age-matched controls, was observed and was associated with the severity of the RPE phenotype. In summary, the Adamtsl4(tvrm267) model provides a valuable tool to further elucidate the molecular basis of zonule formation, the pathophysiology of EL and ADAMTSL4 function in the maintenance of the RPE.

  19. Rhegmatogenous Retinal Detachment Surgery in Elderly People over 70 Years Old: Visual Acuity, Quality of Life, and Cost-Utility Values

    PubMed Central

    Zou, Haidong; Xu, Xiaocheng; Liu, Haiyun; Bai, Lin; Xu, Xun; Zhang, Xi

    2014-01-01

    Background and Purpose To evaluate the influence of rhegmatogenous retinal detachment (RRD) surgery on elderly patients in terms of visual acuity, vision-related quality of life and its cost-effectiveness. Methods Elderly patients over 70 years old, who were diagnosed and underwent RRD surgery at Shanghai First People's Hospital, Shanghai Jiao Tong University, China, from January 1, 2009, through January 1, 2013. The participants received scleral buckling surgery and vitreous surgery with or without scleral buckling under retrobulbar anesthesia. We followed the patients for 1 year and collected best-corrected visual acuity (BCVA), vision-related quality of life, and direct medical costs data. Utility values elicited by time-trade-off were analyzed to determine the quality of life. Quality-adjusted life years (QALYs) gained in life expectancy were calculated and discounted at 3% annually. Costs per QALY gained were reported using the bootstrap method. Further analyses were made for two age groups, age 70–79 and age over 80 years. Sensitivity analyses were performed to test stability of the results. Results 98 patients were included in the study. The BCVA significantly improved by 0.53±0.44 (Logarithm of the Minimum Angle of Resolution (logMAR)) at the 1-year postoperative time point (p<0.001). Utility values increased from 0.77 to 0.84 (p<0.001), and an average of 0.4 QALYs were gained in the life expectancy. Costs per QALY gained from the RRD surgery were 33,186 Chinese Yuan (CNY) (5,276 US dollars (USD))/QALY; 24,535 CNY (3,901 USD)/QALY for the age group of 70–79 years and 71,240 CNY (11,326 USD)/QALY for the age group over 80 years. Conclusions RRD surgery improved the visual acuity and quality of life in the elderly patients over 70 years old. According to the World Health Organization’s recommendation, at a threshold of willingness to pay of 115,062 CNY (18,293 USD)/QALY, RRD surgery is cost effective in the elderly patients. PMID:25330168

  20. Vitrectomy with or without encircling band for pseudophakic retinal detachment: a multi-centre, three-arm, randomised clinical trial. VIPER Study Report No. 1—design and enrolment

    PubMed Central

    Mazinani, B; Baumgarten, S; Schiller, P; Agostini, H; Helbig, H; Limburg, E; Hellmich, M; Walter, P

    2016-01-01

    Purpose Scleral buckling is currently used in addition to vitrectomy for the treatment of pseudophakic retinal detachment (PRD) to better support the vitreous base and better visualisation of the periphery. Aims The aims of this study are to evaluate (1) whether the combination of 20 G vitrectomy and scleral buckling is superior to 20 G vitrectomy alone (control) (confirmatory), and (2) whether transconjunctival 23/25 G vitrectomy is non-inferior to 20 G vitrectomy (both without scleral buckling) regarding operation success (exploratory). Methods The VIPER (Vitrectomy Plus Encircling Band Vs. Vitrectomy Alone For The Treatment Of Pseudophakic Retinal Detachment) study is an unmasked, multi-centre, three-arm randomised trial. Patients with PRD were eligible, excluding complicated retinal detachment or otherwise severe ophthalmologic impairment. Patients were randomised to one of three interventions: 20 G vitrectomy alone (control C), combination of 20 G vitrectomy and circumferential scleral buckling (experimental treatment E1) or 23/25 G vitrectomy alone (experimental treatment E2). The primary endpoint is the absence of any indication for a retina re-attaching procedure during 6 months of follow-up. Secondary endpoints include best corrected visual acuity, retina re-attaching procedures, complications and adverse events. Results From June 2011 to August 2013, 257 patients were enrolled in the study. The internet randomisation service assigned 100 patients each to the treatment arms C and E1, and 57 patients to treatment E2. The imbalance is due to the fact that several retinal surgeons did not qualify for performing E2. The random assignment was stratified and balanced (ie, 1:1 or 1:1:1 ratio) by surgeon. Conclusions The described study represents a methodologically rigorous protocol evaluating the benefits of three different vitrectomy approaches to PRD. The projected results will help to establish their overall efficacy and will permit

  1. Genetic pediatric retinal diseases

    PubMed Central

    Say, Emil Anthony T.

    2014-01-01

    Hereditary pediatric retinal diseases are a diverse group of disorders with pathologies affecting different cellular structures or retinal development. Many can mimic typical pediatric retinal disease such as retinopathy of prematurity, vitreous hemorrhage, retinal detachment and cystoid macular edema. Multisystem involvement is frequently seen in hereditary pediatric retinal disease. A thorough history coupled with a good physical examination can oftentimes lead the ophthalmologist or pediatrician to the correct genetic test and correct diagnosis. In some instances, evaluation of parents or siblings may be required to determine familial involvement when the history is inconclusive or insufficient and clinical suspicion is high.

  2. Genetic pediatric retinal diseases.

    PubMed

    Say, Emil Anthony T

    2014-12-01

    Hereditary pediatric retinal diseases are a diverse group of disorders with pathologies affecting different cellular structures or retinal development. Many can mimic typical pediatric retinal disease such as retinopathy of prematurity, vitreous hemorrhage, retinal detachment and cystoid macular edema. Multisystem involvement is frequently seen in hereditary pediatric retinal disease. A thorough history coupled with a good physical examination can oftentimes lead the ophthalmologist or pediatrician to the correct genetic test and correct diagnosis. In some instances, evaluation of parents or siblings may be required to determine familial involvement when the history is inconclusive or insufficient and clinical suspicion is high. PMID:27625880

  3. Divertor detachment

    NASA Astrophysics Data System (ADS)

    Krasheninnikov, Sergei

    2015-11-01

    The heat exhaust is one of the main conceptual issues of magnetic fusion reactor. In a standard operational regime the large heat flux onto divertor target reaches unacceptable level in any foreseeable reactor design. However, about two decades ago so-called ``detached divertor'' regimes were found. They are characterized by reduced power and plasma flux on divertor targets and look as a promising solution for heat exhaust in future reactors. In particular, it is envisioned that ITER will operate in a partly detached divertor regime. However, even though divertor detachment was studied extensively for two decades, still there are some issues requiring a new look. Among them is the compatibility of detached divertor regime with a good core confinement. For example, ELMy H-mode exhibits a very good core confinement, but large ELMs can ``burn through'' detached divertor and release large amounts of energy on the targets. In addition, detached divertor regimes can be subject to thermal instabilities resulting in the MARFE formation, which, potentially, can cause disruption of the discharge. Finally, often inner and outer divertors detach at different plasma conditions, which can lead to core confinement degradation. Here we discuss basic physics of divertor detachment including different mechanisms of power and momentum loss (ionization, impurity and hydrogen radiation loss, ion-neutral collisions, recombination, and their synergistic effects) and evaluate the roles of different plasma processes in the reduction of the plasma flux; detachment stability; and an impact of ELMs on detachment. We also evaluate an impact of different magnetic and divertor geometries on detachment onset, stability, in- out- asymmetry, and tolerance to the ELMs. Supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences under Award Number DE-DE-FG02-04ER54739 at UCSD.

  4. Branch retinal vein occlusion.

    PubMed

    Hamid, Sadaf; Mirza, Sajid Ali; Shokh, Ishrat

    2008-01-01

    Retinal vein occlusions (RVO) are the second commonest sight threatening vascular disorder. Branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO) are the two basic types of vein occlusion. Branch retinal vein occlusion is three times more common than central retinal vein occlusion and- second only to diabetic retinopathy as the most common retinal vascular cause of visual loss. The origin of branch retinal vein occlusion undoubtedly includes both systemic factors such as hypertension and local anatomic factors such as arteriovenous crossings. Branch retinal vein occlusion causes a painless decrease in vision, resulting in misty or distorted vision. Current treatment options don't address the underlying aetiology of branch retinal vein occlusion. Instead they focus on treating sequelae of the occluded venous branch, such as macular oedema, vitreous haemorrhage and traction retinal detachment from neovascularization. Evidences suggest that the pathogenesis of various types of retinal vein occlusion, like many other ocular vascular occlusive disorders, is a multifactorial process and there is no single magic bullet that causes retinal vein occlusion. A comprehensive management of patients with retinal vascular occlusions is necessary to correct associated diseases or predisposing abnormalities that could lead to local recurrences or systemic event. Along with a review of the literature, a practical approach for the management of retinal vascular occlusions is required, which requires collaboration between the ophthalmologist and other physicians: general practitioner, cardiologist, internist etc. as appropriate according to each case. PMID:19385476

  5. Transcorneal Electrical Stimulation Therapy for Retinal Disease

    ClinicalTrials.gov

    2012-05-03

    Retinitis Pigmentosa; Macula Off; Primary Open Angle Glaucoma; Hereditary Macular Degeneration; Treated Retina Detachment; Retinal Artery Occlusion; Retinal Vein Occlusion; Non-Arthritic-Anterior-Ischemic Optic-Neuropathy; Hereditary Autosomal Dominant Optic Atrophy; Dry Age Related Macular Degeneration; Ischemic Macula Edema

  6. Progressive outer retinal necrosis-like retinitis in immunocompetent hosts.

    PubMed

    Chawla, Rohan; Tripathy, Koushik; Gogia, Varun; Venkatesh, Pradeep

    2016-01-01

    We describe two young immunocompetent women presenting with bilateral retinitis with outer retinal necrosis involving posterior pole with centrifugal spread and multifocal lesions simulating progressive outer retinal necrosis (PORN) like retinitis. Serology was negative for HIV and CD4 counts were normal; however, both women were on oral steroids at presentation for suspected autoimmune chorioretinitis. The retinitis in both eyes responded well to oral valaciclovir therapy. However, the eye with the more fulminant involvement developed retinal detachment with a loss of vision. Retinal atrophy was seen in the less involved eye with preservation of vision. Through these cases, we aim to describe a unique evolution of PORN-like retinitis in immunocompetent women, which was probably aggravated by a short-term immunosuppression secondary to oral steroids. PMID:27511757

  7. Progressive outer retinal necrosis-like retinitis in immunocompetent hosts.

    PubMed

    Chawla, Rohan; Tripathy, Koushik; Gogia, Varun; Venkatesh, Pradeep

    2016-08-10

    We describe two young immunocompetent women presenting with bilateral retinitis with outer retinal necrosis involving posterior pole with centrifugal spread and multifocal lesions simulating progressive outer retinal necrosis (PORN) like retinitis. Serology was negative for HIV and CD4 counts were normal; however, both women were on oral steroids at presentation for suspected autoimmune chorioretinitis. The retinitis in both eyes responded well to oral valaciclovir therapy. However, the eye with the more fulminant involvement developed retinal detachment with a loss of vision. Retinal atrophy was seen in the less involved eye with preservation of vision. Through these cases, we aim to describe a unique evolution of PORN-like retinitis in immunocompetent women, which was probably aggravated by a short-term immunosuppression secondary to oral steroids.

  8. Retinitis Pigmentosa

    MedlinePlus

    ... Action You are here Home › Retinal Diseases Listen Retinitis Pigmentosa What is retinitis pigmentosa? What are the symptoms? ... available? Are there any related diseases? What is retinitis pigmentosa? Retinitis pigmentosa (RP) refers to a group of ...

  9. Color Doppler imaging of retinal diseases.

    PubMed

    Dimitrova, Galina; Kato, Satoshi

    2010-01-01

    Color Doppler imaging (CDI) is a widely used method for evaluating ocular circulation that has been used in a number of studies on retinal diseases. CDI assesses blood velocity parameters by using ultrasound waves. In ophthalmology, these assessments are mainly performed on the retrobulbar blood vessels: the ophthalmic, the central retinal, and the short posterior ciliary arteries. In this review, we discuss CDI use for the assessment of retinal diseases classified into the following: vascular diseases, degenerations, dystrophies, and detachment. The retinal vascular diseases that have been investigated by CDI include diabetic retinopathy, retinal vein occlusions, retinal artery occlusions, ocular ischemic conditions, and retinopathy of prematurity. Degenerations and dystrophies included in this review are age-related macular degeneration, myopia, and retinitis pigmentosa. CDI has been used for the differential diagnosis of retinal detachment, as well as the evaluation of retrobulbar circulation in this condition. CDI is valuable for research and is a potentially useful diagnostic tool in the clinical setting.

  10. The progressive outer retinal necrosis syndrome.

    PubMed

    Holland, G N

    1994-01-01

    The progressive outer retinal necrosis (PORN) syndrome is a recently described clinical variant of necrotizing herpetic retinopathy in patients with the acquired immunodeficiency syndrome (AIDS). It is caused by varicellazoster virus infection of the retina. Its course and clinical features distinguish it from the acute retinal necrosis syndrome and CMV retinopathy. Early disease is characterized by multifocal deep retinal opacification. Lesions rapidly coalesce and progress to total retinal necrosis over a short period of time. Despite aggressive therapy with intravenous antivirial drugs, prognosis is poor; disease progression and/or recurrence is common, and the majority of patients develop no light perception vision. Total retinal detachments are common. Prophylaxis against retinal detachment using laser retinopexy has not been useful in most cases. PORN syndrome is an uncommon, but devastating complication of AIDS.

  11. The progressive outer retinal necrosis syndrome.

    PubMed

    Holland, G N

    1994-01-01

    The progressive outer retinal necrosis (PORN) syndrome is a recently described clinical variant of necrotizing herpetic retinopathy in patients with the acquired immunodeficiency syndrome (AIDS). It is caused by varicellazoster virus infection of the retina. Its course and clinical features distinguish it from the acute retinal necrosis syndrome and CMV retinopathy. Early disease is characterized by multifocal deep retinal opacification. Lesions rapidly coalesce and progress to total retinal necrosis over a short period of time. Despite aggressive therapy with intravenous antivirial drugs, prognosis is poor; disease progression and/or recurrence is common, and the majority of patients develop no light perception vision. Total retinal detachments are common. Prophylaxis against retinal detachment using laser retinopexy has not been useful in most cases. PORN syndrome is an uncommon, but devastating complication of AIDS. PMID:7852023

  12. Acquired retinal folds in the cat.

    PubMed

    MacMillan, A D

    1976-06-01

    Retinal folds were found in 5 cats. The apparent cause of the folding was varied: in 1 cat the folds appeared after a localized retinal detachment; in 2 cats the condition accompanied other intraocular abnormalities associated with feline infectious peritonitis; 1 cat had active keratitis, and the retinal changes were thought to have been injury related; and 1 cat, bilaterally affected, had chronic glomerulonephritis. PMID:945253

  13. Fluid vitreous substitutes in vitreo retinal surgery.

    PubMed

    Saxena, S; Gopal, L

    1996-12-01

    Advances in the surgical instrumentation and vitreoretinal techniques have allowed intraoperative reapproximation of retina to a more normal position. The use of intravitreally injected liquid materials (viscoelastic liquids, liquid perfluorocarbons and silicone oil), as adjunctive agents to vitreo-retinal surgery play an important role in facilitating retinal reattachment. These materials are used as intraoperative instruments to re-establish intraocular volume, assist in separating membranes adherent to the retina, manipulate retinal detachments and mechanically flatten detached retina. Over the longer term, silicone oil maintains intraocular tamponade. One should be cognizant of the potential uses, benefits and risks of each of these vitreous substitutes.

  14. Descemet membrane detachment.

    PubMed

    Mackool, R J; Holtz, S J

    1977-03-01

    Four eyes of three patients had extensive postoperative Descemet membrane (DM) detachment. Blood was present just anterior to the DM in three of the four eyes and later converted to and persisted as pigment. Haziness of the cornea at the level of the DM could be seen with reattachment. Detachments of the DM are classified as planar when there is 1 mm or less separation of the DM from its overlying stroma in all areas. Nonplanar DM detachments exceed 1 mm of separation. Planar detachments have a much better prognosis than nonplanar detachments do, with or without descemetopexy. Repair of DM detachments, when necessary, should include air injection, with the lease possible instrumentation of the DM. PMID:843278

  15. Modeling of Detached Solidification

    NASA Technical Reports Server (NTRS)

    Regel, Liya L.; Wilcox, William R.; Popov, Dmitri

    1997-01-01

    Our long term goal is to develop techniques to achieve detached solidification reliably and reproducibly, in order to produce crystals with fewer defects. To achieve this goal it is necessary to understand thoroughly the physics of detached solidification. It was the primary objective of the current project to make progress toward this complete understanding. 'Me products of this grant are attached. These include 4 papers and a preliminary survey of the observations of detached solidification in space. We have successfully modeled steady state detached solidification, examined the stability of detachment, and determined the influence of buoyancy-driven convection under different conditions. Directional solidification in microgravity has often led to ingots that grew with little or no contact with the ampoule wall. When this occurred, crystallographic perfection was usually greatly improved -- often by several orders of magnitude. Indeed, under the Soviet microgravity program the major objective was to achieve detached solidification with its resulting improvement in perfection and properties. Unfortunately, until recently the true mechanisms underlying detached solidification were unknown. As a consequence, flight experiments yielded erratic results. Within the past three years, we have developed a new theoretical model that explains many of the flight results. This model gives rise to predictions of the conditions required to yield detached solidification.

  16. Retinitis Pigmentosa.

    ERIC Educational Resources Information Center

    Carr, Ronald E.

    1979-01-01

    The author describes the etiology of retinitis pigmentosa, a visual dysfunction which results from progressive loss of the retinal photoreceptors. Sections address signs and symptoms, ancillary findings, heredity, clinical diagnosis, therapy, and research. (SBH)

  17. Retinitis pigmentosa and retinal oedema.

    PubMed Central

    Spalton, D J; Bird, A C; Cleary, P E

    1978-01-01

    Twenty-five patients with retinitis pigmentosa and retinal leakage were investigated. Oedema was present in dominant and X-linked inherited disease and is likely to be present in recessive disease as well. We suggest that this might be a general response seen in many types of tapeto-retinal degeneration to actively degenerating photoreceptors or pigment epithelium. Images PMID:638111

  18. Divertor plasma detachment

    NASA Astrophysics Data System (ADS)

    Krasheninnikov, S. I.; Kukushkin, A. S.; Pshenov, A. A.

    2016-05-01

    Regime with the plasma detached from the divertor targets (detached divertor regime) is a natural continuation of the high recycling conditions to higher density and stronger impurity radiation loss. Both the theoretical considerations and experimental data show clearly that the increase of the impurity radiation loss and volumetric plasma recombination causes the rollover of the plasma flux to the target when the density increases, which is the manifestation of detachment. Plasma-neutral friction (neutral viscosity effects), although important for the sustainment of high density/pressure plasma upstream and providing the conditions for efficient recombination and power loss, is not directly involved in the reduction of the plasma flux to the targets. The stability of detachment is also discussed.

  19. [Intravitreal ganciclovir in cytomegalovirus retinitis in AIDS].

    PubMed

    Olea, J L; Salvat, M; Mateos, J M; Vila, J; Villalonga, C; Riera, M

    1996-04-01

    A retrospective study was made of 26 patients with AIDS who initially presented with retinitis as the only clinical manifestation of cytomegalovirus infection (39 eyes). Sixty-five induction or re-induction therapeutic courses were administered with intravitreal ganciclovir. The efficiency rate of therapy was 93.8%. Thirty-eight maintenance therapeutic courses (200 micrograms/week) were evaluated. The non-compliance rate was 23%. Bilateral retinitis occurred in 44.4% of cases. The systemic administration of therapy had to be substituted for the intravitreal administration in 32% of patients during the clinical course of their conditions. The mean survival rate was 9.5 months. Both retinal detachment and vitreal hemorrhage occurred in 5% of patients. When retinitis is the first clinical manifestation of cytomegalovirus infection, therapy with intravitreal ganciclovir is efficacious to inactivate lesions. Although bilateral retinitis and extraocular dissemination are common, the mean survival rate is high.

  20. Detached rock evaluation device

    DOEpatents

    Hanson, David R.

    1986-01-01

    A rock detachment evaluation device (10) having an energy transducer unit 1) for sensing vibrations imparted to a subject rock (172) for converting the sensed vibrations into electrical signals, a low band pass filter unit (12) for receiving the electrical signal and transmitting only a low frequency segment thereof, a high band pass filter unit (13) for receiving the electrical signals and for transmitting only a high frequency segment thereof, a comparison unit (14) for receiving the low frequency and high frequency signals and for determining the difference in power between the signals, and a display unit (16) for displaying indicia of the difference, which provides a quantitative measure of rock detachment.

  1. Retinal Macroglial Responses in Health and Disease

    PubMed Central

    de Hoz, Rosa; Rojas, Blanca; Ramírez, Ana I.; Salazar, Juan J.; Gallego, Beatriz I.; Triviño, Alberto; Ramírez, José M.

    2016-01-01

    Due to their permanent and close proximity to neurons, glial cells perform essential tasks for the normal physiology of the retina. Astrocytes and Müller cells (retinal macroglia) provide physical support to neurons and supplement them with several metabolites and growth factors. Macroglia are involved in maintaining the homeostasis of extracellular ions and neurotransmitters, are essential for information processing in neural circuits, participate in retinal glucose metabolism and in removing metabolic waste products, regulate local blood flow, induce the blood-retinal barrier (BRB), play fundamental roles in local immune response, and protect neurons from oxidative damage. In response to polyetiological insults, glia cells react with a process called reactive gliosis, seeking to maintain retinal homeostasis. When malfunctioning, macroglial cells can become primary pathogenic elements. A reactive gliosis has been described in different retinal pathologies, including age-related macular degeneration (AMD), diabetes, glaucoma, retinal detachment, or retinitis pigmentosa. A better understanding of the dual, neuroprotective, or cytotoxic effect of macroglial involvement in retinal pathologies would help in treating the physiopathology of these diseases. The extensive participation of the macroglia in retinal diseases points to these cells as innovative targets for new drug therapies. PMID:27294114

  2. [The vitreous and vitreoretinal interface: natural history and associated retinal diseases].

    PubMed

    Giusti, C

    2002-01-01

    Such significant correlations have been found between vitreal changes and retinal breaks that retinal detachment is now considered as a vitreoretinal disease. Concerning this issue, not only the posterior vitreous detachment seems to play an important role in the occurrence of rhegmatogenous retinal detachment but also the vitreoretinal interactions themself seem to be important in the pathogenesis of cystoid and diabetic macular edema, proliferative diabetic retinopathy, age-related macular degeneration, macular pucker, idiopathic macular hole and macular disease associated with optic disk pit. It seemed therefore useful to the author an updated review on alterations of the vitreoretinal interface and associated ocular diseases.

  3. Examination of postmortem retinal folds: A non-invasive study.

    PubMed

    Oshima, Toru; Yoshikawa, Hiroshi; Ohtani, Maki; Mimasaka, Sohtaro

    2015-02-01

    The postmortem retinal fold has been previously documented, but its mechanism of formation is not known. All previous studies of the fold involved invasive techniques and the postmortem ocular fundus has yet to be non-invasively examined. Our study used the non-invasive techniques of monocular indirect ophthalmoscopy and ocular echography to examine 79 postmortem eyes of 42 bodies. We examined whether the postmortem retinal fold was associated with postmortem time, position, and/or age. Age was significantly associated with postmortem retinal fold formation (Mann-Whitney U test, P = 0.013), which led us to examine the effect of posterior vitreous detachment (PVD) on retinal folds. The absence of a PVD was statistically associated with the presence of a retinal fold (Fisher's exact test, P < 0.0001). Interestingly, the presence of a PVD was also significantly correlated with retinal fold height (Mann-Whitney U test, P < 0.0001). Therefore, we hypothesized that retinal folds result from postmortem vitreoretinal traction caused by eyeball flaccidity. We also believe that the loss of retinochoroidal hydrostatic pressure plays a role. It is important that forensic pathologists not confuse a postmortem retinal fold with traumatic retinal detachment or perimacular retinal folds caused by child abuse. When child abuse is suspected, forensic pathologists should perform enucleation and a subsequent histological examination for confirmation. PMID:25623189

  4. Prophylactic treatment of retinal breaks--a systematic review.

    PubMed

    Blindbaek, Søren; Grauslund, Jakob

    2015-02-01

    Prophylactic treatment of retinal breaks has been examined in several studies and reviews, but so far, no studies have successfully applied a systematic approach. In the present systematic review, we examined the need of follow-up after posterior vitreous detachment (PVD) - diagnosed by slit-lamp biomicroscopy or Goldmann 3-mirror examination - with regard to retinal breaks as well as the indication of prophylactic treatment in asymptomatic and symptomatic breaks. A total of 2941 publications were identified with PubMed and Medline searches. Two manual search strategies were used for papers in English published before 2012. Four levels of screening identified 13 studies suitable for inclusion in this systematic review. No meta-analysis was conducted as no data suitable for statistical analysis were identified. In total, the initial examination after symptomatic PVD identified 85-95% of subsequent retinal breaks. Additional retinal breaks were only revealed at follow-up in patients where a full retinal examination was compromised at presentation by, for example, vitreous haemorrhage. Asymptomatic and symptomatic retinal breaks progressed to rhegmatogenous retinal detachment (RRD) in 0-13.8% and 35-47% of cases, respectively. The cumulated incidence of RRD despite prophylactic treatment was 2.1-8.8%. The findings in this review suggest that follow-up after symptomatic PVD is only necessary in cases of incomplete retinal examination at presentation. Prophylactic treatment of symptomatic retinal breaks must be considered, whereas no unequivocal conclusion could be reached with regard to prophylactic treatment of asymptomatic retinal breaks.

  5. Retinal cartography.

    PubMed

    Mosier, M A

    1982-10-01

    This paper analyses retinal cartography in terms of its reflection of anatomic data and its relation to several forms of geographic methods of map-making. It shows that the distances between anatomic landmarks of the eye are reasonably similar to the relative distances on the retinal drawing chart currently used. Two forms of geographic cartography--azimuth equidistant and orthographic--are described and compared with retinal cartography. The retinal drawing chart currently used most closely approximates an azimuth equidistant projection, which suffers from circumferential distortion, a fact that retinal surgeons must keep in mind. It is therefore recommended that the chart be modified to have equally spaced concentric circles and clearer identification of the ora serrata; the present accurate marking of anatomic landmarks, such as the equator and the posterior border of the ciliary body, should be preserved.

  6. Retinal Prosthesis

    PubMed Central

    Weiland, James D.; Humayun, Mark S.

    2015-01-01

    Retinal prosthesis have been translated from the laboratory to the clinical over the past two decades. Currently, two devices have regulatory approval for the treatment of retinitis pigmentosa. These devices provide partial sight restoration and patients use this improved vision in their everyday lives. Improved mobility and object detection are some of the more notable findings from the clinical trials. However, significant vision restoration will require both better technology and improved understanding of the interaction between electrical stimulation and the retina. This paper reviews the recent clinical trials, highlights technology breakthroughs that will contribute to next generation of retinal prostheses. PMID:24710817

  7. Progressive outer retinal necrosis in a patient with nephrotic syndrome.

    PubMed

    Shinoda, K; Inoue, M; Ishida, S; Kawashima, S; Wakabayashi, T; Suzuki, S; Katsura, H

    2001-01-01

    Progressive outer retinal necrosis syndrome (PORN) is a variant of necrotizing herpetic retinopathy and the majority of the described cases were related to acquired immunodeficiency syndrome. We present a patient who is HIV negative with nephrotic syndrome and prednisolone use for 4 months who showed clinical features of PORN. Low CD4 counts and lymphocytopenia suggested immunosuppression. In the left eye, tractional retinal detachment at the posterior pole followed by incomplete posterior vitreous detachment developed. In addition to intravenous administration of acyclovir, vitreous surgeries including stripping of the posterior hyaloid and silicone-oil tamponade were successfully performed to repair the retinal detachment in the left eye and to prevent it in the right eye.

  8. Stability of Detached Solidification

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.; Croell, A.

    2009-01-01

    Bridgman crystal growth can be conducted in the so-called "detached" solidification regime, where the growing crystal is detached from the crucible wall. A small gap between the growing crystal and the crucible wall, of the order of 100 micrometers or less, can be maintained during the process. A meniscus is formed at the bottom of the melt between the crystal and crucible wall. Under proper conditions, growth can proceed without collapsing the meniscus. The meniscus shape plays a key role in stabilizing the process. Thermal and other process parameters can also affect the geometrical steady-state stability conditions of solidification. The dynamic stability theory of the shaped crystal growth process has been developed by Tatarchenko. It consists of finding a simplified autonomous set of differential equations for the radius, height, and possibly other process parameters. The problem then reduces to analyzing a system of first order linear differential equations for stability. Here we apply a modified version of this theory for a particular case of detached solidification. Approximate analytical formulas as well as accurate numerical values for the capillary stability coefficients are presented. They display an unexpected singularity as a function of pressure differential. A novel approach to study the thermal field effects on the crystal shape stability has been proposed. In essence, it rectifies the unphysical assumption of the model that utilizes a perturbation of the crystal radius along the axis as being instantaneous. It consists of introducing time delay effects into the mathematical description and leads, in general, to stability over a broader parameter range. We believe that this novel treatment can be advantageously implemented in stability analyses of other crystal growth techniques such as Czochralski and float zone methods.

  9. Gene Transcription Profile of the Detached Retina (An AOS Thesis)

    PubMed Central

    Zacks, David N.

    2009-01-01

    Purpose: Separation of the neurosensory retina from the retinal pigment epithelium (RPE) yields many morphologic and functional consequences, including death of the photoreceptor cells, Müller cell hypertrophy, and inner retinal rewiring. Many of these changes are due to the separation-induced activation of specific genes. In this work, we define the gene transcription profile within the retina as a function of time after detachment. We also define the early activation of kinases that might be responsible for the detachment-induced changes in gene transcription. Methods: Separation of the retina from the RPE was induced in Brown-Norway rats by the injection of 1% hyaluronic acid into the subretinal space. Retinas were harvested at 1, 7, and 28 days after separation. Gene transcription profiles for each time point were determined using the Affymetrix Rat 230A gene microarray chip. Transcription levels in detached retinas were compared to those of nondetached retinas with the BRB-ArrayTools Version 3.6.0 using a random variance analysis of variance (ANOVA) model. Confirmation of the significant transcriptional changes for a subset of the genes was performed using microfluidic quantitative real-time polymerase chain reaction (qRT-PCR) assays. Kinase activation was explored using Western blot analysis to look for early phosphorylation of any of the 3 main families of mitogen-activated protein kinases (MAPK): the p38 family, the Janus kinase family, and the p42/p44 family. Results: Retinas separated from the RPE showed extensive alterations in their gene transcription profile. Many of these changes were initiated as early as 1 day after separation, with significant increases by 7 days. ANOVA analysis defined 144 genes that had significantly altered transcription levels as a function of time after separation when setting a false discovery rate at ≤0.1. Confirmatory RT-PCR was performed on 51 of these 144 genes. Differential transcription detected on the microarray

  10. Retinal holes.

    PubMed

    Foos, R Y

    1978-09-01

    Holes of the peripheral retina, defined as full-thickness breaks of trophic origin with no associated flap or free operculum, were found in 136 (2.4%) eyes from 2,800 autopsied subjects. Primary retinal holes (those with no indication of a proximal causative lesion and with no lattice degeneration in either eye) occurred in only eight of the 5,600 eyes studied; all were unilateral, single, less than 0.25 disk diameter in size, within the basal zone, and in eyes from elderly subjects. Secondary holes were found in 128 (2.3%) of eyes and of these, lattice degeneration was the most common cause (103). Other lesions complicated by hole formation included zonular traction tufts (10), chorioretinitis (9), meridional folds (3), and pavingstone degeneration (2). Retinal holes in surgically aphakic eyes did not differ qualitatively or quantitatively from those in age-matched phakic eyes.

  11. Retinal toxicity of intravitreal tenecteplase in the rabbit

    PubMed Central

    Rowley, S A; Vijayasekaran, S; Yu, P K; McAllister, I L; Yu, D-Yi

    2004-01-01

    Aim: To investigate the retinal toxicity of intravitreal injection of a novel fibrinolytic tenecteplase in rabbit eyes. Methods: Tenecteplase (25–350 μg in 0.1 ml BSS) was injected into the vitreous cavity of normal rabbit eyes. Control (fellow) eyes received 0.1 ml of BSS. One day, 1 week, and 2 months post-injection, the eyes were examined by slit lamp biomicroscopy, indirect ophthalmoscopy, and electroretinography, and then harvested for histopathological examination. Results: No evidence of retinal toxicity was seen with tenecteplase doses up to and including 50 μg. At a dose of 150 μg ophthalmoscopy was normal, but histology showed mild retinal damage in the inner nuclear layer and electroretinography showed a temporary reduction in B-wave amplitude. At doses of 200 μg and above, there was evidence of retinal toxicity on electroretinography, ophthalmoscopy, and histology. Ophthalmoscopic findings included vitreal fibrosis, retinal necrosis and tractional retinal detachment and light microscopy revealed necrosis of retinal pigment epithelium and other retinal layers. Damage was centred around the injection site but was more widespread with the higher doses. Conclusion: A dose of 50 μg tenecteplase appears safe for intravitreal injection in the rabbit. Tenecteplase could have potential applications in the treatment of submacular haemorrhage and retinal vein occlusion. PMID:15031179

  12. Retinopathy of prematurity: understanding ischemic retinal vasculopathies at an extreme of life

    PubMed Central

    Sapieha, Przemyslaw; Joyal, Jean-Sebastien; Rivera, José Carlos; Kermorvant-Duchemin, Elsa; Sennlaub, Florian; Hardy, Pierre; Lachapelle, Pierre; Chemtob, Sylvain

    2010-01-01

    Retinopathy of prematurity (ROP) is a major complication of preterm birth. It encompasses a spectrum of pathologies that affect vision, from mild disease that resolves spontaneously to severe disease that causes retinal detachment and subsequent blindness. The pathologies are characterized by an arrest in normal retinal vascular development associated with microvascular degeneration. The resulting ischemia and retinal hypoxia lead to excessive abnormal compensatory blood vessel growth. However, this neovascularization can lead to fibrous scar formation and culminate in retinal detachment. Present therapeutic modalities to limit the adverse consequences of aberrant neovascularization are invasive and/or tissue-destructive. In this Review, we discuss current concepts on retinal microvascular degeneration, neovascularization, and available treatments, as well as present future perspectives toward more profound elucidation of the pathogenesis of ROP. PMID:20811158

  13. Sector mapping method for 3D detached retina visualization.

    PubMed

    Zhai, Yi-Ran; Zhao, Yong; Zhong, Jie; Li, Ke; Lu, Cui-Xin; Zhang, Bing

    2016-10-01

    A new sphere-mapping algorithm called sector mapping is introduced to map sector images to the sphere of an eyeball. The proposed sector-mapping algorithm is evaluated and compared with the plane-mapping algorithm adopted in previous work. A simulation that maps an image of concentric circles to the sphere of the eyeball and an analysis of the difference in distance between neighboring points in a plane and sector were used to compare the two mapping algorithms. A three-dimensional model of a whole retina with clear retinal detachment was generated using the Visualization Toolkit software. A comparison of the mapping results shows that the central part of the retina near the optic disc is stretched and its edges are compressed when the plane-mapping algorithm is used. A better mapping result is obtained by the sector-mapping algorithm than by the plane-mapping algorithm in both the simulation results and real clinical retinal detachment three-dimensional reconstruction. PMID:27480739

  14. Progressive outer retinal necrosis (PORN) in AIDS patients: a different appearance of varicella-zoster retinitis.

    PubMed

    Pavesio, C E; Mitchell, S M; Barton, K; Schwartz, S D; Towler, H M; Lightman, S

    1995-01-01

    Retinal infections caused by the varicella-zoster virus (VZV) have been reported in immunocompetent and immunocompromised individuals. Two cases of a VZV-related retinitis are described with the characteristic features of the recently described progressive outer retinal necrosis (PORN) syndrome. Both patients suffered from the acquired immunodeficiency syndrome (AIDS) with greatly reduced peripheral blood CD4+ T lymphocyte counts, and presented with macular retinitis without vitritis. The disease was bilateral in one case and unilateral in the other. The clinical course was rapidly progressive with widespread retinal involvement and the development of rhegmatogenous retinal detachment with complete loss of vision in the affected eyes despite intensive intravenous antiviral therapy. VZV DNA was identified in vitreous biopsies, by molecular techniques based on the polymerase chain reaction (PCR), in both patients. At present, the use of very high-dose intravenous acyclovir may be the best therapeutic option in these patients for whom the visual prognosis is poor. Intravitreal antiviral drugs could also contribute to the management of these cases.

  15. Spectral domain optical coherence tomography imaging in optic disk pit associated with outer retinal dehiscence

    PubMed Central

    Wong, Chee Wai; Wong, Doric; Mathur, Ranjana

    2014-01-01

    A 37-year-old Bangladeshi male presented with an inferotemporal optic disk pit and serous macular detachment in the left eye. Imaging with spectral domain optical coherence tomography (OCT) revealed a multilayer macular schisis pattern with a small subfoveal outer retinal dehiscence. This case illustrates a rare phenotype of optic disk maculopathy with macular schisis and a small outer retinal layer dehiscence. Spectral domain OCT was a useful adjunct in delineating the retinal layers in optic disk pit maculopathy, and revealed a small area of outer retinal layer dehiscence that could only have been detected on high-resolution OCT. PMID:25349471

  16. Acute serous macular detachment and cystoid macular edema after uncomplicated phacoemulsification using standard dose subconjunctival cefuroxime.

    PubMed

    Kontos, Andreas; Mitry, Danny; Althauser, Susanne; Jain, Saurabh

    2014-09-01

    Acute toxic serous macular detachment after cataract surgery is very rare, and has been described previously with the use of high concentrations of intra-cameral cefuroxime. We report a case of serous macular detachment and cystoid macular edema 1 day after uncomplicated phacoemulsification using standard dose subconjunctival cefuroxime at the end of surgery. Our case demonstrates that subconjunctival cefuroxime may cause retinal toxicity in a similar fashion to intra-cameral cefuroxime, possibly due to entry of the drug into the anterior chamber through the section or trans-scleral absorption. To our knowledge, this is the first report of this complication with subconjunctival administration of cefuroxime.

  17. The intracapsular versus the extracapsular cataract technique in relationship to retinal problems.

    PubMed Central

    Wetzig, P C; Thatcher, D B; Christiansen, J M

    1979-01-01

    Five hundred and sixty-four consecutive eyes after cataract surgery with intraocular lens implantation were studied in relationship to the incidence of retinal detachment and cystoid macular edema in the intra vs the extracapsular extraction technique. In 124 eyes undergoing intracapsular cataract extraction, three (2.4%) developed retinal detachment. In 440 eyes undergoing extracapsular cataract extraction two (0.45%) developed retinal detachment. In 87 eyes undergoing intracapsular cataract extraction 7 (8%) developed cystoid macular edema. In 327 eyes undergoing extracapsular cataract extraction 4 (1.2%) developed cystoid macular edema. This study cannot be compared with other series in the literature because high risk cases and those with vitreous loss were excluded. PMID:545830

  18. Screening retinal transplants with Fourier-domain OCT

    NASA Astrophysics Data System (ADS)

    Rao, Bin

    2009-02-01

    Transplant technologies have been studied for the recovery of vision loss from retinitis pigmentosa (RP) and age-related macular degeneration (AMD). In several rodent retinal degeneration models and in patients, retinal progenitor cells transplanted as layers to the subretinal space have been shown to restore or preserve vision. The methods for evaluation of transplants are expensive considering the large amount of animals. Alternatively, time-domain Stratus OCT was previously shown to be able to image the morphological structure of transplants to some extent, but could not clearly identify laminated transplants. The efficacy of screening retinal transplants with Fourier-domain OCT was studied on 37 S334ter line 3 rats with retinal degeneration 6-67 days after transplant surgery. The transplants were morphologically categorized as no transplant, detachment, rosettes, small laminated area and larger laminated area with both Fourier-domain OCT and histology. The efficacy of Fourier-domain OCT in screening retinal transplants was evaluated by comparing the categorization results with OCT and histology. Additionally, 4 rats were randomly selected for multiple OCT examinations (1, 5, 9, 14 and 21days post surgery) in order to determine the earliest image time of OCT examination since the transplanted tissue may need some time to show its tendency of growing. Finally, we demonstrated the efficacy of Fourier-domain OCT in screening retinal transplants in early stages and determined the earliest imaging time for OCT. Fourier-domain OCT makes itself valuable in saving resource spent on animals with unsuccessful transplants.

  19. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M. P.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    The conditions of detached solidification under controlled pressure differential across the meniscus were investigated. Uncoated and graphite- or BN-coated silica and pBN crucibles were used. Detached and partly detached growth was achieved in pBN and BN-coated crucibles, respectively. The results of the experiments are discussed based on the theory of Duffar et al.

  20. Kinematic Fitting of Detached Vertices

    SciTech Connect

    Mattione, Paul

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  1. Dealings between Cataract and Retinal Reattachment Surgery in PVR

    PubMed Central

    Deuchler, Svenja; Singh, Pankaj; Müller, Michael; Kohnen, Thomas; Ackermann, Hanns; Iwanczuk, Joerg; Benjilali, Rachid; Koch, Frank

    2016-01-01

    Introduction. To evaluate the impact of the eye lens status and oil side effects on the outcome of vitreoretinal surgery in retinal detachment with proliferative vitreoretinopathy (PVR) and a temporary silicone oil tamponade (SOT). Methods. 101 eyes were analyzed retrospectively and 103 eyes prospectively in regard to their retinal reattachment success rate and key factors for the outcome. Subgroup analysis of 27 eyes with Scheimpflug lens photography (SLP) before and after retinal reattachment service with SOT was performed. For SLP (65% phakic eyes) a Pentacam densitometry reference body with 3 mm diameter was chosen and 3 segments (anterior/mid/posterior) were evaluated separately after a quality check. Results. The retinal reattachment rate was highest in the prospective pseudophakic group (p = 0.039). Lens transparency loss occurred earlier in middle aged patients than in younger patients. Besides the nucleus, layers posterior and anterior to it showed specific transparency changes. The emulsification rate was higher when eyes had been operated on in the anterior chamber before retinal reattachment service. Conclusions. Retinal reattachment surgery seems to benefit from preoperative cataract removal. We found significant lens changes in the nucleus as well as in the layers anterior and posterior to it. This corresponds to the histology of the lens epithelium published before. PMID:27034821

  2. Influence of cell detachment on the respiration rate of tumor and endothelial cells.

    PubMed

    Danhier, Pierre; Copetti, Tamara; De Preter, Géraldine; Leveque, Philippe; Feron, Olivier; Jordan, Bénédicte F; Sonveaux, Pierre; Gallez, Bernard

    2013-01-01

    Cell detachment is a procedure routinely performed in cell culture and a necessary step in many biochemical assays including the determination of oxygen consumption rates (OCR) in vitro. In vivo, cell detachment has been shown to exert profound metabolic influences notably in cancer but also in other pathologies, such as retinal detachment for example. In the present study, we developed and validated a new technique combining electron paramagnetic resonance (EPR) oximetry and the use of cytodex 1 and collagen-coated cytodex 3 dextran microbeads, which allowed the unprecedented comparison of the OCR of adherent and detached cells with high sensitivity. Hence, we demonstrated that both B16F10 melanoma cells and human umbilical vein endothelial cells (HUVEC) experience strong OCR decrease upon trypsin or collagenase treatments. The reduction of cell oxygen consumption was more pronounced with a trypsin compared to a collagenase treatment. Cells remaining in suspension also encounter a marked intracellular ATP depletion and an increase in the lactate production/glucose uptake ratio. These findings highlight the important influence exerted by cell adhesion/detachment on cell respiration, which can be probed with the unprecedented experimental assay that was developed and validated in this study.

  3. Retinal remodeling in human retinitis pigmentosa.

    PubMed

    Jones, B W; Pfeiffer, R L; Ferrell, W D; Watt, C B; Marmor, M; Marc, R E

    2016-09-01

    Retinitis Pigmentosa (RP) in the human is a progressive, currently irreversible neural degenerative disease usually caused by gene defects that disrupt the function or architecture of the photoreceptors. While RP can initially be a disease of photoreceptors, there is increasing evidence that the inner retina becomes progressively disorganized as the outer retina degenerates. These alterations have been extensively described in animal models, but remodeling in humans has not been as well characterized. This study, using computational molecular phenotyping (CMP) seeks to advance our understanding of the retinal remodeling process in humans. We describe cone mediated preservation of overall topology, retinal reprogramming in the earliest stages of the disease in retinal bipolar cells, and alterations in both small molecule and protein signatures of neurons and glia. Furthermore, while Müller glia appear to be some of the last cells left in the degenerate retina, they are also one of the first cell classes in the neural retina to respond to stress which may reveal mechanisms related to remodeling and cell death in other retinal cell classes. Also fundamentally important is the finding that retinal network topologies are altered. Our results suggest interventions that presume substantial preservation of the neural retina will likely fail in late stages of the disease. Even early intervention offers no guarantee that the interventions will be immune to progressive remodeling. Fundamental work in the biology and mechanisms of disease progression are needed to support vision rescue strategies. PMID:27020758

  4. Genetics Home Reference: retinitis pigmentosa

    MedlinePlus

    ... Me Understand Genetics Home Health Conditions retinitis pigmentosa retinitis pigmentosa Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Retinitis pigmentosa is a group of related eye disorders that ...

  5. Retinal hemorrhages in newborn.

    PubMed

    Govind, A; Kumari, S; Lath, N K

    1989-02-01

    Two hundred and fifty eight newborn babies were studied for the presence of retinal hemorrhages between 1-3 days of birth. The overall incidence of retinal hemorrhages was found to be 18.9%. It was observed that the incidence of retinal hemorrhages was higher in unassisted vaginal deliveries than in assisted births. Also, a two fold higher incidence was noted in term infants as compared to preterm babies. No association was seen with birth asphyxia.

  6. Thrombin induces Sp1-mediated antiviral effects in cytomegalovirus-infected human retinal pigment epithelial cells.

    PubMed

    Scholz, Martin; Vogel, Jens-Uwe; Höver, Gerold; Prösch, Susanna; Kotchetkov, Ruslan; Cinatl, Jaroslav; Koch, Frank; Doerr, Hans Wilhelm; Cinatl, Jindrich

    2004-11-01

    Human cytomegalovirus (HCMV) retinitis causing retinal detachment and destruction of the blood-retina barrier is closely related to retinal hemorrhage/coagulation. However, the effects of procoagulants on HCMV (re)activation in retinal cells have not been investigated yet. Therefore, we studied whether thrombin modulates the expression of HCMV immediate early (IE) and late (L) genes in cultured human retinal pigment epithelial cells (RPE). Thrombin specifically stimulated the protease-activated receptor-1 (PAR-1) on RPE and, surprisingly, inhibited basal and 12,0-tetradecanoylphorbol 13-acetate-stimulated HCMV IE gene expression in infected RPE. On the other hand, HCMV strongly induced Sp1 DNA binding activity, which was prevented by thrombin/PAR1-mediated Sp1 hyperphosphorylation. Our data suggest that thrombin/PAR-1 may inhibit Sp1-dependent HCMV replication, which might be an important regulatory mechanism for HCMV persistence and replication in RPE.

  7. Dynamic stability of detached solidification

    NASA Astrophysics Data System (ADS)

    Mazuruk, K.; Volz, M. P.

    2016-06-01

    A dynamic stability analysis model is developed for meniscus-defined crystal growth processes. The Young-Laplace equation is used to analyze the response of a growing crystal to perturbations to its radius and a thermal transport model is used to analyze the effect of perturbations on the evolution of the crystal-melt interface. A linearized differential equation is used to analyze radius perturbations but a linear integro-differential equation is required for the height perturbations. The stability model is applied to detached solidification under zero-gravity and terrestrial conditions. A numerical analysis is supplemented with an approximate analytical analysis, valid in the limit of small Bond numbers. For terrestrial conditions, a singularity is found to exist in the capillary stability coefficients where, at a critical value of the pressure differential across the meniscus, there is a transition from stability to instability. For the zero-gravity condition, exact formulas for the capillary stability coefficients are derived.

  8. Experimental results from detached plasmas in TFTR

    SciTech Connect

    Strachan, J.D.; Boody, F.P.; Bush, C.E.; Cohen, S.A.; Grek, B.; Grisham, L.; Jobes, F.C.; Johnson, D.W.; Mansfield, D.K.; Medley, S.S.

    1986-10-01

    Detached plasmas are formed in TFTR which have the principal property of the boundary to the high temperature plasma core being defined by a radiating layer. This paper documents the properties of TFTR ohmic-detached plasmas with a range of plasma densities at two different plasma currents.

  9. Modern retinal laser therapy.

    PubMed

    Kozak, Igor; Luttrull, Jeffrey K

    2015-01-01

    Medicinal lasers are a standard source of light to produce retinal tissue photocoagulation to treat retinovascular disease. The Diabetic Retinopathy Study and the Early Treatment Diabetic Retinopathy Study were large randomized clinical trials that have shown beneficial effect of retinal laser photocoagulation in diabetic retinopathy and have dictated the standard of care for decades. However, current treatment protocols undergo modifications. Types of lasers used in treatment of retinal diseases include argon, diode, dye and multicolor lasers, micropulse lasers and lasers for photodynamic therapy. Delivery systems include contact lens slit-lamp laser delivery, indirect ophthalmocope based laser photocoagulation and camera based navigated retinal photocoagulation with retinal eye-tracking. Selective targeted photocoagulation could be a future alternative to panretinal photocoagulation. PMID:25892934

  10. Induction of vitreolysis and vitreous detachment with hyaluronidase and perfluoropropane gas.

    PubMed

    Kang, S W; Hyung, S M; Choi, M Y; Lee, J

    1995-12-01

    To simulate the posterior vitreous detachment (PVD) in the rabbit, 1 IU hyaluronidase and/or 0.2 ml of perfluoropropane gas was intravitreally injected. Ophthalmoscopic, light microscopic examination prepared by cryotechnique, electron microscopic examination, and electroretinogram were done on the 3rd and 28th postoperative days. As a result, the eyes undergone simultaneous intravitreal injection of 1 IU hyaluronidase and 0.2 ml perfluoropropane gas showed membranous structure split from the internal limiting membrane of the superior retina in 3 days after injection. The eyes also demonstrated membranous structure separated from the superior retina after 28 days, simulating vitreous detachment. On the contrary, neither agent alone induced vitreous detachment. No toxic retinal changes associated with simultaneous intravitreal injection of 1 IU hyaluronidase and 0.2 ml perfluoropropane gas were observed. Therefore, with a future support by histologic examination other than cryotechnique and by immunohistochemical analysis, the simultaneous intravitreal injection of perfluoropropane gas and hyaluronidase would be a promising method to induce vitreous detachment in non-vitrectomized eye.

  11. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Vujisic, L.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years, especially under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 micrometers, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5 mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 micrometers. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  12. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Motakef, S.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years especially, under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 microns, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 microns. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  13. Retinal and optic nerve diseases.

    PubMed

    Margalit, Eyal; Sadda, Srinivas R

    2003-11-01

    A variety of disease processes can affect the retina and/or the optic nerve, including vascular or ischemic disease, inflammatory or infectious disease, and degenerative disease. These disease processes may selectively damage certain parts of the retina or optic nerve, and the specific areas that are damaged may have implications for the design of potential therapeutic visual prosthetic devices. Outer retinal diseases include age-related macular degeneration, pathologic myopia, and retinitis pigmentosa. Although the retinal photoreceptors may be lost, the inner retina is relatively well-preserved in these diseases and may be a target for retinal prosthetic devices. Inner retinal diseases include retinal vascular diseases such as diabetic retinopathy, retinal venous occlusive disease, and retinopathy of prematurity. Other retinal diseases such as ocular infections (retinitis, endophthalmitis) may affect all retinal layers. Because the inner retinal cells, including the retinal ganglion cells, may be destroyed in these diseases (inner retinal or whole retinal), prosthetic devices that stimulate the inner retina may not be effective. Common optic nerve diseases include glaucoma, optic neuritis, and ischemic optic neuropathy. Because the ganglion cell nerve fibers themselves are damaged, visual prosthetics for these diseases will need to target more distal portions of the visual pathway, such as the visual cortex. Clearly, a sound understanding of retinal and optic nerve disease pathophysiology is critical for designing and choosing the optimal visual prosthetic device.

  14. Rhodopsin regeneration in the normal and in the detached/replaced retina of the skate.

    PubMed

    Sun, Y; Ripps, H

    1992-11-01

    The bleaching and regeneration of rhodopsin in the skate retina was studied by means of fundus reflectometry, both in the normal eyecup preparation and after the retina had been detached and then replaced on the surface of the pigment epithelium (RPE). After bleaching virtually all the rhodopsin in the retinal test area of the normal eyecup, more than 90% of the photopigment was reformed after about 2 hr in darkness; over most of this time course, rhodopsin density rose linearly at a rate of 0.875% min-1 with a half-time of 55 min. Detaching the retina from its pigment epithelium resulted in a number of abnormalities, both structural and functional. Histological examination of the detached/replaced (D/R) retina showed striking alterations in the structural integrity of the RPE cells at their interface with the neural retina. The cells appeared vacuolated and misshapen, and the apical processes of the RPE, which normally ensheath the receptor outer segments, were shredded and free of their association with the visual cells. These morphological changes, as well as dilution of the IRBP content of the subretinal space caused by separation of the tissues, appear to be the main factors contributing to the functional abnormalities in rhodopsin kinetics. But despite these abnormalities and the persistent detachment, the rate of regeneration and the amount of rhodopsin reformed after bleaching were reduced by less than 50% of their normal values. The fact that a significant fraction of the bleached rhodopsin was regenerated under these conditions indicates that 11-cis retinal formed in the RPE was able to traverse a much greater than normal subretinal space to reach the opsin-bearing photoreceptor membranes. PMID:1478278

  15. Automated segmentation of serous pigment epithelium detachment in SD-OCT images

    NASA Astrophysics Data System (ADS)

    Sun, Zhuli; Shi, Fei; Xiang, Dehui; Chen, Haoyu; Chen, Xinjian

    2015-03-01

    Pigment epithelium detachment (PED) is an important clinical manifestation of multiple chorio-retinal disease processes, which can cause the loss of central vision. A 3-D method is proposed to automatically segment serous PED in SD-OCT images. The proposed method consists of five steps: first, a curvature anisotropic diffusion filter is applied to remove speckle noise. Second, the graph search method is applied for abnormal retinal layer segmentation associated with retinal pigment epithelium (RPE) deformation. During this process, Bruch's membrane, which doesn't show in the SD-OCT images, is estimated with the convex hull algorithm. Third, the foreground and background seeds are automatically obtained from retinal layer segmentation result. Fourth, the serous PED is segmented based on the graph cut method. Finally, a post-processing step is applied to remove false positive regions based on mathematical morphology. The proposed method was tested on 20 SD-OCT volumes from 20 patients diagnosed with serous PED. The average true positive volume fraction (TPVF), false positive volume fraction (FPVF), dice similarity coefficient (DSC) and positive predictive value (PPV) are 97.19%, 0.03%, 96.34% and 95.59%, respectively. Linear regression analysis shows a strong correlation (r = 0.975) comparing the segmented PED volumes with the ground truth labeled by an ophthalmology expert. The proposed method can provide clinicians with accurate quantitative information, including shape, size and position of the PED regions, which can assist diagnose and treatment.

  16. Retinal vein occlusion

    MedlinePlus

    ... most often caused by hardening of the arteries ( atherosclerosis ) and the formation of a blood clot. Blockage ... arteries that have been thickened or hardened by atherosclerosis cross over and place pressure on a retinal ...

  17. Retinal artery occlusion

    MedlinePlus

    ... eds. Textbook of Family Medicine . 9th ed. Philadelphia, PA: Elsevier; 2016:chap 17. Duker JS. Retinal arterial ... M, Duker JS, eds. Ophthalmology. 4th ed. Philadelphia, PA: Elsevier; 2014:chap 6.18. Reiss GR, Sipperley ...

  18. Retinal Changes Induced by Epiretinal Tangential Forces

    PubMed Central

    Romano, Mario R.; Comune, Chiara; Ferrara, Mariantonia; Cennamo, Gilda; De Cillà, Stefano; Toto, Lisa; Cennamo, Giovanni

    2015-01-01

    Two kinds of forces are active in vitreoretinal traction diseases: tangential and anterior-posterior forces. However, tangential forces are less characterized and classified in literature compared to the anterior-posterior ones. Tangential epiretinal forces are mainly due to anomalous posterior vitreous detachment (PVD), vitreoschisis, vitreopapillary adhesion (VPA), and epiretinal membranes (ERMs). Anomalous PVD plays a key role in the formation of the tangential vectorial forces on the retinal surface as consequence of gel liquefaction (synchysis) without sufficient and fast vitreous dehiscence at the vitreoretinal interface. The anomalous and persistent adherence of the posterior hyaloid to the retina can lead to vitreomacular/vitreopapillary adhesion or to a formation of avascular fibrocellular tissue (ERM) resulting from the proliferation and transdifferentiation of hyalocytes resident in the cortical vitreous remnants after vitreoschisis. The right interpretation of the forces involved in the epiretinal tangential tractions helps in a better definition of diagnosis, progression, prognosis, and surgical outcomes of vitreomacular interfaces. PMID:26421183

  19. Current convective instability in detached divertor plasma

    NASA Astrophysics Data System (ADS)

    Krasheninnikov, S. I.; Smolyakov, A. I.

    2016-09-01

    The asymmetry of inner and outer divertors, which cause the inner divertor to detach first, while the outer one is still attached, results in the large temperature difference between the vicinities of inner and outer targets and the onset of large electric potential drop through detached plasma of the inner divertor. A large potential drop along with the inhomogeneity of the resistivity of detached plasma across the divertor leg drives the current convective instability in the inner divertor and subsequent fluctuations of radiation loss similar to that observed in experiments. The estimates of the frequency of plasma parameter fluctuations due to the current convective instability are in a reasonable agreement with experimental data. Once the outer divertor also detaches, the temperature difference between the vicinities of inner and outer targets disappears, and the driving force for the current convective instability, and resulting oscillations of radiation loss, vanishes. This feature is indeed observed in experiments.

  20. Detached plasma in Saturn's front side magnetosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1983-01-01

    Plasma observations in the outer front side Saturnian magnetosphere are discussed which indicate the existence of dense flux tubes outside the plasma sheets. It is suggested that flux tubes are detached from the plasma sheet by a centifugally driven flute instability. The same instability leads to a dispersal of Titan-injected plasma. It is shown that the detached flux tubes will probably break open as they convect into the nightside magnetotail and lose their content in the form of a planetary wind.

  1. Crust rheology, slab detachment and topography

    NASA Astrophysics Data System (ADS)

    Duretz, T.; Gerya, T. V.

    2012-04-01

    The collision between continents following the closure of an ocean can lead to the subduction of continental crust. The introduction of buoyant crust within subduction zones triggers the development of extensional stresses in slabs which eventually result in their detachment. The dynamic consequences of slab detachment affects the development of topography, the exhumation of high-pressure rocks and the geodynamic evolution of collision zones. We employ two-dimensional thermo-mechanical modelling in order to study the importance of crustal rheology on the evolution of spontaneous subduction-collision systems and the occurrence of slab detachment. The modelling results indicate that varying the rheological structure of the crust can results in a broad range of collisional evolutions involving slab detachment, delamination (associated to slab rollback), or the combination of both mechanisms. By enhancing mechanical coupling at the Moho, a strong crust leads to the deep subduction of the crust (180 km). These collisions are subjected to slab detachment and subsequent coherent exhumation of the crust accommodated by eduction (inversion of subduction sense) and thrusting. In these conditions, slab detachment promotes the development of a high (> 4.5 km) and narrow (< 200 km) topographic plateau located in the vicinity of the suture. A contrasting style of collision is obtained by employing a weak crustal rheology. The weak mechanical coupling at the Moho promotes the widespread delamination of the lithosphere, preventing slab detachment to occur. Further shortening leads to buckling and thickening of the crust resulting in the development of topographic bulging on the lower plate. Collisions involving rheologically layered crust are characterised by a decoupling level at mid-crustal depths. These initial condition favours the delamination of the upper crust as well as the deep subduction of the lower crust. These collisions are thus successively affected by delamination

  2. Photovoltaic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Loudin, James; Mathieson, Keith; Kamins, Ted; Wang, Lele; Galambos, Ludwig; Huie, Philip; Sher, Alexander; Harris, James; Palanker, Daniel

    2011-03-01

    Electronic retinal prostheses seek to restore sight to patients suffering from retinal degenerative disorders. Implanted electrode arrays apply patterned electrical stimulation to surviving retinal neurons, producing visual sensations. All current designs employ inductively coupled coils to transmit power and/or data to the implant. We present here the design and initial testing of a photovoltaic retinal prosthesis fabricated with a pixel density of up to 177 pixels/mm2. Photodiodes within each pixel of the subretinal array directly convert light to stimulation current, avoiding the use of bulky coil implants, decoding electronics, and wiring, and thereby reducing surgical complexity. A goggles-mounted camera captures the visual scene and transmits the data stream to a pocket processor. The resulting images are projected into the eyes by video goggles using pulsed, near infrared (~900 nm) light. Prostheses with three pixel densities (15, 55, and 177 pix/mm2) are being fabricated, and tests indicate a charge injection limit of 1.62 mC/cm2 at 25Hz. In vitro tests of the photovoltaic retinal stimulation using a 512-element microelectrode array have recorded stimulated spikes from the ganglion cells, with latencies in the 1-100ms range, and with peak irradiance stimulation thresholds varying from 0.1 to 1 mW/mm2. With 1ms pulses at 25Hz the average irradiance is more than 100 times below the IR retinal safety limit. Elicited retinal response disappeared upon the addition of synaptic blockers, indicating that the inner retina is stimulated rather than the ganglion cells directly, and raising hopes that the prosthesis will preserve some of the retina's natural signal processing.

  3. Membrane-bound and soluble Fas ligands have opposite functions in photoreceptor cell death following separation from the retinal pigment epithelium

    PubMed Central

    Matsumoto, H; Murakami, Y; Kataoka, K; Notomi, S; Mantopoulos, D; Trichonas, G; Miller, J W; Gregory, M S; Ksander, B R; Marshak-Rothstein, A; Vavvas, D G

    2015-01-01

    Fas ligand (FasL) triggers apoptosis of Fas-positive cells, and previous reports described FasL-induced cell death of Fas-positive photoreceptors following a retinal detachment. However, as FasL exists in membrane-bound (mFasL) and soluble (sFasL) forms, and is expressed on resident microglia and infiltrating monocyte/macrophages, the current study examined the relative contribution of mFasL and sFasL to photoreceptor cell death after induction of experimental retinal detachment in wild-type, knockout (FasL−/−), and mFasL-only knock-in (ΔCS) mice. Retinal detachment in FasL−/− mice resulted in a significant reduction of photoreceptor cell death. In contrast, ΔCS mice displayed significantly more apoptotic photoreceptor cell death. Photoreceptor loss in ΔCS mice was inhibited by a subretinal injection of recombinant sFasL. Thus, Fas/FasL-triggered cell death accounts for a significant amount of photoreceptor cell loss following the retinal detachment. The function of FasL was dependent upon the form of FasL expressed: mFasL triggered photoreceptor cell death, whereas sFasL protected the retina, indicating that enzyme-mediated cleavage of FasL determines, in part, the extent of vision loss following the retinal detachment. Moreover, it also indicates that treatment with sFasL could significantly reduce photoreceptor cell loss in patients with retinal detachment. PMID:26583327

  4. Techniques for Processing Eyes Implanted With a Retinal Prosthesis for Localized Histopathological Analysis

    PubMed Central

    Nayagam, David A. X.; McGowan, Ceara; Villalobos, Joel; Williams, Richard A.; Salinas-LaRosa, Cesar; McKelvie, Penny; Lo, Irene; Basa, Meri; Tan, Justin; Williams, Chris E.

    2013-01-01

    With the recent development of retinal prostheses, it is important to develop reliable techniques for assessing the safety of these devices in preclinical studies. However, the standard fixation, preparation, and automated histology procedures are not ideal. Here we describe new procedures for evaluating the health of the retina directly adjacent to an implant. Retinal prostheses feature electrode arrays in contact with eye tissue. Previous methods have not been able to spatially localize the ocular tissue adjacent to individual electrodes within the array. In addition, standard histological processing often results in gross artifactual detachment of the retinal layers when assessing implanted eyes. Consequently, it has been difficult to assess localized damage, if present, caused by implantation and stimulation of an implanted electrode array. Therefore, we developed a method for identifying and localizing the ocular tissue adjacent to implanted electrodes using a (color-coded) dye marking scheme, and we modified an eye fixation technique to minimize artifactual retinal detachment. This method also rendered the sclera translucent, enabling localization of individual electrodes and specific parts of an implant. Finally, we used a matched control to increase the power of the histopathological assessments. In summary, this method enables reliable and efficient discrimination and assessment of the retinal cytoarchitecture in an implanted eye. PMID:23963336

  5. Retinal diseases in a reference center from a Western Amazon capital city

    PubMed Central

    Malerbi, Fernando Korn; Matsudo, Nilson Hideo; Carneiro, Adriano Biondi Monteiro; Lottenberg, Claudio Luiz

    2015-01-01

    ABSTRACT Objective To describe retinal diseases found in patients who were waiting for treatment at a tertiary care hospital in Rio Branco, Acre, Brazil. Methods Patients underwent slit lamp biomicroscopy, dilated fundus exam and ocular ultrasound. Patients were classified according to phakic status and retinal disease of the most severely affected eye. Results A total of 138 patients were examined. The mean age was 51.3 years. Diabetes was present in 35.3% and hypertension in 45.4% of these patients. Cataract was found in 23.2% of patients, in at least one eye. Retinal examination was possible in 129 patients. The main retinal diseases identified were rhegmatogenous retinal detachment (n=23; 17.8%) and diabetic retinopathy (n=32; 24.8%). Out of 40 patients evaluated due to diabetes, 13 (32.5%) had absent or mild forms of diabetic retinopathy and did not need further treatment, only observation. Conclusion Diabetic retinopathy was the main retinal disease in this population. It is an avoidable cause of blindness and can be remotely evaluated, in its initial stages, by telemedicine strategies. In remote Brazilian areas, telemedicine may be an important tool for retinal diseases diagnosis and follow-up. PMID:26761550

  6. Retinal pigment epithelial cell proliferation

    PubMed Central

    Temple, Sally

    2015-01-01

    The human retinal pigment epithelium forms early in development and subsequently remains dormant, undergoing minimal proliferation throughout normal life. Retinal pigment epithelium proliferation, however, can be activated in disease states or by removing retinal pigment epithelial cells into culture. We review the conditions that control retinal pigment epithelial proliferation in culture, in animal models and in human disease and interpret retinal pigment epithelium proliferation in context of the recently discovered retinal pigment epithelium stem cell that is responsible for most in vitro retinal pigment epithelial proliferation. Retinal pigment epithelial proliferation-mediated wound repair that occurs in selected macular diseases is contrasted with retinal pigment epithelial proliferation-mediated fibroblastic scar formation that underlies proliferative vitreoretinopathy. We discuss the role of retinal pigment epithelial proliferation in age-related macular degeneration which is reparative in some cases and destructive in others. Macular retinal pigment epithelium wound repair and regression of choroidal neovascularization are more pronounced in younger than older patients. We discuss the possibility that the limited retinal pigment epithelial proliferation and latent wound repair in older age-related macular degeneration patients can be stimulated to promote disease regression in age-related macular degeneration. PMID:26041390

  7. Analysis of the pre-retinal opacities in Gaucher Disease using spectral domain optical coherent tomography.

    PubMed

    Sheck, Leo H N; Wilson, Callum J; Vincent, Andrea L

    2012-12-01

    Fundal opacities have been reported in patients with Gaucher disease, a rare autosomal recessive lysosomal storage disease, prior to the advent of optical coherent tomography. This report provides a detailed analysis of the fundal opacities in a 14-year-old girl with genetically proven Gaucher disease using spectral domain optical coherent tomography. It illustrates clearly that these opacities were pre-retinal opacities located at the vitreo-retinal interface associated with localized posterior vitreous detachments, rather than vitreous opacities as previously suggested in the literature. PMID:22950450

  8. Probabilistic retinal vessel segmentation

    NASA Astrophysics Data System (ADS)

    Wu, Chang-Hua; Agam, Gady

    2007-03-01

    Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

  9. Bioelectronic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Weiland, James D.

    2016-05-01

    Retinal prosthesis have been translated to clinical use over the past two decades. Currently, two devices have regulatory approval for the treatment of retinitis pigmentosa and one device is in clinical trials for treatment of age-related macular degeneration. These devices provide partial sight restoration and patients use this improved vision in their everyday lives to navigate and to detect large objects. However, significant vision restoration will require both better technology and improved understanding of the interaction between electrical stimulation and the retina. In particular, current retinal prostheses do not provide peripheral visions due to technical and surgical limitations, thus limiting the effectiveness of the treatment. This paper reviews recent results from human implant patients and presents technical approaches for peripheral vision.

  10. Detached auroral arcs in the trough region

    NASA Technical Reports Server (NTRS)

    Anger, C. D.; Moshupi, M. C.; Wallis, D. D.; Murphree, J. S.; Brace, L. H.; Shepherd, G. G.

    1978-01-01

    In a previous paper, Moshupi et al. (1977) have reported on the occurrence of rare auroral 'patches' equatorward of the normally well-defined boundary of diffuse aurora. Some less spectacular but more common arclike features were observed in the same 'trough' region (between the plasmapause and the auroral oval) during the period 1972-1975. These 'detached' arcs show some similarities to stable auroral red arcs in terms of their location and occurrence, but are completely different spectroscopically in that the stable auroral red arcs produce almost pure atomic oxygen red line emissions, whereas the detached arcs are deficient in red line emission - a feature implying totally different production mechanisms. The characteristics of the detached lines are described, including their unusual local time/longitude dependence.

  11. [Impact of ozone therapy on the electrophysiological parameters of the retina in patients operated on for its rhegmatogenous detachment].

    PubMed

    Neroev, V V; Sarygina, O I; Zueva, M V; Tsapenko, I V; Egorova, E N

    2007-01-01

    The impact of ozone therapy on changes in the data of maximum combined electroretinography (ERG), macular ERG (MERG), and rhythmic ERG (RERG) at 12, 32, and 40 Hz was studied in the rehabilitative period in patients operated on for rhegmatogenous retinal detachment. The integral and local glial indices K(g) and K(c) were calculated. Studies were conducted before, within 1 week and 1 and 2 months after a course of therapy. With ozone therapy, ERG and RERG depended on the specific features of changes available in the fundus of the eye before surgery. In the early rehabilitative period after surgery (circlage with subretinal fluid removal), ozone therapy normalized the glial indices, by decreasing the supernormal activity of Muller's glial cells and drastically increasing their reduced activity. The maximum effect was revealed for the function of phororeceptors (except for the eyes showing pronounced myopic dystrophic changes in the fundus). There were increases in MERG, ERG b-wave, and low-frequency RERG by 12 Hz, i.e. improved functions of the macular region and distal neurons of the retinal rod cell system. A latent period was established for the manifestation of a positive effect of ozonwe therapy on the functional of neurons of the internal retinal nuclear layer, as evidenced by RERG changes. Ozone therapy positively affect retinal electrogenesis in cases of total retinal detachment accompanied by a pronounced reduction in the glial index Kg before surgery. The therapy was found to have a positive impact on the functional activity of the retina of pair eyes, by developing within a one-moth latent period.

  12. Pathway to Retinal Oximetry

    PubMed Central

    Beach, James

    2014-01-01

    Events and discoveries in oxygen monitoring over the past two centuries are presented as the background from which oximetry of the human retina evolved. Achievements and the people behind them are discussed, showing parallels between the work in tissue measurements and later in the eye. Developments in the two-wavelength technique for oxygen saturation measurements in retinal vessels are shown to exploit the forms of imaging technology available over time. The last section provides a short summary of the recent research in retinal diseases using vessel oximetry. PMID:25237591

  13. Retinal lesions in septicemia.

    PubMed

    Neudorfer, M; Barnea, Y; Geyer, O; Siegman-Igra, Y

    1993-12-15

    We explored the association between septicemia and specific retinal lesions in a prospective controlled study. Hemorrhages, cotton-wool spots, or Roth's spots were found in 24 of 101 septicemic patients (24%), compared to four of 99 age- and gender-matched control patients (4%) (P = .0002). There was no significant association between types of organisms or focus of infection and the presence of specific lesions. Histologic examination of affected eyes disclosed cytoid bodies in the nerve fiber layer without inflammation. A definite association between septicemia and retinal lesions was found and indicates the need for routine ophthalmoscopy in septicemic patients. PMID:8250076

  14. Detachable microsphere scalpel tips for potential use in ophthalmic surgery with the erbium:YAG laser.

    PubMed

    Hutchens, Thomas C; Darafsheh, Arash; Fardad, Amir; Antoszyk, Andrew N; Ying, Howard S; Astratov, Vasily N; Fried, Nathaniel M

    2014-01-01

    Vitreoretinal surgery is performed using mechanical dissection that sometimes results in iatrogenic complications, including vitreous hemorrhage, retinal breaks, incomplete membrane delamination, retinal distortion, microscopic damage, etc. An ultraprecise laser probe would be an ideal tool for cutting away pathologic membranes; however, the depth of surgery should be precisely controlled to protect the sensitive underlying retina. The ultraprecise surgical microprobe formed by chains of dielectric spheres for use with the erbium:YAG laser source (λ=2940  nm), with extremely short optical penetration depth in tissue, was optimized. Numerical modeling demonstrated a potential advantage of five-sphere focusing chains of sapphire spheres with index n=1.71 for ablating the tissue with self-limited depth around 10 to 20 μm. Novel detachable microsphere scalpel tips formed by chains of 300 μm sapphire (or ruby) spheres were tested on ophthalmic tissues, ex vivo. Detachable scalpel tips could allow for reusability of expensive mid-infrared trunk fibers between procedures, and offer more surgical customization by interchanging various scalpel tip configurations. An innovative method for aiming beam integration into the microsphere scalpel to improve the illumination of the surgical site was also shown. Single Er:YAG pulses of 0.2 mJ and 75-μs duration produced ablation craters in cornea epithelium for one, three, and five sphere structures with the latter generating the smallest crater depth (10 μm) with the least amount of thermal damage depth (30 μm). Detachable microsphere laser scalpel tips may allow surgeons better precision and safety compared to mechanical scalpels when operating on delicate or sensitive areas like the retina.

  15. Choroidal ischemia and serous macular detachment associated with severe postoperative pain.

    PubMed

    Jung, Jee Woong; Lee, Dae Young; Nam, Dong Heun

    2008-06-01

    To report the association of a unilateral serous macular detachment with severe postoperative pain. A 71-year-old woman presented with a sudden decrease in vision in the right eye, seven days after a total knee replacement arthroplasty. The patient's history was unremarkable except for a severe pain greater than the visual analog scale of 8 points for about 2 days after surgery. Retinal examination showed a well differentiated serous detachment that was about 3.5 disc diameter in size and located in the macular area. Fluorecein angiography and indocyanine green angiography showed delayed perfusion of the choriocapillaris without leakage points in the early phase and persistent hypofluorescence with pooling of dye in the subretinal space in the late phase. There was a spontaneous resolution of the serous detachment and the choroidal changes with residual pigment epithelial changes. Severe postoperative pain may influence the sympathetic activity and introduce an ischemic injury with a focal, choroidal vascular compromise and secondary dysfunction of overlying RPE cells in select patients.

  16. Progressive outer retinal necrosis syndrome: a comprehensive review of its clinical presentation, relationship to immune system status, and management.

    PubMed

    Austin

    2000-12-01

    Progressive outer retinal necrosis (PORN) syndrome is a form of the Varicella zoster virus (VZV) chorioretinitis found almost exclusively in people with the acquired immunodeficiency syndrome (AIDS). This destructive infection has an extremely rapid course that may lead to no light perception in affected eyes within days or weeks. Attempts at its treatment have had limited success. Rhegmatogenous retinal detachments often occur after the development of atrophic retinal holes, and silicone oil temponade has been found to be the most successful reattachment procedure. Unfortunately, cataract formation is common after such surgery. PORN needs to be differentiated from acute retinal necrosis (ARN) syndrome, a necrotizing retinitis that can also be caused by VZV. PORN and ARN are found at opposite ends of the spectrum of necrotizing herpetic retinopathies (NHR), where its clinical presentation depends upon immune system status. After a brief case presentation, the distinguishing clinical characteristics of PORN, its differentiation from ARN, attempts at its treatment, the role of the immune system status on its clinical appearance and treatment, and management of complications such as retinal detachment and subsequent cataracts are discussed.

  17. Nanomaterials and Retinal Toxicity

    EPA Science Inventory

    The neuroretina should be considered as a potential site of nanomaterial toxicity. Engineered nanomaterials may reach the retina through three potential routes of exposure including; intra­ vitreal injection of therapeutics; blood-borne delivery in the retinal vasculature an...

  18. Degenerative retinal disorders

    SciTech Connect

    Hollyfield, J.G. Anderson, R.E. LaVail, M.M. . Dept. of Anatomy)

    1987-01-01

    This book contains papers divided among three sections. Some of the paper titles are: Molecular Genetics of Gyrate Atrophy; Molecular Site of Expression and Genetic Interaction of the rd and the rds Loci in the Retina of the Mouse; and Studies on Abnormal Cyclic GMP Metabolism in Animal Models of Retinal Degeneration: Genetic Relationships and Cellular Compartmentalization.

  19. Electrically induced drop detachment and ejection

    NASA Astrophysics Data System (ADS)

    Cavalli, Andrea; Preston, Daniel J.; Tio, Evelyn; Martin, David W.; Miljkovic, Nenad; Wang, Evelyn N.; Blanchette, Francois; Bush, John W. M.

    2016-02-01

    A deformed droplet may leap from a solid substrate, impelled to detach through the conversion of surface energy into kinetic energy that arises as it relaxes to a sphere. Electrowetting provides a means of preparing a droplet on a substrate for lift-off. When a voltage is applied between a water droplet and a dielectric-coated electrode, the wettability of the substrate increases in a controlled way, leading to the spreading of the droplet. Once the voltage is released, the droplet recoils, due to a sudden excess in surface energy, and droplet detachment may follow. The process of drop detachment and lift-off, prevalent in both biology and micro-engineering, has to date been considered primarily in terms of qualitative scaling arguments for idealized superhydrophobic substrates. We here consider the eletrically-induced ejection of droplets from substrates of finite wettability and analyze the process quantitatively. We compare experiments to numerical simulations and analyze how the energy conversion efficiency is affected by the applied voltage and the intrinsic contact angle of the droplet on the substrate. Our results indicate that the finite wettability of the substrate significantly affects the detachment dynamics, and so provide new rationale for the previously reported large critical radius for drop ejection from micro-textured substrates.

  20. Syneresis and delayed detachment in agar plates

    NASA Astrophysics Data System (ADS)

    Divoux, Thibaut; Mao, Bosi; Snabre, Patrick

    Biogels made of crosslinked polymers such as proteins or polysaccharides behave as porous soft solids and store large amount of solvent. These gels undergo spontaneous aging, called syneresis that consists in the shrinkage of the gel matrix and the progressive expulsion of the solvent. As a result, a biogel originally casted in a container often lose contact with the container sidewalls, and the detachment time is a priori difficult to anticipate since it may occur over variable time spans (from hours to days). Here we report on the syneresis phenomena in agar plates that consist in Petri dishes filled with a gel mainly composed of agar. Direct observations and speckle pattern correlation analysis allow us to rationalize the delayed detachment of the gel from the sidewall of the Petri dish. The detachment time $t^*$ is surprisingly not controlled by the mass loss as one would intuitively expect. Instead, $t^*$ is strongly correlated to the gel minimum thickness $e_{min}$ measured along the sidewall of the plate, and increases as a robust function of $e_{min}$ independently of the prior mass-loss history. Time-resolved correlation spectroscopy atypically applied to such weakly diffusive media gives access to the local thinning rate of the gel. This technique also allows us to detect the gel micro-displacements that are triggered by the water evaporation prior to the detachment, and even to anticipate the latter from a few hours. Our work provides observables to predict the detachment time of agar gels in dishes, and highlights the relevance of speckle pattern correlation analysis for the quantitative investigation of the syneresis dynamics in biopolymer gels.

  1. Syneresis and delayed detachment in agar plates.

    PubMed

    Divoux, Thibaut; Mao, Bosi; Snabre, Patrick

    2015-05-14

    Biogels made of crosslinked polymers such as proteins or polysaccharides behave as porous soft solids and store large amounts of solvent. These gels undergo spontaneous aging, called syneresis, which consists of the shrinkage of the gel matrix and the progressive expulsion of solvent. As a result, a biogel originally casted in a container often loses contact with the container sidewalls, and the detachment time is difficult to anticipate a priori, since it may occur over variable time spans (from hours to days). Here we report on syneresis phenomena in agar plates, which consist of Petri dishes filled with a gel mainly composed of agar. Direct observations and speckle pattern correlation analysis allow us to rationalize the delayed detachment of the gel from the sidewall of the Petri dish. The detachment time t* is surprisingly not controlled by the mass loss as one would intuitively expect. Instead, t* is strongly correlated to the gel minimum thickness emin measured along the sidewall of the plate, and increases as a robust function of emin, independently of the prior mass-loss history. Time-resolved correlation spectroscopy atypically applied to such weakly diffusive media gives access to the local thinning rate of the gel. This technique also allows us to detect the gel micro-displacements that are triggered by water evaporation prior to the detachment, and even to anticipate the latter from a few hours. Our work provides observables to predict the detachment time of agar gels in dishes, and highlights the relevance of speckle pattern correlation analysis for the quantitative investigation of the syneresis dynamics in biopolymer gels.

  2. Syneresis and delayed detachment in agar plates.

    PubMed

    Divoux, Thibaut; Mao, Bosi; Snabre, Patrick

    2015-05-14

    Biogels made of crosslinked polymers such as proteins or polysaccharides behave as porous soft solids and store large amounts of solvent. These gels undergo spontaneous aging, called syneresis, which consists of the shrinkage of the gel matrix and the progressive expulsion of solvent. As a result, a biogel originally casted in a container often loses contact with the container sidewalls, and the detachment time is difficult to anticipate a priori, since it may occur over variable time spans (from hours to days). Here we report on syneresis phenomena in agar plates, which consist of Petri dishes filled with a gel mainly composed of agar. Direct observations and speckle pattern correlation analysis allow us to rationalize the delayed detachment of the gel from the sidewall of the Petri dish. The detachment time t* is surprisingly not controlled by the mass loss as one would intuitively expect. Instead, t* is strongly correlated to the gel minimum thickness emin measured along the sidewall of the plate, and increases as a robust function of emin, independently of the prior mass-loss history. Time-resolved correlation spectroscopy atypically applied to such weakly diffusive media gives access to the local thinning rate of the gel. This technique also allows us to detect the gel micro-displacements that are triggered by water evaporation prior to the detachment, and even to anticipate the latter from a few hours. Our work provides observables to predict the detachment time of agar gels in dishes, and highlights the relevance of speckle pattern correlation analysis for the quantitative investigation of the syneresis dynamics in biopolymer gels. PMID:25812667

  3. The Retinal Homeobox (Rx) gene is necessary for retinal regeneration

    PubMed Central

    Martinez-De Luna, Reyna I.; Kelly, Lisa E.; El-Hodiri, Heithem M.

    2011-01-01

    The Retinal Homeobox (Rx) gene is essential for vertebrate eye development. Rx function is required for the specification and maintenance of retinal progenitor cells (RPCs). Loss of Rx function leads to a lack of eye development in a variety of species. Here we show that Rx function is also necessary during retinal regeneration. We performed a thorough characterization of retinal regeneration after partial retinal resection in pre-metamorphic X. laevis. We show that after injury the wound is repopulated with retinal progenitor cells (RPCs) that express Rx and other RPC marker genes. We used an shRNA-based approach to specifically silence Rx expression in vivo in tadpoles. We found that loss of Rx function results in impaired retinal regeneration, including defects in the cells that repopulate the wound and the RPE at the wound site. We show that the regeneration defects can be rescued by provision of exogenous Rx. These results demonstrate for the first time that Rx, in addition to being essential during retinal development, also functions during retinal regeneration. PMID:21334323

  4. Small Animal Retinal Imaging

    NASA Astrophysics Data System (ADS)

    Choi, WooJhon; Drexler, Wolfgang; Fujimoto, James G.

    Developing and validating new techniques and methods for small animal imaging is an important research area because there are many small animal models of retinal diseases such as diabetic retinopathy, age-related macular degeneration, and glaucoma [1-6]. Because the retina is a multilayered structure with distinct abnormalities occurring in different intraretinal layers at different stages of disease progression, there is a need for imaging techniques that enable visualization of these layers individually at different time points. Although postmortem histology and ultrastructural analysis can be performed for investigating microscopic changes in the retina in small animal models, this requires sacrificing animals, which makes repeated assessment of the same animal at different time points impossible and increases the number of animals required. Furthermore, some retinal processes such as neurovascular coupling cannot be fully characterized postmortem.

  5. The peripheral retinal 'map'.

    PubMed Central

    Williams, D. H.

    1975-01-01

    The condition of the periphery of the retinal field of the human eye is of considerable significance, it is suggested, to those participating in various sporting activities. Its boundaries shrink and expand depending upon the physiological conditions imposed both upon the eye and upon the organism as a whole. Consequently its message to the brain may be impaired under stress with resulting danger owing to delayed response. Images Fig. 3 Fig. 4 Fig. 5 PMID:1148574

  6. Inherited Retinal Degenerative Disease Registry

    ClinicalTrials.gov

    2016-03-21

    Eye Diseases Hereditary; Retinal Disease; Achromatopsia; Bardet-Biedl Syndrome; Bassen-Kornzweig Syndrome; Batten Disease; Best Disease; Choroidal Dystrophy; Choroideremia; Cone Dystrophy; Cone-Rod Dystrophy; Congenital Stationary Night Blindness; Enhanced S-Cone Syndrome; Fundus Albipunctatus; Goldmann-Favre Syndrome; Gyrate Atrophy; Juvenile Macular Degeneration; Kearns-Sayre Syndrome; Leber Congenital Amaurosis; Refsum Syndrome; Retinitis Pigmentosa; Retinitis Punctata Albescens; Retinoschisis; Rod-Cone Dystrophy; Rod Dystrophy; Rod Monochromacy; Stargardt Disease; Usher Syndrome

  7. Glutamatergic Retinal Waves

    PubMed Central

    Kerschensteiner, Daniel

    2016-01-01

    Spontaneous activity patterns propagate through many parts of the developing nervous system and shape the wiring of emerging circuits. Prior to vision, waves of activity originating in the retina propagate through the lateral geniculate nucleus (LGN) of the thalamus to primary visual cortex (V1). Retinal waves have been shown to instruct the wiring of ganglion cell axons in LGN and of thalamocortical axons in V1 via correlation-based plasticity rules. Across species, retinal waves mature in three stereotypic stages (I–III), in which distinct circuit mechanisms give rise to unique activity patterns that serve specific functions in visual system refinement. Here, I review insights into the patterns, mechanisms, and functions of stage III retinal waves, which rely on glutamatergic signaling. As glutamatergic waves spread across the retina, neighboring ganglion cells with opposite light responses (ON vs. OFF) are activated sequentially. Recent studies identified lateral excitatory networks in the inner retina that generate and propagate glutamatergic waves, and vertical inhibitory networks that desynchronize the activity of ON and OFF cells in the wavefront. Stage III wave activity patterns may help segregate axons of ON and OFF ganglion cells in the LGN, and could contribute to the emergence of orientation selectivity in V1. PMID:27242446

  8. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    Detached crystal growth technique (dewetting) offers improvement in the quality of the grown crystals by preventing sticking to the walls of the crucible and thus reducing the possibility of parasitic nucleation and formation of lattice defects upon cooling. One of the factors relevant for the phenomena is the pressure differential across the meniscus at the crystal-melt interface. We investigated this effect experimentally. The growth took place in closed ampoules under the pressure of an inert gas (forming gas: 96% Ar + 4% H2). The pressure above the melt was adjustable and allowed for a control of the pressure difference between the top and bottom menisci. The crystals were characterized, particularly by taking profilometer measurements along the grown crystals surface. The effects of the experimental conditions on the detachment were compared with those predicted based on the theory of Duffar et al.

  9. High and Low Temperature Oceanic Detachment Faults

    NASA Astrophysics Data System (ADS)

    Titarenko, Sofya; McCaig, Andrew

    2013-04-01

    One of the most important discoveries in Plate Tectonics in the last ten years is a "detachment mode" of seafloor spreading. Up to 50% of the Atlantic seafloor has formed by a combination of magmatism and slip on long-lived, convex-up detachment faults, forming oceanic core complexes (OCC). Two end-member types of OCC can be defined: The Atlantis Bank on the Southwest Indian Ridge is a high temperature OCC sampled by ODP Hole 735b. Deformation was dominated by crystal-plastic flow both above and below the solidus at 800-950 °C, over a period of around 200 ka. In contrast, the Atlantis Massif at 30 °N in the Atlantic, sampled by IODP Hole 1309D, is a low temperature OCC in which crystal plastic deformation of gabbro is very rare and greenschist facies deformation was localised onto talc-tremolite-chlorite schists in serpentinite, and breccia zones in gabbro and diabase. The upper 100m of Hole 1309D contains about 43% diabase intruded into hydrated fault breccias. This detachment fault zone can be interpreted as a dyke-gabbro transition, which was originally (before flexural unroofing) a lateral boundary between active hydrothermal circulation in the fault zone and hangingwall, and intrusion of gabbroic magma in the footwall. Thus a major difference between high and low temperature detachment faults may be cooling of the latter by active hydrothermal circulation. 2-D thermal modelling suggests that if a detachment fault is formed in a magmatically robust segment of a slow spreading ridge, high temperature mylonites can be formed for 1-2 ka provided there is no significant hydrothermal cooling of the fault zone. In contrast, if the fault zone is held at temperatures of 400 °C by fluid circulation, cooling of the upper 1 km of the fault footwall occurs far too rapidly for extensive mylonites to form. Our models are consistent with published cooling rate data from geospeedometry and isotopic closure temperatures. The control on this process is likely a combination of

  10. On Transients in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.

    2011-01-01

    In detached Bridgman growth, a gap exists between the growing crystal and the crucible wall. According to crystal shape stability theory, only specific gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. The transient shapes are calculated assuming that the growth angle is constant. Anisotropy and dynamic contact angle effects are considered. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. However, heat transfer will influence the crystal-melt interface shape. The local angles and the crystal-melt-vapor triple junction are analyzed and the applicability of the Herring formula is discussed. A potential microgravity experiment is proposed which would enhance our understanding of the detached growth dynamic stability problem.

  11. Responsive systems for cell sheet detachment

    PubMed Central

    Patel, Nikul G.; Zhang, Ge

    2013-01-01

    Cell sheet engineering has been progressing rapidly during the past few years and has emerged as a novel approach for cell based therapy. Cell sheet harvest technology enables fabrication of viable, transplantable cell sheets for various tissue engineering applications. Currently, the majority of cell sheet studies use thermo-responsive systems for cell sheet detachment. However, other responsive systems began showing their potentials for cell sheet harvest. This review provides an overview of current techniques in creating cell sheets using different types of responsive systems including thermo-responsive, electro-responsive, photo-responsive, pH-responsive and magnetic systems. Their mechanism, approach, as well as applications for cell detachment have been introduced. Further development of these responsive systems will allow efficient cell sheet harvesting and patterning of cells to reconstruct complex tissue for broad clinical applications. PMID:23820033

  12. Mechanism of bubble detachment from vibrating walls

    SciTech Connect

    Kim, Dongjun; Park, Jun Kwon Kang, Kwan Hyoung; Kang, In Seok

    2013-11-15

    We discovered a previously unobserved mechanism by which air bubbles detach from vibrating walls in glasses containing water. Chaotic oscillation and subsequent water jets appeared when a wall vibrated at greater than a critical level. Wave forms were developed at water-air interface of the bubble by the wall vibration, and water jets were formed when sufficiently grown wave-curvatures were collapsing. Droplets were pinched off from the tip of jets and fell to the surface of the glass. When the solid-air interface at the bubble-wall attachment point was completely covered with water, the bubble detached from the wall. The water jets were mainly generated by subharmonic waves and were generated most vigorously when the wall vibrated at the volume resonant frequency of the bubble. Bubbles of specific size can be removed by adjusting the frequency of the wall's vibration.

  13. Mitochondrial dysfunction in retinal diseases.

    PubMed

    Barot, Megha; Gokulgandhi, Mitan R; Mitra, Ashim K

    2011-12-01

    The mitochondrion is a vital intracellular organelle for retinal cell function and survival. There is growing confirmation to support an association between mitochondrial dysfunction and a number of retinal degenerations. Investigations have also unveiled mitochondrial genomic instability as one of the contributing factors for age-related retinal pathophysiology. This review highlights the role of mitochondrial dysfunction originating from oxidative stress in the etiology of retinal diseases including diabetic retinopathy, glaucoma and age-related macular degeneration (AMD). Moreover, mitochondrial DNA (mtDNA) damage associated with AMD due to susceptibility of mtDNA to oxidative damage and failure of mtDNA repair pathways is also highlighted in this review. The susceptibility of neural retina and retinal pigment epithelium (RPE) mitochondria to oxidative damage with ageing appears to be a major factor in retinal degeneration. It thus appears that the mitochondrion is a weak link in the antioxidant defenses of retinal cells. In addition, failure of mtDNA repair pathways can also specifically contribute towards pathogenesis of AMD. This review will further summarize the prospective role of mitochondria targeting therapeutic agents for the treatment of retinal disease. Mitochondria based drug targeting to diminish oxidative stress or promote repair of mtDNA damage may offer potential alternatives for the treatment of various retinal degenerative diseases.

  14. Detached Growth of Germanium and Germaniumsilicon

    NASA Technical Reports Server (NTRS)

    Dold, P.; Schweizer, M.; Szofran, F.; Benz, K. W.

    1999-01-01

    Up to now, detached growth was observed mainly under microgravity, i.e. under the absence of hydrostatic pressure that hinders the formation of a free melt meniscus. the detached growth of germanium doped with gallium was obtained under 1 g conditions, the growth was performed in quartz-glass ampoule. Part of the crystal grew without wall contact, the detached growth was observed in-situ with a CCD-camera as well as after the growth process in form of growth lines and the formation of <111> facets on the crystal surface. GeSi crystal (oriientation: <111>, maximum silicon content: 4 at%, seed material: Ge) was grown in a pBN crucible (excluding the possibility of in-situ monitoring of the growth process). The grown crystal exhibits three growth facets, indicating also wall free growth. Surface analysis of the crystals (NDIC, SEM) and characterization of crystal segregation (EDAX, resistivity measurement) and defect structure (EPD, x-ray diffraction measurements) will be presented.

  15. [Application of retinal oximeter in ophthalmology].

    PubMed

    Li, Jing; Ma, Jianmin; Wang, Ningli

    2015-11-01

    Retinal oximeter is a new machine which has been used in the diagnose, treatment and research of several ophthalmic diseases for recent years. It allows ophthalmologists to gain retinal oxygen saturation directly. Therefore, retinal oximeter might be useful for ophthalmologists to understand ophthalmic diseases more deeper and clarify the impact of ischemia on retinal function. It has been reported in the literatures that retinal oximeter has potentially useful diagnostic and therapeutic indications in various eye diseases such as diabetic retinopathy, central retinal vein and artery occlusion, retinitis pigmentosa, glaucomatous optic neuropathy, et al. In this thesis, the application of retinal oximeter in ophthalmology is reviewed.

  16. Heavy silicone oil as a long-term endotamponade agent for complicated retinal detachments.

    PubMed

    Prazeres, Juliana; Magalhães, Octaviano; Lucatto, Luiz F A; Navarro, Rodrigo Milan; Moraes, Nilva S; Farah, Michel E; Maia, André; Maia, Maurício

    2014-01-01

    We retrospectively evaluated a heavy silicone oil (HSO) as a long-term intraocular endotamponade agent to treat complicated RD by inferior PVR in 25 eyes of 25 patients. Patients underwent PPV and injection of Oxane HD as an internal tamponade agent. A comparison of preoperative and postoperative BCVA at month 1, month 6, and last visit was made in the group in which HSO was removed and in the group in which HSO was not removed. Statistical calculations were performed using the Wilcoxon test. The HSO was removed from 11 patients after a mean of 26.55 ± 21.38 months. The HSO remained inside the vitreous cavity in 14 eyes due to a high chance of PVR recurrence (mean follow-up period, 11.07 ± 7.44 months). Anatomic success was achieved in 92%. The BCVA in the group, in which HSO was not removed, improved significantly during the first 6 months. Among the patients who had the oil removed, there was improvement in BCVA after 1 month. Oil emulsification was the most common adverse effect in 52% of eyes. HSO is an effective tamponade in complex rhegmatogenous and tractional RD complicated by PVR. HSO can remain in the eye for long periods with relative tolerability and safety. PMID:24822176

  17. Contact angles of substances used for internal tamponade in retinal detachment surgery.

    PubMed

    Fawcett, I M; Williams, R L; Wong, D

    1994-07-01

    In order to ascertain the tamponade effect of air and silicone oil we examined the contact angles subtended by ex vivo human retina, Teflon and Perspex to find a suitable experimental material which would mimic the surface properties of the retina at a three-phase interface. Using the captive bubble technique to measure the contact angle, it was found that air subtended a larger contact angle (38.8 degrees) with the retina than did silicone oil (18.2 degrees). On coating the Perspex surface with protein (PCP), it was observed that the surface properties were modified such that PCP subtended contact angles with air (43.0 degrees) and silicone oil (16.4 degrees) similar to those subtended by ex vivo human retina. Using PCP as an experimental material that mimics ex vivo human retina, spherical chambers were employed in order to examine qualitatively and to quantify the arc of contact obtained with air and silicone oil. It was found that air gave a greater arc of contact for the same percentage fill than silicone oil. PMID:7926877

  18. Intraocular retinal prosthesis.

    PubMed Central

    Humayun, M S

    2001-01-01

    PURPOSE: An electronic implant that can bypass the damaged photoreceptors and electrically stimulate the remaining retinal neurons to restore useful vision has been proposed. A number of key questions remain to make this approach feasible. The goal of this thesis is to address the following 2 specific null hypotheses: (1) Stimulus parameters make no difference in the electrically elicited retinal responses. (2) Just as we have millions of photoreceptors, so it will take a device that can generate millions of pixels/light points to create useful vision. METHODS: For electrophysiologic experiments, 2 different setups were used. In the first setup, charge-balanced pulses were delivered to the retinal surface via electrodes inserted through an open sky approach in normal or blind retinal degenerate (rd) mice. In the second setup, the rabbit retina was removed under red light conditions from an enucleated eye and then maintained in a chamber while being superfused with oxygenated, heated Ames media. In both setups, stimulating electrodes and recording electrodes were positioned on the retinal surface to evaluate the effect of varying stimulation parameters on the orthodromic retinal responses (i.e., recording electrode placed between stimulating electrodes and optic nerve head). For psychophysical experiments, visual images were divided into pixels of light that could be projected in a pattern on the retina in up to 8 sighted volunteers. Subjects were asked to perform various tasks ranging from reading and face recognition to various activities of daily living. RESULTS: Electrophysiologic experiments: In a normal mouse, a single cycle of a 1-kHz sine wave was significantly more efficient than a 1-kHz square wave (P < .05), but no such difference was noted in either of the 8- or 16-week-old rd mouse groups (8-week-old, P = .426; 16-week-old, P = .078). Charge threshold was significantly higher in 16-week-old rd mouse versus both 8-week-old rd and normal mouse for every

  19. Two-Dimensional Island Shape Determined by Detachment

    NASA Astrophysics Data System (ADS)

    Saito, Yukio; Kawasaki, Ryo

    2007-07-01

    Effect of an anisotropic detachment on a heteroepitaxial island shape is studied by means of a kinetic Monte Carlo simulation of a square lattice gas model. Only with molecular deposition followed by surface diffusion, islands grow in a ramified dendritic shape, similar to diffusion-limited aggregate (DLA). Introduction of molecular detachment from edges makes islands compact. To understand an anisotropic island shape observed in the experiment of pentacene growth on a hydrogen-terminated Si(111) vicinal surface, asymmetry in detachment around the substrate step is assumed. Edge molecules detach more to the higher terrace than to the lower terrace. The island edge from which molecules are easy to detach is smooth and the one hard to detach is dendritic. If islands are close to each other, islands tend to align in a line, since detached molecules from the smooth edge of the right island are fed to the dendritic and fast growing edge of the left island.

  20. Retinal Imaging and Image Analysis

    PubMed Central

    Abràmoff, Michael D.; Garvin, Mona K.; Sonka, Milan

    2011-01-01

    Many important eye diseases as well as systemic diseases manifest themselves in the retina. While a number of other anatomical structures contribute to the process of vision, this review focuses on retinal imaging and image analysis. Following a brief overview of the most prevalent causes of blindness in the industrialized world that includes age-related macular degeneration, diabetic retinopathy, and glaucoma, the review is devoted to retinal imaging and image analysis methods and their clinical implications. Methods for 2-D fundus imaging and techniques for 3-D optical coherence tomography (OCT) imaging are reviewed. Special attention is given to quantitative techniques for analysis of fundus photographs with a focus on clinically relevant assessment of retinal vasculature, identification of retinal lesions, assessment of optic nerve head (ONH) shape, building retinal atlases, and to automated methods for population screening for retinal diseases. A separate section is devoted to 3-D analysis of OCT images, describing methods for segmentation and analysis of retinal layers, retinal vasculature, and 2-D/3-D detection of symptomatic exudate-associated derangements, as well as to OCT-based analysis of ONH morphology and shape. Throughout the paper, aspects of image acquisition, image analysis, and clinical relevance are treated together considering their mutually interlinked relationships. PMID:21743764

  1. Perceptual Fading without Retinal Adaptation

    ERIC Educational Resources Information Center

    Hsieh, Po-Jang; Colas, Jaron T.

    2012-01-01

    A retinally stabilized object readily undergoes perceptual fading and disappears from consciousness. This startling phenomenon is commonly believed to arise from local bottom-up sensory adaptation to edge information that occurs early in the visual pathway, such as in the lateral geniculate nucleus of the thalamus or retinal ganglion cells. Here…

  2. High resolution optoelectronic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Loudin, Jim; Dinyari, Rostam; Huie, Phil; Butterwick, Alex; Peumans, Peter; Palanker, Daniel

    2009-02-01

    Electronic retinal prostheses seek to restore sight in patients with retinal degeneration by delivering pulsed electric currents to retinal neurons via an array of microelectrodes. Most implants use inductive or optical transmission of information and power to an intraocular receiver, with decoded signals subsequently distributed to retinal electrodes through an intraocular cable. Surgical complexity could be minimized by an "integrated" prosthesis, in which both power and data are delivered directly to the stimulating array without any discrete components or cables. We present here an integrated retinal prosthesis system based on a photodiode array implant. Video frames are processed and imaged onto the retinal implant by a video goggle projection system operating at near-infrared wavelengths (~ 900 nm). Photodiodes convert light into pulsed electric current, with charge injection maximized by specially optimized series photodiode circuits. Prostheses of three different pixel densities (16 pix/mm2, 64 pix/mm2, and 256 pix/mm2) have been designed, simulated, and prototyped. Retinal tissue response to subretinal implants made of various materials has been investigated in RCS rats. The resulting prosthesis can provide sufficient charge injection for high resolution retinal stimulation without the need for implantation of any bulky discrete elements such as coils or tethers. In addition, since every pixel functions independently, pixel arrays may be placed separately in the subretinal space, providing visual stimulation to a larger field of view.

  3. Retinal connectivity and primate vision

    PubMed Central

    Lee, Barry B.; Martin, Paul R.; Grünert, Ulrike

    2012-01-01

    The general principles of retinal organization are now well known. It may seem surprising that retinal organization in the primate, which has a complex visual behavioral repertoire, appears relatively simple. In this review, we primarily consider retinal structure and function in primate species. Photoreceptor distribution and connectivity are considered as are connectivity in the outer and inner retina. One key issue is the specificity of retinal connections; we suggest that the retina shows connectional specificity but this is seldom complete, and we consider here the functional consequences of imprecise wiring. Finally, we consider how retinal systems can be linked to psychophysical descriptions of different channels, chromatic and luminance, which are proposed to exist in the primate visual system. PMID:20826226

  4. Selective inner retinal layer involvement in early syphilitic retinitis as evidenced by spectral domain OCT

    PubMed Central

    Klemencic, Stephanie A.; Newman, Tricia L.; Messner, Leonard V.

    2011-01-01

    Retinitis as a feature of syphilitic uveitis in immunocompromised individuals is a common finding. We present spectral domain OCT images of early syphilitic retinitis pre and post treatment with penicillin. This case suggests that the inner retinal layers may be selectively involved with early syphilitic retinitis. Early treatment is important to avoid outer layer retinal involvement and to decrease ocular morbidity.

  5. Telemedicine for retinal care in developing nations: the ORBIS Cyber-Sight programme, 2003-2011.

    PubMed

    Amin, Sarina; Patel, Rikin; Beilan, Jonathan; Helveston, Eugene M; Shaikh, Saad

    2014-05-29

    ORBIS International has provided a web-based ophthalmic disease consultation service, Cyber-Sight, for developing nations since 2003. The system connects partner physicians with mentor physicians. We have reviewed consultations concerning retinal cases submitted from June 2003 to December 2011. Of 943 retinal consultations reviewed, 117 were excluded, mainly for reasons of technical limitations at the partner sites. Of the 826 included cases, 504 patients were male and 322 were female. The average age of the patients was 43 years (range 2 months to 86 years). Cases were submitted from partner physicians in 30 countries, with five countries accounting for 82% of the cases (India, Vietnam, Indonesia, China, Jordan). There was a rise in the case submission rate to a peak of 251 cases in 2010. The mean consultant response time was 5 days (SD 9). The mean time to case closure was 19 days (SD 92). The most common diagnoses were diabetic retinopathy (n = 101), retinal vascular occlusion (n = 75) and retinal detachment (n = 61). The working diagnosis submitted by the partner did not match the mentor's diagnosis in 153 cases (19%). The number of incorrect initial partner diagnoses demonstrates that the teleretinal programme serves a useful diagnostic role for partner physicians. The Cyber-Sight programme is a viable method of delivering advanced retinal expertise to partner institutions and increasing capacity for partner doctors in the developing world.

  6. Retinal functional alterations in mice lacking intermediate filament proteins glial fibrillary acidic protein and vimentin.

    PubMed

    Wunderlich, Kirsten A; Tanimoto, Naoyuki; Grosche, Antje; Zrenner, Eberhart; Pekny, Milos; Reichenbach, Andreas; Seeliger, Mathias W; Pannicke, Thomas; Perez, Maria-Thereza

    2015-12-01

    Vimentin (Vim) and glial fibrillary acidic protein (GFAP) are important components of the intermediate filament (IF) (or nanofilament) system of astroglial cells. We conducted full-field electroretinogram (ERG) recordings and found that whereas photoreceptor responses (a-wave) were normal in uninjured GFAP(-/-)Vim(-/-) mice, b-wave amplitudes were increased. Moreover, we found that Kir (inward rectifier K(+)) channel protein expression was reduced in the retinas of GFAP(-/-)Vim(-/-) mice and that Kir-mediated current amplitudes were lower in Müller glial cells isolated from these mice. Studies have shown that the IF system, in addition, is involved in the retinal response to injury and that attenuated Müller cell reactivity and reduced photoreceptor cell loss are observed in IF-deficient mice after experimental retinal detachment. We investigated whether the lack of IF proteins would affect cell survival in a retinal ischemia-reperfusion model. We found that although cell loss was induced in both genotypes, the number of surviving cells in the inner retina was lower in IF-deficient mice. Our findings thus show that the inability to produce GFAP and Vim affects normal retinal physiology and that the effect of IF deficiency on retinal cell survival differs, depending on the underlying pathologic condition.

  7. Herpetic (non-cytomegalovirus) retinal infections in patients with the acquired immunodeficiency syndrome.

    PubMed

    Stewart, Michael W

    2013-04-01

    Human herpes viruses cause significant morbidity in patients with the acquired immunodeficiency syndrome. Even after the introduction of highly active anti-retroviral therapy (HAART), herpes viruses remain the leading causes of blindness in AIDS patients. Cytomegalovirus (CMV) retinitis and the closely-related immune reconstitution uveitis syndrome are the most common causes of blindness, but progressive outer retinal necrosis and acute retinal necrosis due to varicella zoster and herpes simplex are also important causes of vision loss. Successful treatment of these conditions requires an aggressive approach with multi-drug intravenous therapy or repeated intravitreal antiviral injections. Since the rate of retinal detachment is alarmingly high despite successful antiviral therapy, internists and ophthalmologists must work closely together to recognize and treat complications as they arise. Fortunately, Epstein-Barr virus is a rare cause of retinal infection and human herpes virus (HHV)-6, HHV-7, and HHV-8 do not appear to be primary pathogens. However, increasing evidence suggests that HHV-6 and HHV-7 play important roles in modulating the immune system and potentiating infection by CMV.

  8. Telemedicine for retinal care in developing nations: the ORBIS Cyber-Sight programme, 2003-2011.

    PubMed

    Amin, Sarina; Patel, Rikin; Beilan, Jonathan; Helveston, Eugene M; Shaikh, Saad

    2014-05-29

    ORBIS International has provided a web-based ophthalmic disease consultation service, Cyber-Sight, for developing nations since 2003. The system connects partner physicians with mentor physicians. We have reviewed consultations concerning retinal cases submitted from June 2003 to December 2011. Of 943 retinal consultations reviewed, 117 were excluded, mainly for reasons of technical limitations at the partner sites. Of the 826 included cases, 504 patients were male and 322 were female. The average age of the patients was 43 years (range 2 months to 86 years). Cases were submitted from partner physicians in 30 countries, with five countries accounting for 82% of the cases (India, Vietnam, Indonesia, China, Jordan). There was a rise in the case submission rate to a peak of 251 cases in 2010. The mean consultant response time was 5 days (SD 9). The mean time to case closure was 19 days (SD 92). The most common diagnoses were diabetic retinopathy (n = 101), retinal vascular occlusion (n = 75) and retinal detachment (n = 61). The working diagnosis submitted by the partner did not match the mentor's diagnosis in 153 cases (19%). The number of incorrect initial partner diagnoses demonstrates that the teleretinal programme serves a useful diagnostic role for partner physicians. The Cyber-Sight programme is a viable method of delivering advanced retinal expertise to partner institutions and increasing capacity for partner doctors in the developing world. PMID:24875929

  9. Induction of Rapid Detachment in Shewanella oneidensis MR-1 Biofilms

    PubMed Central

    Thormann, Kai M.; Saville, Renée M.; Shukla, Soni; Spormann, Alfred M.

    2005-01-01

    Active detachment of cells from microbial biofilms is a critical yet poorly understood step in biofilm development. We discovered that detachment of cells from biofilms of Shewanella oneidensis MR-1 can be induced by arresting the medium flow in a hydrodynamic biofilm system. Induction of detachment was rapid, and substantial biofilm dispersal started as soon as 5 min after the stop of flow. We developed a confocal laser scanning microscopy-based assay to quantify detachment. The extent of biomass loss was found to be dependent on the time interval of flow stop and on the thickness of the biofilm. Up to 80% of the biomass of 16-h-old biofilms could be induced to detach. High-resolution microscopy studies revealed that detachment was associated with an overall loosening of the biofilm structure and a release of individual cells or small cell clusters. Swimming motility was not required for detachment. Although the loosening of cells from the biofilm structure was observed evenly throughout thin biofilms, the most pronounced detachment in thicker biofilms occurred in regions exposed to the flow of medium, suggesting a metabolic control of detachability. Deconvolution of the factors associated with the stop of medium flow revealed that a sudden decrease in oxygen tension is the predominant trigger for initiating detachment of individual cells. In contrast, carbon limitation did not trigger any substantial detachment, suggesting a physiological link between oxygen sensing or metabolism and detachment. In-frame deletions were introduced into genes encoding the known and putative global transcriptional regulators ArcA, CRP, and EtrA (FNR), which respond to changes in oxygen tension in S. oneidensis MR-1. Biofilms of null mutants in arcA and crp were severely impacted in the stop-of-flow-induced detachment response, suggesting a role for these genes in regulation of detachment. In contrast, an ΔetrA mutant displayed a variable detachment phenotype. From this genetic

  10. The ironic detachment of Edward Gibbon.

    PubMed

    Trosman, Harry

    2009-06-01

    Edward Gibbon, the author of The History of the Decline and Fall of the Roman Empire, has been widely recognized as a master of irony. The historian's early life with parents he found self-serving and unreliable, his reaction to the events surrounding the death of his mother at the age of 9 and the decline of his father, left an impact on his personality and played a role in determining his choice of his life work. Irony has been approached from a psychoanalytic perspective as a mode of communication, as a stylistic device, as a modality through which one might view reality and as a way of uncovering the linkage between pretense and aspiration, between the apparent and the real. Gibbon's ironic detachment can be understood as rooted in his life history. He felt detached from his family of origin, in need of a protective device which would enable him to deal with passion. Sexual and aggressive impulses mobilized defensive postures that were later transformed into an attitude of skepticism and an interest in undercutting false beliefs and irrational authority, positions he attributes to religious ideation which served to instigate historical decline.

  11. The Cave Canyon Detachment: A Standard for Deformation Expected of the Sevier Desert Detachment

    NASA Astrophysics Data System (ADS)

    Anders, M. H.

    2007-12-01

    The Cave Canyon detachment (CCd)is a Neogene normal fault in the Mineral Mountains of west-central Utah. The Mineral Mountains are located directly south of the Sevier Desert basin. Because of its location, orientation and age constraints the Cave Canyon detachment has been proposed to be a non-active splay of the Sevier Desert detachment. The Sevier Desert detachment (SDd) is thought to be one of the largest displaced active normal faults in North America accruing as much as 47 km of displacement. There are some fundamental differences between the CCd and the SDd, one of those being that the CCd places Paleozoic limestone directly on a granitic pluton whereas the SDd beneath the basin places Neogene terrestrial sediments directly on Paleozoic limestones. Nevertheless, the temperature and depth at the time of movement are similar, thus making the CCd an appropriate analog to what might be expected of material potentially recovered by scientific drilling of the SDd. A suite of samples from above and below the CCd yields a distinctive pattern of brittle deformation. In the lower plate granites deformation is mostly brittle, and in the upper plate there is only a minor zone a few cm thick of mylonitized carbonate. The lower plate granites are characterized by an aureole of healed microfractures that decrease in abundance from the contact to background at over 100 m. Cataclasis is observed well over 100 m from the detachment, and is so intense at the contact that no grain is unaffected. Significant growth of new minerals and cross-cutting quartz veins are observed within a few meters of the detachment. In upper plate carbonate rocks, a cm-thick zone of dynamic recrystallization is observed, above which there is a meter or so of extensive undulose extinction of grains. Outward from this is a zone of strongly preferred oriented twinning. At a distance of 15 m from the contact only minor carbonate veinlets distinguish fault zone rock from unaffected limestone. If the SDd

  12. Detection of detachments and inhomogeneities in frescos by Compton scattering

    NASA Astrophysics Data System (ADS)

    Castellano, A.; Cesareo, R.; Buccolieri, G.; Donativi, M.; Palamà, F.; Quarta, S.; De Nunzio, G.; Brunetti, A.; Marabelli, M.; Santamaria, U.

    2005-07-01

    A mobile instrument has been developed for the detection and mapping of detachments in frescos by using Compton back scattered photons. The instrument is mainly composed of a high energy X-ray tube, an X-ray detection system and a translation table. The instrument was first applied to samples simulating various detachment situations, and then transferred to the Vatican Museum to detect detachments and inhomogeneities in the stanza di Eliodoro, one of the "Raphael's stanze".

  13. Intercellular Adhesion-Dependent Cell Survival and ROCK-Regulated Actomyosin-Driven Forces Mediate Self-Formation of a Retinal Organoid.

    PubMed

    Lowe, Albert; Harris, Raven; Bhansali, Punita; Cvekl, Ales; Liu, Wei

    2016-05-10

    In this study we dissected retinal organoid morphogenesis in human embryonic stem cell (hESC)-derived cultures and established a convenient method for isolating large quantities of retinal organoids for modeling human retinal development and disease. Epithelialized cysts were generated via floating culture of clumps of Matrigel/hESCs. Upon spontaneous attachment and spreading of the cysts, patterned retinal monolayers with tight junctions formed. Dispase-mediated detachment of the monolayers and subsequent floating culture led to self-formation of retinal organoids comprising patterned neuroretina, ciliary margin, and retinal pigment epithelium. Intercellular adhesion-dependent cell survival and ROCK-regulated actomyosin-driven forces are required for the self-organization. Our data supports a hypothesis that newly specified neuroretina progenitors form characteristic structures in equilibrium through minimization of cell surface tension. In long-term culture, the retinal organoids autonomously generated stratified retinal tissues, including photoreceptors with ultrastructure of outer segments. Our system requires minimal manual manipulation, has been validated in two lines of human pluripotent stem cells, and provides insight into optic cup invagination in vivo. PMID:27132890

  14. Evolution of the combat and operational stress control detachment.

    PubMed

    Dailey, Jason I; Ijames, Victoria L

    2014-01-01

    Medical units designed to provide combat and operational stress control services have evolved since World War II into the current Combat and Operational Stress Control (COSC) detachments. Yet the structure of these COSC detachments differ greatly between what is authorized in the table of organization and equipment (TO&E) and what is doctrinally described in the current field manual guiding combat and operational stress control operations. We therefore explore the evolution of the COSC detachment, compare the organizations found in current doctrine with that currently authorized on the TO&E, and conclude with a proposed structure of a modern COSC detachment that is functionally modular with more clear chains of command.

  15. Flexible retinal electrode array

    DOEpatents

    Okandan, Murat; Wessendorf, Kurt O.; Christenson, Todd R.

    2006-10-24

    An electrode array which has applications for neural stimulation and sensing. The electrode array can include a large number of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. The electrode array can be formed from a combination of bulk and surface micromachining, with electrode tips that can include an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis where the electrodes can be tailored to provide a uniform gentle contact pressure with optional sensing of this contact pressure at one or more of the electrodes.

  16. Resveratrol inhibits epithelial-mesenchymal transition of retinal pigment epithelium and development of proliferative vitreoretinopathy

    PubMed Central

    Ishikawa, Keijiro; He, Shikun; Terasaki, Hiroto; Nazari, Hossein; Zhang, Huiming; Spee, Christine; Kannan, Ram; Hinton, David R

    2015-01-01

    Proliferative vitreoretinopathy (PVR) is a serious complication of retinal detachment and ocular trauma, and its recurrence may lead to irreversible vision loss. Epithelial to mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is a critical step in the pathogenesis of PVR, which is characterized by fibrotic membrane formation and traction retinal detachment. In this study, we investigated the potential impact of resveratrol (RESV) on EMT and the fibrotic process in cultured RPE cells and further examined the preventive effect of RESV on PVR development using a rabbit model of PVR. We found that RESV induces mesenchymal to epithelial transition (MET) and inhibits transforming growth factor-β2(TGF-β2)-induced EMT of RPE cells by deacetylating SMAD4. The effect of RESV on MET was dependent on sirtuin1 activation. RESV suppressed proliferation, migration and fibronectin synthesis induced by platelet-derived growth factor-BB or TGF-β2. In vivo, RESV inhibited the progression of experimental PVR in rabbit eyes. Histological findings showed that RESV reduced fibrotic membrane formation and decreased α-SMA expression in the epiretinal membranes. These results suggest the potential use of RESV as a therapeutic agent to prevent the development of PVR by targeting EMT of RPE. PMID:26552368

  17. Intraocular retinal transplantation: a review.

    PubMed

    Hammer, R M; Yinon, U

    1991-01-01

    This review covers intraocular transplantation of retinal tissue. This has importance both for theoretical understanding of retinal and neural development and for possible future clinical application. Transplantation sites have ranged from the anterior chamber through the retina to the subretinal space. Transplanted tissue has ranged from whole retina to specific retinal layers or specific types of retinal cells. Both within-species and inter-species transplants have been performed, and donor age has ranged from embryonic to adult. The ability of transplanted tissue to be accepted and to differentiate in host eyes has been studied. The conditions under which successful transplants are obtained, host-graft interactions, and transplantation methodologies have been explored. Morphological, and to a small extent, also functional characteristics of the transplants have been studied. PMID:1747393

  18. Detachment of a single water drop

    NASA Astrophysics Data System (ADS)

    Chashechkin, Yu. D.; Prokhorov, V. E.

    2014-01-01

    The detachment process of a single water drop from a nozzle made of poorly wetted material is followed using high-speed video equipment. The formation and motion dynamics of various flow components are investigated. These are the drop itself; a liquid bridge (jumper), which connects the drop with the mother liquid; the primary satellite, which is formed from the jumper; and a microsatellite, which is thrown from the satellite and flies to the mother liquid. The strong influence of surface effects, under which the satellite initially moves upward and only at a certain time starts to fall along the ballistic trajectory, is established. Bounce of the microsatellite from the mother liquid, which precedes its absorption, is fixed. It is shown that a stable connection of the formation mechanism of satellites with the jumper dynamics opens the possibility of obtaining uniform-sized drops.

  19. Crystal Shape Evolution in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2013-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described.

  20. Changes in spectral properties of detached leaves

    NASA Technical Reports Server (NTRS)

    Daughtry, C. S. T.; Biehl, L. L.

    1984-01-01

    If leaf senescence can be delayed for several days without significant changes in spectral properties, then samples of leaves at remote test sites could be prepared and shipped to laboratories to measure spectral properties. The changes in spectral properties of detached leaves were determined. Leaves from red birch and red pine were immersed in water or 0.001 M benzylaminopurine (BAP) and stored in plastic bags in the dark at either 5 or 25 C. Total directional-hemispherical reflectance and transmittance of the adaxial surface of birch leaves were measured over the 400 to 1100 nm wavelength region with a spectroradiometer and integrating sphere. Pine needles were taped together and reflectance of the mat of needles was measured. Spectral properties changed less than 5% of initial values during the first week when leaves were stored at 5 C. Storage at 25 C promoted rapid senescence and large changes in spectral properties. BAP delayed, but did not stop, senescence at 25 C.

  1. Crystal Shape Evolution in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2013-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described

  2. DETACHMENT OF BACTERIOPHAGE FROM ITS CARRIER PARTICLES.

    PubMed

    Hetler, D M; Bronfenbrenner, J

    1931-05-20

    The active substance (phage) present in the lytic broth filtrate is distributed through the medium in the form of particles. These particles vary in size within broad limits. The average size of these particles as calculated on the basis of the rate of diffusion approximates 4.4 mmicro in radius. Fractionation by means of ultrafiltration permits partial separation of particles of different sizes. Under conditions of experiments here reported the particles varied in the radius size from 0.6 mmicro to 11.4 mmicro. The active agent apparently is not intimately identified with these particles. It is merely carried by them by adsorption, and under suitable experimental conditions it can be detached from the larger particles and redistributed on smaller particles of the medium.

  3. Microsystems Technology for Retinal Implants

    NASA Astrophysics Data System (ADS)

    Weiland, James

    2005-03-01

    The retinal prosthesis is targeted to treat age-related macular degeneration, retinitis pigmentosa, and other outer retinal degenerations. Simulations of artificial vision have predicted that 600-1000 individual pixels will be needed if a retinal prosthesis is to restore function such as reading large print and face recognition. An implantable device with this many electrode contacts will require microsystems technology as part of its design. An implantable retinal prosthesis will consist of several subsystems including an electrode array and hermetic packaging. Microsystems and microtechnology approaches are being investigated as possible solutions for these design problems. Flexible polydimethylsiloxane (PDMS) substrate electrode arrays and silicon micromachined electrode arrays are under development. Inactive PDMS electrodes have been implanted in 3 dogs to assess mechanical biocompatibility. 3 dogs were followed for 6 months. The implanted was securely fastened to the retina with a single retinal tack. No post-operative complications were evident. The array remained within 100 microns of the retinal surface. Histological evaluation showed a well preserved retina underneath the electrode array. A silicon device with electrodes suspended on micromachined springs has been implanted in 4 dogs (2 acute implants, 2 chronic implants). The device, though large, could be inserted into the eye and positioned on the retina. Histological analysis of the retina from the spring electrode implants showed that spring mounted posts penetrated the retina, thus the device will be redesigned to reduce the strength of the springs. These initial implants will provide information for the designers to make the next generation silicon device. We conclude that microsystems technology has the potential to make possible a retinal prosthesis with 1000 individual contacts in close proximity to the retina.

  4. Recurrent Annular Peripheral Choroidal Detachment after Trabeculectomy

    PubMed Central

    Liu, Shaohui; Sun, Lisa L.; Kavanaugh, A. Scott; Langford, Marlyn P.; Liang, Chanping

    2013-01-01

    We report a challenging case of recurrent flat anterior chamber without hypotony after trabeculectomy in a 54-year-old Black male with a remote history of steroid-treated polymyositis, cataract surgery, and uncontrolled open angle glaucoma. The patient presented with a flat chamber on postoperative day 11, but had a normal fundus exam and intraocular pressure (IOP). Flat chamber persisted despite treatment with cycloplegics, steroids, and a Healon injection into the anterior chamber. A transverse B-scan of the peripheral fundus revealed a shallow annular peripheral choroidal detachment. The suprachoroidal fluid was drained. The patient presented 3 days later with a recurrent flat chamber and an annular peripheral choroidal effusion. The fluid was removed and reinforcement of the scleral flap was performed with the resolution of the flat anterior chamber. A large corneal epithelial defect developed after the second drainage. The oral prednisone was tapered quickly and the topical steroid was decreased. One week later, his vision decreased to count fingers with severe corneal stromal edema and Descemet's membrane folds that improved to 20/50 within 24 h of resumption of the oral steroid and frequent topical steroid. The patient's visual acuity improved to 20/20 following a slow withdrawal of the oral and topical steroid. Eight months after surgery, the IOP was 15 mm Hg without glaucoma medication. The detection of a shallow anterior choroidal detachment by transverse B-scan is critical to making the correct diagnosis. Severe cornea edema can occur if the steroid is withdrawn too quickly. Thus, steroids should be tapered cautiously in steroid-dependent patients. PMID:24348402

  5. The Oman Ophiolite from Detachment to Obduction

    NASA Astrophysics Data System (ADS)

    Boudier, F. I.

    2014-12-01

    An overview model is presented accounting for older and up-dated published data. Detachment of the Oman ophiolite exhumed a 20 km thick fragment of oceanic lithosphere 500 x 100 km2 in extension. This detachment occurred at margin of a fast spreading NeoTethyan Ocean, at P/T conditions ~900°C-200 MPa, 95-95.5 Ma ago. The Hawasinah nappes underlying the ophiolite at present, represent the stacking of the sedimentary cover deposited on the Arabian continental margin, thinned and rifted since Permian time, and extending more than 300 km north from the present shore. The sedimentary record points to the collapse of the continental basement at Jurassic-Cretaceous boundary, 140 Ma ago. Subduction of the rifted continental margin is inferred, as recorded in the Saih Hatat high-pressure rocks whose metamorphic age 80-140 Ma is discussed, as well as the vergence of related subduction. Late Cretaceous time 85-70 Ma marks the emplacement of the Oman ophiolite in the Muti Basin, to its present position inland the Permo-Triassic continental margin. These episodes are not similarly recorded in the northern part of the Oman Mountains, that do not expose any HP metamorphic belt, but granulitic crustal rocks and large development of syn-obduction non-MORB magmatism in the ophiolite crustal section. Collision is achieved at the northern tip, the Musandam area, linked to the opening of the Gulf of Aden 25 Ma ago, and northward drift of the Arabian Plate.

  6. Retinal oxygen extraction in humans

    NASA Astrophysics Data System (ADS)

    Werkmeister, René M.; Schmidl, Doreen; Aschinger, Gerold; Doblhoff-Dier, Veronika; Palkovits, Stefan; Wirth, Magdalena; Garhöfer, Gerhard; Linsenmeier, Robert A.; Leitgeb, Rainer A.; Schmetterer, Leopold

    2015-10-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal blood flow was 44.3 ± 9.0 μl/min during baseline and decreased to 18.7 ± 4.2 μl/min during 100% oxygen breathing (P < 0.001) resulting in a pronounced decrease in retinal oxygen extraction from 2.33 ± 0.51 μl(O2)/min to 0.88 ± 0.14 μl(O2)/min during breathing of 100% oxygen. The method presented in this paper may have significant potential to study oxygen metabolism in hypoxic retinal diseases such as diabetic retinopathy.

  7. Retinal implants: a systematic review.

    PubMed

    Chuang, Alice T; Margo, Curtis E; Greenberg, Paul B

    2014-07-01

    Retinal implants present an innovative way of restoring sight in degenerative retinal diseases. Previous reviews of research progress were written by groups developing their own devices. This systematic review objectively compares selected models by examining publications describing five representative retinal prostheses: Argus II, Boston Retinal Implant Project, Epi-Ret 3, Intelligent Medical Implants (IMI) and Alpha-IMS (Retina Implant AG). Publications were analysed using three criteria for interim success: clinical availability, vision restoration potential and long-term biocompatibility. Clinical availability: Argus II is the only device with FDA approval. Argus II and Alpha-IMS have both received the European CE Marking. All others are in clinical trials, except the Boston Retinal Implant, which is in animal studies. Vision restoration: resolution theoretically correlates with electrode number. Among devices with external cameras, the Boston Retinal Implant leads with 100 electrodes, followed by Argus II with 60 electrodes and visual acuity of 20/1262. Instead of an external camera, Alpha-IMS uses a photodiode system dependent on natural eye movements and can deliver visual acuity up to 20/546. Long-term compatibility: IMI offers iterative learning; Epi-Ret 3 is a fully intraocular device; Alpha-IMS uses intraocular photosensitive elements. Merging the results of these three criteria, Alpha-IMS is the most likely to achieve long-term success decades later, beyond current clinical availability. PMID:24403565

  8. Intravitreal Injection of Bevacizumab in Primary Vitrectomy to Decrease the Rate of Retinal Redetachment: A Randomized Pilot Study

    PubMed Central

    Tousi, Adib; Hasanpour, Hossein; Soheilian, Masoud

    2016-01-01

    Purpose: To evaluate the effect of intravitreal bevacizumab (IVB) as a surgical adjunct in prevention of proliferative vitreoretinopathy (PVR) after retinal detachment surgery. Methods: In this controlled, randomized pilot study, 27 patients with primary retinal detachment undergoing pars plana deep vitrectomy were included. Of these, 12 received IVB at the end of procedure. The anatomic success and best corrected visual acuity (BCVA) were compared to the control group at months 3 and 6 postoperatively. Results: At three month follow-up, 3 of 11 eyes (27.3%) had detached retinas in the IVB group versus 6 of 12 (50.0%) in the control group (P = 0.40). At six-month follow-up, 3 of 10 eyes (30%) had detached retinas in the IVB group versus 3 in 8 (37.5%) in the control group (P > 0.99). Mean logMAR BCVA improved significantly in both groups relative to baseline, but did not show a significant difference at three-and six-month follow-ups between the two groups. Conclusion: Our preliminary results show neither a benefit nor any harm from intervention in both anatomic and visual outcomes. Our results support conducting additional studies to evaluate the effect of intravitreal bevacizumab on postoperative PVR. PMID:27621784

  9. Role of edge turbulence in detached divertor plasmas

    NASA Astrophysics Data System (ADS)

    Gang, F. Y.; Sigmar, D. J.; Krasheninnikov, S. I.

    1996-04-01

    The role of edge turbulence in detached divertor plasmas is investigated. It is shown that the edge turbulence, through poloidal transport of parallel momentum, can produce a significant plasma pressure drop along the magnetic field lines toward the divertor plate, a feature that characterizes the detached divertor plasma regime.

  10. Frictional and elastic energy in gecko adhesive detachment.

    PubMed

    Gravish, Nick; Wilkinson, Matt; Autumn, Kellar

    2008-03-01

    Geckos use millions of adhesive setae on their toes to climb vertical surfaces at speeds of over 1 m s(-1). Climbing presents a significant challenge for an adhesive since it requires both strong attachment and easy, rapid removal. Conventional pressure-sensitive adhesives are either strong and difficult to remove (e.g. duct tape) or weak and easy to remove (e.g. sticky notes). We discovered that the energy required to detach adhering tokay gecko setae (W(d)) is modulated by the angle (theta) of a linear path of detachment. Gecko setae resist detachment when dragged towards the animal during detachment (theta = 30 degrees ) requiring W(d) = 5.0+/-0.86(s.e.) J m(-2) to detach, largely due to frictional losses. This external frictional loss is analogous to viscous internal frictional losses during detachment of pressure-sensitive adhesives. We found that, remarkably, setae possess a built-in release mechanism. Setae acted as springs when loaded in tension during attachment and returned elastic energy when detached along the optimal path (theta=130 degrees ), resulting in W(d) = -0.8+/-0.12 J m(-2). The release of elastic energy from the setal shaft probably causes spontaneous release, suggesting that curved shafts may enable easy detachment in natural, and synthetic, gecko adhesives.

  11. Ruptured retinal arterial macroaneurysm: diagnosis and management.

    PubMed

    Speilburg, Ashley M; Klemencic, Stephanie A

    2014-01-01

    Retinal arterial macroaneurysm is an acquired, focal dilation of a retinal artery, typically occurring within the first three bifurcations of the central retinal artery. The clinical presentation of a retinal arterial macroaneurysm is highly variable, making initial diagnosis difficult and differentials many. Identification of retinal arterial macroaneurysms is crucial to appropriately co-manage with the primary care physician for hypertension control. Prognosis is generally good and observation is often an adequate treatment. However, in cases of macular threat or involvement, some treatment options are available and referral to a retinal specialist is indicated.

  12. Spontaneous Solitaire™ AB Thrombectomy Stent Detachment During Stroke Treatment

    SciTech Connect

    Akpinar, Suha Yilmaz, Guliz

    2015-04-15

    Spontaneous Solitaire™ stent retriever detachment is a rarely defined entity seen during stroke treatment, which can result in a disastrous clinical outcome if it cannot be solved within a critical stroke treatment time window. Two solutions to this problem are presented in the literature. The first is to leave the stent in place and apply angioplasty to the detached stent, while the second involves surgically removing the stent from the location at which it detached. Here, we present a case of inadvertent stent detachment during stroke treatment for a middle cerebral artery M1 occlusion resulting in progressive thrombosis. The detached stent was removed endovascularly by another Solitaire stent, resulting in the recanalization of the occluded middle cerebral artery.

  13. Droplet detachment by air flow for microstructured superhydrophobic surfaces.

    PubMed

    Hao, Pengfei; Lv, Cunjing; Yao, Zhaohui

    2013-04-30

    Quantitative correlation between critical air velocity and roughness of microstructured surface has still not been established systematically until the present; the dynamics of water droplet detachment by air flow from micropillar-like superhydrophobic surfaces is investigated by combining experiments and simulation comparisons. Experimental evidence demonstrates that the onset of water droplet detachment from horizontal micropillar-like superhydrophobic surfaces under air flow always starts with detachment of the rear contact lines of the droplets from the pillar tops, which exhibits a similar dynamic mechanism for water droplet motion under a gravity field. On the basis of theoretical analysis and numerical simulation, an explicit analytical model is proposed for investigating the detaching mechanism, in which the critical air velocity can be fully determined by several intrinsic parameters: water-solid interface area fraction, droplet volume, and Young's contact angle. This model gives predictions of the critical detachment velocity of air flow that agree well with the experimental measurements.

  14. Three-dimensional necking during viscous slab detachment

    NASA Astrophysics Data System (ADS)

    Tscharner, M.; Schmalholz, S. M.; Duretz, T.

    2014-06-01

    We study the three-dimensional (3-D) deformation during detachment of a lithospheric slab with simple numerical models using the finite element method. An initially vertical layer of power law viscous fluid mimics the slab and is surrounded by a linear or power law viscous fluid representing asthenospheric mantle. We quantify the impact of slab size and shape (symmetric/asymmetric) on slab detachment and identify two processes that control the lateral (i.e., along-trench) slab deformation: (1) the horizontal deflection of the lateral, vertical slab sides (> 100 km with velocities up to 16 mm/yr) and (2) the propagation of localized thinning (necking) inside the slab (with velocities >9 cm/yr). The lateral propagation velocity is approximately constant during slab detachment. Larger slabs (here wider than approximately 300 km) detach with rates similar to those predicted by 2-D models, whereas smaller slabs detach slower. Implications for geodynamic processes and interpretations of seismic tomography are discussed.

  15. Dissociative detachment relates to psychotic symptoms and personality decompensation.

    PubMed

    Allen, J G; Coyne, L; Console, D A

    1997-01-01

    Previous studies have addressed the prominence of psychotic symptoms in conjunction with multiple personality disorder (now dissociative identity disorder). The present study examines the relation between psychotic symptoms and a more pervasive form of dissociative disturbance, namely dissociative detachment. Two hundred sixty-six women in inpatient treatment for severe trauma-related disorders completed the Dissociative Experiences Scale (DES), and 102 of these patients also completed the Millon Clinical Multiaxial Inventory (MCMI-III). A factor analysis of the DES yielded two dimensions of dissociative detachment: detachment from one's own actions and detachment from the self and the environment. Each of these DES dimensions relates strongly to the thought disorder and schizotypal personality disorder scales of the MCMI-III. We propose that severe dissociative detachment, by virtue of loosening the moorings in inner and outer reality, is conducive to psychotic symptoms and personality decompensation.

  16. A novel platform for minimally invasive delivery of cellular therapy as a thin layer across the subretina for treatment of retinal degeneration

    NASA Astrophysics Data System (ADS)

    Rotenstreich, Ygal; Tzameret, Adi; Kalish, Sapir E.; Belkin, Michael; Meir, Amilia; Treves, Avraham J.; Nagler, Arnon; Sher, Ifat

    2015-03-01

    Incurable retinal degenerations affect millions worldwide. Stem cell transplantation rescued visual functions in animal models of retinal degeneration. In those studies cells were transplanted in subretinal "blebs", limited number of cells could be injected and photoreceptor rescue was restricted to areas in proximity to the injection sites. We developed a minimally-invasive surgical platform for drug and cell delivery in a thin layer across the subretina and extravascular spaces of the choroid. The novel system is comprised of a syringe with a blunt-tipped needle and an adjustable separator. Human bone marrow mesenchymal stem cells (hBM-MSCs) were transplanted in eyes of RCS rats and NZW rabbits through a longitudinal triangular scleral incision. No immunosuppressants were used. Retinal function was determined by electroretinogram analysis and retinal structure was determined by histological analysis and OCT. Transplanted cells were identified as a thin layer across the subretina and extravascular spaces of the choroid. In RCS rats, cell transplantation delayed photoreceptor degeneration across the entire retina and significantly enhanced retinal functions. No retinal detachment or choroidal hemorrhages were observed in rabbits following transplantation. This novel platform opens a new avenue for drug and cell delivery, placing the transplanted cells in close proximity to the damaged RPE and retina as a thin layer, across the subretina and thereby slowing down cell death and photoreceptor degeneration, without retinal detachment or choroidal hemorrhage. This new transplantation system may increase the therapeutic effect of other cell-based therapies and therapeutic agents. This study is expected to directly lead to phase I/II clinical trials for autologous hBM-MSCs transplantation in retinal degeneration patients.

  17. Tricuspid valve detachment in closure of congenital ventricular septal defect.

    PubMed

    Zhao, Jinping; Li, Jun; Wei, Xiang; Zhao, Bo; Sun, Wei

    2003-01-01

    From January 1991 through December 2001, 600 patients underwent closure of a perimembranous ventricular septal defect through a right atrial approach at our institution. In 122 of these patients, the operation included temporary detachment of a tricuspid valve septal leaflet from the annulus to allow complete visualization of a perimembranous ventricular septal defect The mean age of the patients at surgery was 4.6 years in those who underwent leaflet detachment and 4.7 years in the 478 patients who did not (P > 0.05). Preoperatively, all patients were in sinus rhythm. Echocardiography showed trivial tricuspid regurgitation in 21 of the patients undergoing detachment and in 39 of the non-detachment patients. There was no difference in bypass time or aortic cross-clamp time between the 2 groups. Postoperatively, 3 patients in the non-detachment group had heart block; all other patients were in sinus rhythm. Echocardiograms on the 7th postoperative day showed small residual ventricular septal defects in none of the patients who underwent valve detachment and in 10 of the non-detachment patients; mild tricuspid regurgitation was present in 12 non-detachment patients only; and trivial tricuspid regurgitation was present in 19 patients who underwent valve detachment and in 29 who did not. There was no hospital death in either group. Long-term follow-up showed no progression of tricuspid regurgitation or tricuspid stenosis. All patients remained in sinus rhythm. This study suggests that tricuspid valve detachment is a safe, effective technique that improves exposure for ventricular septal defect repair and does not adversely affect valve competence. PMID:12638669

  18. Optoacoustic online temperature determination during retinal laser photocoagulation

    NASA Astrophysics Data System (ADS)

    Schlott, Kerstin; Stalljohann, Jens; Weber, Benjamin; Kandulla, Jochen; Herrmann, Katharina; Birngruber, Reginald; Brinkmann, Ralf

    2007-07-01

    Retinal photocoagulation is an established treatment of different retinal diseases. The treatment relies on a short, local heating of the tissue which induces a denaturation. The resulting scar formation may for example prevent the further detachment of the retina. The extent of the coagulation is besides other parameters mostly dependent on the induced temperature increase. However, until today a temperature based dosimetry for photocoagulation does not exist. The dosage is rather based on the experience of the treating physicians to achieve visible whitish lesions on the retina. In this work a technique is presented, which allows an online temperature monitoring during photocoagulation. If an absorbing material is irradiated with short laser pulses, a thermoelastic expansion of the absorber induces an acoustic wave. Its amplitude is dependent on the temperature of the absorber. For analyzing the applicability of the optoacoustic temperature determination for dosimetry, measurements were performed on enucleated porcine eye globes. The pressure transients are detected by an ultrasonic transducer, which is embedded in an ophthalmologic contact lens. As long as no strong lesions occur, the determined temperatures are almost proportional to the power of the treatment laser. Using a spot diameter of 200 μm and different laser powers, the temperature rise at the end of the 400 ms irradiation was found to be approximately 0.16 °C/mW. The onset of the denaturation was observed around 50°C. The far aim of this project is an automatic regulation of the treatment laser onto a desired temperature course.

  19. Temperature controlled retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Schlott, Kerstin; Koinzer, Stefan; Baade, Alexander; Birngruber, Reginald; Roider, Johann; Brinkmann, Ralf

    2013-06-01

    Retinal photocoagulation lacks objective dosage in clinical use, thus the commonly applied lesions are too deep and strong, associated with pain reception and the risk of visual field defects and induction of choroidal neovascularisations. Optoacoustics allows real-time non-invasive temperature measurement in the fundus during photocoagulation by applying short probe laser pulses additionally to the treatment radiation, which excite the emission of ultrasonic waves. Due to the temperature dependence of the Grüneisen parameter, the amplitudes of the ultrasonic waves can be used to derive the temperature of the absorbing tissue. By measuring the temperatures in real-time and automatically controlling the irradiation by feedback to the treatment laser, the strength of the lesions can be defined. Different characteristic functions for the time and temperature dependent lesion sizes were used as rating curves for the treatment laser, stopping the irradiation automatically after a desired lesion size is achieved. The automatically produced lesion sizes are widely independent of the adjusted treatment laser power and individual absorption. This study was performed on anaesthetized rabbits and is a step towards a clinical trial with automatically controlled photocoagulation.

  20. Retinal Endothelial Cell Apoptosis Stimulates Recruitment of Endothelial Progenitor Cells

    PubMed Central

    Bhatwadekar, Ashay D.; Glenn, Josephine V.; Curtis, Tim M.; Grant, Maria B.; Stitt, Alan W.; Gardiner, Tom A.

    2013-01-01

    Purpose Bone marrow–derived endothelial progenitor cells (EPCs) contribute to vascular repair although it is uncertain how local endothelial cell apoptosis influences their reparative function. This study was conducted to determine how the presence of apoptotic bodies at sites of endothelial damage may influence participation of EPCs in retinal microvascular repair. Methods Microlesions of apoptotic cell death were created in monolayers of retinal microvascular endothelial cells (RMECs) by using the photodynamic drug verteporfin. The adhesion of early-EPCs to these lesions was studied before detachment of the apoptotic cells or after their removal from the wound site. Apoptotic bodies were fed to normal RMECs and mRNA levels for adhesion molecules were analyzed. Results Endothelial lesions where apoptotic bodies were left attached at the wound site showed a fivefold enhancement in EPC recruitment (P < 0.05) compared with lesions where the apoptotic cells had been removed. In intact RMEC monolayers exposed to apoptotic bodies, expression of ICAM, VCAM, and E-selectin was upregulated by 5- to 15-fold (P < 0.05– 0.001). EPCs showed a characteristic chemotactic response (P < 0.05) to conditioned medium obtained from apoptotic bodies, whereas analysis of the medium showed significantly increased levels of VEGF, IL-8, IL-6, and TNF-α when compared to control medium; SDF-1 remained unchanged. Conclusions The data indicate that apoptotic bodies derived from retinal capillary endothelium mediate release of proangiogenic cytokines and chemokines and induce adhesion molecule expression in a manner that facilitates EPC recruitment. PMID:19474402

  1. Pseudotumoral and Multiple Retinal Pigment Epithelium Proliferation in Vogt-Koyanagi-Harada Disease.

    PubMed

    Yepez, Juan B; Murati, Felipe; Petitto, Michele; Arevalo, J Fernando

    2015-01-01

    We report a case of pseudotumoral retinal pigment epithelium (RPE) proliferation in Vogt-Koyanagi-Harada (VKH) disease, in a 50-year-old female who presented with a juxtapapillary and peripheral subretinal hyperpigmented lesions in the left eye and "sunset glow fundus," hyperpigmented striae, and multiple atrophic chorioretinal spots in the periphery. The darkly pigmented exuberant larger subretinal mass extended to the periphery with associated subretinal fibrosis. This patient demonstrated the entire clinical presentation of VKH disease, which tends to course with a chronic, bilateral, granulomatous panuveitis and exudative retinal detachment associated with poliosis, vitiligo, alopecia, and central nervous system and auditory signs. Our case is unique for the presence of exuberant, pseudotumoral RPE proliferation at the juxtapapillary region and peripheral area. Although this complication has rarely been reported, a high index of suspicion is warranted for early diagnosis and avoids unnecessary treatments of a pseudotumor. PMID:26509089

  2. Descemet's Membrane Detachment Management Following Trabeculectomy

    PubMed Central

    Sharifipour, Farideh; Nassiri, Saman; Idan, Aida

    2016-01-01

    Purpose: To present a case of total Descemet's membrane detachment (DMD) after trabeculectomy and its surgical management. Case Report: A 68-year-old woman presented with large DMD and corneal edema one day after trabeculectomy. Intracameral air injection on day 3 was not effective. Choroidal effusion complicated the clinical picture with Descemet's membrane (DM) touching the lens. Choroidal tap with air injection on day 6 resulted in DM attachment and totally clear cornea on the next day. However, on day 12 the same scenario was repeated with choroidal effusion, shallow anterior chamber (AC), and DM touching the lens. The third surgery included transconjunctival closure of the scleral flap with 10/0 nylon sutures, choroidal tap, and intracameral injection of 20% sulfur hexafluoride. After the third surgery, DM remained attached with clear cornea. Suture removal and needling bleb revision preserved bleb function. Lens opacity progressed, and the patient underwent uneventful cataract surgery 4 months later. Conclusion: Scleral flap closure using transconjunctival sutures can be used for DMD after trabeculectomy to make the eye a closed system. Surgical drainage of choroidal effusions should be considered to increase the AC depth. PMID:27621793

  3. Descemet's Membrane Detachment Management Following Trabeculectomy

    PubMed Central

    Sharifipour, Farideh; Nassiri, Saman; Idan, Aida

    2016-01-01

    Purpose: To present a case of total Descemet's membrane detachment (DMD) after trabeculectomy and its surgical management. Case Report: A 68-year-old woman presented with large DMD and corneal edema one day after trabeculectomy. Intracameral air injection on day 3 was not effective. Choroidal effusion complicated the clinical picture with Descemet's membrane (DM) touching the lens. Choroidal tap with air injection on day 6 resulted in DM attachment and totally clear cornea on the next day. However, on day 12 the same scenario was repeated with choroidal effusion, shallow anterior chamber (AC), and DM touching the lens. The third surgery included transconjunctival closure of the scleral flap with 10/0 nylon sutures, choroidal tap, and intracameral injection of 20% sulfur hexafluoride. After the third surgery, DM remained attached with clear cornea. Suture removal and needling bleb revision preserved bleb function. Lens opacity progressed, and the patient underwent uneventful cataract surgery 4 months later. Conclusion: Scleral flap closure using transconjunctival sutures can be used for DMD after trabeculectomy to make the eye a closed system. Surgical drainage of choroidal effusions should be considered to increase the AC depth.

  4. Stability of Menisci in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.

    2013-01-01

    Detached growth, also referred to as dewetted growth, is a Bridgman crystal growth process in which the melt is in contact with the crucible wall but the crystal is not. A meniscus bridges the gap between the top of the crystal and the crucible wall. The meniscus shape depends on the contact angle of the melt with the crucible wall, the growth angle of the melt with respect to the solidifying crystal, the gas pressure differential, the Weber number describing the rotation rate of the crucible, and the Bond number. Only some of the meniscus shapes are stable and the stability criterion is the sign of the second variation of the potential energy upon admissible meniscus shape perturbations. The effects of confined gas volumes above and below the melt and crucible rotation are evaluated. The analysis is applicable to the non-stationary case where the crystal radius changes during growth. Static stability maps (crystal radius versus pressure differential) are obtained for a series of Bond numbers, growth angles and Weber numbers. Also, the specific cases of Ge and InSb, in both terrestrial and microgravity conditions, are analyzed. Stability was found to depend significantly on whether the interior surface was considered to be microscopically rough or smooth, corresponding to pinned or unpinned states. It was also found that all meniscus shapes are statically stable in a microgravity environment.

  5. Magnetic Nozzle and Plasma Detachment Experiment

    NASA Technical Reports Server (NTRS)

    Chavers, Gregory; Dobson, Chris; Jones, Jonathan; Martin, Adam; Bengtson, Roger D.; Briezman, Boris; Arefiev, Alexey; Cassibry, Jason; Shuttpelz, Branwen; Deline, Christopher

    2006-01-01

    High power plasma propulsion can move large payloads for orbit transfer (such as the ISS), lunar missions, and beyond with large savings in fuel consumption owing to the high specific impulse. At high power, lifetime of the thruster becomes an issue. Electrodeless devices with magnetically guided plasma offer the advantage of long life since magnetic fields confine the plasma radially and keep it from impacting the material surfaces. For decades, concerns have been raised about the plasma remaining attached to the magnetic field and returning to the vehicle along the closed magnetic field lines. Recent analysis suggests that this may not be an issue of the magnetic field is properly shaped in the nozzle region and the plasma has sufficient energy density to stretch the magnetic field downstream. An experiment was performed to test the theory regarding the Magneto-hydrodynamic (MHD) detachment scenario. Data from this experiment will be presented. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) being developed by the Ad Astra Rocket Company uses a magnetic nozzle as described above. The VASIMR is also a leading candidate for exploiting an electric propulsion test platform being considered for the ISS.

  6. Using optical coherence tomography to elucidate the impact of fixation on retinal laser pathology

    NASA Astrophysics Data System (ADS)

    McCall, Michelle; Harkrider, Curtis J.; Deramo, Vincent; Bailey, Sarah F.; Winter, Katrina P.; Rockwell, Benjamin A.; Stolarski, David J.; Toth, Cynthia A.

    2001-07-01

    Purpose: The direct comparison of in-vivo OCT images with fixed tissues sections assumes the fixation of tissue has no effect on the size and configuration of final pathology images such as light micrographs. Fixation artifact has been a concern in numerous studies of the pathology of retinal laser lesions. We tested this hypothesis. Methods: The Humphrey OCT model 2000 with a custom mirror and lens assembly was used to scan tissue phantoms and both fresh and fixed ex-vivum tissue samples. The optical configuration was determined by optimization of the contrast and signal strength on tissue phantoms. Fresh porcine retinas were scanned using this optimal configuration, then fixed using either glutaraldehyde or formalin. OCT images were taken of the tissue at various stages during the fixation process. Additionally, we examined fixed retinal tissue containing retinal laser lesions as a part of our study of ultrashort-pulsed laser effects on the macacca mulatta retina. Histologic sections were prepared and evaluated. Results: In this presentation, we describe our optical setup and image optimization process and assess the effects of glutaraldehyde and formalin processing on OCT image quality. The OCT images of glutaraldehyde-fixed laser lesions are compared with similar images of laser lesions in-vivo. Fixation artifacts appeared on OCT at 2 to 24 hours. Opacification of the lumen of large vessels was seen at two hours with both glutaraldehyde and formalin, while fixation induced retinal detachment appeared at 24 hours. Overall, there was a grater delineation of the laser lesions by OCT at 24 hours when compared to at 1 or 2 hours of fixation. Conclusions: Fixations induced changes in OCT scans of retinal tissue are present as early as 2 hours after immersion in fixative. Although both glutaraldehyde and formalin fixation preserve much of the tissue structure, these method of fixation have s significant effect on OCT imaging of both normal retinal tissue and laser

  7. Immediate retinal adhesion by CO2 laser irradiation using a fiberoptic intraocular probe.

    PubMed

    DeRowe, A; Bartov, E; Treister, G; Belkin, M; Katzir, A

    1992-01-01

    Using an experimental fiberoptically guided CO2 laser system, we produced lesions on fresh bovine retinas. These lesions were shown to achieve immediate measurable chorioretinal adhesion. This model provides preliminary data on the use of a fiberoptic CO2 laser probe to produce chorioretinal lesions and possible future use in intraocular surgery for retinal detachment. The advantages of using CO2 laser energy are minimal damage surrounding desired lesion and its versatility as a coagulator and cutter. With modifications, CO2 endolaser may have a role in intraocular surgery. PMID:1453861

  8. [Unusual retinal abnormality: retinal hemorrhages related to scurvy].

    PubMed

    Errera, M-H; Dupas, B; Man, H; Gualino, V; Gaudric, A; Massin, P

    2011-03-01

    A diet restricted to rice and boiled fruit and vegetables leads to vitamin C deficiency. We describe the third case, to our knowledge, of retinal hemorrhages related to scurvy. Reduced bilateral visual acuity in a 50-year-old patient was associated with macrocytic anemia, denutrition, and cutaneous ecchymoses. Oral vitamin C treatment provided subjective clinical improvement and regression of the retinal hemorrhages on fundus examination, with no side effects. Vitamin C plays an important role in collagen stability in vascular and bone walls. PMID:21392843

  9. [Unusual retinal abnormality: retinal hemorrhages related to scurvy].

    PubMed

    Errera, M-H; Dupas, B; Man, H; Gualino, V; Gaudric, A; Massin, P

    2011-03-01

    A diet restricted to rice and boiled fruit and vegetables leads to vitamin C deficiency. We describe the third case, to our knowledge, of retinal hemorrhages related to scurvy. Reduced bilateral visual acuity in a 50-year-old patient was associated with macrocytic anemia, denutrition, and cutaneous ecchymoses. Oral vitamin C treatment provided subjective clinical improvement and regression of the retinal hemorrhages on fundus examination, with no side effects. Vitamin C plays an important role in collagen stability in vascular and bone walls.

  10. Optical coherence tomography imaging of retinal damage in real time under a stimulus electrode

    NASA Astrophysics Data System (ADS)

    Cohen, Ethan; Agrawal, Anant; Connors, Megan; Hansen, Barry; Charkhkar, Hamid; Pfefer, Joshua

    2011-10-01

    We have developed a novel method to study the effects of electrical stimulation of the local retina directly under an epiretinal stimulus electrode in real time. Using optical coherence tomography (OCT) and a superfused retinal eyecup preparation, we obtained high-resolution images of the rabbit retina directly under an optically transparent saline-filled fluoropolymer stimulation tube electrode. During OCT imaging, 50 Hz trains of biphasic current pulses 1 ms/phase (23-749 µC cm-2 ph-1) were applied to the retinal surface for 5 min. After imaging, the stimulated regions were stained with the dye propidium iodide (PI) to reveal cytotoxic damage. Pulse train stimulation at 44-133 µC cm-2 ph-1 had little effect on the retina; however, trains >=442 µC cm-2 ph-1 caused increases in the reflectance of the inner plexiform layer (IPL) and edema. The damage seen in retinal OCT images matched the pattern observed in histological sections, and in the PI staining. With pulse trains >=442 µC cm-2 ph-1, rapid increases in the reflectivity of the IPL could be observed under the stimulus electrode. Below the electrode, we observed a ring-like pattern of retinal detachment in the subretinal space. The OCT imaging method may be useful for analyzing overstimulation of neuronal tissue by electrodes in many brain regions. This paper was originally submitted for the special issue containing contributions from the Sixth Biennial Research Congress of The Eye and the Chip.

  11. Retinal spot size with wavelength

    NASA Astrophysics Data System (ADS)

    Rockwell, Benjamin A.; Hammer, Daniel X.; Kennedy, Paul K.; Amnotte, Rodney E.; Eilert, Brent; Druessel, Jeffrey J.; Payne, Dale J.; Phillips, Shana L.; Stolarski, David J.; Noojin, Gary D.; Thomas, Robert J.; Cain, Clarence P.

    1997-06-01

    We have made an indirect in-vivo determination of spot size focusing in the rhesus monkey model. Measurement of the laser induced breakdown threshold both in-vitro and in-vivo allow correlation and assignment of a spot size after focusing through the living eye. We discuss and analyze the results and show how trends in minimum visible lesion data should be assessed in light of chromatic aberration. National laser safety standards are based on minimal visual lesion (MVL) threshold studies in different animal models. The energy required for a retinal lesion depends upon may parameters including wavelength and retinal spot size. We attempt to explain trends in reported MVL threshold studies using a model of the eye which allows calculation of changes in retinal spot size due to chromatic aberration.

  12. Clinical Trials in Retinal Dystrophies.

    PubMed

    Grob, Seanna R; Finn, Avni; Papakostas, Thanos D; Eliott, Dean

    2016-01-01

    Research development is burgeoning for genetic and cellular therapy for retinal dystrophies. These dystrophies are the focus of many research efforts due to the unique biology and accessibility of the eye, the transformative advances in ocular imaging technology that allows for in vivo monitoring, and the potential benefit people would gain from success in the field - the gift of renewed sight. Progress in the field has revealed the immense complexity of retinal dystrophies and the challenges faced by researchers in the development of this technology. This study reviews the current trials and advancements in genetic and cellular therapy in the treatment of retinal dystrophies and also discusses the current and potential future challenges. PMID:26957839

  13. Exploring the retinal connectome

    PubMed Central

    Anderson, James R.; Jones, Bryan W.; Watt, Carl B.; Shaw, Margaret V.; Yang, Jia-Hui; DeMill, David; Lauritzen, James S.; Lin, Yanhua; Rapp, Kevin D.; Mastronarde, David; Koshevoy, Pavel; Grimm, Bradley; Tasdizen, Tolga; Whitaker, Ross

    2011-01-01

    Purpose A connectome is a comprehensive description of synaptic connectivity for a neural domain. Our goal was to produce a connectome data set for the inner plexiform layer of the mammalian retina. This paper describes our first retinal connectome, validates the method, and provides key initial findings. Methods We acquired and assembled a 16.5 terabyte connectome data set RC1 for the rabbit retina at ≈2 nm resolution using automated transmission electron microscope imaging, automated mosaicking, and automated volume registration. RC1 represents a column of tissue 0.25 mm in diameter, spanning the inner nuclear, inner plexiform, and ganglion cell layers. To enhance ultrastructural tracing, we included molecular markers for 4-aminobutyrate (GABA), glutamate, glycine, taurine, glutamine, and the in vivo activity marker, 1-amino-4-guanidobutane. This enabled us to distinguish GABAergic and glycinergic amacrine cells; to identify ON bipolar cells coupled to glycinergic cells; and to discriminate different kinds of bipolar, amacrine, and ganglion cells based on their molecular signatures and activity. The data set was explored and annotated with Viking, our multiuser navigation tool. Annotations were exported to additional applications to render cells, visualize network graphs, and query the database. Results Exploration of RC1 showed that the 2 nm resolution readily recapitulated well known connections and revealed several new features of retinal organization: (1) The well known AII amacrine cell pathway displayed more complexity than previously reported, with no less than 17 distinct signaling modes, including ribbon synapse inputs from OFF bipolar cells, wide-field ON cone bipolar cells and rod bipolar cells, and extensive input from cone-pathway amacrine cells. (2) The axons of most cone bipolar cells formed a distinct signal integration compartment, with ON cone bipolar cell axonal synapses targeting diverse cell types. Both ON and OFF bipolar cells receive

  14. Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2015-01-01

    A theory describing the shape evolution of detached Bridgman crystals in microgravity has been developed. A starting crystal of initial radius r0 will evolve to one of the following states: Stable detached gap; Attachment to the crucible wall; Meniscus collapse. Only crystals where alpha plus omega is great than 180 degrees will achieve stable detached growth in microgravity. Results of the crystal shape evolution theory are consistent with predictions of the dynamic stability of crystallization (Tatarchenko, Shaped Crystal Growth, Kluwer, 1993). Tests of transient crystal evolution are planned for ICESAGE, a series of Ge and GeSi crystal growth experiments planned to be conducted on the International Space Station (ISS).

  15. Sensitivity of detachment extent to magnetic configuration and external parameters

    NASA Astrophysics Data System (ADS)

    Lipschultz, Bruce; Parra, Felix I.; Hutchinson, Ian H.

    2016-05-01

    Divertor detachment may be essential to reduce heat loads to magnetic fusion tokamak reactor divertor surfaces. Yet in experiments it is difficult to control the extent of the detached, low pressure, plasma region. At maximum extent the front edge of the detached region reaches the X-point and can lead to degradation of core plasma properties. We define the ‘detachment window’ in a given position control variable C (for example, the upstream plasma density) as the range in C within which the front location can be stably held at any position from the target to the X-point; increased detachment window corresponds to better control. We extend a 1D analytic model [1] to determine the detachment window for the following control variables: the upstream plasma density, the impurity concentration and the power entering the scrape-off layer (SOL). We find that variations in magnetic configuration can have strong effects; increasing the ratio of the total magnetic field at the X-point to that at the target, {{B}×}/{{B}t} , (total flux expansion, as in the super-x divertor configuration) strongly increases the detachment window for all control variables studied, thus strongly improving detachment front control and the capability of the divertor plasma to passively accommodate transients while still staying detached. Increasing flux tube length and thus volume in the divertor, through poloidal flux expansion (as in the snowflake or x-divertor configurations) or length of the divertor, also increases the detachment window, but less than the total flux expansion does. The sensitivity of the detachment front location, z h , to each control variable, C, defined as \\partial {{z}h}/\\partial C , depends on the magnetic configuration. The size of the radiating volume and the total divertor radiation increase \\propto {{≤ft({{B}×}/{{B}t}\\right)}2} and \\propto {{B}×}/{{B}t} , respectively, but not by increasing divertor poloidal flux expansion or field line length. We

  16. Rat retinal transcriptome

    PubMed Central

    Kozhevnikova, Oyuna S.; Korbolina, Elena E.; Ershov, Nikita I.; Kolosova, Natalia G.

    2013-01-01

    Pathogenesis of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly, remains poorly understood due to the paucity of animal models that fully replicate the human disease. Recently, we showed that senescence-accelerated OXYS rats develop a retinopathy similar to human AMD. To identify alterations in response to normal aging and progression of AMD-like retinopathy, we compared gene expression profiles of retina from 3- and 18-mo-old OXYS and control Wistar rats by means of high-throughput RNA sequencing (RNA-Seq). We identified 160 and 146 age-regulated genes in Wistar and OXYS retinas, respectively. The majority of them are related to the immune system and extracellular matrix turnover. Only 24 age-regulated genes were common for the two strains, suggestive of different rates and mechanisms of aging. Over 600 genes showed significant differences in expression between the two strains. These genes are involved in disease-associated pathways such as immune response, inflammation, apoptosis, Ca2+ homeostasis and oxidative stress. The altered expression for selected genes was confirmed by qRT-PCR analysis. To our knowledge, this study represents the first analysis of retinal transcriptome from young and old rats with biologic replicates generated by RNA-Seq technology. We can conclude that the development of AMD-like retinopathy in OXYS rats is associated with an imbalance in immune and inflammatory responses. Aging alters the expression profile of numerous genes in the retina, and the genetic background of OXYS rats has a profound impact on the development of AMD-like retinopathy. PMID:23656783

  17. New Wrinkles in Retinal Densitometry

    PubMed Central

    Masella, Benjamin D.; Hunter, Jennifer J.; Williams, David R.

    2014-01-01

    Purpose. Retinal densitometry provides objective information about retinal function. But, a number of factors, including retinal reflectance changes that are not directly related to photopigment depletion, complicate its interpretation. We explore these factors and suggest a method to minimize their impact. Methods. An adaptive optics scanning light ophthalmoscope (AOSLO) was used to measure changes in photoreceptor reflectance in monkeys before and after photopigment bleaching with 514-nm light. Reflectance measurements at 514 nm and 794 nm were recorded simultaneously. Several methods of normalization to extract the apparent optical density of the photopigment were compared. Results. We identified stimulus-related fluctuations in 794-nm reflectance that are not associated with photopigment absorptance and occur in both rods and cones. These changes had a magnitude approaching those associated directly with pigment depletion, precluding the use of infrared reflectance for normalization. We used a spatial normalization method instead, which avoided the fluctuations in the near infrared, as well as a confocal AOSLO designed to minimize light from layers other than the receptors. However, these methods produced a surprisingly low estimate of the apparent rhodopsin density (animal 1: 0.073 ± 0.006, animal 2: 0.032 ± 0.003). Conclusions. These results confirm earlier observations that changes in photopigment absorption are not the only source of retinal reflectance change during dark adaptation. It appears that the stray light that has historically reduced the apparent density of cone photopigment in retinal densitometry arises predominantly from layers near the photoreceptors themselves. Despite these complications, this method provides a valuable, objective measure of retinal function. PMID:25316726

  18. Retinal Image Quality During Accommodation

    PubMed Central

    López-Gil, N.; Martin, J.; Liu, T.; Bradley, A.; Díaz-Muñoz, D.; Thibos, L.

    2013-01-01

    Purpose We asked if retinal image quality is maximum during accommodation, or sub-optimal due to accommodative error, when subjects perform an acuity task. Methods Subjects viewed a monochromatic (552nm), high-contrast letter target placed at various viewing distances. Wavefront aberrations of the accommodating eye were measured near the endpoint of an acuity staircase paradigm. Refractive state, defined as the optimum target vergence for maximising retinal image quality, was computed by through-focus wavefront analysis to find the power of the virtual correcting lens that maximizes visual Strehl ratio. Results Despite changes in ocular aberrations and pupil size during binocular viewing, retinal image quality and visual acuity typically remain high for all target vergences. When accommodative errors lead to sub-optimal retinal image quality, acuity and measured image quality both decline. However, the effect of accommodation errors of on visual acuity are mitigated by pupillary constriction associated with accommodation and binocular convergence and also to binocular summation of dissimilar retinal image blur. Under monocular viewing conditions some subjects displayed significant accommodative lag that reduced visual performance, an effect that was exacerbated by pharmacological dilation of the pupil. Conclusions Spurious measurement of accommodative error can be avoided when the image quality metric used to determine refractive state is compatible with the focusing criteria used by the visual system to control accommodation. Real focusing errors of the accommodating eye do not necessarily produce a reliably measurable loss of image quality or clinically significant loss of visual performance, probably because of increased depth-of-focus due to pupil constriction. When retinal image quality is close to maximum achievable (given the eye’s higher-order aberrations), acuity is also near maximum. A combination of accommodative lag, reduced image quality, and reduced

  19. Retinal Optical Coherence Tomography Imaging

    NASA Astrophysics Data System (ADS)

    Drexler, Wolfgang; Fujimoto, James G.

    The eye is essentially transparent, transmitting light with only minimal optical attenuation and scattering providing easy optical access to the anterior segment as well as the retina. For this reason, ophthalmic and especially retinal imaging has been not only the first but also most successful clinical application for optical coherence tomography (OCT). This chapter focuses on the development of OCT technology for retinal imaging. OCT has significantly improved the potential for early diagnosis, understanding of retinal disease pathogenesis, as well as monitoring disease progression and response to therapy. Development of ultrabroad bandwidth light sources and high-speed detection techniques has enabled significant improvements in ophthalmic OCT imaging performance, demonstrating the potential of three-dimensional, ultrahigh-resolution OCT (UHR OCT) to perform noninvasive optical biopsy of the living human retina, i.e., the in vivo visualization of microstructural, intraretinal morphology in situ approaching the resolution of conventional histopathology. Significant improvements in axial resolution and speed not only enable three-dimensional rendering of retinal volumes but also high-definition, two-dimensional tomograms, topographic thickness maps of all major intraretinal layers, as well as volumetric quantification of pathologic intraretinal changes. These advances in OCT technology have also been successfully applied in several animal models of retinal pathologies. The development of light sources emitting at alternative wavelengths, e.g., around #1,060 nm, not only enabled three-dimensional OCT imaging with enhanced choroidal visualization but also improved OCT performance in cataract patients due to reduced scattering losses in this wavelength region. Adaptive optics using deformable mirror technology, with unique high stroke to correct higher-order ocular aberrations, with specially designed optics to compensate chromatic aberration of the human eye, in

  20. Comparative retinal physiology in anthropoids.

    PubMed

    Kremers, J; Lee, B B

    1998-11-01

    During the last decade it has become clear that colour vision in platyrrhines (New World monkeys) differs from the uniform trichromatic pattern normally found in catarrhines (Old World monkeys, apes and human). Colour vision in most platyrrhine species is polymorphic, with many dichromatic individuals. The comparison of response properties in retinal ganglion cells and lateral geniculate cells between catarrhines and playrrhines elucidates how the evolution of trichromatic colour vision influenced the post-receptoral processing. We find that spatial and temporal processing is very similar in the platyrrhine and catarrhine retina, strongly suggesting that the retinal structure and function, found in living anthropoids, was already present in their common ancestor. PMID:9893846

  1. Retinitis pigmentosa in southern Africa.

    PubMed

    Greenberg, J; Bartmann, L; Ramesar, R; Beighton, P

    1993-11-01

    Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal disorders which are a common cause of genetic blindness. The relative frequencies of the different forms of RP in South Africa, as determined from the register at the DNA banking centre for RP at the Department of Human Genetics, University of Cape Town, are presented and discussed. Of the 125 families analysed, 29 (23%) showed autosomal dominant, 33 (27%) autosomal recessive and 3 (3%) X-linked inheritance. In 10 families the pedigree data were insufficient to allow accurate genetic subtyping and a further 50 patients were sporadic without a family history of RP or other syndromic features which would allow categorization.

  2. Carbon dioxide fixation by detached cereal caryopses

    SciTech Connect

    Watson, P.A.; Duffus, C.M. )

    1988-06-01

    Immature detached cereal caryposes from barley (Hordeum vulgare L. var distichum cv Midas) and wheat (Triticum aestivum L. cv Sicco) were shown to be capable of fixing externally supplied {sup 14}CO{sub 2} in the light or dark. Green cross cells and the testa contained the majority of the {sup 14}C-labeled material. Some {sup 14}C-labeled material was also found in the outer, or transparent, layer and in the endosperm/embryo fraction. More {sup 14}C was recovered from caryopses when they were incubated in {sup 14}CO{sub 2} without the transparent layer, thus suggesting that this layer is a barrier to the uptake of CO{sub 2}. In all cases, significant amounts of {sup 14}C-labeled material were found in caryopses after dark incubation with {sup 14}CO{sub 2}. Interestingly, CO{sub 2} fixation in the chlorophyll-less mutant Albino lemma was significantly greater in the light than in the dark. The results indicate that intact caryopses have the ability to translocate {sup 14}C-labeled assimilate derived from external CO{sub 2} to the endosperm/embryo. Carboxylating activity in the transparent layer appears to be confined to phosphoenolpyruvate carboxylase activity but that in the chloroplast-containing cross-cells may be accounted for by both ribulose-1,5-bisphosphate carboxylase-oxygenase and phosphoenolpyruvate carboxylase activity. Depending on a number of assumptions, the amount of CO{sub 2} fixed is sufficient to account for about 2% of the weight of starch found in the mature caryposis.

  3. A detachable mobile and adjustable telemetry system

    PubMed Central

    Parker, Tommy S; Persons, William E; Bradley, Joseph G; Gregg, Margaret; Gonzales, Shinelle K; Helton, Jesse S

    2013-01-01

    Many traditional mobile telemetry systems require permanently mounting a rod through the cabin of a vehicle to serve as the mast for a directional antenna. In this article we present an alternative to this configuration by providing a platform that can be placed atop the vehicle in which the antenna mast can be mounted and controlled from the cabin of the vehicle. Thereby making this design a viable option for researchers who share vehicles with others that may not approve of permanent vehicle modifications such as placing a hole in the roof of the vehicle as required by traditional mobile configurations. We tested the precision and accuracy of detachable mobile and adjustable telemetry system (DMATS) in an urban park with varying terrain, tree stands, overhead wires, and other structures that can contribute to signal deflection. We placed three radiocollars 50 m apart and 1.2 m above the ground then established three testing stations ∼280 m from the location of the radiocollars. The DMATS platform required 12 h for completion and cost $1059 USD. Four technicians were randomly assigned radio collars to triangulate using DMATS and a handheld telemetry system. We used a one-way analysis of variance (ANOVA) with a Scheffe post hoc test to compare error ellipses between azimuths taken using DMATS and the hand held system. Average error ellipses for all testers was 1.96 ± 1.22 ha. No significant differences were found between error ellipses of testers (P = 0.292). Our design, the DMATS, does not require any vehicle modification; thereby, making this a viable option for researchers sharing vehicles with others that may not approve of permanent vehicle alterations. PMID:23919133

  4. ACUTE RETINAL ARTERIAL OCCLUSIVE DISORDERS

    PubMed Central

    Hayreh, Sohan Singh

    2011-01-01

    The initial section deals with basic sciences; among the various topics briefly discussed are the anatomical features of ophthalmic, central retinal and cilioretinal arteries which may play a role in acute retinal arterial ischemic disorders. Crucial information required in the management of central retinal artery occlusion (CRAO) is the length of time the retina can survive following that. An experimental study shows that CRAO for 97 minutes produces no detectable permanent retinal damage but there is a progressive ischemic damage thereafter, and by 4 hours the retina has suffered irreversible damage. In the clinical section, I discuss at length various controversies on acute retinal arterial ischemic disorders. Classification of acute retinal arterial ischemic disorders These are of 4 types: CRAO, branch retinal artery occlusion (BRAO), cotton wools spots and amaurosis fugax. Both CRAO and BRAO further comprise multiple clinical entities. Contrary to the universal belief, pathogenetically, clinically and for management, CRAO is not one clinical entity but 4 distinct clinical entities – non-arteritic CRAO, non-arteritic CRAO with cilioretinal artery sparing, arteritic CRAO associated with giant cell arteritis (GCA) and transient non-arteritic CRAO. Similarly, BRAO comprises permanent BRAO, transient BRAO and cilioretinal artery occlusion (CLRAO), and the latter further consists of 3 distinct clinical entities - non-arteritic CLRAO alone, non-arteritic CLRAO associated with central retinal vein occlusion and arteritic CLRAO associated with GCA. Understanding these classifications is essential to comprehend fully various aspects of these disorders. Central retinal artery occlusion The pathogeneses, clinical features and management of the various types of CRAO are discussed in detail. Contrary to the prevalent belief, spontaneous improvement in both visual acuity and visual fields does occur, mainly during the first 7 days. The incidence of spontaneous visual

  5. One- and two-photon detachment of O-

    NASA Astrophysics Data System (ADS)

    Génévriez, Matthieu; Urbain, Xavier; Dochain, Arnaud; Cyr, Alain; Dunseath, Kevin M.; Terao-Dunseath, Mariko

    2016-08-01

    Cross sections for one- and two-photon detachment of O-(1 s22 s22 p5P2o) have been determined in a joint experimental and theoretical study. The absolute measurement is based on the animated-crossed-beam technique, which is extended to the case of pulsed lasers, pulsed ion beams, and multiphoton detachment. The ab initio calculations employ R -matrix Floquet theory, with simple descriptions of the initial bound state and the residual oxygen atom which reproduce well the electron affinity and ground-state polarizability. For one-photon detachment, the measured and computed cross sections are in good mutual agreement, departing significantly from previous reference experiments and calculations. The generalized two-photon detachment cross section, measured at the Nd:YAG laser wavelength, is in good agreement with the R -matrix Floquet calculations. Long-standing discrepancies between theory and experiment are thus resolved.

  6. On Favorable Thermal Fields for Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Stelian, Carmen; Volz, Martin P.; Derby, Jeffrey J.

    2009-01-01

    The thermal fields of two Bridgman-like configurations, representative of real systems used in prior experiments for the detached growth of CdTe and Ge crystals, are studied. These detailed heat transfer computations are performed using the CrysMAS code and expand upon our previous analyses [14] that posited a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. Computational results indicate that heat transfer conditions that led to successful detached growth in both of these systems are in accordance with our prior assertion, namely that the prevention of crystal reattachment to the crucible wall requires the avoidance of any undercooling of the melt meniscus during the growth run. Significantly, relatively simple process modifications that promote favorable thermal conditions for detached growth may overcome detrimental factors associated with meniscus shape and crucible wetting. Thus, these ideas may be important to advance the practice of detached growth for many materials.

  7. O1 DETACHED GARAGE FRONT ELEVATION. Naval Magazine Lualualei, Headquarters ...

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

    O-1 DETACHED GARAGE FRONT ELEVATION. - Naval Magazine Lualualei, Headquarters Branch, Garage for Building O, Sixty-sixth Street between Constitution & Amberjack Streets, behind Building O, Pearl City, Honolulu County, HI

  8. O1 DETACHED GARAGE FRONT AND SIDE VIEW. Naval Magazine ...

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

    O-1 DETACHED GARAGE FRONT AND SIDE VIEW. - Naval Magazine Lualualei, Headquarters Branch, Garage for Building O, Sixty-sixth Street between Constitution & Amberjack Streets, behind Building O, Pearl City, Honolulu County, HI

  9. Prospects of Stem Cells for Retinal Diseases.

    PubMed

    Ng, Tsz Kin; Lam, Dennis S C; Cheung, Herman S

    2013-01-01

    Retinal diseases, including glaucoma, retinitis pigmentosa, diabetic retinopathy, and age-related macular degeneration, are the leading causes of irreversible visual impairment and blindness in developed countries. Traditional and current treatment regimens are based on surgical or medical interventions to slow down the disease progression. However, the number of retinal cells would continue to diminish, and the diseases could not be completely cured. There is an emerging role of stem cells in retinal research. The stem cell therapy on retinal diseases is based on 2 theories: cell replacement therapy and neuroprotective effect. The former hypothesizes that new retinal cells could be regenerated from stem cells to substitute the damaged cells in the diseased retina, whereas the latter believes that the paracrine effects of stem cells modulate the microenvironments of the diseased retina so as to protect the retinal neurons. This article summarizes the choice of stem cells in retinal research. Moreover, the current progress of retinal research on stem cells and the clinical applications of stem cells on retinal diseases are reviewed. In addition, potential challenges and future prospects of retinal stem cell research are discussed.

  10. Simulating Biofilm Deformation and Detachment with the Immersed Boundary Method

    NASA Astrophysics Data System (ADS)

    Sudarsan, Rangarajan; Ghosh, Sudeshna; Stockie, John M.; Eberl, Hermann J.

    2016-03-01

    We apply the immersed boundary (or IB) method to simulate deformation and detachment of a periodic array of wall-bounded biofilm colonies in response to a linear shear flow. The biofilm material is represented as a network of Hookean springs that are placed along the edges of a triangulation of the biofilm region. The interfacial shear stress, lift and drag forces acting on the biofilm colony are computed by using fluid stress jump method developed by Williams, Fauci and Gaver [Disc. Contin. Dyn. Sys. B 11(2):519-540, 2009], with a modified version of their exclusion filter. Our detachment criterion is based on the novel concept of an averaged equivalent continuum stress tensor defined at each IB point in the biofilm which is then used to determine a corresponding von Mises yield stress; wherever this yield stress exceeds a given critical threshold the connections to that node are severed, thereby signalling the onset of a detachment event. In order to capture the deformation and detachment behaviour of a biofilm colony at different stages of growth, we consider a family of four biofilm shapes with varying aspect ratio. Our numerical simulations focus on the behaviour of weak biofilms (with relatively low yield stress threshold) and investigate features of the fluid-structure interaction such as locations of maximum shear and increased drag. The most important conclusion of this work is that the commonly employed detachment strategy in biofilm models based only on interfacial shear stress can lead to incorrect or inaccurate results when applied to the study of shear induced detachment of weak biofilms. Our detachment strategy based on equivalent continuum stresses provides a unified and consistent IB framework that handles both sloughing and erosion modes of biofilm detachment, and is consistent with strategies employed in many other continuum based biofilm models.

  11. 1. Streetscape with south sides of Medical Detachment Barracks on ...

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

    1. Streetscape with south sides of Medical Detachment Barracks on Ramp No. 5. Part of Building No. 9962-A with door is on far right. Also shown are the south A-sides of Buildings Nos. 9963, 9964, 9965, 9966, 9967 and 9968. The new Madigan Army Medical Center, which opened in 1992, is in far distance on right. - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  12. Tracing detached and attached care practices in nursing education.

    PubMed

    Soffer, Ann Katrine B

    2014-07-01

    The implementation of skills labs in Danish nursing education can, in itself, be viewed as a complexity. The students are expected to eventually carry out their work in a situated hospital practice, but they learn their professional skills in a different space altogether, detached and removed from the hospitals and practising on plastic dummies. Despite the apparent artificiality of the skills lab, this article will show that it is possible to analyse some of the fundamental aspects of care in nursing by ethnographically following this phenomenon of simulation-based training. These particular aspects of care are not explicated in the curriculum or textbooks; however, they surfaced once this crooked approach to studying care in a simulated practice was applied. The article start from the assertion that detached engagements are not recognized within the field of nursing education as an equal component to attachments. Yet empirical cases from the skills lab and hospitals illustrate how students sometimes felt emotionally attached to plastic dummies and how experienced nurses sometimes practised a degree of detachment in relation to human patients. Detached engagements will therefore be presented as part of care practices of nurses - rendering the ability to detach in engagement with patients a professional skill that students also need to learn. In the analysis to follow, attached and detached engagements are located on an equal plane by integrating both into the same conceptual framework, rather than imposing a priori notions about their dialectic relation. The analysis shows that it is the particular intertwinement of attachment and detachment that gives care its fundamental meaning. In conclusion, the need for a conceptual shift from a strong emphasis on attached engagement to a more balanced analytical approach to care work, as involving both attached and detached engagement within Danish nursing education, is advocated.

  13. HAMLET binding to α-actinin facilitates tumor cell detachment.

    PubMed

    Trulsson, Maria; Yu, Hao; Gisselsson, Lennart; Chao, Yinxia; Urbano, Alexander; Aits, Sonja; Mossberg, Ann-Kristin; Svanborg, Catharina

    2011-03-08

    Cell adhesion is tightly regulated by specific molecular interactions and detachment from the extracellular matrix modifies proliferation and survival. HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is a protein-lipid complex with tumoricidal activity that also triggers tumor cell detachment in vitro and in vivo, suggesting that molecular interactions defining detachment are perturbed in cancer cells. To identify such interactions, cell membrane extracts were used in Far-western blots and HAMLET was shown to bind α-actinins; major F-actin cross-linking proteins and focal adhesion constituents. Synthetic peptide mapping revealed that HAMLET binds to the N-terminal actin-binding domain as well as the integrin-binding domain of α-actinin-4. By co-immunoprecipitation of extracts from HAMLET-treated cancer cells, an interaction with α-actinin-1 and -4 was observed. Inhibition of α-actinin-1 and α-actinin-4 expression by siRNA transfection increased detachment, while α-actinin-4-GFP over-expression significantly delayed rounding up and detachment of tumor cells in response to HAMLET. In response to HAMLET, adherent tumor cells rounded up and detached, suggesting a loss of the actin cytoskeletal organization. These changes were accompanied by a reduction in β1 integrin staining and a decrease in FAK and ERK1/2 phosphorylation, consistent with a disruption of integrin-dependent cell adhesion signaling. Detachment per se did not increase cell death during the 22 hour experimental period, regardless of α-actinin-4 and α-actinin-1 expression levels but adherent cells with low α-actinin levels showed increased death in response to HAMLET. The results suggest that the interaction between HAMLET and α-actinins promotes tumor cell detachment. As α-actinins also associate with signaling molecules, cytoplasmic domains of transmembrane receptors and ion channels, additional α-actinin-dependent mechanisms are discussed.

  14. [Progress of research in retinal image registration].

    PubMed

    Yu, Lun; Wei, Lifang; Pan, Lin

    2011-10-01

    The retinal image registration has important applications in the processes of auxiliary diagnosis and treatment for a variety of diseases. The retinal image registration can be used to measure the disease process and the therapeutic effect. A variety of retinal image registration techniques have been studied extensively in recent years. However, there are still many problems existing and there are numerous research possibilities. Based on extensive investigation of existing literatures, the present paper analyzes the feature of retinal image and current challenges of retinal image registration, and reviews the transformation models of the retinal image registration technology and the main research algorithms in current retinal image registration, and analyzes the advantages and disadvantages of various types of algorithms. Some research challenges and future developing trends are also discussed.

  15. Functional verification of pulse frequency modulation-based image sensor for retinal prosthesis by in vitro electrophysiological experiments using frog retina.

    PubMed

    Furumiya, Tetsuo; Ng, David C; Yasuoka, Koutaro; Kagawa, Keiichiro; Tokuda, Takashi; Nunoshita, Masahiro; Ohta, Jun

    2006-01-15

    The functioning of a 16 x 16 pixel pulse frequency modulation (PFM) image sensor for retinal prosthesis is verified through in vitro electrophysiological experiments using detached frog retinas. This image sensor is a prototype for demonstrating the application to in vitro electrophysiological experiments. Each pixel of the image sensor consists of a pulse generator (PFM photosensor), a stimulus circuit, and a stimulus electrode (Al bonding pad). The image sensor is fabricated using standard 0.6 microm CMOS technology. For in vitro electrophysiological experiments, a Pt/Au stacked electrode is formed on the Al bonding pad of each pixel and the entire sensor is fixed in epoxy resin. The PFM image sensor is confirmed experimentally to provide electrical stimulus to the retinal cells in a detached frog retina.

  16. Improved Crystal Quality By Detached Solidification in Microgravity

    NASA Technical Reports Server (NTRS)

    Regel, Liya L.; Wilcox, William R.; Wang, Yaz-Hen; Wang, Jian-Bin

    2003-01-01

    Many microgravity directional solidification experiments yielded ingots with portions that grew without contacting the ampoule wall, leading to greatly improved crystallographic perfection. Our long term goals have been: (1) To develop a complete understanding of all of the phenomena of detached solidification.; (2) To make it possible to achieve detached solidification reproducibly; (3) To increase crystallographic perfection through detached solidification. We have three major achievements to report here: (1) We obtained a new material balance solution for the Moving Meniscus Model of detached solidification. This solution greatly clarifies the physics as well as the roles of the parameters in the system; (2) We achieved detached solidification of InSb growing on earth in BN-coated ampoules; (3) We performed an extensive series of experiments on freezing water that showed how to form multiple gas bubbles or tubes on the ampoule wall. However, these did not propagate around the wall and lead to fully detached solidification unless the ampoule wall was extremely rough and non-wetted.

  17. Growth and Detachment of 5 Helix DNA Ribbons.

    PubMed

    Bashar, Saima; Hwang, Si Un; Lee, Junwye; Amin, Rashid; Dugasani, Sreekantha Reddy; Ha, Tai Hwan; Park, Sung Ha

    2016-04-01

    We report on the concentration-dependent surface-assisted growth and time-temperature-dependent detachment of one-dimensional 5 helix DNA ribbons (5HR) on a mica substrate. The growth coverage ratio was determined by varying the concentration of the 5HR strands in a test tube, and the detachment rate of 5HR on mica was determined by varying the incubation time at a fixed temperature on a heat block. The topological changes in the concentration-dependent attachment and the time-temperature-dependent detachment for 5HR on mica were observed via atomic force microscopy. The observations indicate that 5HR started to grow on mica at ~10 nM and provided full coverage at ~50 nM. In contrast, 5HR at 65 °C started to detach from mica after 5 min and was completely removed after 10 min. The growth and detachment coverage show a sinusoidal variation in the growth ratio and a linear variation with a rate of detachment of 20%/min, respectively. The physical parameters that control the stability of the DNA structures on a given substrate should be studied to successfully integrate DNA structures for physical and chemical applications. PMID:27451775

  18. Defect Density Characterization of Detached-Grown Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Cobb, S. D.; Volz, M. P.; Szoke, J.; Szofran, F. R.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several (111)-oriented, Ga-doped germanium crystals were grown in pyrolytic boron nitride (pBN) containers by the Bridgman and the detached Bridgman growth techniques. Growth experiments in closed-bottom pBN containers resulted in nearly completely detached-grown crystals, because the gas pressure below the melt can build up to a higher pressure than above the melt. With open-bottom tubes the gas pressure above and below the melt is balanced during the experiment, and thus no additional force supports the detachment. In this case the crystals grew attached to the wall. Etch pit density (EPD) measurements along the axial growth direction indicated a strong improvement of the crystal quality of the detached-grown samples compared to the attached samples. Starting in the seed with an EPD of 6-8 x 10(exp 3)/square cm it decreased in the detached-grown crystals continuously to about 200-500/square cm . No significant radial difference between the EPD on the edge and the middle of the crystal exists. In the attached grown samples the EPD increases up to a value of about 2-4 x 10(exp 4)/square cm (near the edge) and up to 1 x 10(exp 4)/square cm in the middle of the sample. Thus the difference between the detached- and the attached-grown crystals with respect to the EPD is approximately two orders of magnitude.

  19. Effects of Nanoscale Surface Roughness on Colloid Detachment

    NASA Astrophysics Data System (ADS)

    Rasmuson, J. A.; Johnson, W. P.

    2015-12-01

    Recent advances in colloid transport science have demonstrated the importance of surface roughness on colloid attachment; however, few studies have investigated the influence of nano-scale roughness on colloid detachment. This study explores the effects of flow perturbations on a variety of mineral surfaces, as well as NaOH treated (i.e. rough, Figure 1a) and untreated (i.e. smooth, Figure 1b) surfaces for colloids of various sizes attached in an impinging jet system under flowing and stagnant conditions. These experiments showed minimal detachment from the roughened surfaces (treated glass) and significant detachment from the smooth surfaces (untreated glass and mica). A correlation between residence time and attachment irreversibility was also revealed, indicating that the particles that spent the longest time attached to the surface developed the strongest adhesion. The representative surface-heterogeneity model developed by Pazmino et al. (2014) was used to conduct detachment simulations under similar geochemical and flow conditions. While simulated results show qualitative agreement with experimental results, they tend to over-predict detachment, highlighting differences among simulated versus real surfaces, which may be related to surface roughness. These results suggest that more sophisticated models that incorporate surface roughness and time-based adhesion are needed to accurately predict colloid detachment in environmental systems.

  20. Retinitis Pigmentosa and Education Issues

    ERIC Educational Resources Information Center

    Brown, Thomas J.

    2005-01-01

    Retinitis Pigmentosa includes a number of inherited diseases which usually result in blindness. The disease is progressive in nature and begins with the deterioration of cells in the eye responsible for peripheral vision. As the condition worsens there is a gradual loss of peripheral vision and night blindness. Proper educational planning requires…

  1. Automatic temperature controlled retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Schlott, Kerstin; Koinzer, Stefan; Ptaszynski, Lars; Bever, Marco; Baade, Alex; Roider, Johann; Birngruber, Reginald; Brinkmann, Ralf

    2012-06-01

    Laser coagulation is a treatment method for many retinal diseases. Due to variations in fundus pigmentation and light scattering inside the eye globe, different lesion strengths are often achieved. The aim of this work is to realize an automatic feedback algorithm to generate desired lesion strengths by controlling the retinal temperature increase with the irradiation time. Optoacoustics afford non-invasive retinal temperature monitoring during laser treatment. A 75 ns/523 nm Q-switched Nd:YLF laser was used to excite the temperature-dependent pressure amplitudes, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. A 532 nm continuous wave Nd:YAG laser served for photocoagulation. The ED50 temperatures, for which the probability of ophthalmoscopically visible lesions after one hour in vivo in rabbits was 50%, varied from 63°C for 20 ms to 49°C for 400 ms. Arrhenius parameters were extracted as ΔE=273 J mol-1 and A=3.1044 s-1. Control algorithms for mild and strong lesions were developed, which led to average lesion diameters of 162+/-34 μm and 189+/-34 μm, respectively. It could be demonstrated that the sizes of the automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.

  2. Fluids drainage along detachments: the West Cycladic Detachment System and synkinematic skarns on Serifos Island (Cyclades, Greece)

    NASA Astrophysics Data System (ADS)

    Ducoux, Maxime; Jolivet, Laurent; Arbaret, Laurent; Branquet, Yannick; Rabillard, Aurélien

    2014-05-01

    Back-arc extension in the Aegean Sea has been accommodated by several large-scale detachments such as the West Cycladic Detachment System (WCDS) in the Oligocene and Miocene. The WCDS is associated on Serifos island (Cyclades) with a synkinematic granodioritic intrusion. Serifos is also well known for its skarn deposit and a rich mineralogy as well as colder Fe-Ba ore deposits that were exploited until 1963. The geometrical and kinematic relations between the detachments and ore bodies have so far been little studied. Different types of skarn can be observed (1) massive garnet endoskarns, (2) garnet-pyroxene endoskarns in the granodiorite, (3) garnet-pyroxene cracks exoskarns, (4) brecciated pyroxene +/- ilvaite skarn within the Meghàlo Livadhi and Kavos Kiklopas detachments. Fields observations show that the formation of the skarn is intimately associated with the detachments and the deformation of the intrusion in the footwall. Endo and exo-skarn deposits formed before, during and after the ductile and brittle structures resulting from the activity of the WCDS. They are represented by echelon veins, veins with antithetic shear and boudinaged veins wrapped within sheath folds, with a shearing movement top SSW or SW compatible with the regional tectonics, deformation in host-rock and the emplacement of the syn-tectonic granodioritic intrusion. Skarnified breccias formed within the two main detachments attesting for the intense circulation of fluids at a certain distance from the main intrusion. These skarn parageneses were deposited by hydrothermal fluids associated with the intrusion, mixed with meteoric or oceanic fluids forming at the regional level of pyroxene. The two detachments acted as preferential crustal-scale drains during footwall exhumation. This example illustrates the potential of detachments to channelize large amount of fluids in the crust during extension.

  3. Retinal vascular changes in hypertensive patients in Ibadan, Sub-Saharan Africa

    PubMed Central

    Oluleye, Sunday Tunji; Olusanya, Bolutife Ayokunu; Adeoye, Abiodun Moshood

    2016-01-01

    Background Earlier studies in Nigeria reported the rarity of retinal vascular changes in hypertensives. The aim of this study was to describe the various retinal vascular changes in the hypertensive patients of Nigeria. Patients and methods Nine hundred and three hypertensive patients were studied. This study was approved by the ethical and research committee of the University of Ibadan and University College Hospital, Ibadan, Nigeria. Blood pressure and anthropometric measurements were measured. Cardiac echocardiography was performed on 156 patients. All patients had dilated fundoscopy and fundus photography using the Kowa portable fundus camera and an Apple iPhone with 20 D lens. Statistical analysis was done with Statistical Packages for the Social Sciences (Version 21). Results The mean age of patients was 57 years with a male:female ratio of 1. No retinopathy was found in 556 (61.5%) patients. In all, 175 (19.4%) patients had features of hypertensive retinopathy. Retinal vascular occlusion was a significant finding in 121 patients (13.4%), of which branch retinal vein occlusion, 43 (4.7%), and central retinal vein occlusion, 30 (3.3%), were the most prominent ones in cases. Hemicentral retinal vein occlusion, 26 (2.9%), and central retinal artery occlusion, 17 (1.9%), were significant presentations. Other findings included nonarteritic anterior ischemic optic neuropathy in five (0.6%) patients, hypertensive choroidopathy in seven (0.8%) patients, and hemorrhagic choroidal detachment in five (0.6%) patients. Left ventricular (LV) geometry was abnormal in 85 (55.5%) patients. Concentric remodeling, eccentric hypertrophy, and concentric hypertrophy were observed in 43 (27.6%), 26 (17.2%), and 15 (9.7%) patients, respectively. LV hypertrophy was found in 42 (27%) patients, while 60 (39%) patients had increased relative wall thickness. In this study, bivariate analysis showed a correlation between LV relative wall thickness and severity of retinopathy in both eyes

  4. Retinal vasculature classification using novel multifractal features

    NASA Astrophysics Data System (ADS)

    Ding, Y.; Ward, W. O. C.; Duan, Jinming; Auer, D. P.; Gowland, Penny; Bai, L.

    2015-11-01

    Retinal blood vessels have been implicated in a large number of diseases including diabetic retinopathy and cardiovascular diseases, which cause damages to retinal blood vessels. The availability of retinal vessel imaging provides an excellent opportunity for monitoring and diagnosis of retinal diseases, and automatic analysis of retinal vessels will help with the processes. However, state of the art vascular analysis methods such as counting the number of branches or measuring the curvature and diameter of individual vessels are unsuitable for the microvasculature. There has been published research using fractal analysis to calculate fractal dimensions of retinal blood vessels, but so far there has been no systematic research extracting discriminant features from retinal vessels for classifications. This paper introduces new methods for feature extraction from multifractal spectra of retinal vessels for classification. Two publicly available retinal vascular image databases are used for the experiments, and the proposed methods have produced accuracies of 85.5% and 77% for classification of healthy and diabetic retinal vasculatures. Experiments show that classification with multiple fractal features produces better rates compared with methods using a single fractal dimension value. In addition to this, experiments also show that classification accuracy can be affected by the accuracy of vessel segmentation algorithms.

  5. Possible Relation between Lack of Posterior Vitreous Detachment and Severe Endogenous Endophthalmitis

    PubMed Central

    Suzuki, Jun; Wakabayashi, Yoshihiro; Goto, Hiroshi

    2016-01-01

    Purpose. Endogenous endophthalmitis (EE) is a rare ocular disease caused by bacterial or fungal infection of intraocular spaces by hematogenous spread of pathogens from distant infectious loci in the body. We investigated the clinical characteristics and management of eyes with EE in ten consecutive patients. Methods. Ten patients (10 eyes) with EE treated at Tokyo Medical University Hospital in 2014 were reviewed. We retrospectively studied the causative organisms, systemic complications, pre/postoperative mean best-corrected visual acuity (BCVA), and status of posterior vitreous detachment (PVD). Results. The 10 patients comprised 8 males and 2 females, with mean age of 71.2 years. The causative organisms were bacteria in 6 eyes and fungi in 4 eyes. Systemic complications included septicemia or disseminated intravascular coagulation in 5 patients and diabetes mellitus in 4 patients. Postoperative BCVA was improved by 0.2log⁡MAR or greater in 4 eyes and decreased in 4 eyes. Vitrectomy was performed in all eyes, and 4 required multiple surgeries. During vitrectomy, PVD was absent in 8 eyes, 4 of which showed retinal necrosis. The mean age of patients with no PVD was 71.2 years. Conclusion. Despite an advanced age, PVD was absent in the majority of patients with EE. PVD may be related to the pathogenesis and aggravation of EE. PMID:27766175

  6. Retinal Protective Effects of Resveratrol via Modulation of Nitric Oxide Synthase on Oxygen-induced Retinopathy

    PubMed Central

    Kim, Woo Taek

    2010-01-01

    Purpose Retinopathy of prematurity (ROP) is one of the leading causes of blindness, with retinal detachment occurring due to oxygen toxicity in preterm infants. Recently, advances in neonatal care have led to improved survival rates for preterm infants, and ROP has increased in incidence. In the present study, we aimed to determine whether or not resveratrol exhibits protective effects in an animal model of ROP and in primary retinal cell cultures of neonatal rat via nitric oxide (NO)-modulating actions using western blotting and real-time PCR with inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS) and neuronal NOS (nNOS) antibodies and mRNAs. Methods In an in vivo oxygen-induced retinopathy (OIR) model, cyclic hyperoxia was induced with 80% O2 for one day and 21% O2 for one day from P1 to P14 in newborn Sprague-Dawley (SD) rats. Resveratrol was injected intravitreally for seven days and rats were sacrificed at P21. In vitro OIR primary retinal cell culture was performed using P0-2 SD rats. Hyperoxia injuries were induced through 100% O2 exposure for six hours. Western blotting and real-time PCR using iNOS, eNOS, nNOS antibodies and primers were performed in the rat model of ROP and the dispersed retinal cell culture. Results In both in vivo and in vitro OIR, the expression of iNOS antibody and mRNA was increased and of eNOS and nNOS were reduced in the resveratrol-treated group. Conclusions In conclusion, resveratrol appeared to exert retinal protective effects via modulation of NO-mediated mechanism in in vivo and in vitro OIR models. PMID:20379461

  7. Mesospheric electron detachment and LORE recovery times

    NASA Astrophysics Data System (ADS)

    Gordillo-Vazquez, Francisco J.; Haldoupis, Christos; Luque, Alejandro

    2015-04-01

    We present new results concerning the recovery times (> 10 minutes) of LOng Recovery Early VLF events (LORE) in the upper mesosphere connected to electromagnetic pulses (EMP) of large (> 250 kA km) charge moment change (CMC) ± CG (cloud to ground) lightning capable of producing elves or elve-sprite pairs (in the case of +CG parent lightning) [1], [2]. We have modeled two possible scenarios considering first the relaxation of slightly perturbed ambient electron densities (ne0 + Δne) without an impulsive ionization source and another scenario where the ambient electron density is considerably enhanced due to an impulsive ionization source (the lightning EMP). The full non-equilibrium kinetic and 2D EMP modelling of the perturbed mesosphere in the 76 km - 92 km range during LORE occurring conditions indicates that the electron density relaxation time (defined as the time the perturbed electron density, Δne, takes to decay a factor 1/e of the way to the ambient electron density (ne0)) is critically controlled at each altitude by the relative importance of associative detachment (of O- by, respectively, O and CO and of O2- by O) with respect to electron loss mechanisms (mainly 3-body, 2-body attachment and electron-ion recombination at the highest altitudes). We found that the maximum electron density relaxation time (> 15000 s) occur between 80 km and 82 km while it decreases with increasing altitudes to 12000 s (at 85 km) and about 2000 s (at 92 km). However, LORES are presumably due to VLF scattering from electron density enhancements caused by lightning-induced EMPs in the uppermost D region ionosphere (85 - 92 km). Thus the observed VLF signal recoveries (LORE recovery times) should associate with the relaxation of the maximum enhanced electron densities produced by elves between 85 km and 92 km [3]. Finally, our results for the lowest altitudes considered (76 km and 77 km) are in good agreement with the recovery times (between 20 s and 120 s) of the typical

  8. Adhesion and detachment of a capsule in axisymmetric flow

    NASA Astrophysics Data System (ADS)

    Keh, M. P.; Leal, L. G.

    2016-05-01

    The adhesion and detachment of a capsule on a solid boundary surface is studied via a combination of scaling theory and numerical simulation and the behavior is compared and contrasted with a vesicle. It is shown that the dominant physical property for both capsules and vesicles is the area dilation modulus Ks of the membrane. The nonzero shear modulus Gs for capsules increases the resistance to deformation and thus decreases slightly the equilibrium contact radius for an adhered capsule compared to an adhered vesicle. The detachment process in this study is due to an external axisymmetric flow. Unlike a rigid body that must be pulled away without change of shape, capsules (and vesicles) almost always detach dominantly by peeling in which the contact radius decreases but the minimum separation distance does not change until the final moments of detachment. Compared to a vesicle with the same Ks, a capsule maintains a more compact shape and is harder to elongate under a given external flow. Hence, the detachment process is slower for capsules compared to vesicles with the same Ks.

  9. Analytical calculations for impurity seeded partially detached divertor conditions

    NASA Astrophysics Data System (ADS)

    Kallenbach, A.; Bernert, M.; Dux, R.; Reimold, F.; Wischmeier, M.; ASDEX Upgrade Team

    2016-04-01

    A simple analytical formula for the impurity seeded partially detached divertor operational point has been developed using 1D modelling. The inclusion of charge exchange momentum loss terms improves the 1D modelling for ASDEX Upgrade conditions and its extrapolation to larger devices. The investigations are concentrated around a partially detached divertor working point of low heat flux and an electron temperature around 2.5 eV at the target which are required to maintain low sputtering rates at a tungsten target plate. An experimental formula for the onset of detachment by nitrogen seeding in ASDEX Upgrade is well reproduced, and predictions are given for N, Ne and Ar seeding for variable device size. Moderate deviations from a linear {{P}\\text{sep}}/R size dependence of the detachment threshold are seen in the modelling caused by upstream radiation at longer field line lengths. The presented formula allows the prediction of the neutral gas or seed impurity pressure which is required to achieve partial detachment for a given {{P}\\text{sep}} in devices with a closed divertor similar to the geometry in ASDEX Upgrade.

  10. Miocene detachment faulting predating EPR propagation: Southern Baja California

    NASA Astrophysics Data System (ADS)

    Bot, Anna; Geoffroy, Laurent; Authemayou, Christine; Bellon, Hervé; Graindorge, David; Pik, Raphaël.

    2016-05-01

    At the southern tip of the Baja California peninsula, we characterize the onshore structures and kinematics associated with crustal necking leading up to the Pliocene breakup and early East Pacific Rise seafloor spreading. From a combination of tectonic field investigations, K-Ar and cosmogenic isotope dating and geomorphology, we propose that the Los Cabos block represents the exhumed footwall of a major detachment fault. This north trending detachment fault is marked by a conspicuous low-dipping brittle-ductile shear zone showing a finite displacement with top to the SE ending to the ESE. This major feature is associated with fluid circulations which led to rejuvenation of the deformed Cretaceous magmatic rocks at a maximum of 17.5 Ma. The detachment footwall displays kilometer-scale corrugations controlling the present-day drainage pattern. This major detachment is synchronous with the development of the San José del Cabo Basin where syntectonic sedimentation took place from the middle Miocene to probably the early Pliocene. We propose that this seaward dipping detachment fault accommodates the proximal crustal necking of the Baja California passive margin, which predates the onset of formation of the East Pacific Rise spreading axis in the Cabo-Puerto Vallarta segment. Our data illustrate an apparent anticlockwise rotation of the stretching direction in Baja California Sur from ~17 Ma to the Pliocene.

  11. Effect of electric currents on bacterial detachment and inactivation.

    PubMed

    Hong, Seok Hoon; Jeong, Joonseon; Shim, Soojin; Kang, Heekyoung; Kwon, Sunghoon; Ahn, Kyung Hyun; Yoon, Jeyong

    2008-06-01

    Since biofilms show strong resistance to conventional disinfectants and antimicrobials, control of initial bacterial adhesion is generally accepted as one of the most effective strategies for preventing biofilm formation. Although electrical methods have been widely studied, the specific properties of cathodic, anodic, and block currents that influence the bacterial detachment and inactivation remained largely unclear. This study investigated the specific role of electric currents in the detachment and inactivation of bacteria adhered to an electrode surface. A real-time bacterial adhesion observation and control system was employed that consisted of Pseudomonas aeruginosa PAO1 (PAO1) with green fluorescent protein as the indicator microorganism and a flow cell reactor mounted on a fluorescent microscope. The results suggest that the bacteria that remained on the electrode surface after application of a cathodic current were alive, although the extent of detachment was significant. In contrast, when an anodic current was applied, the bacteria that remained on the surface became inactive with time, although bacterial detachment was not significant. Further, under these conditions, active bacterial motions were observed, which weakened the binding between the electrode surface and bacteria. This phenomenon of bacterial motion on the surface can be used to maximize bacterial detachment by manipulation of the shear rate. These findings specific for each application of a cathodic or anodic electric current could successfully explain the effectiveness of block current application in controlling bacterial adhesion. PMID:18080346

  12. Dynamic displacement of normal and detached semicircular canal cupula.

    PubMed

    Rabbitt, Richard D; Breneman, Kathryn D; King, Curtis; Yamauchi, Angela M; Boyle, Richard; Highstein, Stephen M

    2009-12-01

    The dynamic displacement of the semicircular canal cupula and modulation of afferent nerve discharge were measured simultaneously in response to physiological stimuli in vivo. The adaptation time constant(s) of normal cupulae in response to step stimuli averaged 36 s, corresponding to a mechanical lower corner frequency for sinusoidal stimuli of 0.0044 Hz. For stimuli equivalent to 40-200 deg/s of angular head velocity, the displacement gain of the central region of the cupula averaged 53 nm per deg/s. Afferents adapted more rapidly than the cupula, demonstrating the presence of a relaxation process that contributes significantly to the neural representation of angular head motions by the discharge patterns of canal afferent neurons. We also investigated changes in time constants of the cupula and afferents following detachment of the cupula at its apex-mechanical detachment that occurs in response to excessive transcupular endolymph pressure. Detached cupulae exhibited sharply reduced adaptation time constants (300 ms-3 s, n = 3) and can be explained by endolymph flowing rapidly over the apex of the cupula. Partially detached cupulae reattached and normal afferent discharge patterns were recovered 5-7 h following detachment. This regeneration process may have relevance to the recovery of semicircular canal function following head trauma.

  13. Current perspectives of herpesviral retinitis and choroiditis.

    PubMed

    Madhavan, H N; Priya, K; Biswas, J

    2004-10-01

    Vision-threatening viral retinitis are primarily caused by members of the herpesvirus family. The biology and molecular characterization of herpesviruses, clinical presentations of retinopathies, pathology and pathogenesis including the host responses, epidemiology and the laboratory methods of aetiological diagnosis of these diseases are described. Clinical syndromes are acute retinal necrosis (ARN), progressive outer retinal necrosis (PORN), cytomegalovirus (CMV) retinitis, multifocal choroiditis and serpiginous choroiditis besides other viral retinopathies. Herpes simplex virus (HSV) retinitis is more common in immunocompetent persons while varicella zoster virus (VZV) affects both immunocompetent and immunosuppressed patients equally. CMV retinitis is most common among patients with AIDS. The currently employed laboratory methods of antigen detection, virus isolation and antibody detection by enzyme linked immuno-sorbent assay (ELISA) have low sensitivity. Polymerase chain reaction (PCR) has increased the value of diagnosis due to its high clinical sensitivity and absolute specificity in detection of herpesviruses in intraocular specimens. PMID:16295367

  14. Current perspectives of herpesviral retinitis and choroiditis.

    PubMed

    Madhavan, H N; Priya, K; Biswas, J

    2004-10-01

    Vision-threatening viral retinitis are primarily caused by members of the herpesvirus family. The biology and molecular characterization of herpesviruses, clinical presentations of retinopathies, pathology and pathogenesis including the host responses, epidemiology and the laboratory methods of aetiological diagnosis of these diseases are described. Clinical syndromes are acute retinal necrosis (ARN), progressive outer retinal necrosis (PORN), cytomegalovirus (CMV) retinitis, multifocal choroiditis and serpiginous choroiditis besides other viral retinopathies. Herpes simplex virus (HSV) retinitis is more common in immunocompetent persons while varicella zoster virus (VZV) affects both immunocompetent and immunosuppressed patients equally. CMV retinitis is most common among patients with AIDS. The currently employed laboratory methods of antigen detection, virus isolation and antibody detection by enzyme linked immuno-sorbent assay (ELISA) have low sensitivity. Polymerase chain reaction (PCR) has increased the value of diagnosis due to its high clinical sensitivity and absolute specificity in detection of herpesviruses in intraocular specimens.

  15. Retinal blood vessels extraction using probabilistic modelling.

    PubMed

    Kaba, Djibril; Wang, Chuang; Li, Yongmin; Salazar-Gonzalez, Ana; Liu, Xiaohui; Serag, Ahmed

    2014-01-01

    The analysis of retinal blood vessels plays an important role in detecting and treating retinal diseases. In this review, we present an automated method to segment blood vessels of fundus retinal image. The proposed method could be used to support a non-intrusive diagnosis in modern ophthalmology for early detection of retinal diseases, treatment evaluation or clinical study. This study combines the bias correction and an adaptive histogram equalisation to enhance the appearance of the blood vessels. Then the blood vessels are extracted using probabilistic modelling that is optimised by the expectation maximisation algorithm. The method is evaluated on fundus retinal images of STARE and DRIVE datasets. The experimental results are compared with some recently published methods of retinal blood vessels segmentation. The experimental results show that our method achieved the best overall performance and it is comparable to the performance of human experts.

  16. Retinal abnormalities in β-thalassemia major.

    PubMed

    Bhoiwala, Devang L; Dunaief, Joshua L

    2016-01-01

    Patients with beta (β)-thalassemia (β-TM: β-thalassemia major, β-TI: β-thalassemia intermedia) have a variety of complications that may affect all organs, including the eye. Ocular abnormalities include retinal pigment epithelial degeneration, angioid streaks, venous tortuosity, night blindness, visual field defects, decreased visual acuity, color vision abnormalities, and acute visual loss. Patients with β-thalassemia major are transfusion dependent and require iron chelation therapy to survive. Retinal degeneration may result from either retinal iron accumulation from transfusion-induced iron overload or retinal toxicity induced by iron chelation therapy. Some who were never treated with iron chelation therapy exhibited retinopathy, and others receiving iron chelation therapy had chelator-induced retinopathy. We will focus on retinal abnormalities present in individuals with β-thalassemia major viewed in light of new findings on the mechanisms and manifestations of retinal iron toxicity. PMID:26325202

  17. Role of retinal vascular endothelial cells in development of CMV retinitis.

    PubMed Central

    Rao, N A; Zhang, J; Ishimoto, S

    1998-01-01

    PURPOSE: Although cytomegalovirus (CMV) retinitis is known to occur in association with retinal microangiopathy in individuals with marked immunodeficiency, glial cells are believed to be the initial target cells in the development of retinitis. Moreover, it has been hypothesized that CMV gains access to the retinal glia because of altered vascular permeability. In an attempt to address the hypothesis, we studied 30 autopsy eyes of AIDS patients with systemic CMV infection, with or without clinically apparent CMV retinitis. METHODS: The autopsy eyes were processed in three ways. First, dual immunohistochemical studies were done by using anti-CMV antibodies for immediate early, early, and late antigens. The retinal cell types infected with the virus were then determined by using anti-GFAP, anti-VonWillebrand's factor, neuronal specific enolase, and leukocyte marker CD68. Second, selected eyes were processed for in situ hybridization with DNA probe specific to CMV. Third, an eye with clinically apparent CMV retinitis was submitted for electron microscopic examination. RESULTS: At the site of retinal necrosis in those eyes with a clinical diagnosis of CMV retinitis, the immunohistochemical, in situ hybridization, and ultrastructural examinations revealed that CMV was present primarily in the Müller cells and in perivascular glial cells. Adjacent to these infected cells, focal areas of positive staining for CMV antigen were seen in the glial cells, neuronal cells, and retinal pigment epithelial cells. At these sites most of the retinal capillaries were devoid of endothelial cells. Few vessels located at the advancing margin of retinal necrosis showed the presence of viral proteins in the endothelial cells. CONCLUSIONS: The present results indicate that retinal vascular endothelial cells could be the initial target in the development of viral retinitis, with subsequent spread of the infection to perivascular glia, Müller cells, and other retinal cells, including the

  18. Retinal vein occlusion: current treatment.

    PubMed

    Lattanzio, Rosangela; Torres Gimeno, Ana; Battaglia Parodi, Maurizio; Bandello, Francesco

    2011-01-01

    Retinal vein occlusion (RVO) is a pathology noted for more than 150 years. Although a lot has been written on the matter, it is still a frequent condition with multifactorial etiopathogenesis with many unclear aspects. The RVO pathogenesis has varied systemic and local implications that make it difficult to elaborate treatment guidelines. The management of the patient with RVO is very complex and a multidisciplinary approach is required in order to identify and correct the associated risk factors. Laser therapy remains the gold standard in RVO, but only modest functional improvement has been shown in branch retinal occlusion forms. Multicenter studies of intravitreal drugs present them as an option to combine with laser. Anti-vascular endothelial growth factor, corticosteroids and sustained-release implants are the future weapons to stop disease progression and get a better visual outcome. Consequently, it is useful to clarify some aspects of the pathology that allow a better patient management. PMID:20938213

  19. Retinal fibrosis in diabetic retinopathy.

    PubMed

    Roy, Sayon; Amin, Shruti; Roy, Sumon

    2016-01-01

    In response to injury, reparative processes are triggered to restore the damaged tissue; however, such processes are not always successful in rebuilding the original state. The formation of fibrous connective tissue is known as fibrosis, a hallmark of the reparative process. For fibrosis to be successful, delicately balanced cellular events involving cell proliferation, cell migration, and extracellular matrix (ECM) remodeling must occur in a highly orchestrated manner. While successful repair may result in a fibrous scar, this often restores structural stability and functionality to the injured tissue. However, depending on the functionality of the injured tissue, a fibrotic scar can have a devastating effect. For example, in the retina, fibrotic scarring may compromise vision and ultimately lead to blindness. In this review, we discuss some of the retinal fibrotic complications and highlight mechanisms underlying the development of retinal fibrosis in diabetic retinopathy.

  20. Gene Therapy for Retinal Diseases

    PubMed Central

    Samiy, Nasrollah

    2014-01-01

    Gene therapy has a growing research potential particularly in the field of ophthalmic and retinal diseases owing to three main characteristics of the eye; accessibility in terms of injections and surgical interventions, its immune-privileged status facilitating the accommodation to the antigenicity of a viral vector, and tight blood-ocular barriers which save other organs from unwanted contamination. Gene therapy has tremendous potential for different ocular diseases. In fact, the perspective of gene therapy in the field of eye research does not confine to exclusive monogenic ophthalmic problems and it has the potential to include gene based pharmacotherapies for non-monogenic problems such as age related macular disease and diabetic retinopathy. The present article has focused on how gene transfer into the eye has been developed and used to treat retinal disorders with no available therapy at present. PMID:25709778

  1. Retinal vein occlusion: current treatment.

    PubMed

    Lattanzio, Rosangela; Torres Gimeno, Ana; Battaglia Parodi, Maurizio; Bandello, Francesco

    2011-01-01

    Retinal vein occlusion (RVO) is a pathology noted for more than 150 years. Although a lot has been written on the matter, it is still a frequent condition with multifactorial etiopathogenesis with many unclear aspects. The RVO pathogenesis has varied systemic and local implications that make it difficult to elaborate treatment guidelines. The management of the patient with RVO is very complex and a multidisciplinary approach is required in order to identify and correct the associated risk factors. Laser therapy remains the gold standard in RVO, but only modest functional improvement has been shown in branch retinal occlusion forms. Multicenter studies of intravitreal drugs present them as an option to combine with laser. Anti-vascular endothelial growth factor, corticosteroids and sustained-release implants are the future weapons to stop disease progression and get a better visual outcome. Consequently, it is useful to clarify some aspects of the pathology that allow a better patient management.

  2. Retinitis pigmentosa in southern Africa.

    PubMed

    Greenberg, J; Bartmann, L; Ramesar, R; Beighton, P

    1993-11-01

    Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal disorders which are a common cause of genetic blindness. The relative frequencies of the different forms of RP in South Africa, as determined from the register at the DNA banking centre for RP at the Department of Human Genetics, University of Cape Town, are presented and discussed. Of the 125 families analysed, 29 (23%) showed autosomal dominant, 33 (27%) autosomal recessive and 3 (3%) X-linked inheritance. In 10 families the pedigree data were insufficient to allow accurate genetic subtyping and a further 50 patients were sporadic without a family history of RP or other syndromic features which would allow categorization. PMID:8313621

  3. Operational challenges of retinal prostheses.

    PubMed

    Schmid, Erich W; Fink, Wolfgang; Wilke, Robert

    2014-12-01

    Two computational models for research on retinal implants are presented. In the first model, the electric field produced by a multi-electrode array in a uniform retina is calculated. It is shown how cross talk of activated electrodes and the resulting bunching of field lines in monopole and dipole activation prevent high resolution imaging with retinal implants. Furthermore, it is demonstrated how sequential stimulation and multipolar stimulation may overcome this limitation. In the second model a target volume, i.e., a probe cylinder approximating a bipolar cell, in the retina is chosen, and the passive Heaviside cable equation is solved inside this target volume to calculate the depolarization of the cell membrane. The depolarization as a function of time indicates that shorter signals stimulate better as long as the current does not change sign during stimulation of the retina, i.e., mono-phasic stimulation. Both computational models are equally applicable to epiretinal, subretinal, and suprachoroidal vision implants. PMID:25443535

  4. Aberrant protein trafficking in retinal degenerations: The initial phase of retinal remodeling.

    PubMed

    Bales, Katie L; Gross, Alecia K

    2016-09-01

    Retinal trafficking proteins are involved in molecular assemblies that govern protein transport, orchestrate cellular events involved in cilia formation, regulate signal transduction, autophagy and endocytic trafficking, all of which if not properly controlled initiate retinal degeneration. Improper function and or trafficking of these proteins and molecular networks they are involved in cause a detrimental cascade of neural retinal remodeling due to cell death, resulting as devastating blinding diseases. A universal finding in retinal degenerative diseases is the profound detection of retinal remodeling, occurring as a phased modification of neural retinal function and structure, which begins at the molecular level. Retinal remodeling instigated by aberrant trafficking of proteins encompasses many forms of retinal degenerations, such as the diverse forms of retinitis pigmentosa (RP) and disorders that resemble RP through mutations in the rhodopsin gene, retinal ciliopathies, and some forms of glaucoma and age-related macular degeneration (AMD). As a large majority of genes associated with these different retinopathies are overlapping, it is imperative to understand their underlying molecular mechanisms. This review will discuss some of the most recent discoveries in vertebrate retinal remodeling and retinal degenerations caused by protein mistrafficking. PMID:26632497

  5. Retinal pathways influence temporal niche

    PubMed Central

    Doyle, Susan E.; Yoshikawa, Tomoko; Hillson, Holly; Menaker, Michael

    2008-01-01

    In mammals, light input from the retina entrains central circadian oscillators located in the suprachiasmatic nuclei (SCN). The phase of circadian activity rhythms with respect to the external light:dark cycle is reversed in diurnal and nocturnal species, although the phase of SCN rhythms relative to the light cycle remains unchanged. Neural mechanisms downstream from the SCN are therefore believed to determine diurnality or nocturnality. Here, we report a switch from nocturnal to diurnal entrainment of circadian activity rhythms in double-knockout mice lacking the inner-retinal photopigment melanopsin (OPN4) and RPE65, a key protein used in retinal chromophore recycling. These mice retained only a small amount of rod function. The change in entrainment phase of Rpe65−/−;Opn4−/− mice was accompanied by a reversal of the rhythm of clock gene expression in the SCN and a reversal in acute masking effects of both light and darkness on activity, suggesting that the nocturnal to diurnal switch is due to a change in the neural response to light upstream from the SCN. A switch from nocturnal to diurnal activity rhythms was also found in wild-type mice transferred from standard intensity light:dark cycles to light:dark cycles in which the intensity of the light phase was reduced to scotopic levels. These results reveal a novel mechanism by which changes in retinal input can mediate acute temporal-niche switching. PMID:18695249

  6. Multineuronal codes in retinal signaling.

    PubMed Central

    Meister, M

    1996-01-01

    The visual world is presented to the brain through patterns of action potentials in the population of optic nerve fibers. Single-neuron recordings show that each retinal ganglion cell has a spatially restricted receptive field, a limited integration time, and a characteristic spectral sensitivity. Collectively, these response properties define the visual message conveyed by that neuron's action potentials. Since the size of the optic nerve is strictly constrained, one expects the retina to generate a highly efficient representation of the visual scene. By contrast, the receptive fields of nearby ganglion cells often overlap, suggesting great redundancy among the retinal output signals. Recent multineuron recordings may help resolve this paradox. They reveal concerted firing patterns among ganglion cells, in which small groups of nearby neurons fire synchronously with delays of only a few milliseconds. As there are many more such firing patterns than ganglion cells, such a distributed code might allow the retina to compress a large number of distinct visual messages into a small number of optic nerve fibers. This paper will review the evidence for a distributed coding scheme in the retinal output. The performance limits of such codes are analyzed with simple examples, illustrating that they allow a powerful trade-off between spatial and temporal resolution. PMID:8570603

  7. Paleostress analyses in the uppermost footwalls of the Whipple detachment and the West Salton detachment faults, southern California

    NASA Astrophysics Data System (ADS)

    Luther, A. L.; Axen, G. J.; Selverstone, J.; Michelsen, K. J.

    2010-12-01

    Low-angle normal faults (LANFs) slip while nearly perpendicular to the regional S1, presenting a mechanical paradox that may be explained by rotation of S1 toward the fault as it is approached, weak materials reducing friction and/or high pore-fluid pressure. Well-exposed LANF footwalls provide opportunities for detailed studies of weak faults. Paleostress inversions of fault-slip data coupled with structural and chemical analyses of footwall rocks are in progress on the Whipple detachment fault (WDF; >40 km Miocene slip; evolved from ductile shear zone to brittle fault) and the West Salton detachment fault (WSDF; ~10 km slip during dextral-wrench tectonism coeval with San Andreas Fault slip). Both were folding during detachment slip. Paleostress analyses indicate that both faults slipped mainly in extensional stress fields (sub-vertical S1) and in axial compression (S2 ≈ S3). Over 40% of extensional stress fields yield S1 plunging >70° relative to the detachment, but ~30% yield plunges of 40° to 60° relative to the detachment. Thus, the stress field may have been locally and/or temporarily rotated away from sub-vertical during detachment slip. About 15% of the inversions yield shortening stress fields (S1 ~horizontal) consistent with folding and/or dextral-wrench deformation. Mutually cross-cutting relationships between fracture sets suggest that the stress fields may have alternated through time. “Mini-detachments” (MDs) are small, detachment-parallel faults that are structurally analogous to the main faults. Inversions yield S1 ~45° from the MDs and a larger magnitude of S2 relative to S3. Damage zones subjacent to MD fault cores commonly yield more moderately plunging S1 than do MD fault cores or deeper rocks. Petrological evidence suggests that the MDs formed early in the detachment history (Selverstone et al., GSA Abstract, 2009). If their damage zones also formed early, then S1 may have been shallower early in detachment history and(or) at greater

  8. Detachment energies of spheroidal particles from fluid-fluid interfaces

    NASA Astrophysics Data System (ADS)

    Davies, Gary B.; Krüger, Timm; Coveney, Peter V.; Harting, Jens

    2014-10-01

    The energy required to detach a single particle from a fluid-fluid interface is an important parameter for designing certain soft materials, for example, emulsions stabilised by colloidal particles, colloidosomes designed for targeted drug delivery, and bio-sensors composed of magnetic particles adsorbed at interfaces. For a fixed particle volume, prolate and oblate spheroids attach more strongly to interfaces because they have larger particle-interface areas. Calculating the detachment energy of spheroids necessitates the difficult measurement of particle-liquid surface tensions, in contrast with spheres, where the contact angle suffices. We develop a simplified detachment energy model for spheroids which depends only on the particle aspect ratio and the height of the particle centre of mass above the fluid-fluid interface. We use lattice Boltzmann simulations to validate the model and provide quantitative evidence that the approach can be applied to simulate particle-stabilized emulsions, and highlight the experimental implications of this validation.

  9. Shape of heteroepitaxial island determined by asymmetric detachment

    NASA Astrophysics Data System (ADS)

    Saito, Yukio; Kawasaki, Ryo

    2008-02-01

    Square lattice gas models for heteroepitaxial growth are studied by means of kinetic Monte Carlo simulations, in order to find a possible origin of anisotropic island shape observed in growth experiments of long organic molecules. When deposited molecules form clusters irreversibly at their encounter during surface diffusion, islands grow in a ramified dendritic shape, similar to DLA. Introduction of molecular detachment from edges makes islands compact with smooth edges. Tilting of adsorbed long molecules or steps in a vicinal substrate may induce orientation dependence in the detachment rate of edge molecules from an island. In simulations with orientation-dependent detachment rates, a clear anisotropy in an island shape is observed. Shape anisotropy on a vicinal substrate is enhanced as steps get dense, in agreement to the experimental observation.

  10. Intense field double detachment of atomic versus molecular anions

    NASA Astrophysics Data System (ADS)

    Albeck, Y.; Lerner, G.; Kandhasamy, D. M.; Chandrasekaran, V.; Strasser, D.

    2015-12-01

    The interaction of intense ultrafast laser pulses with atomic F- and with molecular S F6 - anions is directly compared. The double-detachment mechanism is investigated by a systematic variation of peak intensity, polarization ellipticity, and pulse shape. For both systems, the observed weak polarization ellipticity dependence is not consistent with a rescattering-based mechanism. A double-detachment saturation intensity of 22 ±4 ×1013W /c m2 is determined for the atomic anion, which is significantly higher than the 9 ±2 ×1013W /c m2 of the analogous molecular system. The different atomic and molecular responses to spectral chirp and third-order dispersion induced pulse shapes are discussed in the context of the double-detachment time scale.

  11. Streetscape showing north sides of five of eight Medical Detachment ...

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

    Streetscape showing north sides of five of eight Medical Detachment Barracks on Ramp No. 5. Note that Building No. 9966-B on right has a wooden frame sun porch. This Standard Ward construction is different than most of the other Medical Detachment Barracks, which are all- brick. On the opposite side of this building, the construction is all-brick (Building No. 9966-A, not shown). Buildings No. 9967-B and 9968-B (not shown) also have wooden frame sun porches. Other buildings in photo are, on right, the north B-sides of Buildings Nos. 9965, 9964, 9963 and 9962. On left is Building No. 9971-A on Ramp No. 6. Corridor A is visible in far distance. - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  12. Update on Pharmacologic Retinal Vascular Toxicity.

    PubMed

    Schwartz, Stephen G; Grzybowski, Andrzej; Wasinska-Borowiec, Weronika; Flynn, Harry W; Mieler, William F

    2015-01-01

    Several medications are associated with retinal vascular toxicity. These include intraocular aminoglycosides, oral contraceptives, interferon alpha, several other agents, and talc, which occurs as a vehicle in some oral medications that may be abused intravenously. As a group, these entities represent a small but clinically relevant category of retinal toxicity from medications. Some of the manifestations (e.g., retinal vascular occlusion) are nonspecific, but others are more specific, including clinically visible talc emboli in retinal vessels. Toxicity may be asymptomatic or may cause irreversible visual loss. By maintaining a high index of suspicion, the correct diagnosis can usually be made.

  13. [Novel mechanism for retinal vascular diseases].

    PubMed

    Suzuma, Kiyoshi

    2015-03-01

    I. A new therapeutic target for diabetic retinopathy. Recent reports state that succinate may be an independent retinal angiogenic factor. We evaluated concentrations in vitreous from proliferative diabetic retinopathy (PDR), and found that succinate increased significantly in PDR. Interestingly, levels of succinate from bevacizumab-pre-injected PDR were normal, suggesting that vascular endothelial growth factor (VEGF) had a positive feedback mechanism for succinate since succinate was previously reported to induce VEGF. II. A new understanding of central retinal vein occlusion (CRVO). We evaluated retinal blood flow velocity with laser speckle flowgraphy (LSFG) made in Japan, and found that cases in which both macular edema and retinal blood flow velocity improved after anti-VEGF therapy had better prognosis. In ischemic CRVO at final visit, mean retinal blood velocity was less than 50% of fellow eyes after 1st anti-VEGF therapy, suggesting that those cases might have poor prognosis. LSFG is useful for evaluation and decision in CRVO treatment. III. From exploration for mechanism in retinal vascular diseases to re-vascularization therapy. The standard treatment for retinal non-perfusion area is scatter laser photocoagulation, which is both invasive of the peripheral retina and may prove destructive. Re-vascularization is an ideal strategy for treatment of retinal non-perfusion area. To develop a new methods for re-vascularization in retinal non-perfusion area, we have designed experiments using a retina without vasculature differentiated from induced pluripotent stem(iPS) cells.

  14. Retinal Cell Degeneration in Animal Models

    PubMed Central

    Niwa, Masayuki; Aoki, Hitomi; Hirata, Akihiro; Tomita, Hiroyuki; Green, Paul G.; Hara, Akira

    2016-01-01

    The aim of this review is to provide an overview of various retinal cell degeneration models in animal induced by chemicals (N-methyl-d-aspartate- and CoCl2-induced), autoimmune (experimental autoimmune encephalomyelitis), mechanical stress (optic nerve crush-induced, light-induced) and ischemia (transient retinal ischemia-induced). The target regions, pathology and proposed mechanism of each model are described in a comparative fashion. Animal models of retinal cell degeneration provide insight into the underlying mechanisms of the disease, and will facilitate the development of novel effective therapeutic drugs to treat retinal cell damage. PMID:26784179

  15. Update on Pharmacologic Retinal Vascular Toxicity.

    PubMed

    Schwartz, Stephen G; Grzybowski, Andrzej; Wasinska-Borowiec, Weronika; Flynn, Harry W; Mieler, William F

    2015-01-01

    Several medications are associated with retinal vascular toxicity. These include intraocular aminoglycosides, oral contraceptives, interferon alpha, several other agents, and talc, which occurs as a vehicle in some oral medications that may be abused intravenously. As a group, these entities represent a small but clinically relevant category of retinal toxicity from medications. Some of the manifestations (e.g., retinal vascular occlusion) are nonspecific, but others are more specific, including clinically visible talc emboli in retinal vessels. Toxicity may be asymptomatic or may cause irreversible visual loss. By maintaining a high index of suspicion, the correct diagnosis can usually be made. PMID:26350526

  16. Radial optic neurotomy in treating central retinal vein occlusion: a Meta-analysis

    PubMed Central

    Chen, Zhen-Na; Shao, Yan; Li, Xiao-Rong

    2016-01-01

    AIM To assess the feasibility of radial optic neurotomy (RON) in central retinal vein occlusion (CRVO) treatment with a Meta-analysis. METHODS Electronic databases were searched for comprehensive articles that compared efficacy of RON with that of other treatments in CRVO. Study quality was assessed and risk ratio (RR) and 95% confidence interval (CI) with fix- or random-effects model were calculated according to the heterogeneity. RESULTS A total of 200 eyes from 5 studies were included. The results indicated that no significant differences were found between groups with and without RON in improvement of visual acuity (VA) at 6mo follow-up (pooled RR 0.51, 95%CI 0.22 to 1.18, P=0.117) while improvement of VA showed significantly favourable in patients receiving RON treatment at 12mo follow-up (pooled RR 2.27, 95%CI 1.31 to 3.95, P=0.004). For complications, RON treatment was more effective in reducing neovascular glaucoma (pooled RR 0.45, 95%CI 0.21 to 0.97, P=0.042) but was comparable in retinal detachment (pooled RR 2.41, 95%CI 0.51 to 11.39, P=0.267) and vitreous hemorrhage (pooled RR 0.91, 95%CI 0.33 to 2.46, P=0.847). CONCLUSION Compared with some certain treatment modalities, RON might offer better VA at 12mo and decrease the rate of neovascular glaucoma without changing the rate of retinal detachment and vitreous hemorrhage. Further studies are required considering the limitation of the research. PMID:27366695

  17. Detached Solidification of Germanium-Silicon Crystals on the ISS

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.; Croell, A.

    2016-01-01

    A series of Ge(sub 1-x) Si(sub x) crystal growth experiments are planned to be conducted in the Low Gradient Furnace (LGF) onboard the International Space Station. The primary objective of the research is to determine the influence of containment on the processing-induced defects and impurity incorporation in germanium-silicon alloy crystals. A comparison will be made between crystals grown by the normal and "detached" Bridgman methods and the ground-based float zone technique. Crystals grown without being in contact with a container have superior quality to otherwise similar crystals grown in direct contact with a container, especially with respect to impurity incorporation, formation of dislocations, and residual stress in crystals. "Detached" or "dewetted" Bridgman growth is similar to regular Bridgman growth in that most of the melt is in contact with the crucible wall, but the crystal is separated from the wall by a small gap, typically of the order of 10-100 microns. Long duration reduced gravity is essential to test the proposed theory of detached growth. Detached growth requires the establishment of a meniscus between the crystal and the ampoule wall. The existence of this meniscus depends on the ratio of the strength of gravity to capillary forces. On Earth, this ratio is large and stable detached growth can only be obtained over limited conditions. Crystals grown detached on the ground exhibited superior structural quality as evidenced by measurements of etch pit density, synchrotron white beam X-ray topography and double axis X-ray diffraction.

  18. Crewmembers in the middeck with the Retinal Photography experiment.

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mission Pilot Robert Cabana conducting the Retinal Photography life sciences experiment on test subject Mission Specialist Michael Clifford. The Retinal Photography experiment is Detailed Supplementary Objective # 474.

  19. DUAL ORIGIN OF AEROSOLS IN TITAN'S DETACHED HAZE LAYER

    SciTech Connect

    Cours, T.; Burgalat, J.; Rannou, P.; Rodriguez, S.; Brahic, A.

    2011-11-10

    We have analyzed scattered light profiles from the Cassini Imaging Science Subsystem, taken at the limb and at several large phase angles. We also used results from an occultation observed by Ultraviolet Imaging Spectrograph in the ultraviolet. We found that particles responsible for the scattering in the detached haze have an effective radius around 0.15 {mu}m and the aerosol size distribution follows a power law (exponent about -4.5). We discuss these results along with microphysical constraints and thermal equilibrium of the detached haze, and we conclude that only a strong interaction with atmospheric dynamics can explain such a structure.

  20. Cenozoic Evolution of the West Cycladic Detachment System

    NASA Astrophysics Data System (ADS)

    Iglseder, Christoph; Grasemann, Bernhard; Schneider, Dave A.; Senkowski, Carley A.; Stöckli, Dani

    2010-05-01

    Extension in the Aegean led to the formation of metamorphic core complexes and domes, with multistage extensional detachments cutting rocks of the Attic-Cycladic Crystalline at different structural and lithostratigraphic levels. Four kinematic provenances are here distinguished in the Cycladic extensional detachment system: (1) The North (Andros-Ikaria) and (2) Central (Naxos-Paros) Cycladic Detachment Systems, showing top N/NE sense of shear; (3) the South Cycladic Detachment System (Ios-Amorgos), part of the South Cycladic Shear Zone, with evidence for two opposite kinematic domains, an older top S/SE and a younger top N/NW sense of shear. In contrast, the newly documented (4) West Cycladic Detachment System (Sifnos-Lavrion) is dominated by a top SW/SSW sense of shear. Low-angled extensional detachments nucleated in the ductile regime and show progressive overprinting by ductile-brittle and then brittle deformation processes on Kea, Kythnos and Serifos. On Sifnos, an older top NE and brittle-ductile younger event, with top SW kinematics has been documented. In comparison, on the Greek mainland in Attica, top SW/SSW sense of shear allows the regional structure to be expanded. At both Lavrion in Attica and Serifos, the extensional detachments were intruded by syn-tectonic Late Miocene granodiorites. Cenozoic extension in the Western Cyclades is suggested to begin in the Eocene, with early S-type granite intrusion on Serifos at 43-37 Ma (U-Pb zircon). This is supported by Eocene/Early Oligocene Rb/Sr and Ar/Ar (cooling) ages of hanging-wall schists and marbles. Similar cooling ages, (post-) dating high-pressure/low-temperature metamorphism, have been described from Sifnos. During the Oligocene/Miocene, a decrease in greenschist-facies ages has been determined on the Serifos-Kythnos-Kea transect. Similar ages of greenschist-facies metamorphism have also been found on Sifnos. Initial stages of the Serifos granodiorite intrusion, coeval with initiation of the main

  1. Rotational auto-detachment of dipole-bound anions

    NASA Astrophysics Data System (ADS)

    Ard, S. G.; Compton, R. N.; Garrett, W. R.

    2016-04-01

    Rotational auto-detachment of acetonitrile, trimethyl-acetonitrile, acetone, and cyclobutanone dipole-bound anions was studied under varying conditions in a Rydberg electron transfer (RET) time-of-flight apparatus. Varying amounts of auto-detachment was observed for anions with similar electron affinity and dipole moment, but different moments of inertia. These results were found to be consistent with predictions based on the calculated rotational spectra for these anions, highlighting the importance of critical binding properties in understanding the stability and lifetime of dipole bound systems.

  2. Magnetic Detachment and Plume Control in Escaping Magnetized Plasma

    SciTech Connect

    P. F. Schmit and N. J. Fisch

    2008-11-05

    The model of two-fluid, axisymmetric, ambipolar magnetized plasma detachment from thruster guide fields is extended to include plasmas with non-zero injection angular velocity profiles. Certain plasma injection angular velocity profiles are shown to narrow the plasma plume, thereby increasing exhaust efficiency. As an example, we consider a magnetic guide field arising from a simple current ring and demonstrate plasma injection schemes that more than double the fraction of useful exhaust aperture area, more than halve the exhaust plume angle, and enhance magnetized plasma detachment.

  3. Evaluation of bacterial detachment rates in porous media

    SciTech Connect

    Peyton, B.M.; Hooker, B.S.; Skeen, R.S.; Cunningham, A.B.; Lundman, R.W.

    1994-05-01

    The ability of published biomass detachment rate expressions to describe experimental data obtained from porous media reactors using Pseudomonas aeruginosa grown aerobically on glucose was evaluated. A first-order rate expression on attached biomass concentration best reflected effluent substrate concentration for combined data sets. Detachment rate coefficient k{sub d1} was dependent on initial substrate concentration. Simulation of porous media reactor experiments indicated that responses using higher influent substrate concentrations possessed greater sensitivity to variations in k{sub d1}. Simulations of field bioremediation systems suggest the use of accurate biofilm development kinetics is important in the prediction of well bore biofouling.

  4. Dissociative detachment and memory impairment: reversible amnesia or encoding failure?

    PubMed

    Allen, J G; Console, D A; Lewis, L

    1999-01-01

    The authors propose that clinicians endeavor to differentiate between reversible and irreversible memory failures in patients with dissociative symptoms who report "memory gaps" and "lost time." The classic dissociative disorders, such as dissociative amnesia and dissociative identity disorder, entail reversible memory failures associated with encoding experience in altered states. The authors propose another realm of memory failures associated with severe dissociative detachment that may preclude the level of encoding of ongoing experience needed to support durable autobiographical memories. They describe how dissociative detachment may be intertwined with neurobiological factors that impair memory, and they spell out the significance of distinguishing reversible and irreversible memory impairment for diagnosis, patient education, psychotherapy, and research.

  5. 2. Overview showing Medical Detachment Barracks on both Ramp No. ...

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

    2. Overview showing Medical Detachment Barracks on both Ramp No. 5 (left buildings) and Ramp No. 6 (right buildings). View is to west from roof of Corridor A. Note that a pedestrian sidewalk separates buildings instead of a street for automobiles. In left foreground is the north end of Building No. 9962-B; followed by the north B-sides of Buildings Nos. 9963, 9964, 9965, 9966, 9967 and 9968 on Ramp No. 5. Large white building in far distance is a barracks on the other side of Wilson Avenue. - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  6. [Retinal and corneal dysplasias in the Yorkshire terrier and other dog breeds in Austria].

    PubMed

    Walde, I

    1997-01-01

    Mother and son of a Yorkshire Terrier family showed excessive multifocal retinal dysplasia (RD1) and geographical retinal dysplasia (RD2), intra- and preretinal hemorrhages partial and total retinal detachment (total RD/RD3), residues of the pupillary membrane and as a newness in this combination a geographical, subepithelial corneal opacity, composed of small dots. One, not examined son of the same litter was congenitally blind. Similar corneal opacities were also found in two Rough Collies affected with CEA, RD, and microphthalmia, a young German Wirehair Pointer with primary absolute glaucoma in conjunction with goniodysplasia and RD in the healthy seeming fellow eye as well as in a poodle puppy affected with bilateral posterior suture-line cataract in connection with persistent primary hyperplastic vitreous (PHPV) in one and a globe-shaped deformed retina in connection with a persistent, blood conducting hyaloid artery in the other eye. The latter finally resulted in intraocular hemorrhage and secondary glaucoma. A pathogenetic connection between ocular malformations and subepithelial corneal opacity seems to be likely.

  7. Second harmonic generation from Langmuir-Blodgett films of retinal and retinal Schiff bases

    SciTech Connect

    Huang, J.; Lewis, A.; Rasing, T.

    1988-04-07

    The second harmonic signal from monolayers of retinal and retinal Schiff bases is reported. The results have yielded information on the monolayer structure and demonstrate that retinal and retinal Schiff bases have large second-order molecular hyperpolarizabilities with values of 1.4 x 10/sup -28/, 1.2 x 10/sup -28/, and 2.3 x 10/sup -28/ esu for retinal, the unprotonated Schiff base, and the protonated Schiff base, respectively. These values compare well with the known variation in the alteration in the dipole moment of such chromophores upon excitation.

  8. The detached haze layer in Titan's mesosphere: The formation process

    NASA Astrophysics Data System (ADS)

    Lavvas, P.; Yelle, R. V.; Vuitton, V.

    2008-09-01

    Cassini observations made by the Imaging Science Subsystem (ISS) [1] and by the UltraViolet Imaging Spectrometer (UVIS) [2,3] have revealed the presence of a detached haze layer in Titan's mesosphere at an altitude of 520 km. Analysis of the observed optical properties presented in the accompanying talk [5], suggests that the average size of particles in the detached layer is of ~40 nm, with an imaginary index k < 0.3 at 187.5 nm and a number density of ˜30 particles cm-3, while calculations of the sedimentation velocity of the haze particles coupled with the derived number density imply a mass flux of 1.9-3.2 × 10-14 g cm-2 s-1. This is approximately equal to the mass flux required to explain the main haze layer and suggests that the main haze layer in Titan's stratosphere is formed primarily by sedimentation and coagulation of particles in the detached layer [5,6]. The HASI data clearly show that the haze is coincident with a temperature maximum. This rules out condensation as the source of the detached haze. We have also considered a more complicated scenario in which the detached layer is caused by an increase in the density of condensation nuclei near 520 km. This is motivated by the fact that silicate micrometeorites ablate near 500 km [7,8]. Recondensation of the refractory vapor creates `smoke' particles that could serve as condensation nuclei. Combination of Pioneer measurements along with theoretical estimations for the particles velocity distribution, suggest a mass flux of ~10-17 g cm-2 s-1 at Saturn's region [9], while measurements from the Cassini Dust Analyser (CDA) suggest a similar magnitude at Titan's location [10]. These fluxes are ~3 orders of magnitude smaller than the lower limit of the estimated mass flux out of the detached haze layer, so meteorite ablation can not be the direct cause of the aerosol layer. However, if the ablated meteoritic material reforms 1 nm particles, the implied number flux would be 2.4 × 103 particles cm-2 s-1

  9. The bacterial toxin CNF1 as a tool to induce retinal degeneration reminiscent of retinitis pigmentosa

    PubMed Central

    Guadagni, Viviana; Cerri, Chiara; Piano, Ilaria; Novelli, Elena; Gargini, Claudia; Fiorentini, Carla; Caleo, Matteo; Strettoi, Enrica

    2016-01-01

    Retinitis pigmentosa (RP) comprises a group of inherited pathologies characterized by progressive photoreceptor degeneration. In rodent models of RP, expression of defective genes and retinal degeneration usually manifest during the first weeks of postnatal life, making it difficult to distinguish consequences of primary genetic defects from abnormalities in retinal development. Moreover, mouse eyes are small and not always adequate to test pharmacological and surgical treatments. An inducible paradigm of retinal degeneration potentially extensible to large animals is therefore desirable. Starting from the serendipitous observation that intraocular injections of a Rho GTPase activator, the bacterial toxin Cytotoxic Necrotizing Factor 1 (CNF1), lead to retinal degeneration, we implemented an inducible model recapitulating most of the key features of Retinitis Pigmentosa. The model also unmasks an intrinsic vulnerability of photoreceptors to the mechanism of CNF1 action, indicating still unexplored molecular pathways potentially leading to the death of these cells in inherited forms of retinal degeneration. PMID:27775019

  10. Retinal nerve fiber layer thickness and retinal vessel calibers in children with thalassemia minor

    PubMed Central

    Acer, Semra; Balcı, Yasemin I; Pekel, Gökhan; Ongun, Tuğba T; Polat, Aziz; Çetin, Ebru N; Yağcı, Ramazan

    2016-01-01

    Objectives: Evaluation of the peripapillary retinal nerve fiber layer thickness, subfoveal choroidal thickness, and retinal vessel caliber measurements in children with thalassemia minor. Methods: In this cross-sectional and comparative study, 30 thalassemia minor patients and 36 controls were included. Heidelberg spectral domain optical coherence tomography was used for peripapillary retinal nerve fiber layer thickness, subfoveal choroidal thickness, and retinal vessel caliber measurements. Results: There was no statistically significant difference in retinal nerve fiber layer thickness and subfoveal choroidal thickness between the two groups (p > 0.05). There was no correlation between retinal nerve fiber layer thickness and hemoglobin values. Both the arterioral and venular calibers were higher in thalassemia minor group (p < 0.05). Conclusion: There is increased retinal arterioral and venular calibers in children with thalassemia minor compared with controls. PMID:27540484

  11. Liquid Droplet Detachment and Entrainment in Microscale Flows

    NASA Astrophysics Data System (ADS)

    Hidrovo, Carlos

    2005-11-01

    In this talk we will present a first order study of liquid water detachment and entrainment into air flows in hydrophobic microchannels. Silicon based microstructures consisting of 23 mm long U-shaped channels of different geometry were used for this purpose. The structures are treated with a Molecular Vapor Deposition (MVD) process that renders them hydrophobic. Liquid water is injected through a side slot located 2/3 of the way downstream from the air channel inlet. The water entering the air channel beads up into slugs or droplets that grow in size at this injection location until they fill and flood the channel or are carried away by the air flow. The slugs/droplets dimensions at detachment are correlated against superficial gas velocity and proper dimensionless parameters are postulated and examined to compare hydrodynamic forces against surface tension. It is found that slug/droplet detachment is dominated by two main forces: pressure gradient drag, arising from confinement of a viscous flow in the channel, and inertial drag, arising from the stagnation of the air due to obstruction by the slugs/droplets. A detachment regime map is postulated based on the relative importance of these forces under different flow conditions.

  12. Sampling device with a capped body and detachable handle

    DOEpatents

    Jezek, Gerd-Rainer

    2000-01-01

    The apparatus is a sampling device having a pad for sample collection, a body which supports the pad, a detachable handle connected to the body and a cap which encloses and retains the pad and body to protect the integrity of the sample.

  13. Turbulent Simulations of Divertor Detachment Based On BOUT + + Framework

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xu, Xueqiao; Xia, Tianyang; Ye, Minyou

    2015-11-01

    China Fusion Engineering Testing Reactor is under conceptual design, acting as a bridge between ITER and DEMO. The detached divertor operation offers great promise for a reduction of heat flux onto divertor target plates for acceptable erosion. Therefore, a density scan is performed via an increase of D2 gas puffing rates in the range of 0 . 0 ~ 5 . 0 ×1023s-1 by using the B2-Eirene/SOLPS 5.0 code package to study the heat flux control and impurity screening property. As the density increases, it shows a gradually change of the divertor operation status, from low-recycling regime to high-recycling regime and finally to detachment. Significant radiation loss inside the confined plasma in the divertor region during detachment leads to strong parallel density and temperature gradients. Based on the SOLPS simulations, BOUT + + simulations will be presented to investigate the stability and turbulent transport under divertor plasma detachment, particularly the strong parallel gradient driven instabilities and enhanced plasma turbulence to spread heat flux over larger surface areas. The correlation between outer mid-plane and divertor turbulence and the related transport will be analyzed. Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-675075.

  14. Photo-Detachment of a Noncollinear Triatomic Anion

    NASA Astrophysics Data System (ADS)

    Afaq, A.; Farooq, K.

    2014-12-01

    Photo-detachment of a noncollinear triatomic anion is investigated by considering each atom of the molecular anion as a coherent source of detached-electron waves, originating in all possible directions. The waves traveling along three different trajectories result in a quantum interference that displays on a screen placed at a very large distance from the system. To explain this quantum interference, an analytical formula of detached-electron flux is derived using a collinear three-center model recently published. The detached-electron flux versus laser photon energy expression displays molecular geometry-dependent oscillatory structures on an observation plane. This oscillatory behavior in the result can be explained using the semiclassical closed-orbit theory. The outgoing electron waves produced from one coherent center are propagated in the vicinity of the sources at other two coherent centers which cause these oscillations. It is also observed that in a particular case, the noncollinear triatomic system reduces to the collinear three-center system.

  15. 3. Ramp No. 6 connection between Medical Detachment Barracks: Building ...

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

    3. Ramp No. 6 connection between Medical Detachment Barracks: Building Nos. 9970-B (left) and 9969-B (right). The many windows makes this section almost unique among the ramps and corridors. - Madigan Hospital, Corridors & Ramps, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  16. Fundus autofluorescence applications in retinal imaging

    PubMed Central

    Gabai, Andrea; Veritti, Daniele; Lanzetta, Paolo

    2015-01-01

    Fundus autofluorescence (FAF) is a relatively new imaging technique that can be used to study retinal diseases. It provides information on retinal metabolism and health. Several different pathologies can be detected. Peculiar AF alterations can help the clinician to monitor disease progression and to better understand its pathogenesis. In the present article, we review FAF principles and clinical applications. PMID:26139802

  17. Argus II retinal prosthesis system: An update.

    PubMed

    Rachitskaya, Aleksandra V; Yuan, Alex

    2016-09-01

    This review focuses on a description of the Argus II retinal prosthesis system (Argus II; Second Sight Medical Products, Sylmar, CA) that was approved for humanitarian use by the FDA in 2013 in patients with retinitis pigmentosa with bare or no light perception vision. The article describes the components of Argus II, the studies on the implant, and future directions. PMID:26855177

  18. Activation of glucocorticoid receptors in Müller glia is protective to retinal neurons and suppresses microglial reactivity

    PubMed Central

    Gallina, Donika; Zelinka, Christopher Paul; Cebulla, Colleen; Fischer, Andy J.

    2015-01-01

    Reactive microglia and macrophages are prevalent in damaged retinas. Glucocorticoid signaling is known to suppress inflammation and the reactivity of microglia and macrophages. In the vertebrate retina, the glucocorticoid receptor (GCR) is known to be activated and localized to the nuclei of Müller glia (Gallina et al., 2014). Accordingly, we investigated how signaling through GCR influences the survival of neurons using the chick retina in vivo as a model system. We applied intraocular injections of GCR agonist or antagonist, assessed microglial reactivity, and the survival of retinal neurons following different damage paradigms. Microglial reactivity was increased in retinas from eyes that were injected with vehicle, and this reactivity was decreased by GCR-agonist dexamethasone (Dex) and increased by GCR-antagonist RU486. We found that activation of GCR suppresses the reactivity of microglia and inhibited the loss of retinal neurons resulting from excitotoxicity. We provide evidence that the protection-promoting effects of Dex were maintained when the microglia were selectively ablated. Similarly, intraocular injections of Dex protected ganglion cells from colchicine-treatment and protected photoreceptors from damage caused by retinal detachment. We conclude that activation of GCR promotes the survival of ganglion cells in colchicine-damaged retinas, promotes the survival of amacrine and bipolar cells in excitotoxin-damaged retinas, and promotes the survival of photoreceptors in detached retinas. We propose that suppression of microglial reactivity is secondary to activation of GCR in Müller glia, and this mode of signaling is an effective means to lessen the damage and vision loss resulting from different types of retinal damage. PMID:26272753

  19. Seismic Slip on an Oblique Detachment Fault at Low Angles

    NASA Astrophysics Data System (ADS)

    Janecke, S. U.; Steely, A. N.; Evans, J. P.

    2008-12-01

    Pseudotachylytes are one of the few accepted indicators of seismic slip along ancient faults. Low-angle normal faults have produced few large earthquakes in historic times and low-angle normal faults (detachment faults) are typically severely misoriented relative to a vertical maximum compressive stress. As a result many geoscientists question whether low-angle normal faults produce earthquakes at low angles. Relationships in southern California show that a major low-angle normal-oblique fault slipped at low angles and produced large earthquakes. The exhumed Late Cenozoic West Salton detachment fault preserves spectacular fault- related pseudotachylytes along its fault plane and injected into its hanging wall and footwall. Composite pseudotachylyte zones are up to 1.25 m thick and persists over lateral distances of at least 10's of meters. Pseudotachylyte is common in most thin sections of damaged fault rocks with more than 20% (by volume) of cataclasite. We recognized the presence of original melt using numerous criteria: abundant spherulites in thin sections, injection structures at both the thin-section and outcrop scale, black aphanitic textures, quenched vein margins, variations in microcrystallite textures and/or size with respect to the vein margin, and glassy textures in hand sample. Multiple earthquakes are inferred to produce the layered "stratigraphy" in some exposures of pseudotachylytes. We infer that the West Salton detachment fault formed and slipped at low angles because it nearly perfectly reactivates a Cretaceous ductile thrust system at the half km scale and dips between 10 and 45 degrees. The about 30 degree NNE dip of the detachment fault on the north side of Yaqui Ridge is likely steeper than its dip during detachment slip because there is local steepening on the flanks of the Yaqui Ridge antiform in a contractional stepover of a crosscutting Quaternary San Felipe dextral fault zone. These relationships indicate a low dip on the detachment

  20. Retinal artery occlusions in children.

    PubMed

    Dharmasena, Aruna; Wallis, Simon

    2014-01-01

    The purpose of this study is to present a case of RAO in a 13 year old girl with a preceding history of hyperextension of the neck at her hairdressers for a long duration and use of her mobile phone handset resting it against the side of her neck presumably exerting some pressure on carotids during the same time. Materials and methods of this study was reported as case report and review of literature. A 13 year-old girl presented with the left supero-nasal scotoma due to an inferior temporal branch retinal artery occlusion (BRAO). She underwent extensive investigations and no underlying cause was discovered. She gave a history of cervical extension over a long period of time while having the hair coloured twice in the preceding week. She also mentioned that she was using her mobile phone more or less continuously during both these occasions keeping it against her neck. Given the above history it is possible that the pressure on the ipsilateral carotid arteries or the prolong neck extension may have been responsible for the formation of a platelet embolus resulting in the BRAO. In conclusion, although cerebro-vascular accidents due to 'beauty parlor stroke syndrome' (JAMA 269:2085-2086, 1993) have been reported previously it has not been reported in children to our knowledge. On the other hand, 'beauty parlor stroke syndrome' occurs due to a dissection of the vertebral arteries or due to mechanical compression of the vertebral arteries during the prolonged hyperextension of the neck. The central retinal artery originates from the internal carotid circulation and it is highly unlikely for an embolus to enter the retinal circulation from the vertebral arteries. Therefore, the authors favour the possibility that the compulsive use of a mobile phone exerting pressure on the carotid arteries for a long time may have led to the formation of an embolus and subsequent RAO in this case.

  1. The cell stress machinery and retinal degeneration.

    PubMed

    Athanasiou, Dimitra; Aguilà, Monica; Bevilacqua, Dalila; Novoselov, Sergey S; Parfitt, David A; Cheetham, Michael E

    2013-06-27

    Retinal degenerations are a group of clinically and genetically heterogeneous disorders characterised by progressive loss of vision due to neurodegeneration. The retina is a highly specialised tissue with a unique architecture and maintaining homeostasis in all the different retinal cell types is crucial for healthy vision. The retina can be exposed to a variety of environmental insults and stress, including light-induced damage, oxidative stress and inherited mutations that can lead to protein misfolding. Within retinal cells there are different mechanisms to cope with disturbances in proteostasis, such as the heat shock response, the unfolded protein response and autophagy. In this review, we discuss the multiple responses of the retina to different types of stress involved in retinal degenerations, such as retinitis pigmentosa, age-related macular degeneration and glaucoma. Understanding the mechanisms that maintain and re-establish proteostasis in the retina is important for developing new therapeutic approaches to fight blindness. PMID:23684651

  2. Bacterial detachment from salivary conditioning films by dentifrice supernates.

    PubMed

    van der Mei, Henny C; White, Donald J; Cox, Ed R; Geertsema-Doornbusch, Gesinda I; Busscher, Henk J

    2002-01-01

    This study compared the detachment by supernates of nine different dentifrices of four oral bacterial strains adhering to a salivary pellicle in a parallel plate flow chamber. Ultra-thin bovine enamel slabs were coated for 1.5 h with human whole saliva. Following buffer rinsing, a bacterial suspension of Streptococcus oralis, Streptococcus sanguis, Streptococcus mutans or Actinomyces naeslundii was perfused through the flow chamber at a shear rate of 30 s-1 for four hours, and the number of adhering bacteria n4h was enumerated by image analysis after buffer rinsing at the same shear rate. Then, a 25 wt%-dentifrice/water supernate was perfused through the flow chamber for four minutes, followed by eight minutes of buffer rinsing and another enumeration of the number of bacteria that had remained adhering nad. Finally, an air-bubble was passed through the flow chamber to mimic the occasionally high detachment forces occurring in the oral cavity, and the adhering bacteria nab were counted again. On average, S. sanguis was the easiest to detach (73% averaged over all dentifrice supernates), while A. naeslundii was the most difficult (22% on average). The combined detachment of bacteria by dentifrice supernates and air-bubble ranged from a low of 16% to a high of 80%. Dentifrices containing pyrophosphate and polymeric polyphosphate (hexametaphosphate) surface active ingredients appeared to produce the most consistent and strongest desorption effects on plaque bacteria. Factors apparently important to bacterial detachment from pellicle-covered tooth surfaces by dentifrice formulations include the nature of adhesion of bacterial strains and chemical composition of the dentifrice formulations, including pH, surfactant system and the effect of added ingredients (dispersants, metal ions, peroxides, baking soda). PMID:11507932

  3. Bacterial detachment from salivary conditioning films by dentifrice supernates.

    PubMed

    van der Mei, Henny C; White, Donald J; Cox, Ed R; Geertsema-Doornbusch, Gesinda I; Busscher, Henk J

    2002-01-01

    This study compared the detachment by supernates of nine different dentifrices of four oral bacterial strains adhering to a salivary pellicle in a parallel plate flow chamber. Ultra-thin bovine enamel slabs were coated for 1.5 h with human whole saliva. Following buffer rinsing, a bacterial suspension of Streptococcus oralis, Streptococcus sanguis, Streptococcus mutans or Actinomyces naeslundii was perfused through the flow chamber at a shear rate of 30 s-1 for four hours, and the number of adhering bacteria n4h was enumerated by image analysis after buffer rinsing at the same shear rate. Then, a 25 wt%-dentifrice/water supernate was perfused through the flow chamber for four minutes, followed by eight minutes of buffer rinsing and another enumeration of the number of bacteria that had remained adhering nad. Finally, an air-bubble was passed through the flow chamber to mimic the occasionally high detachment forces occurring in the oral cavity, and the adhering bacteria nab were counted again. On average, S. sanguis was the easiest to detach (73% averaged over all dentifrice supernates), while A. naeslundii was the most difficult (22% on average). The combined detachment of bacteria by dentifrice supernates and air-bubble ranged from a low of 16% to a high of 80%. Dentifrices containing pyrophosphate and polymeric polyphosphate (hexametaphosphate) surface active ingredients appeared to produce the most consistent and strongest desorption effects on plaque bacteria. Factors apparently important to bacterial detachment from pellicle-covered tooth surfaces by dentifrice formulations include the nature of adhesion of bacterial strains and chemical composition of the dentifrice formulations, including pH, surfactant system and the effect of added ingredients (dispersants, metal ions, peroxides, baking soda).

  4. Primary Reactions in Retinal Proteins

    NASA Astrophysics Data System (ADS)

    Diller, R.

    Conversion of sunlight into energy or information and their storage on a chemical level is essential for life on earth. An important family of chromoproteins performing these tasks is that of retinal binding proteins. Prominent examples are rhodopsin (Rh) [1,2] as the visual pigment in vertebrate and invertebrate animals, the archaeal rhodopsins bacteriorhodopsin (BR) [3] as a light driven proton pump, halorhodopsin (HR) [4,5] as a light driven chloride pump, sensory rhodopsin I and II (SRI, SRII) [6] as photoreceptors, and proteorhodopsin (PR) [7] as another bacterial proton pump.

  5. Cell Therapy Applications for Retinal Vascular Diseases: Diabetic Retinopathy and Retinal Vein Occlusion.

    PubMed

    Park, Susanna S

    2016-04-01

    Retinal vascular conditions, such as diabetic retinopathy and retinal vein occlusion, remain leading causes of vision loss. No therapy exists to restore vision loss resulting from retinal ischemia and associated retinal degeneration. Tissue regeneration is possible with cell therapy. The goal would be to restore or replace the damaged retinal vasculature and the retinal neurons that are damaged and/or degenerating from the hypoxic insult. Currently, various adult cell therapies have been explored as potential treatment. They include mesenchymal stem cells, vascular precursor cells (i.e., CD34+ cells, hematopoietic cells or endothelial progenitor cells), and adipose stromal cells. Preclinical studies show that all these cells have a paracrine trophic effect on damaged ischemic tissue, leading to tissue preservation. Endothelial progenitor cells and adipose stromal cells integrate into the damaged retinal vascular wall in preclinical models of diabetic retinopathy and ischemia-reperfusion injury. Mesenchymal stem cells do not integrate as readily but appear to have a primary paracrine trophic effect. Early phase clinical trials have been initiated and ongoing using mesenchymal stem cells or autologous bone marrow CD34+ cells injected intravitreally as potential therapy for diabetic retinopathy or retinal vein occlusion. Adipose stromal cells or pluripotent stem cells differentiated into endothelial colony-forming cells have been explored in preclinical studies and show promise as possible therapies for retinal vascular disorders. The relative safety or efficacy of these various cell therapies for treating retinal vascular disorders have yet to be determined.

  6. Genetic networks controlling retinal injury

    PubMed Central

    Vazquez-Chona, Felix R.; Khan, Amna N.; Chan, Chun K.; Moore, Anthony N.; Dash, Pramod K.; Hernandez, M. Rosario; Lu, Lu; Chesler, Elissa J.; Manly, Kenneth F.; Williams, Robert W.; Geisert, Eldon E.

    2010-01-01

    Purpose The present study defines genomic loci underlying coordinate changes in gene expression following retinal injury. Methods A group of acute phase genes expressed in diverse nervous system tissues was defined by combining microarray results from injury studies from rat retina, brain, and spinal cord. Genomic loci regulating the brain expression of acute phase genes were identified using a panel of BXD recombinant inbred (RI) mouse strains. Candidate upstream regulators within a locus were defined using single nucleotide polymorphism databases and promoter motif databases. Results The acute phase response of rat retina, brain, and spinal cord was dominated by transcription factors. Three genomic loci control transcript expression of acute phase genes in brains of BXD RI mouse strains. One locus was identified on chromosome 12 and was highly correlated with the expression of classic acute phase genes. Within the locus we identified the inhibitor of DNA binding 2 (Id2) as a candidate upstream regulator. Id2 was upregulated as an acute phase transcript in injury models of rat retina, brain, and spinal cord. Conclusions We defined a group of transcriptional changes associated with the retinal acute injury response. Using genetic linkage analysis of natural transcript variation, we identified regulatory loci and candidate regulators that control transcript levels of acute phase genes. PMID:16288200

  7. Fixation strategies for retinal immunohistochemistry.

    PubMed

    Stradleigh, Tyler W; Ishida, Andrew T

    2015-09-01

    Immunohistochemical and ex vivo anatomical studies have provided many glimpses of the variety, distribution, and signaling components of vertebrate retinal neurons. The beauty of numerous images published to date, and the qualitative and quantitative information they provide, indicate that these approaches are fundamentally useful. However, obtaining these images entailed tissue handling and exposure to chemical solutions that differ from normal extracellular fluid in composition, temperature, and osmolarity. Because the differences are large enough to alter intercellular and intracellular signaling in neurons, and because retinae are susceptible to crush, shear, and fray, it is natural to wonder if immunohistochemical and anatomical methods disturb or damage the cells they are designed to examine. Tissue fixation is typically incorporated to guard against this damage and is therefore critically important to the quality and significance of the harvested data. Here, we describe mechanisms of fixation; advantages and disadvantages of using formaldehyde and glutaraldehyde as fixatives during immunohistochemistry; and modifications of widely used protocols that have recently been found to improve cell shape preservation and immunostaining patterns, especially in proximal retinal neurons. PMID:25892361

  8. Measurement of retinal blood velocity

    NASA Astrophysics Data System (ADS)

    Winchester, Leonard W., Jr.; Chou, Nee-Yin

    2006-02-01

    A fundus camera was modified to illuminate the retina of a rabbit model with low power laser light in order to obtain laser speckle images. A fast-exposure charge-coupled device (CCD) camera was used to capture laser speckle images of the retina. Image acquisition was synchronized with the arterial pulses of the rabbit to ensure that all images are obtained at the same point in the cardiac cycle. The rabbits were sedated and a speculum was inserted to prevent the eyelid from closing. Both albino (New Zealand; pigmented (Dutch belted) rabbits were used in the study. The rabbit retina is almost avascular. The measurements are obtained for choroidal tissue as well as retinal tissue. Because the retina is in a region of high metabolism, blood velocity is strongly affected by blood oxygen saturation. Measurements of blood velocity obtained over a wide range of O II saturations (58%-100%) showed that blood velocity increases with decreasing O II saturation. For most experiments, the left eye of the rabbit was used for laser measurements whereas the right eye served as a control. No observable difference between pre- and post-experimented eye was noted. Histological examinations of retinal tissue subjected to repeated laser measurements showed no indication of tissue damage.

  9. Fixation Strategies For Retinal Immunohistochemistry

    PubMed Central

    Stradleigh, Tyler W.; Ishida, Andrew T.

    2015-01-01

    Immunohistochemical and ex vivo anatomical studies have provided many glimpses of the variety, distribution, and signaling components of vertebrate retinal neurons. The beauty of numerous images published to date, and the qualitative and quantitative information they provide, indicate that these approaches are fundamentally useful. However, obtaining these images entailed tissue handling and exposure to chemical solutions that differ from normal extracellular fluid in composition, temperature, and osmolarity. Because the differences are large enough to alter intercellular and intracellular signaling in neurons, and because retinae are susceptible to crush, shear, and fray, it is natural to wonder if immunohistochemical and anatomical methods disturb or damage the cells they are designed to examine. Tissue fixation is typically incorporated to guard against this damage and is therefore critically important to the quality and significance of the harvested data. Here, we describe mechanisms of fixation; advantages and disadvantages of using formaldehyde and glutaraldehyde as fixatives during immunohistochemistry; and modifications of widely used protocols that have recently been found to improve cell shape preservation and immunostaining patterns, especially in proximal retinal neurons. PMID:25892361

  10. Neural remodeling in retinal degeneration.

    PubMed

    Marc, Robert E; Jones, Bryan W; Watt, Carl B; Strettoi, Enrica

    2003-09-01

    Mammalian retinal degenerations initiated by gene defects in rods, cones or the retinal pigmented epithelium (RPE) often trigger loss of the sensory retina, effectively leaving the neural retina deafferented. The neural retina responds to this challenge by remodeling, first by subtle changes in neuronal structure and later by large-scale reorganization. Retinal degenerations in the mammalian retina generally progress through three phases. Phase 1 initiates with expression of a primary insult, followed by phase 2 photoreceptor death that ablates the sensory retina via initial photoreceptor stress, phenotype deconstruction, irreversible stress and cell death, including bystander effects or loss of trophic support. The loss of cones heralds phase 3: a protracted period of global remodeling of the remnant neural retina. Remodeling resembles the responses of many CNS assemblies to deafferentation or trauma, and includes neuronal cell death, neuronal and glial migration, elaboration of new neurites and synapses, rewiring of retinal circuits, glial hypertrophy and the evolution of a fibrotic glial seal that isolates the remnant neural retina from the surviving RPE and choroid. In early phase 2, stressed photoreceptors sprout anomalous neurites that often reach the inner plexiform and ganglion cell layers. As death of rods and cones progresses, bipolar and horizontal cells are deafferented and retract most of their dendrites. Horizontal cells develop anomalous axonal processes and dendritic stalks that enter the inner plexiform layer. Dendrite truncation in rod bipolar cells is accompanied by revision of their macromolecular phenotype, including the loss of functioning mGluR6 transduction. After ablation of the sensory retina, Müller cells increase intermediate filament synthesis, forming a dense fibrotic layer in the remnant subretinal space. This layer invests the remnant retina and seals it from access via the choroidal route. Evidence of bipolar cell death begins in

  11. Detached macroalgae: Its importance to inshore sandy beach fauna

    NASA Astrophysics Data System (ADS)

    Orr, Kyla K.; Wilding, Thomas A.; Horstmeyer, Lena; Weigl, Simon; Heymans, Johanna J.

    2014-10-01

    Kelp forests shed a large proportion of their biomass through storm-mediated defoliation, senescence of kelp blades, and constant erosion of particulate organic matter from the kelp fronds. Much of this detached macroalgae drifts in the water column and is deposited on intertidal zones of beaches. Detached macroalgae may provide inshore sandy beach fauna with refuge and food subsidies in an exposed and bare environment, with limited in situ primary production. We evaluated the relationship between detached macroalgae and the density of inshore fauna, where 'inshore' was the body of water extending from low water seawards for approximately 50 m. Inshore fauna were sampled using a push-net (1 mm mesh) on 11 beaches, and using a beam-trawl (4 mm mesh) on a subset of 8 beaches. On each beach, the density of detached macroalgae in the water column was quantified, together with a suite of physico-chemical beach characteristics. Push-net samples principally comprised omnivorous and detritivorous crustaceans such as gammarid amphipods, mysids and valviferan isopods, which have limited swimming abilities and reside inshore year-round. Beam-trawl fauna were mainly carnivorous decapods and fish, which undergo seasonal inshore-offshore migrations to utilize sandy beaches as nursery habitats. Linear models predicted increases of 11% (95% CI: 3.5-19%) and 2.4% (95% CI: 0.7-4.2%) in the density of push-net and beam-trawl fauna, respectively, with a 1 ℓ.100 m-3 increase in detached macroalgae. This suggests that detached macroalgae is more important in the provision of food and shelter to small, weak-swimming detritivores/omnivores than to larger and more mobile predators. The densities of large predators were mostly explained by physical beach characteristics, which overshadowed the role of macroalgae. Maximum abundances of decapods and fish were found on wide, flat beaches with low wave heights. Large accumulations of macroalgae may inhibit the foraging efficiencies of

  12. Assessment of blood-retinal barrier integrity.

    PubMed

    Vinores, S A

    1995-01-01

    The blood-retinal barrier consists of two components which are comprised of the retinal vascular endothelium and the retinal pigment epithelium, respectively. Its functional integrity can be recognized by tight junctions between these cells with a paucity of endocytic vesicles within them and the presence of the molecules that regulate the ionic and metabolic gradients that constitute the barrier. The barrier is compromised in several disease processes and by a variety of agents, but in most cases the location and mechanism for barrier failure is not understood. Perfusion with a variety of radiolabeled tracer molecules, vitreous fluorophotometry, or magnetic resonance imaging can be used to quantitate blood-retinal barrier leakage. Fluorescein angiography or magnetic resonance imaging can localize sites of leakage in vivo with limited resolution. Evans blue dye can be used to visualize blood-retinal barrier failure in gross pathological specimens and immuno-histochemical labeling of serum proteins such as albumin or fibrinogen can be used to localize sites of blood-retinal barrier breakdown by light microscopy. Tracers such as horseradish peroxidase, microperoxidase, or lanthanum, or the immunocytochemical demonstration of albumin can be used to reveal blood-retinal barrier breakdown at the ultrastructural level and provide insights into the mechanisms involved. This review discusses the advantages and limitations of each of these methods to aid in selection of the appropriate techniques to derive the desired information.

  13. Optical Coherence Tomography Angiography in Retinal Diseases

    PubMed Central

    Chalam, K. V.; Sambhav, Kumar

    2016-01-01

    Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA) algorithm (a vital component of OCTA software) helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD), retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV) in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA). Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases. PMID:27195091

  14. Optical Coherence Tomography Angiography in Retinal Diseases.

    PubMed

    Chalam, K V; Sambhav, Kumar

    2016-01-01

    Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA) algorithm (a vital component of OCTA software) helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD), retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV) in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA). Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases.

  15. The active transport of fluorescein by the retinal vessels and the retina

    PubMed Central

    Cunha-Vaz, J. G.; Maurice, D. M.

    1967-01-01

    1. The movement of fluorescein across the retinal surface of the rabbit's eye was estimated by measuring the concentration gradient of the dye in the vitreous body. These measurements were made in vivo by means of a slit-lamp fluorophotometer, or were taken from frozen sections of enucleated eyes. 2. In the normal eye, fluorescein does not pass from the blood to the vitreous body across any part of the retina. When injected into the vitreous body it passes rapidly out across the entire retinal surface, even against a very large concentration gradient. 3. A variety of metabolic and competitive inhibitors, effective in blocking organic anion transport in the kidney and liver, tend to abolish this unidirectional movement of fluorescein across the retina. 4. The region occupied by the retinal vessels is more sensitive to inhibition than other areas of the retina. Occlusion of the vessels by diathermy prevents the exchange of fluorescein in this region. 5. It appears, then, that there is an active transport of organic anions out of the vitreous body, both by the retinal capillaries and by the retina itself. The latter system is probably located in the pigment epithelium and seems to be carried forward to the rear surface of the iris. 6. Since the walls of the retinal vessels of the rabbit are freely in contact with the vitreous body, the active transport must take place across the capillary endothelial cells themselves. These vessels have structural and permeability characteristics found only in the central nervous system and it is to be presumed that the anion transport system is shared by the capillaries of the brain. 7. The function of the transport in the retina may be to protect the nervous tissue from toxic materials by preventing their entry from the blood or by removing products of metabolism conjugated as organic anions. Alternatively, the mechanism may be concerned in maintaining the normal adhesion of the retina to the choroid, since retinal detachment was

  16. The outcomes and prognostic factors of vitrectomy in chronic diabetic traction macular detachment

    PubMed Central

    Abunajma, Muneera A; Al-Dhibi, Hassan; Abboud, Emad B; Al Zahrani, Yahya; Alharthi, Essam; Alkharashi, Abdullah; Ghazi, Nicola G

    2016-01-01

    Purpose To investigate the outcomes of pars plana vitrectomy (PPV) for chronic diabetic traction macular detachment (CTMD). Methods Ninety-six eyes that underwent PPV for CTMD of at least 6 months duration were retrospectively analyzed. Retinal reattachment rate, final vision, and prognostic factors for poor visual outcome were the main outcome measures. Results All eyes had long-standing TMD (median 12, range: 6–70 months). The median postoperative follow-up was 15 (range: 3–65) months. Eighty-seven eyes (90.6%) had their retina and macula reattached after one PPV. At final examination, 84 eyes (87.5%) had stable vision or at least one line improvement, and three had no light perception. Seventeen (17.7%) and 41 (43%) eyes had preoperative visual acuity of ≥20/200 and ≥5/200 as compared to 40 (41.6%; P=0.0005) and 64 (66.7%; P=0.0014) eyes at final follow-up, respectively. Age >50 years (Odds ratio [OR] =5.84, 95% confidence interval [CI] =1.53–22.19, P=0.01), preoperative vision <20/400 (OR =7.012, 95% CI =1.82–26.93, P=0.005), and ischemic macula (OR =14.13, 95% CI =3.61–55.33, P<0.001) were significantly associated with final vision <20/400. Conclusion PPV for CTMD may be beneficial particularly in patients who are relatively younger and have good baseline vision and no macular ischemia.

  17. The outcomes and prognostic factors of vitrectomy in chronic diabetic traction macular detachment

    PubMed Central

    Abunajma, Muneera A; Al-Dhibi, Hassan; Abboud, Emad B; Al Zahrani, Yahya; Alharthi, Essam; Alkharashi, Abdullah; Ghazi, Nicola G

    2016-01-01

    Purpose To investigate the outcomes of pars plana vitrectomy (PPV) for chronic diabetic traction macular detachment (CTMD). Methods Ninety-six eyes that underwent PPV for CTMD of at least 6 months duration were retrospectively analyzed. Retinal reattachment rate, final vision, and prognostic factors for poor visual outcome were the main outcome measures. Results All eyes had long-standing TMD (median 12, range: 6–70 months). The median postoperative follow-up was 15 (range: 3–65) months. Eighty-seven eyes (90.6%) had their retina and macula reattached after one PPV. At final examination, 84 eyes (87.5%) had stable vision or at least one line improvement, and three had no light perception. Seventeen (17.7%) and 41 (43%) eyes had preoperative visual acuity of ≥20/200 and ≥5/200 as compared to 40 (41.6%; P=0.0005) and 64 (66.7%; P=0.0014) eyes at final follow-up, respectively. Age >50 years (Odds ratio [OR] =5.84, 95% confidence interval [CI] =1.53–22.19, P=0.01), preoperative vision <20/400 (OR =7.012, 95% CI =1.82–26.93, P=0.005), and ischemic macula (OR =14.13, 95% CI =3.61–55.33, P<0.001) were significantly associated with final vision <20/400. Conclusion PPV for CTMD may be beneficial particularly in patients who are relatively younger and have good baseline vision and no macular ischemia. PMID:27616879

  18. The detached haze layer in Titan's mesosphere: observations and analysis

    NASA Astrophysics Data System (ADS)

    Yelle, R. V.; Lavvas, P.; Vuitton, V.

    2008-09-01

    The Cassini observations reveal the presence of a detached haze layer in Titan's mesosphere at an altitude of 520 km, well above the stratosphere. Observations of scattered light made by the Imaging Science Subsystem (ISS) [1] reveal a clearly defined layer encircling low and mid-latitude regions. The aerosol layer is also detected in stellar occultation measurements of UV extinction by the UltraViolet Imaging Spectrometer (UVIS) [2,3]. The haze is a global and permanent feature of Titan's atmosphere. Furthermore the location of the detached haze layer is coincident with and the likely cause of a local maximum in the temperature profile measured by the Huygens Atmospheric Structure Instrument (HASI) [4]. This temperature inversion is also permanent and global, having been detected in several ground-based stellar occultations [5]. The correlation between the extinction profile and temperature profile imply that the detached haze cannot be due to condensation, as previously suggested [3]. Analysis of the observed optical properties (Fig. 2) implies that the average size of particles in the detached layer is <45 nm, with an imaginary index < 0.3 at 187.5 nm. Using the solutions shown in Fig. 2 we calculate the imaginary index, number density, sedimentation velocity, and mass flux for the detached haze. The results are shown in Fig. 3. Non-LTE calculations of the temperature perturbation due to the detached haze show that the average size of the haze particles must be greater than 35 nm or implied heating rates are far too large (Fig. 4). Calculation of a suite of thermal structure models as a function of assumed particle size show that the observed temperature rise implies a mean particle radius greater than 35 nm. Thus, we conclude that the particle radius in the detached layer must be in the 35- 45 nm range. Consideration of sources for the haze also implies larger particle sizes. As shown in Fig. 3, a mean particle radius less than 35 nm implies a mass flux greater

  19. Retinal venous pressure: the role of endothelin.

    PubMed

    Flammer, Josef; Konieczka, Katarzyna

    2015-01-01

    The retinal venous pressure (RVP) can be measured non-invasively. While RVP is equal to or slightly above intraocular pressure (IOP) in healthy people, it is often markedly increased in patients with eye or systemic diseases. Beside a mechanical obstruction, the main cause of such an elevation is a local dysregulation of a retinal vein, particularly a constriction induced by endothelin-1 (ET-1). A local increase of ET-1 can result from a high plasma level, as ET-1 can diffuse from the fenestrated capillaries of the choroid into the optic nerve head (ONH), bypassing the blood retinal barrier. A local increase can also result from increased local production either by a sick neighboring artery or retinal tissue. Generally, the main factors increasing ET-1 are inflammations and hypoxia, either locally or in a remote organ. RVP is known to be increased in patients with glaucoma, retinal vein occlusion (RVO), diabetic retinopathy, high mountain disease, and primary vascular dysregulation (PVD). PVD is the major vascular component of Flammer syndrome (FS). An increase of RVP decreases perfusion pressure, which heightens the risk for hypoxia. An increase of RVP also elevates transmural pressure, which in turn heightens the risk for retinal edema. In patients with RVO, a high level of RVP may not only be a consequence but also a potential cause of the occlusion; therefore, it risks causing a vicious circle. Narrow retinal arteries and particularly dilated retinal veins are known risk indicators for future cardiovascular events. As the major cause for such a retinal venous dilatation is an increased RVP, RVP may likely turn out to be an even stronger predictor. PMID:26504500

  20. Aging Changes in Retinal Microglia and their Relevance to Age-related Retinal Disease.

    PubMed

    Ma, Wenxin; Wong, Wai T

    2016-01-01

    Age-related retinal diseases, such as age-related macular degeneration (AMD) and glaucoma, contain features of chronic retinal inflammation that may promote disease progression. However, the relationship between aging and neuroinflammation is unclear. Microglia are long-lived, resident immune cells of the retina, and mediate local neuroinflammatory reactions. We hypothesize that aging changes in microglia may be causally linked to neuroinflammatory changes underlying age-dependent retinal diseases. Here, we review the evidence for (1) how the retinal microglial phenotype changes with aging, (2) the factors that drive microglial aging in the retina, and (3) aging-related changes in microglial gene expression. We examine how these aspects of microglial aging changes may relate to pathogenic mechanisms of immune dysregulation driving the progression of age-related retinal disease. These relationships can highlight microglial aging as a novel target for the prevention and treatment of retinal disease.

  1. Histopathology of rabbit eyes with silicone-fluorosilicone copolymer oil as six months internal retinal tamponade.

    PubMed

    Doi, M; Refojo, M F

    1995-10-01

    Silicone-fluorosilicone copolymer oil has low viscosity (175-185 cSt) and is heavier than water (density, 1.16 g cm-3). Short term retinal tolerance (within 2 months) of the silicone-fluorosilicone copolymer oil has been reported to be the same as that of currently used intraocular silicone oil. Ocular response of the purified silicone-fluorosilicone copolymer oil were examined clinically and histopathologically from 2.5 months to 6 months after vitreous cavity injection in rabbit phakic eyes, and compared the oil tolerance with that of purified silicone oil (0.97 g cm-3, 5000 cSt). The effects in anterior chamber also were examined within 4 weeks of the silicone-fluorosilicone copolymer oil injection in different rabbits. Silicone-fluorosilicone copolymer oil recovered from the vitreous cavity at 6 months was analysed for cholesterol and retinol content by high performance liquid chromatography. Because of its low viscosity, silicone-fluorosilicone copolymer oil was easy to inject and remove from the vitreous cavity with a 20-G needle. After the vitreous injection, discrete droplet formation by the silicone-fluorosilicone copolymer oil occurred more easily than by silicone oil. Medullary ray detachment was seen in a silicone oil-, and some silicone-fluorosilicone copolymer oil-injected eyes at 4-6 months. Histopathologically, after 3-6 months disappearance of outer plexiform layer and disorganization of the photoreceptor layer of silicone oil-, and silicone-fluorosilicone copolymer oil-injected eyes were seen in the superior and the inferior retina, respectively. Migration of the photoreceptor cell nuclei to the photoreceptor layer was found in the inferior retina of silicone-fluorosilicone copolymer oil-injected eyes at 5-6 months. Small droplets ingested by mononuclear cells were found in the vitreous cavity or preretina at 4-6 months in silicone-fluorosilicone copolymer oil-injected eyes. After the anterior chamber injection, silicone-fluorosilicone copolymer

  2. Retinoids for Treatment of Retinal Diseases

    PubMed Central

    Palczewski, Krzysztof

    2010-01-01

    Knowledge about retinal photoreceptor signal transduction and the visual cycle required for normal eyesight has expanded exponentially over the past decade. Substantial progress in human genetics has allowed identification of candidate genes and complex networks underlying inherited retinal diseases. Natural mutations in animal models that mimic human diseases have been characterized and advanced genetic manipulation now permits generation of small mammalian models of human retinal diseases. Pharmacological repair of defective visual processes in animal models not only validates their involvement in vision but also provides great promise for developing improved therapies for the millions that are progressing towards blindness or are almost completely robbed of eyesight. PMID:20435355

  3. [New drug therapy for retinal degeneration].

    PubMed

    Ohguro, Hiroshi

    2008-01-01

    Retinitis pigmentosa (RP) is an inherited retinal degeneration characterized by nyctalopia, ring scotoma, and bone-spicule pigmentation of the retina. So far, no effective therapy has been found for RP. As a possible molecular etiology of RP, retina-specific gene deficits are most likely involved, but little has been identified in terms of intracellular mechanisms leading to retinal photoreceptor cell death at post-translational levels. In order to find an effective therapy for RP, we must look for underlying common mechanisms that are responsible for the development of RP, instead of designing a specific therapy for each of the RP types with different causes. Therefore, in the present study, several animal models with different causes of RP were studied, including (1)Royal College of Surgeons (RCS) rats with a deficit of retinal pigment epithelium (RPE) function caused by rhodopsin mutation; (2) P23H rats, (3) S334ter rats, (4) photo stress rats, (5) retinal degeneration (rd) mice with a deficit of phosphodiesterase(PDE) function; and (6) cancer-associated retinopathy (CAR) model rats with a deficit of recoverin-dependent photoreceptor adaptation function. In each of these models, the following assessments were made in order to elucidate common pathological mechanisms among the models: (1) retinal function assessed by electroretinogram (ERG), (2) retinal morphology, (3) retinoid analysis, (4) rhodopsin regeneration, (5) rhodopsin phosphorylation and dephosphorylation, and (6) cytosolic cGMP levels. We found that unregulated photoreceptor adaptation processes caused by an imbalance of rhodopsin phosphorylation and dephosphorylation caused retinal dysfunction leading to photoreceptor cell death. As possible candidate drugs for normalizing these retinal dysfunctions and stopping further retinal degeneration, nilvadipine, a Ca channel blocker, retinoid derivatives, and anthocyanine were chosen and tested to determine their effect on the above animal models with

  4. Surgical treatment of central retinal vein occlusion.

    PubMed

    Berker, Nilufer; Batman, Cosar

    2008-05-01

    The treatment of central retinal vein occlusion (CRVO) is still a subject of debate. Medical therapy efforts, as well as retinal laser photocoagulation, have mostly dealt with management of the sequelae of CRVO, and have shown limited success in improving visual acuity. The unsatisfactory results of such therapeutic efforts led to the development of new treatment strategies focused on the surgical treatment of the occluded retinal vein. The purpose of this review is to summarize the outcomes of commonly reported surgical treatment strategies and to review different opinions on the various surgical approaches to the treatment of CRVO.

  5. Aerosols optical propertites in Titan's Detached Haze Layer

    NASA Astrophysics Data System (ADS)

    Seignovert, Benoît; Rannou, Pascal; Lavvas, Panayotis; Cours, Thibaud; West, Robert A.

    2016-06-01

    Titan's Detached Haze Layer (DHL) first observed in 1983 by Rages and Pollack during the Voyager 2 [1] is a consistent spherical haze feature surrounding Titan's upper atmosphere and detached from the main haze. Since 2005, the Imaging Science Subsystem (ISS) instrument on board the Cassini mission performs a continuous survey of the Titan's atmosphere and confirmed its persistence at 500 km up to the equinox (2009) before its drop and disappearance in 2012 [2]. Previous analyses showed, that this layer corresponds to the transition area between small spherical aerosols and large fractal aggregates and play a key role in the aerosols formation in Titan's atmosphere [3-5]. In this study we perform UV photometric analyses on ISS observations taken from 2005 to 2007 based on radiative transfer inversion to retrieve aerosols particles properties in the DHL (bulk and monomer size, fractal dimension and local density).

  6. The highly eccentric detached eclipsing binaries in ACVS and MACC

    NASA Astrophysics Data System (ADS)

    Shivvers, Isaac; Bloom, Joshua S.; Richards, Joseph W.

    2014-06-01

    Next-generation synoptic photometric surveys will yield unprecedented (for the astronomical community) volumes of data and the processes of discovery and rare-object identification are, by necessity, becoming more autonomous. Such autonomous searches can be used to find objects of interest applicable to a wide range of outstanding problems in astronomy, and in this paper we present the methods and results of a largely autonomous search for highly eccentric detached eclipsing binary systems in the Machine-learned All-Sky Automated Survey Classification Catalog. 106 detached eclipsing binaries with eccentricities of e ≳ 0.1 are presented, most of which are identified here for the first time. We also present new radial-velocity curves and absolute parameters for six of those systems with the long-term goal of increasing the number of highly eccentric systems with orbital solutions, thereby facilitating further studies of the tidal circularization process in binary stars.

  7. Heat and detachment in core-complex extension

    NASA Technical Reports Server (NTRS)

    Lucchitta, I.

    1985-01-01

    It is proposed here that the Miocene to Recent structural and volcanic features of the Basin and Range Province can be explained by a single thermotectonic process acting through time. This process consists of a thermal pulse resulting in a high-temperature regime that includes a steep thermal front moving first up toward the topographic surface, then down owing to cooling induced by a combination of convection and conduction. Within the front is a condition defining a critical surface that separates brittle from ductile behavior, and is marked by a nearly horizonal detachment fault. The most prominent and structurally highest position of the detachment results from interaction between the critical surface and a hydrothermal system near the topographic surface. These various features can be superposed on older ones through thermal remobilization or structural reactivation.

  8. Evaluation of metal trace detachment from dosing pumps using PIXE

    NASA Astrophysics Data System (ADS)

    Lozano, Omar; Mejia, Jorge; Laloy, Julie; Alpan, Lütfiye; Toussaint, Olivier; Dogné, Jean-Michel; Lucas, Stéphane

    2014-07-01

    Metal trace detachment evaluation is essential for instruments destined for pharmaceutical applications, such as pumps. Particle-Induced X-ray Emission (PIXE) was used to determine and quantify metal traces originated from stainless steel and ceramic dosing pumps. Metal traces were quantified from either distilled water samples or cellulose filters in two tests: a short-term test of 16 h mimicking a daily cycle of a dosing pump for industrial applications, and a long-term test of 9 days evaluating the pump wearing. The main result is that ceramic dosing pumps present lower metal detachment than stainless steel counterparts. Traces of Si and Al were found originating from pieces around the pumps (pipes and joints).

  9. "Aequanimitas" Redux: William Osler on detached concern versus humanistic empathy.

    PubMed

    Bryan, Charles S

    2006-01-01

    Recent critics make William Osler "the father of cool detachment" in medicine, largely because of his "Aequanimitas" address emphasizing objectivity and imperturbability. Closer analysis suggests that Osler's aequanimitas resembles more nearly the metriopatheia of later Stoic philosophy than the apatheia of the early Stoics. A previously unpublished memoir clarifies at least in part Osler's motive for teaching control of the "medullary centres" to minimize facial expression: he did not want to frighten patients, who typically had serious illnesses for which he lacked effective therapy. Twenty-first century challenges to medicine as a profession differ substantially from those of Osler's era. Physicians and educators must focus more closely on the tension between detached concern ("competence") and humanistic empathy ("caring") if medicine is to thrive as a learned profession as opposed to a technical service, a commodity to be bought and sold like any other.

  10. Abrupt tectonics and rapid slab detachment with grain damage.

    PubMed

    Bercovici, David; Schubert, Gerald; Ricard, Yanick

    2015-02-01

    A simple model for necking and detachment of subducting slabs is developed to include the coupling between grain-sensitive rheology and grain-size evolution with damage. Necking is triggered by thickened buoyant crust entrained into a subduction zone, in which case grain damage accelerates necking and allows for relatively rapid slab detachment, i.e., within 1 My, depending on the size of the crustal plug. Thick continental crustal plugs can cause rapid necking while smaller plugs characteristic of ocean plateaux cause slower necking; oceanic lithosphere with normal or slightly thickened crust subducts without necking. The model potentially explains how large plateaux or continental crust drawn into subduction zones can cause slab loss and rapid changes in plate motion and/or induce abrupt continental rebound. PMID:25605890

  11. Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2015-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. In microgravity, the parameters that influence the existence of a stable gap are the growth angle of the solidifying crystal, the contact angle between the melt and the crucible wall, and the pressure difference across the meniscus. During actual crystal growth, the initial crystal radius will not have the precise value required for stable detached growth. Beginning with a crystal diameter that differs from stable conditions, numerical calculations are used to analyze the transient crystal growth process. Depending on the initial conditions and growth parameters, the crystal shape will either evolve towards attachment at the crucible wall, towards a stable gap width, or inwards towards eventual collapse of the meniscus. Dynamic growth stability is observed only when the sum of the growth and contact angles exceeds 180 degrees.

  12. First experimental photo-detachment spectrum of H2-

    NASA Astrophysics Data System (ADS)

    Rudnev, Vitaly; Schlösser, Magnus; Telle, Helmut H.; González Ureña, Ángel

    2015-10-01

    This letter reports the first photo-detachment spectrum of the hydrogen anion, H2-. The spectrum was recorded over the range of excitation energies Ehν = 17 600-17 750 cm-1, at known laser fluence and under non-saturation conditions. This permitted us to extract absolute values for the photo-depletion cross-section which varies in the range 1-6 × 10-18 cm2 and exhibits oscillatory behaviour. This interesting behaviour was attributed to an electro-dynamical interaction between of the highly-rotating hydrogen daughter molecule and the detached electron. The presence of such oscillations may open new ways to investigate exotic anions relevant to molecular astrophysics and plasma physics.

  13. Abrupt tectonics and rapid slab detachment with grain damage.

    PubMed

    Bercovici, David; Schubert, Gerald; Ricard, Yanick

    2015-02-01

    A simple model for necking and detachment of subducting slabs is developed to include the coupling between grain-sensitive rheology and grain-size evolution with damage. Necking is triggered by thickened buoyant crust entrained into a subduction zone, in which case grain damage accelerates necking and allows for relatively rapid slab detachment, i.e., within 1 My, depending on the size of the crustal plug. Thick continental crustal plugs can cause rapid necking while smaller plugs characteristic of ocean plateaux cause slower necking; oceanic lithosphere with normal or slightly thickened crust subducts without necking. The model potentially explains how large plateaux or continental crust drawn into subduction zones can cause slab loss and rapid changes in plate motion and/or induce abrupt continental rebound.

  14. Modeling detachment physics in the NSTX snowflake divertor

    NASA Astrophysics Data System (ADS)

    Meier, E. T.; Soukhanovskii, V. A.; Bell, R. E.; Diallo, A.; Kaita, R.; LeBlanc, B. P.; McLean, A. G.; Podestà, M.; Rognlien, T. D.; Scotti, F.

    2015-08-01

    The snowflake divertor is a proposed technique for coping with the tokamak power exhaust problem in next-step experiments and eventually reactors, where extreme power fluxes to material surfaces represent a leading technological and physics challenge. In lithium-conditioned National Spherical Torus Experiment (NSTX) discharges, application of the snowflake divertor typically induced partial outer divertor detachment and severalfold heat flux reduction. UEDGE is used to analyze and compare conventional and snowflake divertor configurations in NSTX. Matching experimental upstream profiles and divertor measurements in the snowflake requires target recycling of 0.97 vs. 0.91 in the conventional case, implying partial saturation of the lithium-based pumping mechanism. Density scans are performed to analyze the mechanisms that facilitate detachment in the snowflake, revealing that increased divertor volume provides most of the parallel heat flux reduction. Also, neutral gas power loss is magnified by the increased wetted area in the snowflake, and plays a key role in generating volumetric recombination.

  15. Intellectual property rights and detached human body parts.

    PubMed

    Pila, Justine

    2014-01-01

    This paper responds to an invitation by the editors to consider whether the intellectual property (IP) regime suggests an appropriate model for protecting interests in detached human body parts. It begins by outlining the extent of existing IP protection for body parts in Europe, and the relevant strengths and weaknesses of the patent system in that regard. It then considers two further species of IP right of less obvious relevance. The first are the statutory rights of ownership conferred by domestic UK law in respect of employee inventions, and the second are the economic and moral rights recognised by European and international law in respect of authorial works. In the argument made, both of these species of IP right may suggest more appropriate models of sui generis protection for detached human body parts than patent rights because of their capacity better to accommodate the relevant public and private interests in respect of the same.

  16. Abrupt tectonics and rapid slab detachment with grain damage

    PubMed Central

    Bercovici, David; Schubert, Gerald; Ricard, Yanick

    2015-01-01

    A simple model for necking and detachment of subducting slabs is developed to include the coupling between grain-sensitive rheology and grain-size evolution with damage. Necking is triggered by thickened buoyant crust entrained into a subduction zone, in which case grain damage accelerates necking and allows for relatively rapid slab detachment, i.e., within 1 My, depending on the size of the crustal plug. Thick continental crustal plugs can cause rapid necking while smaller plugs characteristic of ocean plateaux cause slower necking; oceanic lithosphere with normal or slightly thickened crust subducts without necking. The model potentially explains how large plateaux or continental crust drawn into subduction zones can cause slab loss and rapid changes in plate motion and/or induce abrupt continental rebound. PMID:25605890

  17. Retinal Stimulation on Rabbit Using Complementary Metal Oxide Semiconductor Based Multichip Flexible Stimulator toward Retinal Prosthesis

    NASA Astrophysics Data System (ADS)

    Tokuda, Takashi; Asano, Ryosuke; Sugitani, Sachie; Taniyama, Mari; Terasawa, Yasuo; Nunoshita, Masahiro; Nakauchi, Kazuaki; Fujikado, Takashi; Tano, Yasuo; Ohta, Jun

    2008-04-01

    The Functionality of a complementary metal oxide semiconductor (CMOS) LSI-based, multichip flexible retinal stimulator was demonstrated in retinal stimulation experiments on rabbits. A 1×4-configured multichip stimulator was fabricated for application to experiments on animals. An experimental procedure including surgical operations was developed, and retinal stimulation was performed with the fabricated multichip stimulator. Neural responses on the visual cortex were successfully evoked by the fabricated stimulator. The stimulator is confirmed to be applicable to acute animal experiments.

  18. Multiples Among Detached Eclipsing Binaries from the ASAS Catalog

    NASA Astrophysics Data System (ADS)

    Hełminiak, K. G.; Konacki, M.; Ratajczak, M.; Jordán, A.; Espinoza, N.; Brahm, R.; Kambe, E.; Ukita, N.

    2015-07-01

    We have been conducting a spectroscopic survey of detached eclipsing binaries (DEBs) from the All-Sky Automated Survey (ASAS) database for more than three years. Thousands of high-resolution spectra of >300 systems have been secured, and used for radial velocity measurements and spectral analysis. We have found a zoo of multiple systems in our sample, such as spectroscopic triples and quadruples, visual binaries with eclipsing components, and circumbinary low-mass companions, including sub-stellar-mass candidates.

  19. Particle detachment from fluid interfaces: theory vs. experiments.

    PubMed

    Anachkov, Svetoslav E; Lesov, Ivan; Zanini, Michele; Kralchevsky, Peter A; Denkov, Nikolai D; Isa, Lucio

    2016-09-28

    Microparticle adsorption and self-assembly at fluid interfaces are strongly affected by the particle three-phase contact angle θ. On the single-particle level, θ can be determined by several techniques, including colloidal-probe AFM, the gel-trapping technique (GTT) and the freeze-fracture shadow-casting (FreSCa) method. While GTT and FreSCa provide contact angle distributions measured over many particles, colloidal-probe AFM measures the wettability of an individual (specified) particle attached onto an AFM cantilever. In this paper, we extract θ for smooth microparticles through the analysis of force-distance curves upon particle approach and retraction from the fluid interface. From each retraction curve, we determine: (i) the maximal force, Fmax; (ii) the detachment distance, Dmax; and (iii) the work for quasistatic detachment, W. To relate Fmax, Dmax and W to θ, we developed a detailed theoretical model based on the capillary theory of flotation. The model was validated in three different ways. First, the contact angles, evaluated from Fmax, Dmax and W, are all close in value and were used to calculate the entire force-distance curves upon particle retraction without any adjustable parameters. Second, the model was successfully applied to predict the experimental force-distance curve of a truncated sphere, whose cut is positioned below the point of particle detachment from the interface. Third, our theory was confirmed by the excellent agreement between the particle contact angles obtained from the colloidal-probe AFM data and the ensemble-average contact angles measured by both GTT and FreSCa. Additionally, we devised a very accurate closed-form expression for W (representing the energy barrier for particle detachment), thus extending previous results in the literature.

  20. Aetiology and management of the 'detached' rectus muscle.

    PubMed Central

    MacEwen, C J; Lee, J P; Fells, P

    1992-01-01

    The clinical features and management of 17 cases of detached extraocular muscles are described. They are classified into four groups: (1) the muscle which is cut and lost during squint surgery, (2) the muscle which breaks during squint surgery, (3) the muscle which slips following squint surgery, and (4) the muscle which is damaged during facial or orbital trauma. The prognosis for group 1 is poor whereas groups 2-4 have a good chance of successful muscle relocation. Images PMID:1540554

  1. Detached cataclysmic variables are crossing the orbital period gap

    NASA Astrophysics Data System (ADS)

    Zorotovic, M.; Schreiber, M. R.; Parsons, S. G.; Gänsicke, B. T.; Hardy, A.; Agurto-Gangas, C.; Nebot Gómez-Morán, A.; Rebassa-Mansergas, A.; Schwope, A. D.

    2016-04-01

    A central hypothesis in the theory of cataclysmic variable (CV) evolution is the need to explain the observed lack of accreting systems in the ≃2-3 h orbital period range, known as the period gap. The standard model, disrupted magnetic braking (DMB), reproduces the gap by postulating that CVs transform into inconspicuous detached white dwarf (WD) plus main sequence systems, which no longer resemble CVs. However, observational evidence for this standard model is currently indirect and thus this scenario has attracted some criticism throughout the last decades. Here, we perform a simple but exceptionally strong test of the existence of detached CVs (dCVs). If the theory is correct, dCVs should produce a peak in the orbital period distribution of detached close binaries consisting of a WD and an M4-M6 secondary star. We measured six new periods which brings the sample of such binaries with known periods below 10 h to 52 systems. An increase of systems in the ≃2-3 h orbital period range is observed. Comparing this result with binary population models, we find that the observed peak cannot be reproduced by post-common envelope binaries (PCEBs) alone and that the existence of dCVs is needed to reproduce the observations. Also, the WD mass distribution in the gap shows evidence of two populations in this period range, i.e. PCEBs and more massive dCVs, which is not observed at longer periods. We therefore conclude that CVs are indeed crossing the gap as detached systems, which provides strong support for the DMB theory.

  2. Particle detachment from fluid interfaces: theory vs. experiments.

    PubMed

    Anachkov, Svetoslav E; Lesov, Ivan; Zanini, Michele; Kralchevsky, Peter A; Denkov, Nikolai D; Isa, Lucio

    2016-09-28

    Microparticle adsorption and self-assembly at fluid interfaces are strongly affected by the particle three-phase contact angle θ. On the single-particle level, θ can be determined by several techniques, including colloidal-probe AFM, the gel-trapping technique (GTT) and the freeze-fracture shadow-casting (FreSCa) method. While GTT and FreSCa provide contact angle distributions measured over many particles, colloidal-probe AFM measures the wettability of an individual (specified) particle attached onto an AFM cantilever. In this paper, we extract θ for smooth microparticles through the analysis of force-distance curves upon particle approach and retraction from the fluid interface. From each retraction curve, we determine: (i) the maximal force, Fmax; (ii) the detachment distance, Dmax; and (iii) the work for quasistatic detachment, W. To relate Fmax, Dmax and W to θ, we developed a detailed theoretical model based on the capillary theory of flotation. The model was validated in three different ways. First, the contact angles, evaluated from Fmax, Dmax and W, are all close in value and were used to calculate the entire force-distance curves upon particle retraction without any adjustable parameters. Second, the model was successfully applied to predict the experimental force-distance curve of a truncated sphere, whose cut is positioned below the point of particle detachment from the interface. Third, our theory was confirmed by the excellent agreement between the particle contact angles obtained from the colloidal-probe AFM data and the ensemble-average contact angles measured by both GTT and FreSCa. Additionally, we devised a very accurate closed-form expression for W (representing the energy barrier for particle detachment), thus extending previous results in the literature. PMID:27531425

  3. Antimicrobials Influence Bond Stiffness and Detachment of Oral Bacteria.

    PubMed

    Song, L; Hou, J; van der Mei, H C; Veeregowda, D H; Busscher, H J; Sjollema, J

    2016-07-01

    Oral biofilm can never be fully removed by oral hygiene measures. Biofilm left behind after brushing is often left behind on the same sites and exposed multiple times to antimicrobials from toothpastes and mouthrinses, after which removal becomes increasingly difficult. On the basis of this observation, we hypothesize that oral bacteria adhering to salivary conditioning films become more difficult to remove after adsorption of antimicrobials due to stiffening of their adhesive bond. To verify this hypothesis, bacteria adhering to bare and saliva-coated glass were exposed to 3 different mouthrinses, containing chlorhexidine-digluconate, cetylpyridinium-chloride, or amine-fluoride, after which bacterial vibration spectroscopy was carried out or a liquid-air interface was passed over the adhering bacteria to stimulate their detachment. Brownian motion-induced nanoscopic vibration amplitudes of 4 oral streptococcal strains, reflecting their bond stiffness, decreased after exposure to mouthrinses. Concurrently, the percentage detachment of adhering bacteria upon the passage of a liquid-air interface decreased after exposure to mouthrinses. A buffer control left both vibration amplitudes and detachment percentages unaffected. Exposure to either of the selected mouthrinses yielded more positively charged bacteria by particulate microelectrophoresis, suggesting antimicrobial adsorption to bacterial cell surface components. To rule out that exposure of adhering bacteria to the mouthrinses stimulated polysaccharide production with an impact on their detachment, Fourier transform infrared spectroscopy was carried out on bacteria adhering to an internal reflection element, prior to and after exposure to the mouthrinses. Infrared absorption band areas indicated no significant change in amount of polysaccharides after exposure of adhering bacteria to mouthrinses, but wave number shifts demonstrated stiffening of polysaccharides in the bond, as a result of antimicrobial

  4. Detachable connection for a nuclear reactor fuel assembly

    DOEpatents

    Christiansen, D.W.; Karnesky, R.A.

    1983-08-29

    A locking connection for releasably attaching a handling socket to the duct tube of a fuel assembly for a nuclear reactor. The connection comprises a load pad housing mechanically attached to the duct tube and a handling socket threadably secured within the housing. A retaining ring is interposed between the housing and the handling socket and is formed with a projection and depression engagable within a cavity and groove of the housing and handling socket, respectively, to form a detachable interlocked connection assembly.

  5. Detachable connection for a nuclear reactor fuel assembly

    DOEpatents

    Christiansen, David W.; Karnesky, Richard A.

    1986-01-01

    A locking connection for releasably attaching a handling socket to the duct tube of a fuel assembly for a nuclear reactor. The connection comprises a load pad housing mechanically attached to the duct tube and a handling socket threadably secured within the housing. A retaining ring is interposed between the housing and the handling socket and is formed with a projection and depression engageable within a cavity and groove of the housing and handling socket, respectively, to form a detachable interlocked connection assembly.

  6. Physics of Coanda jet detachment at high-pressure ratio

    NASA Astrophysics Data System (ADS)

    Cornelius, Kenneth C.; Lucius, Gerald A.

    1994-05-01

    Experimental measurements of surface pressure for an underexpanded two-dimensional supersonic Coanda flow with static conditions exterior to the jet flow was obtained for a fixed slot height to a radius ratio of 0.04. The data demonstrate that an oblique shock forms near the jet exit plane which vectors the jet flow from the curved surface at a pressure ratio of 7.6. The jet detachment occurs at a pressure ratio which is a function of the ratio of slot height to cylinder radius. An increase in the pressure ratio to 11.5 before jet detachment has been demonstrated by the translation of the upper wall providing for a converging-diverging geometry. The physics of the Coanda expansion and the jet detachment are qualitatively described using an optical schlieren system. A compressible inviscid model was derived analytically to demonstrate the variation in Mach number and surface pressure as a function of the geometric parameters with increasing pressure ratio.

  7. Computation of particle detachment from floors due to human walking

    NASA Astrophysics Data System (ADS)

    Elhadidi, Basman; Khalifa, Ezzat

    2005-11-01

    A computational model for detachment of fine particles due to the unsteady flow under a foot is developed. As the foot approaches the floor, fluid volume is displaced laterally as a wall jet from the perimeter of the contact area at high velocity and acceleration. Unsteady aerodynamic forces on particles attached to the floor are considered. Results show that the jet velocity is ˜40 m/s for a foot idealized as a 15 cm circular disk approaching the floor at 1 m/s with a final gap of 0.8 mm. This velocity is sufficient to detach small particles (1˜μm). The flow accelerates at ˜400 m/s^2 which affects the detachment of larger sized particles (˜100 μm). As the disk is brought to rest, the unsteady jet expands outwards, advecting a vortex ring closely attached to it. At the disk edge, a counter rotating vortex is generated by the sudden deceleration of the disk. Both vortices can play a role in entrainment of the suspended particles in the flowfield. Numerical studies also show that the maximum jet velocity is ˜20 m/s for a simplified foot immediately after heel contact in the stance phase of the gait.

  8. Modeling of extinguishing ELMs in detached divertor plasmas

    NASA Astrophysics Data System (ADS)

    Pigarov, A.; Krasheninnikov, S.; Hollmann, E.; Rognlien, T.

    2015-11-01

    Detached plasmas, the primary operational regime for divertors in next-step fusion devices, should be compatible with both good H-mode confinement and relatively small ELMs providing tolerable heat power loads on divertor targets. Here, dynamics of boundary plasma, impurities and material walls over a sequence of many type-I ELM events under detached divertor plasma conditions is studied with UEGDE-MB-W, the newest version of 2D edge plasma transport code, which incorporates Macro-Blob (MB) approach to simulate non-diffusive filamentary transport and various ``Wall'' (W) models for time-dependent hydrogen wall inventory and recycling. We present the results of multi-parametric analysis on the impact of the size and frequency of ELMs on the divertor plasma parameters where we vary the MB characteristics under different pedestals and divertor configurations. We discuss the conditions, under which small but frequent type-I ELMs (typical for high-power H-mode discharges on current tokamaks with hard deuterium gas puff) are not ``burning through'' the formed detached divertor plasma. In this case, the inner and outer divertors are filled by sub-eV, recombining, highly-impure plasma. Variations of impurity plasma content, radiation pattern, and deuterium wall inventory over the ELM cycle are analyzed. UEDGE-MB-W modeling results are compared to available experimental data.

  9. Biofilm detachment mechanisms in a liquid-fluidized bed.

    PubMed

    Chang, H T; Rittmann, B E; Amar, D; Heim, R; Ehlinger, O; Lesty, Y

    1991-08-20

    Bed fluidization offers the possibility of gaining the advantages of fixed-film biological processes without the disadvantage of pore clogging. However, the biofilm detachment rate, due to hydrodynamics and particle-to-particle attrition, is very poorly understood for fluidized-bed biofilm processes. In this work, a two-phase fluidized-bed biofilm was operated under a constant surface loading (0.09 mg total organic carbon/cm(2) day) and with a range of bed height (H), fluid velocities (U), and support-particle concentrations (C(p)). Direct measurements were made for the specific biofilm loss rate coefficient (b(s))and the total biofilm accumulation (X(f)L(f)). A hydrodynamic model allowed independent determination of the biofilm density (X(f)), biofilm thickness (L(f)), liquid shear stress (tau), and Reynolds number (Re). Multiple regression analysis of the results showed that increased particle-to-particle attrition, proportional to C(p) and increased turbulence, described by Re, caused the biofilms to be denser and thinner. The specific detachment rate coefficient (b(s)) increased as C(p) and Re increased. Almost all of the 6, values were larger than predicted by a previous model derived for smooth biofilms on a nonfluidized surface. Therefore, the turbulence and attrition of bed fluidization appear to be dominant detachment mechanisms.

  10. Adhesion and friction in gecko toe attachment and detachment.

    PubMed

    Tian, Yu; Pesika, Noshir; Zeng, Hongbo; Rosenberg, Kenny; Zhao, Boxin; McGuiggan, Patricia; Autumn, Kellar; Israelachvili, Jacob

    2006-12-19

    Geckos can run rapidly on walls and ceilings, requiring high friction forces (on walls) and adhesion forces (on ceilings), with typical step intervals of approximately 20 ms. The rapid switching between gecko foot attachment and detachment is analyzed theoretically based on a tape model that incorporates the adhesion and friction forces originating from the van der Waals forces between the submicron-sized spatulae and the substrate, which are controlled by the (macroscopic) actions of the gecko toes. The pulling force of a spatula along its shaft with an angle between theta 0 and 90 degrees to the substrate, has a "normal adhesion force" contribution, produced at the spatula-substrate bifurcation zone, and a "lateral friction force" contribution from the part of spatula still in contact with the substrate. High net friction and adhesion forces on the whole gecko are obtained by rolling down and gripping the toes inward to realize small pulling angles between the large number of spatulae in contact with the substrate. To detach, the high adhesion/friction is rapidly reduced to a very low value by rolling the toes upward and backward, which, mediated by the lever function of the setal shaft, peels the spatulae off perpendicularly from the substrates. By these mechanisms, both the adhesion and friction forces of geckos can be changed over three orders of magnitude, allowing for the swift attachment and detachment during gecko motion. The results have obvious implications for the fabrication of dry adhesives and robotic systems inspired by the gecko's locomotion mechanism.

  11. Gene therapy for retinal degeneration.

    PubMed

    Reichel, M B; Ali, R R; Hunt, D M; Bhattacharya, S S

    1997-01-01

    Inherited retinal degenerations are a group of diseases leading to blindness through progressive loss of vision in many patients. Although with the cloning of more and more disease genes the knowledge on the molecular genetics of these conditions and on the apoptotic pathway as the common disease mechanism is steadily increasing, there is still no cure for those affected. In recent years, new experimental treatments have evolved through the efforts of many investigators and have been explored in animal models. The rationale of the different strategies for developing a treatment based on gene replacement or rescue of the diseased neuronal tissue with growth factors will be outlined and discussed in this paper. PMID:9323717

  12. Integration of retinal image sequences

    NASA Astrophysics Data System (ADS)

    Ballerini, Lucia

    1998-10-01

    In this paper a method for noise reduction in ocular fundus image sequences is described. The eye is the only part of the human body where the capillary network can be observed along with the arterial and venous circulation using a non invasive technique. The study of the retinal vessels is very important both for the study of the local pathology (retinal disease) and for the large amount of information it offers on systematic haemodynamics, such as hypertension, arteriosclerosis, and diabetes. In this paper a method for image integration of ocular fundus image sequences is described. The procedure can be divided in two step: registration and fusion. First we describe an automatic alignment algorithm for registration of ocular fundus images. In order to enhance vessel structures, we used a spatially oriented bank of filters designed to match the properties of the objects of interest. To evaluate interframe misalignment we adopted a fast cross-correlation algorithm. The performances of the alignment method have been estimated by simulating shifts between image pairs and by using a cross-validation approach. Then we propose a temporal integration technique of image sequences so as to compute enhanced pictures of the overall capillary network. Image registration is combined with image enhancement by fusing subsequent frames of a same region. To evaluate the attainable results, the signal-to-noise ratio was estimated before and after integration. Experimental results on synthetic images of vessel-like structures with different kind of Gaussian additive noise as well as on real fundus images are reported.

  13. Neurovascular embolization: in vitro evaluation of a mechanical detachable platinum coil system.

    PubMed

    Murphy, K J; Mandai, S; Gailloud, P; Clint, H; Szopinski, K; Quie, H; Martin, J B; Rüfenacht, D A

    2000-12-01

    The authors evaluated a mechanically detachable platinum coil system intended for neurovascular use. The introduction characteristics, ease of delivery, ease of retrieval, and detachability were studied with fluoroscopic guidance with in vitro silicone models. All the coils passed easily through the microcatheter. The detachment maneuver occurred within 20 seconds with 20 or fewer rotations of the pusher wire. One of 229 coils detached prematurely but only after deliberate and extreme manipulation. The detachment system is safe, reliable, and consistent and will be useful for interventional neuroradiologists.

  14. Regulatory and Economic Considerations of Retinal Drugs.

    PubMed

    Shah, Ankoor R; Williams, George A

    2016-01-01

    The advent of anti-VEGF therapy for neovascular age-related macular degeneration and macular edema secondary to retinal vein occlusion and diabetes mellitus has prevented blindness in tens of thousands of people. However, the costs of these drugs are without precedent in ophthalmic drug therapeutics. An analysis of the financial implications of retinal drugs and the impact of the Food and Drug Administration on treatment of retinal disease must include not only an evaluation of the direct costs of the drugs and the costs associated with their administration, but also the cost savings which accrue from their clinical benefit. This chapter will discuss the financial and regulatory issues associated with retinal drugs.

  15. [Retinal vein occlusion in a young patient].

    PubMed

    Zemba, Mihail; Ochinciuc, Uliana; Sarbu, Laura; Avram, Corina; Camburu, Raluca; Stamate, Alina

    2013-01-01

    We present a case report of a 27 years old pacient with central retinal vein occlussion and macular edema. The pacient has a significant reduction of the macular aedema with complete recovery of vision after the treatment.

  16. Retinal fractals and acute lacunar stroke.

    PubMed

    Cheung, Ning; Liew, Gerald; Lindley, Richard I; Liu, Erica Y; Wang, Jie Jin; Hand, Peter; Baker, Michelle; Mitchell, Paul; Wong, Tien Y

    2010-07-01

    This study aimed to determine whether retinal fractal dimension, a quantitative measure of microvascular branching complexity and density, is associated with lacunar stroke. A total of 392 patients presenting with acute ischemic stroke had retinal fractal dimension measured from digital photographs, and lacunar infarct ascertained from brain imaging. After adjusting for age, gender, and vascular risk factors, higher retinal fractal dimension (highest vs lowest quartile and per standard deviation increase) was independently and positively associated with lacunar stroke (odds ratio [OR], 4.27; 95% confidence interval [CI], 1.49-12.17 and OR, 1.85; 95% CI, 1.20-2.84, respectively). Increased retinal microvascular complexity and density is associated with lacunar stroke.

  17. Imaging retinal mosaics in the living eye.

    PubMed

    Rossi, E A; Chung, M; Dubra, A; Hunter, J J; Merigan, W H; Williams, D R

    2011-03-01

    Adaptive optics imaging of cone photoreceptors has provided unique insight into the structure and function of the human visual system and has become an important tool for both basic scientists and clinicians. Recent advances in adaptive optics retinal imaging instrumentation and methodology have allowed us to expand beyond cone imaging. Multi-wavelength and fluorescence imaging methods with adaptive optics have allowed multiple retinal cell types to be imaged simultaneously. These new methods have recently revealed rod photoreceptors, retinal pigment epithelium (RPE) cells, and the smallest retinal blood vessels. Fluorescence imaging coupled with adaptive optics has been used to examine ganglion cells in living primates. Two-photon imaging combined with adaptive optics can evaluate photoreceptor function non-invasively in the living primate retina.

  18. Imaging retinal mosaics in the living eye

    PubMed Central

    Rossi, E A; Chung, M; Dubra, A; Hunter, J J; Merigan, W H; Williams, D R

    2011-01-01

    Adaptive optics imaging of cone photoreceptors has provided unique insight into the structure and function of the human visual system and has become an important tool for both basic scientists and clinicians. Recent advances in adaptive optics retinal imaging instrumentation and methodology have allowed us to expand beyond cone imaging. Multi-wavelength and fluorescence imaging methods with adaptive optics have allowed multiple retinal cell types to be imaged simultaneously. These new methods have recently revealed rod photoreceptors, retinal pigment epithelium (RPE) cells, and the smallest retinal blood vessels. Fluorescence imaging coupled with adaptive optics has been used to examine ganglion cells in living primates. Two-photon imaging combined with adaptive optics can evaluate photoreceptor function non-invasively in the living primate retina. PMID:21390064

  19. Stem Cells, Retinal Ganglion Cells, and Glaucoma

    PubMed Central

    Sluch, Valentin M.; Zack, Donald J.

    2015-01-01

    Retinal ganglion cells represent an essential neuronal cell type for vision. These cells receive inputs from light-sensing photoreceptors via retinal interneurons and then relay these signals to the brain for further processing. Retinal ganglion cell diseases that result in cell death, e.g. glaucoma, often lead to permanent damage since mammalian nerves do not regenerate. Stem cell differentiation can generate cells needed for replacement or can be used to generate cells capable of secreting protective factors to promote survival. In addition, stem cell-derived cells can be used in drug screening research. Here, we discuss the current state of stem cell research potential for interference in glaucoma and other optic nerve diseases with a focus on stem cell differentiation to retinal ganglion cells. PMID:24732765

  20. Regulatory and Economic Considerations of Retinal Drugs.

    PubMed

    Shah, Ankoor R; Williams, George A

    2016-01-01

    The advent of anti-VEGF therapy for neovascular age-related macular degeneration and macular edema secondary to retinal vein occlusion and diabetes mellitus has prevented blindness in tens of thousands of people. However, the costs of these drugs are without precedent in ophthalmic drug therapeutics. An analysis of the financial implications of retinal drugs and the impact of the Food and Drug Administration on treatment of retinal disease must include not only an evaluation of the direct costs of the drugs and the costs associated with their administration, but also the cost savings which accrue from their clinical benefit. This chapter will discuss the financial and regulatory issues associated with retinal drugs. PMID:26502165

  1. What Is Next for Retinal Gene Therapy?

    PubMed

    Vandenberghe, Luk H

    2015-10-01

    The field of gene therapy for retinal blinding disorders is experiencing incredible momentum, justified by hopeful results in early stage clinical trials for inherited retinal degenerations. The premise of the use of the gene as a drug has come a long way, and may have found its niche in the treatment of retinal disease. Indeed, with only limited treatment options available for retinal indications, gene therapy has been proven feasible, safe, and effective and may lead to durable effects following a single injection. Here, we aim at putting into context the promise and potential, the technical, clinical, and economic boundaries limiting its application and development, and speculate on a future in which gene therapy is an integral component of ophthalmic clinical care.

  2. What Is Next for Retinal Gene Therapy?

    PubMed Central

    Vandenberghe, Luk H.

    2015-01-01

    The field of gene therapy for retinal blinding disorders is experiencing incredible momentum, justified by hopeful results in early stage clinical trials for inherited retinal degenerations. The premise of the use of the gene as a drug has come a long way, and may have found its niche in the treatment of retinal disease. Indeed, with only limited treatment options available for retinal indications, gene therapy has been proven feasible, safe, and effective and may lead to durable effects following a single injection. Here, we aim at putting into context the promise and potential, the technical, clinical, and economic boundaries limiting its application and development, and speculate on a future in which gene therapy is an integral component of ophthalmic clinical care. PMID:25877395

  3. Photoreceptor Cells Influence Retinal Vascular Degeneration in Mouse Models of Retinal Degeneration and Diabetes

    PubMed Central

    Liu, Haitao; Tang, Jie; Du, Yunpeng; Saadane, Aicha; Tonade, Deoye; Samuels, Ivy; Veenstra, Alex; Palczewski, Krzysztof; Kern, Timothy S.

    2016-01-01

    Purpose Loss of photoreceptor cells is associated with retinal vascular degeneration in retinitis pigmentosa, whereas the presence of photoreceptor cells is implicated in vascular degeneration in diabetic retinopathy. To investigate how both the absence and presence of photoreceptors could damage the retinal vasculature, we compared two mouse models of photoreceptor degeneration (opsin−/− and RhoP23H/P23H ) and control C57Bl/5J mice, each with and without diabetes. Methods Retinal thickness, superoxide, expression of inflammatory proteins, ERG and optokinetic responses, leukocyte cytotoxicity, and capillary degeneration were evaluated at 1 to 10 months of age using published methods. Results Retinal photoreceptor cells degenerated completely in the opsin mutants by 2 to 4 months of age, and visual function subsided correspondingly. Retinal capillary degeneration was substantial while photoreceptors were still present, but slowed after the photoreceptors degenerated. Diabetes did not further exacerbate capillary degeneration in these models of photoreceptor degeneration, but did cause capillary degeneration in wild-type animals. Photoreceptor cells, however, did not degenerate in wild-type diabetic mice, presumably because the stress responses in these cells were less than in the opsin mutants. Retinal superoxide and leukocyte damage to retinal endothelium contributed to the degeneration of retinal capillaries in diabetes, and leukocyte-mediated damage was increased in both opsin mutants during photoreceptor cell degeneration. Conclusions Photoreceptor cells affect the integrity of the retinal microvasculature. Deterioration of retinal capillaries in opsin mutants was appreciable while photoreceptor cells were present and stressed, but was less after photoreceptors degenerated. This finding proves relevant to diabetes, where persistent stress in photoreceptors likewise contributes to capillary degeneration. PMID:27548901

  4. Retinal Vascular Fractals and Cognitive Impairment

    PubMed Central

    Ong, Yi-Ting; Hilal, Saima; Cheung, Carol Yim-lui; Xu, Xin; Chen, Christopher; Venketasubramanian, Narayanaswamy; Wong, Tien Yin; Ikram, Mohammad Kamran

    2014-01-01

    Background Retinal microvascular network changes have been found in patients with age-related brain diseases such as stroke and dementia including Alzheimer's disease. We examine whether retinal microvascular network changes are also present in preclinical stages of dementia. Methods This is a cross-sectional study of 300 Chinese participants (age: ≥60 years) from the ongoing Epidemiology of Dementia in Singapore study who underwent detailed clinical examinations including retinal photography, brain imaging and neuropsychological testing. Retinal vascular parameters were assessed from optic disc-centered photographs using a semiautomated program. A comprehensive neuropsychological battery was administered, and cognitive function was summarized as composite and domain-specific Z-scores. Cognitive impairment no dementia (CIND) and dementia were diagnosed according to standard diagnostic criteria. Results Among 268 eligible nondemented participants, 78 subjects were categorized as CIND-mild and 69 as CIND-moderate. In multivariable adjusted models, reduced retinal arteriolar and venular fractal dimensions were associated with an increased risk of CIND-mild and CIND-moderate. Reduced fractal dimensions were associated with poorer cognitive performance globally and in the specific domains of verbal memory, visuoconstruction and visuomotor speed. Conclusion A sparser retinal microvascular network, represented by reduced arteriolar and venular fractal dimensions, was associated with cognitive impairment, suggesting that early microvascular damage may be present in preclinical stages of dementia. PMID:25298774

  5. Robotic Assisted Cannulation of Occluded Retinal Veins

    PubMed Central

    Meenink, Thijs C. M.; Janssens, Tom; Vanheukelom, Valerie; Naus, Gerrit J. L.; Beelen, Maarten J.; Meers, Caroline; Jonckx, Bart; Stassen, Jean-Marie

    2016-01-01

    Purpose To develop a methodology for cannulating porcine retinal venules using a robotic assistive arm after inducing a retinal vein occlusion using the photosensitizer rose bengal. Methodology Retinal vein occlusions proximal to the first vascular branch point were induced following intravenous injection of rose bengal by exposure to 532nm laser light delivered by slit-lamp or endolaser probe. Retinal veins were cannulated by positioning a glass catheter tip using a robotically controlled micromanipulator above venules with an outer diameter of 80μm or more and performing a preset piercing maneuver, controlled robotically. The ability of a balanced salt (BSS) solution to remove an occlusion by repeat distention of the retinal vein was also assessed. Results Cannulation using the preset piercing program was successful in 9 of 9 eyes. Piercing using the micromanipulator under manual control was successful in only 24 of 52 attempts, with several attempts leading to double piercing. The best location for cannulation was directly proximal to the occlusion. Infusion of BSS did not result in the resolution of the occlusion. Conclusion Cannulation of venules using a robotic microassistive arm can be achieved with consistency, provided the piercing is robotically driven. The model appears robust enough to allow testing of therapeutic strategies aimed at eliminating a retinal vein thrombus and its evolution over time. PMID:27676261

  6. Retinal synaptic regeneration via microfluidic guiding channels.

    PubMed

    Su, Ping-Jung; Liu, Zongbin; Zhang, Kai; Han, Xin; Saito, Yuki; Xia, Xiaojun; Yokoi, Kenji; Shen, Haifa; Qin, Lidong

    2015-08-28

    In vitro culture of dissociated retinal neurons is an important model for investigating retinal synaptic regeneration (RSR) and exploring potentials in artificial retina. Here, retinal precursor cells were cultured in a microfluidic chip with multiple arrays of microchannels in order to reconstruct the retinal neuronal synapse. The cultured retinal cells were physically connected through microchannels. Activation of electric signal transduction by the cells through the microchannels was demonstrated by administration of glycinergic factors. In addition, an image-based analytical method was used to quantify the synaptic connections and to assess the kinetics of synaptic regeneration. The rate of RSR decreased significantly below 100 μM of inhibitor glycine and then approached to a relatively constant level at higher concentrations. Furthermore, RSR was enhanced by chemical stimulation with potassium chloride. Collectively, the microfluidic synaptic regeneration chip provides a novel tool for high-throughput investigation of RSR at the cellular level and may be useful in quality control of retinal precursor cell transplantation.

  7. Digital imaging-based retinal photocoagulation system

    NASA Astrophysics Data System (ADS)

    Barrett, Steven F.; Wright, Cameron H. G.; Oberg, Erik D.; Rockwell, Benjamin A.; Cain, Clarence P.; Rylander, Henry G., III; Welch, Ashley J.

    1997-05-01

    Researchers at the USAF Academy and the University of Texas are developing a computer-assisted retinal photocoagulation system for the treatment of retinal disorders (i.e. diabetic retinopathy, retinal tears). Currently, ophthalmologists manually place therapeutic retinal lesions, an acquired technique that is tiring for both the patient and physician. The computer-assisted system under development can rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a matter of seconds. Separate prototype subsystems have been developed to control lesion depth during irradiation and lesion placement to compensate for retinal movement. Both subsystems have been successfully demonstrated in vivo on pigmented rabbits using an argon continuous wave laser. Two different design approaches are being pursued to combine the capabilities of both subsystems: a digital imaging-based system and a hybrid analog-digital system. This paper will focus on progress with the digital imaging-based prototype system. A separate paper on the hybrid analog-digital system, `Hybrid Retinal Photocoagulation System', is also presented in this session.

  8. Retinal imaging using adaptive optics technology☆

    PubMed Central

    Kozak, Igor

    2014-01-01

    Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of wave front distortions. Retinal imaging using AO aims to compensate for higher order aberrations originating from the cornea and the lens by using deformable mirror. The main application of AO retinal imaging has been to assess photoreceptor cell density, spacing, and mosaic regularity in normal and diseased eyes. Apart from photoreceptors, the retinal pigment epithelium, retinal nerve fiber layer, retinal vessel wall and lamina cribrosa can also be visualized with AO technology. Recent interest in AO technology in eye research has resulted in growing number of reports and publications utilizing this technology in both animals and humans. With the availability of first commercially available instruments we are making transformation of AO technology from a research tool to diagnostic instrument. The current challenges include imaging eyes with less than perfect optical media, formation of normative databases for acquired images such as cone mosaics, and the cost of the technology. The opportunities for AO will include more detailed diagnosis with description of some new findings in retinal diseases and glaucoma as well as expansion of AO into clinical trials which has already started. PMID:24843304

  9. Retinal synaptic regeneration via microfluidic guiding channels

    PubMed Central

    Su, Ping-Jung; Liu, Zongbin; Zhang, Kai; Han, Xin; Saito, Yuki; Xia, Xiaojun; Yokoi, Kenji; Shen, Haifa; Qin, Lidong

    2015-01-01

    In vitro culture of dissociated retinal neurons is an important model for investigating retinal synaptic regeneration (RSR) and exploring potentials in artificial retina. Here, retinal precursor cells were cultured in a microfluidic chip with multiple arrays of microchannels in order to reconstruct the retinal neuronal synapse. The cultured retinal cells were physically connected through microchannels. Activation of electric signal transduction by the cells through the microchannels was demonstrated by administration of glycinergic factors. In addition, an image-based analytical method was used to quantify the synaptic connections and to assess the kinetics of synaptic regeneration. The rate of RSR decreased significantly below 100 μM of inhibitor glycine and then approached to a relatively constant level at higher concentrations. Furthermore, RSR was enhanced by chemical stimulation with potassium chloride. Collectively, the microfluidic synaptic regeneration chip provides a novel tool for high-throughput investigation of RSR at the cellular level and may be useful in quality control of retinal precursor cell transplantation. PMID:26314276

  10. Retinal imaging using adaptive optics technology.

    PubMed

    Kozak, Igor

    2014-04-01

    Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of wave front distortions. Retinal imaging using AO aims to compensate for higher order aberrations originating from the cornea and the lens by using deformable mirror. The main application of AO retinal imaging has been to assess photoreceptor cell density, spacing, and mosaic regularity in normal and diseased eyes. Apart from photoreceptors, the retinal pigment epithelium, retinal nerve fiber layer, retinal vessel wall and lamina cribrosa can also be visualized with AO technology. Recent interest in AO technology in eye research has resulted in growing number of reports and publications utilizing this technology in both animals and humans. With the availability of first commercially available instruments we are making transformation of AO technology from a research tool to diagnostic instrument. The current challenges include imaging eyes with less than perfect optical media, formation of normative databases for acquired images such as cone mosaics, and the cost of the technology. The opportunities for AO will include more detailed diagnosis with description of some new findings in retinal diseases and glaucoma as well as expansion of AO into clinical trials which has already started. PMID:24843304

  11. Retinal synaptic regeneration via microfluidic guiding channels.

    PubMed

    Su, Ping-Jung; Liu, Zongbin; Zhang, Kai; Han, Xin; Saito, Yuki; Xia, Xiaojun; Yokoi, Kenji; Shen, Haifa; Qin, Lidong

    2015-01-01

    In vitro culture of dissociated retinal neurons is an important model for investigating retinal synaptic regeneration (RSR) and exploring potentials in artificial retina. Here, retinal precursor cells were cultured in a microfluidic chip with multiple arrays of microchannels in order to reconstruct the retinal neuronal synapse. The cultured retinal cells were physically connected through microchannels. Activation of electric signal transduction by the cells through the microchannels was demonstrated by administration of glycinergic factors. In addition, an image-based analytical method was used to quantify the synaptic connections and to assess the kinetics of synaptic regeneration. The rate of RSR decreased significantly below 100 μM of inhibitor glycine and then approached to a relatively constant level at higher concentrations. Furthermore, RSR was enhanced by chemical stimulation with potassium chloride. Collectively, the microfluidic synaptic regeneration chip provides a novel tool for high-throughput investigation of RSR at the cellular level and may be useful in quality control of retinal precursor cell transplantation. PMID:26314276

  12. Electroretinographic effects of retinal dragging and retinal folds in eyes with familial exudative vitreoretinopathy

    PubMed Central

    Yaguchi, Yukari; Katagiri, Satoshi; Fukushima, Yoko; Yokoi, Tadashi; Nishina, Sachiko; Kondo, Mineo; Azuma, Noriyuki

    2016-01-01

    We evaluated the retinal function of retinal dragging (Rdrag) and radial retinal folds (Rfolds) in eyes with familial exudative vitreoretinopathy (FEVR) using full-field electroretinography (ERG). Seventeen eyes of nine patients with FEVR who had Rdrag or Rfolds were retrospectively studied. Eyes were classified into four groups according to the severity of the retinal alterations: Group 1, without Rdrag or Rfolds (5 eyes); Group 2, with Rdrag (4 eyes); Group 3, with Rfolds (6 eyes); and Group 4, with Rfolds in which all major retinal vessels were involved (2 eyes). The amplitudes of all ERG components and the implicit times of the photopic a- and b-waves and 30-Hz flicker responses were decreased or prolonged as the severity of the retinal alterations increased (P < 0.01). The photopic negative response was most severely affected and nearly undetectable in all eyes in Groups 3 and 4, although the other ERG components were detectable in all eyes in Group 3 and one eye in Group 4. These results suggest the decrease of retinal functions was correlated with the degree of severity of Rdrag and Rfolds in eyes with FEVR. In addition, the function of the retinal ganglion cells appears to be more severely affected compared with the others. PMID:27456314

  13. Increased aqueous flare is associated with thickening of inner retinal layers in eyes with retinitis pigmentosa

    PubMed Central

    Nagasaka, Yosuke; Ito, Yasuki; Ueno, Shinji; Terasaki, Hiroko

    2016-01-01

    Retinitis pigmentosa(RP) is a hereditary retinal disease that causes photoreceptor, outer retinal, degeneration. Although the pathogenesis is still unclear, there have been numerous reports regarding inner retinal changes in RP eyes. The aim of this study is to retrospectively evaluate the changes in the thicknesses of different retinal layers of RP eyes, and its association with aqueous flare, which is used for measuring the intensity of intraocular inflammation. A total of 125 eyes of 64 patients with RP and 13 normal eyes were studied. The thicknesses of total neural retina,nerve fiber layer(NFL),ganglion cell layer(GCL),inner plexiform layer(IPL),inner nuclear layer(INL),outer layers and foveal thickness were measured in the optical coherence tomographic images. Aqueous flare was measured with a laser flare-cell meter. The associations between those parameters, visual acuity and visual field were determined in RP eyes using multivariate analysis. The results of this study showed the significant thickening of NFL, GCL and INL, the significant thinning of outer layers and the association of them with increased aqueous flare, whereas NFL and INL thickening associated with outer retinal thinning. These results can suggest the involvement of intraocular inflammation in the pathogenesis of inner retinal thickening as a secondary change following outer retinal degeneration. PMID:27653207

  14. Slab detachment under the Eastern Alps seen by seismic anisotropy

    PubMed Central

    Qorbani, Ehsan; Bianchi, Irene; Bokelmann, Götz

    2015-01-01

    We analyze seismic anisotropy for the Eastern Alpine region by inspecting shear-wave splitting from SKS and SKKS phases. The Eastern Alpine region is characterized by a breakdown of the clear mountain-chain-parallel fast orientation pattern that has been previously documented for the Western Alps and for the western part of the Eastern Alps. The main interest of this paper is a more detailed analysis of the anisotropic character of the Eastern Alps, and the transition to the Carpathian–Pannonian region. SK(K)S splitting measurements reveal a rather remarkable lateral change in the anisotropy pattern from the west to the east of the Eastern Alps with a transition area at about 12°E. We also model the backazimuthal variation of the measurements by a vertical change of anisotropy. We find that the eastern part of the study area is characterized by the presence of two layers of anisotropy, where the deeper layer has characteristics similar to those of the Central Alps, in particular SW–NE fast orientations of anisotropic axes. We attribute the deeper layer to a detached slab from the European plate. Comparison with tomographic studies of the area indicates that the detached slab might possibly connect with the lithosphere that is still in place to the west of our study area, and may also connect with the slab graveyard to the East, at the depth of the upper mantle transition zone. On the other hand, the upper layer has NW–SE fast orientations coinciding with a low-velocity layer which is found above a more-or-less eastward dipping high-velocity body. The anisotropy of the upper layer shows large-scale NW–SE fast orientation, which is consistent with the presence of asthenospheric flow above the detached slab foundering into the deeper mantle. PMID:25843968

  15. Middle Miocene Displacement Along the Rand Detachment Fault, Rand Mountains

    NASA Astrophysics Data System (ADS)

    Shulaker, D. Z.; Grove, M. J.

    2015-12-01

    Laramide flat-slab subduction extinguished Sierra Nevada pluton emplacement in southern California by ca. 85 Ma as trench-derived sediments were underthrust and accreted beneath arc basement. These relationships are well illustrated in the Rand Mountains, situated just south of the Garlock fault in the northwestern Mojave Desert. Here, accreted rocks within the Rand Mountains are referred to as Rand Schist. The Rand Detachment fault juxtaposes Rand Schist beneath 87 Ma Sierran granitoids. New zircon (U-Th)/He age results from schist and basement juxtaposed across the Rand Detachment fault are 15 ± 3 Ma and 30 ± 5 Ma, respectively. When considered within the context of previously reported thermochronology from the Rand Mountains, our data shows that the Rand Detachment fault in the Rand Mountains is a middle Miocene fault that facilitated extension of the northwest Mojave Desert. This timing is in temporal and spatial agreement with regional extension throughout the Mojave triggered by northern migration of the slab window after collision of the Mendocino Triple Junction with the southern California margin. Further evidence of slab-window-related magmatism in the easternmost Rand Mountains is provided by the 19 Ma Yellow Aster pluton and 19 Ma rhyolite porphyry. It is possible that Miocene extension re-activated an older structure within the Rand Mountains. For example, a similar low-angle fault juxtaposing schist and basement present in the San Emigdio Mountains is believed to have accommodated large scale Late Cretaceous displacement, exhuming Rand Schist and overlying deepest Sierran basement to shallow crustal levels by 77 Ma [1]. However, 68-72 Ma phengite cooling ages and other thermochronology from the Rand Mountains indicates that any pre-Miocene extension in this area must postdate that in the San Emigdio Mountains. [1] Chapman et al., 2012. Geosphere, 8, 314-341.

  16. The disappearance and reappearance of Titan's detached haze layer

    NASA Astrophysics Data System (ADS)

    West, Robert; Rannou, Pascal; Lavvas, Panayotis; Seignovert, Benoit; Turtle, Elizabeth P.; Perry, Jason; Ovanessian, Aida; Roy, Mou

    2016-10-01

    Titan's extended haze is a prominent and long-lived feature of the atmosphere that encompasses a rich variety of chemical, dynamical and microphysical processes operating over a wide range of temporal and spatial scales. The so-called 'detached' haze layer is easily seen in high-resolution short-wave (near-UV and blue wavelengths) images and is a consequence of a nearly global (outside of the winter polar hood region) layer depleted in aerosol content. It was first seen near 350 Km altitude in Voyager images (Rages and Pollack, 1983) and later observed by the Cassini ISS cameras (Porco et al., 2005; West et al., 2010) and UV stellar occultation profiles (Koskinen et al. 2011). A series of Cassini images from 2009 to 2010 revealed what appears to be a seasonally related altitude variation with remarkable regularity (comparing the Voyager and Cassini images). The drop in altitude is most rapid at equinox. Here we report on images of the upper haze layer over the period 2012 to early 2016. In the early part of this period the detached haze continued to drop in altitude and disappeared. There was no evidence for it beginning late in 2012 and extending to early 2016 when it was again detected with very low contrast at an altitude near 500 Km. We document this behavior and examine the evolution of the haze as functions of both latitude and time. These new details put additional constraints on models that attempt to account for the existence of the detached layer. Part of this work was done by the Jet Propulsion Laboratory, California Institute of Technology. References: Rages, K., and J. B. Pollack (1983), Vertical distribution of scattering hazes in Titan's upper atmosphere, Icarus, 55, 50–62, doi:10.1016/0019-1035 (83)90049-0; Porco, C. C. et al., Imaging Titan from the Cassini Spacecraft, Nature 434, 159-168 (2005); West, R. A. et al., The evolution of Titans detached haze layer near equinox in 2009", Geophys. Res. Lett. 38, L06204, doi:10.1029/2011GL046843, 2011

  17. Early Miocene mylonitization and detachment faulting, South Mountains, central Arizona

    SciTech Connect

    Reynolds, S.J.; Shafiqullah, M.; Damon, P.E.; DeWitt, E.

    1986-04-01

    The South Mountains of central Arizona are one of the geologically simplest metamorphic core complexes of the North American Cordillera. An early Miocene age of mylonitization is indicated by crosscutting relationships between mylonitic fabric and a composite pluton dated at 22-25 Ma by Rb-Sr, U-Th-Pb, and K-Ar techniques. The kinematic agreement and close temporal association of mylonitization and detachment faulting support models in which the two processes are related to an evolving crustal shear zone that accommodated mid-Tertiary continental extension. 19 references, 3 figures, 2 tables.

  18. Young-Person's Guide to Detached-Eddy Simulation Grids

    NASA Technical Reports Server (NTRS)

    Spalart, Philippe R.; Streett, Craig (Technical Monitor)

    2001-01-01

    We give the "philosophy", fairly complete instructions, a sketch and examples of creating Detached-Eddy Simulation (DES) grids from simple to elaborate, with a priority on external flows. Although DES is not a zonal method, flow regions with widely different gridding requirements emerge, and should be accommodated as far as possible if a good use of grid points is to be made. This is not unique to DES. We brush on the time-step choice, on simple pitfalls, and on tools to estimate whether a simulation is well resolved.

  19. High-T Detachment Shear Zone in Mirdita Ophiolite (albania)

    NASA Astrophysics Data System (ADS)

    Jousselin, D.; Nicolas, A. A.; Boudier, F. I.; Meshi, A.

    2013-12-01

    Two oceanic core complex (OCC) extending over 50km have been mapped in the northern part of the Mirdita ophiolite. Despite the fact that the ophiolite is encased between major Dinaric thrusts, a late Jurassic marine topography is still preserved, as demonstrated by the nearly horizontal sedimentary cover. The study area exposes two peridotite domes, aligned on a N-S trend, separated by a talweg 1km wide, occupied by gabbros. This alignment is parallel to the paleoridge indicated by the sheeted dike complex, exposed at the eastern margin, and trending N-S. The two mantle domes composed of clinopyroxene bearing harzburgite with high-T porphyroclastic textures are roofed by a ~1km thick mylonitic shell, particularly well exposed at the limit with the gabbros, and interpreted as an oceanic high-T detachment shear zone. Six mylonite samples are studied for textures and crystal preferred orientation (CPO) aiming to improve the kinematics of the oceanic detachment. The mylonitic peridotite are exceptionally fresh, serpentine minerals being restricted to the bordering porphyroclastic harzburgites. They exhibit a tight millimetric layering formed by olivine / olivine+orthopyroxene / olivine+clinopyroxene or pargasitic amphibole, with grain-size 100-200μm in olivine bands vs 20-50μm in polyphase bands; plagioclase is ubiquitous. Orthopyroxene porphyroclasts show both body rotation and slip with boudinage in the flowing matrix. Electron back scattering diffraction (EBSD) maps provide precise modal composition and phase distribution. Although olivine CPO is not strong, it consistently records solid state flow on the [100](0kl)(010) slip system; the slight obliquity of [100] slip line on the mineral lineation marks the sense of shear. Pargasitic amphibole having grown in the mylonitic development has a strong CPO with [001]pg parallel to [100]ol. The most surprising result is a weak but constant orientation of [001]opx, known as the unique slip direction in orthopyroxene, at

  20. The role of partners and children for employees' psychological detachment from work and well-being.

    PubMed

    Hahn, Verena C; Dormann, Christian

    2013-01-01

    This study examined the role of partners and children for employees' psychological detachment from work during off-job time. Building on boundary theory, we hypothesized that not only employees' own work-home segmentation preference but also their partners' work-home segmentation preference is associated with employees' psychological detachment. In addition, partners' psychological detachment should influence employees' psychological detachment. We hypothesized that the presence of children in the household moderates partners' influence on employees' psychological detachment. Further, we expected both employees' and their partners' psychological detachment to contribute to employees' well-being. Participants were 114 dual-earner couples who responded to Web-based questionnaires. The hypotheses were tested with multilevel analyses, using the actor-partner interdependence model. Results confirmed our hypotheses. Employees' and their partners' work-home segmentation preferences were associated with employees' psychological detachment. The presence of children moderated the relation between partners' work-home segmentation preference and employees' psychological detachment. The relation was weaker when there were children in the household. Moreover, employees' and their partners' psychological detachment were positively associated. Again, the relation was weaker when there were children in the household. Finally, both employees' and their partners' psychological detachment contributed to employees' well-being.

  1. Toward high-resolution optoelectronic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Palanker, Daniel; Huie, Philip; Vankov, Alexander; Asher, Alon; Baccus, Steven

    2005-04-01

    It has been already demonstrated that electrical stimulation of retina can produce visual percepts in blind patients suffering from macular degeneration and retinitis pigmentosa. Current retinal implants provide very low resolution (just a few electrodes), while several thousand pixels are required for functional restoration of sight. We present a design of the optoelectronic retinal prosthetic system that can activate a retinal stimulating array with pixel density up to 2,500 pix/mm2 (geometrically corresponding to a visual acuity of 20/80), and allows for natural eye scanning rather than scanning with a head-mounted camera. The system operates similarly to "virtual reality" imaging devices used in military and medical applications. An image from a video camera is projected by a goggle-mounted infrared LED-LCD display onto the retina, activating an array of powered photodiodes in the retinal implant. Such a system provides a broad field of vision by allowing for natural eye scanning. The goggles are transparent to visible light, thus allowing for simultaneous utilization of remaining natural vision along with prosthetic stimulation. Optical control of the implant allows for simple adjustment of image processing algorithms and for learning. A major prerequisite for high resolution stimulation is the proximity of neural cells to the stimulation sites. This can be achieved with sub-retinal implants constructed in a manner that directs migration of retinal cells to target areas. Two basic implant geometries are described: perforated membranes and protruding electrode arrays. Possibility of the tactile neural stimulation is also examined.

  2. Proteomic Profiling of Cigarette Smoke Induced Changes in Retinal Pigment Epithelium Cells.

    PubMed

    Merl-Pham, Juliane; Gruhn, Fabian; Hauck, Stefanie M

    2016-01-01

    Age-related macular degeneration (AMD) is a medical condition usually affecting older adults and resulting in a loss of vision in the macula, the center of the visual field. The dry form of this disease presents with atrophy of the retinal pigment epithelium, resulting in the detachment of the retina and loss of photoreceptors. Cigarette smoke is one main risk factor for dry AMD and increases the risk of developing the disease by three times. In order to understand the influence of cigarette smoke on retinal pigment epithelial cells, cultured human ARPE-19 cells were treated with cigarette smoke extract for 24 h. Using quantitative mass spectrometry more than 3000 proteins were identified and their respective abundances were compared between cigarette smoke-treated and untreated cells. Altogether 1932 proteins were quantified with at least two unique peptides, with 686 proteins found to be significantly differentially abundant with p > 0.05. Of these proteins the abundance of 64 proteins was at least 2-fold down-regulated after cigarette smoke treatment while 120 proteins were 2-fold up-regulated. The analysis of associated biological processes revealed an alteration of proteins involved in RNA processing and transport as well as extracellular matrix remodelling in response to cigarette smoke treatment.

  3. Central retinal artery occlusion by proxy: a cause for sudden blindness in an airline passenger.

    PubMed

    Polk, J D; Rugaber, Christopher; Kohn, Gary; Arenstein, Ronald; Fallon, William F

    2002-04-01

    The use of gas media in ophthalmologic procedures is relatively commonplace. Scleral buckle and pneumatic retinopexy procedures using air-gas mediums are a widely accepted treatment for retinal detachment. We present a patient who had a scleral buckle with pneumatic retinopexy performed and subsequently flew in a commercial airliner 2 wk later. The patient experienced sudden blindness due to central retinal artery occlusion brought about by expansion of the air bubble when the aircraft reached cruise altitude and a cabin pressure of 8000 ft. The intraocular pressure exceeded the central artery pressure thereby collapsing the artery. The patient's symptoms were relieved when an onboard flight surgeon identified the problem and the cabin pressure was reset to 2000 ft. Flying after an ophthalmic procedure that incorporates intraocular gas may have complications due to the bubble expansion in accordance with Boyle's Law. The ophthalmologic surgeon must be diligent in forewarning patients of the potential complications of flying for weeks to months after a procedure that utilizes intraocular gas. PMID:11952061

  4. Inhibitory Effect of Bone Morphogenetic Protein 4 in Retinal Pigment Epithelial-Mesenchymal Transition

    PubMed Central

    Yao, Haipei; Li, Hui; Yang, Shuai; Li, Min; Zhao, Chun; Zhang, Jingfa; Xu, Guotong; Wang, Fang

    2016-01-01

    Proliferative vitreoretinopathy (PVR), a serious vision-threatening complication of retinal detachment (RD), is characterized by the formation of contractile fibrotic membranes, in which epithelial-mesenchymal transition (EMT) of the retinal pigment epithelium (RPE) is a major event. Recent studies suggest an important role of bone morphogenetic protein 4 (BMP4) in the suppression of fibrosis. In this study, we aimed to investigate the role of BMP4 in the pathological process of PVR, particularly in the EMT of RPE cells. We found that BMP4 and its receptors were co-labelled with cytokeratin and α-SMA positive cells within the PVR membrane. Moreover, the mRNA and protein expression levels of BMP4 were decreased whereas BMP4 receptors ALK2, ALK3 and ALK6 were increased during TGF-β-induced EMT in primary RPE cells. Exogenous BMP4 inhibited TGF-β-induced epithelial marker down-regulation, as well as mesenchymal marker up-regulation at both the mRNA and protein levels in RPE cells. In addition, BMP4 treatment attenuated the TGF-β-induced gel contraction, cell migration and Smad2/3 phosphorylation. However, knockdown of endogenous BMP4 stimulated changes in EMT markers. Our results confirm the hypothesis that BMP4 might inhibit TGF-β-mediated EMT in RPE cells via the Smad2/3 pathway and suppress contraction. This might represent a potential treatment for PVR. PMID:27586653

  5. Proteomic Profiling of Cigarette Smoke Induced Changes in Retinal Pigment Epithelium Cells.

    PubMed

    Merl-Pham, Juliane; Gruhn, Fabian; Hauck, Stefanie M

    2016-01-01

    Age-related macular degeneration (AMD) is a medical condition usually affecting older adults and resulting in a loss of vision in the macula, the center of the visual field. The dry form of this disease presents with atrophy of the retinal pigment epithelium, resulting in the detachment of the retina and loss of photoreceptors. Cigarette smoke is one main risk factor for dry AMD and increases the risk of developing the disease by three times. In order to understand the influence of cigarette smoke on retinal pigment epithelial cells, cultured human ARPE-19 cells were treated with cigarette smoke extract for 24 h. Using quantitative mass spectrometry more than 3000 proteins were identified and their respective abundances were compared between cigarette smoke-treated and untreated cells. Altogether 1932 proteins were quantified with at least two unique peptides, with 686 proteins found to be significantly differentially abundant with p > 0.05. Of these proteins the abundance of 64 proteins was at least 2-fold down-regulated after cigarette smoke treatment while 120 proteins were 2-fold up-regulated. The analysis of associated biological processes revealed an alteration of proteins involved in RNA processing and transport as well as extracellular matrix remodelling in response to cigarette smoke treatment. PMID:26427490

  6. Inhibitory Effect of Bone Morphogenetic Protein 4 in Retinal Pigment Epithelial-Mesenchymal Transition

    NASA Astrophysics Data System (ADS)

    Yao, Haipei; Li, Hui; Yang, Shuai; Li, Min; Zhao, Chun; Zhang, Jingfa; Xu, Guotong; Wang, Fang

    2016-09-01

    Proliferative vitreoretinopathy (PVR), a serious vision-threatening complication of retinal detachment (RD), is characterized by the formation of contractile fibrotic membranes, in which epithelial-mesenchymal transition (EMT) of the retinal pigment epithelium (RPE) is a major event. Recent studies suggest an important role of bone morphogenetic protein 4 (BMP4) in the suppression of fibrosis. In this study, we aimed to investigate the role of BMP4 in the pathological process of PVR, particularly in the EMT of RPE cells. We found that BMP4 and its receptors were co-labelled with cytokeratin and α-SMA positive cells within the PVR membrane. Moreover, the mRNA and protein expression levels of BMP4 were decreased whereas BMP4 receptors ALK2, ALK3 and ALK6 were increased during TGF-β-induced EMT in primary RPE cells. Exogenous BMP4 inhibited TGF-β-induced epithelial marker down-regulation, as well as mesenchymal marker up-regulation at both the mRNA and protein levels in RPE cells. In addition, BMP4 treatment attenuated the TGF-β-induced gel contraction, cell migration and Smad2/3 phosphorylation. However, knockdown of endogenous BMP4 stimulated changes in EMT markers. Our results confirm the hypothesis that BMP4 might inhibit TGF-β-mediated EMT in RPE cells via the Smad2/3 pathway and suppress contraction. This might represent a potential treatment for PVR.

  7. Inhibitory Effect of Bone Morphogenetic Protein 4 in Retinal Pigment Epithelial-Mesenchymal Transition.

    PubMed

    Yao, Haipei; Li, Hui; Yang, Shuai; Li, Min; Zhao, Chun; Zhang, Jingfa; Xu, Guotong; Wang, Fang

    2016-01-01

    Proliferative vitreoretinopathy (PVR), a serious vision-threatening complication of retinal detachment (RD), is characterized by the formation of contractile fibrotic membranes, in which epithelial-mesenchymal transition (EMT) of the retinal pigment epithelium (RPE) is a major event. Recent studies suggest an important role of bone morphogenetic protein 4 (BMP4) in the suppression of fibrosis. In this study, we aimed to investigate the role of BMP4 in the pathological process of PVR, particularly in the EMT of RPE cells. We found that BMP4 and its receptors were co-labelled with cytokeratin and α-SMA positive cells within the PVR membrane. Moreover, the mRNA and protein expression levels of BMP4 were decreased whereas BMP4 receptors ALK2, ALK3 and ALK6 were increased during TGF-β-induced EMT in primary RPE cells. Exogenous BMP4 inhibited TGF-β-induced epithelial marker down-regulation, as well as mesenchymal marker up-regulation at both the mRNA and protein levels in RPE cells. In addition, BMP4 treatment attenuated the TGF-β-induced gel contraction, cell migration and Smad2/3 phosphorylation. However, knockdown of endogenous BMP4 stimulated changes in EMT markers. Our results confirm the hypothesis that BMP4 might inhibit TGF-β-mediated EMT in RPE cells via the Smad2/3 pathway and suppress contraction. This might represent a potential treatment for PVR. PMID:27586653

  8. The Incidence of Rhegmatogenous Retinal Complications in Macular Surgery After Prophylactic Preoperative Laser Retinopexy

    PubMed Central

    Tosi, Gian Marco; Esposti, Pierluigi; Romeo, Napoleone; Marigliani, Davide; Cevenini, Gabriele; Massimo, Patrizio; Nuti, Elisabetta; Esposti, Giulia; Ripandelli, Guido

    2016-01-01

    Abstract The aim of the study is to evaluate the clinical characteristics of intraoperative retinal breaks (RBs) and postoperative retinal detachment (RRD) in patients undergoing pars plana vitrectomy (PPV) for macular disorders, who were treated preoperatively with prophylactic peripheral laser retinopexy. This observational cohort study comprised of 254 patients who underwent macular surgery and were preoperatively subjected to prophylactic laser retinopexy anterior to the equator. The main outcome measures were the incidence and characteristics of intraoperative RBs and postoperative RRD. Intraoperative RBs occurred in 14 patients (5.5%). Ten patients presented a sclerotomy-related RB (3.9%) and 4 patients a nonsclerotomy-related RB (1.6%). Two patients showed postoperative RRD (0.7%). Neither of the 2 patients with postoperative RRD was macula-off at presentation: one of them was successfully operated on with scleral buckling and the other was managed by observation alone. A significantly increased risk for the intraoperative development of sclerotomy-related RB was found in 20-gauge PPV compared with 23/25-gauge PPV. Preoperative prophylactic peripheral laser retinopexy does not guarantee the prevention of intraopertaive RBs or postoperative RRD. However, it might prevent the involvement of the macula when RRD occurs postoperatively. PMID:27057893

  9. Central retinal artery occlusion by proxy: a cause for sudden blindness in an airline passenger.

    PubMed

    Polk, J D; Rugaber, Christopher; Kohn, Gary; Arenstein, Ronald; Fallon, William F

    2002-04-01

    The use of gas media in ophthalmologic procedures is relatively commonplace. Scleral buckle and pneumatic retinopexy procedures using air-gas mediums are a widely accepted treatment for retinal detachment. We present a patient who had a scleral buckle with pneumatic retinopexy performed and subsequently flew in a commercial airliner 2 wk later. The patient experienced sudden blindness due to central retinal artery occlusion brought about by expansion of the air bubble when the aircraft reached cruise altitude and a cabin pressure of 8000 ft. The intraocular pressure exceeded the central artery pressure thereby collapsing the artery. The patient's symptoms were relieved when an onboard flight surgeon identified the problem and the cabin pressure was reset to 2000 ft. Flying after an ophthalmic procedure that incorporates intraocular gas may have complications due to the bubble expansion in accordance with Boyle's Law. The ophthalmologic surgeon must be diligent in forewarning patients of the potential complications of flying for weeks to months after a procedure that utilizes intraocular gas.

  10. Ciliary neurotrophic factor (CNTF) for human retinal degeneration: phase I trial of CNTF delivered by encapsulated cell intraocular implants.

    PubMed

    Sieving, Paul A; Caruso, Rafael C; Tao, Weng; Coleman, Hanna R; Thompson, Darby J S; Fullmer, Keri R; Bush, Ronald A

    2006-03-01

    Neurotrophic factors are agents with a promising ability to retard progression of neurodegenerative diseases and are effective in slowing photoreceptor degeneration in animal models of retinitis pigmentosa. Here we report a human clinical trial of a neurotrophic factor for retinal neurodegeneration. In this Phase I safety trial, human ciliary neurotrophic factor (CNTF) was delivered by cells transfected with the human CNTF gene and sequestered within capsules that were surgically implanted into the vitreous of the eye. The outer membrane of the encapsulated cell implant is semipermeable to allow CNTF to reach the retina. Ten participants received CNTF implants in one eye. When the implants were removed after 6 months, they contained viable cells with minimal cell loss and gave CNTF output at levels previously shown to be therapeutic for retinal degeneration in rcd1 dogs. Although the trial was not powered to form a judgment as to clinical efficacy, of seven eyes for which visual acuity could be tracked by conventional reading charts, three eyes reached and maintained improved acuities of 10-15 letters, equivalent to two- to three-line improvement on standard Snellen acuity charts. A surgically related choroidal detachment in one eye resulted in a transient acuity decrease that resolved with conservative management. This Phase I trial indicated that CNTF is safe for the human retina even with severely compromised photoreceptors. The approach to delivering therapeutic proteins to degenerating retinas using encapsulated cell implants may have application beyond disease caused by genetic mutations.

  11. An Assessment of Molten Metal Detachment Hazards for Electron Beam Welding in the Space Environment: Analysis and Test Results

    NASA Technical Reports Server (NTRS)

    Nunes, A. C., Jr.; Russell, C.; Bhat, B.; Fragomeni, J. M.

    1998-01-01

    Conditions under which molten metal detachments might occur in a space welding environment are analyzed. A weld pool detachment parameter specifying conditions for pool detachment by impact is derived and corroborated by experimental evidence. Impact detachment for the pool is unlikely. Impact detachment for a drop of metal on the end of the weld wire may be possible under extreme conditions. Other potential causes of molten metal detachment considered, vaporization pressure forces and wire flickout from the pool, did not appear to present significant detachment threats.

  12. Non-responsiveness to intravitreal aflibercept treatment in neovascular age-related macular degeneration: implications of serous pigment epithelial detachment

    PubMed Central

    Nagai, Norihiro; Suzuki, Misa; Uchida, Atsuro; Kurihara, Toshihide; Kamoshita, Mamoru; Minami, Sakiko; Shinoda, Hajime; Tsubota, Kazuo; Ozawa, Yoko

    2016-01-01

    The prognosis of neovascular age-related macular degeneration (AMD) has been improved by anti-vascular endothelial growth factor treatments, including intravitreal aflibercept (IVA) treatment. However, many patients remain incurable. In this study, we retrospectively evaluated non-responsiveness to IVA monotherapy at 12 months in 133 eyes of 133 AMD patients. Sixty-two patients were initially treatment-naive, and 71 had received other treatments before IVA (the treatment-switched group). Mean best-corrected visual acuity (BCVA) was improved in the treatment-naive group but not in the treatment-switched group, although mean central retinal thickness (CRT) decreased in both groups. The respective percentages of non-responders as determined by worsened BCVA in the treatment-naive and treatment-switched groups were 8.1% and 15.5%, and via fundus findings, they were 12.9% and 8.5%. Multivariate analyses adjusted for age, gender, CRT, and greatest linear dimension showed that serous pigment epithelial detachment (PED) at baseline was associated with non-responsiveness in both groups as determined by BCVA and by fundus findings, and fibrovascular PED measurements indicated no response as determined by fundus findings in the treatment-switched group. The results reported herein may assist the formulation of appropriate treatment protocols for AMD patients. PMID:27403807

  13. Amyloidosis in Retinal Neurodegenerative Diseases.

    PubMed

    Masuzzo, Ambra; Dinet, Virginie; Cavanagh, Chelsea; Mascarelli, Frederic; Krantic, Slavica

    2016-01-01

    As a part of the central nervous system, the retina may reflect both physiological processes and abnormalities related to pathologies that affect the brain. Amyloidosis due to the accumulation of amyloid-beta (Aβ) was initially regarded as a specific and exclusive characteristic of neurodegenerative alterations seen in the brain of Alzheimer's disease (AD) patients. More recently, it was discovered that amyloidosis-related alterations, similar to those seen in the brain of Alzheimer's patients, also occur in the retina. Remarkably, these alterations were identified not only in primary retinal pathologies, such as age-related macular degeneration (AMD) and glaucoma, but also in the retinas of Alzheimer's patients. In this review, we first briefly discuss the biogenesis of Aβ, a peptide involved in amyloidosis. We then discuss some pathological aspects (synaptic dysfunction, mitochondrial failure, glial activation, and vascular abnormalities) related to the neurotoxic effects of Aβ. We finally highlight common features shared by AD, AMD, and glaucoma in the context of Aβ amyloidosis and further discuss why the retina, due to the transparency of the eye, can be considered as a "window" to the brain. PMID:27551275

  14. Amyloidosis in Retinal Neurodegenerative Diseases

    PubMed Central

    Masuzzo, Ambra; Dinet, Virginie; Cavanagh, Chelsea; Mascarelli, Frederic; Krantic, Slavica

    2016-01-01

    As a part of the central nervous system, the retina may reflect both physiological processes and abnormalities related to pathologies that affect the brain. Amyloidosis due to the accumulation of amyloid-beta (Aβ) was initially regarded as a specific and exclusive characteristic of neurodegenerative alterations seen in the brain of Alzheimer’s disease (AD) patients. More recently, it was discovered that amyloidosis-related alterations, similar to those seen in the brain of Alzheimer’s patients, also occur in the retina. Remarkably, these alterations were identified not only in primary retinal pathologies, such as age-related macular degeneration (AMD) and glaucoma, but also in the retinas of Alzheimer’s patients. In this review, we first briefly discuss the biogenesis of Aβ, a peptide involved in amyloidosis. We then discuss some pathological aspects (synaptic dysfunction, mitochondrial failure, glial activation, and vascular abnormalities) related to the neurotoxic effects of Aβ. We finally highlight common features shared by AD, AMD, and glaucoma in the context of Aβ amyloidosis and further discuss why the retina, due to the transparency of the eye, can be considered as a “window” to the brain. PMID:27551275

  15. Multi-MHz retinal OCT

    PubMed Central

    Klein, Thomas; Wieser, Wolfgang; Reznicek, Lukas; Neubauer, Aljoscha; Kampik, Anselm; Huber, Robert

    2013-01-01

    We analyze the benefits and problems of in vivo optical coherence tomography (OCT) imaging of the human retina at A-scan rates in excess of 1 MHz, using a 1050 nm Fourier-domain mode-locked (FDML) laser. Different scanning strategies enabled by MHz OCT line rates are investigated, and a simple multi-volume data processing approach is presented. In-vivo OCT of the human ocular fundus is performed at different axial scan rates of up to 6.7 MHz. High quality non-mydriatic retinal imaging over an ultra-wide field is achieved by a combination of several key improvements compared to previous setups. For the FDML laser, long coherence lengths and 72 nm wavelength tuning range are achieved using a chirped fiber Bragg grating in a laser cavity at 419.1 kHz fundamental tuning rate. Very large data sets can be acquired with sustained data transfer from the data acquisition card to host computer memory, enabling high-quality averaging of many frames and of multiple aligned data sets. Three imaging modes are investigated: Alignment and averaging of 24 data sets at 1.68 MHz axial line rate, ultra-dense transverse sampling at 3.35 MHz line rate, and dual-beam imaging with two laser spots on the retina at an effective line rate of 6.7 MHz. PMID:24156052

  16. Intrinsically photosensitive retinal ganglion cells.

    PubMed

    Do, Michael Tri Hoang; Yau, King-Wai

    2010-10-01

    Life on earth is subject to alternating cycles of day and night imposed by the rotation of the earth. Consequently, living things have evolved photodetective systems to synchronize their physiology and behavior with the external light-dark cycle. This form of photodetection is unlike the familiar "image vision," in that the basic information is light or darkness over time, independent of spatial patterns. "Nonimage" vision is probably far more ancient than image vision and is widespread in living species. For mammals, it has long been assumed that the photoreceptors for nonimage vision are also the textbook rods and cones. However, recent years have witnessed the discovery of a small population of retinal ganglion cells in the mammalian eye that express a unique visual pigment called melanopsin. These ganglion cells are intrinsically photosensitive and drive a variety of nonimage visual functions. In addition to being photoreceptors themselves, they also constitute the major conduit for rod and cone signals to the brain for nonimage visual functions such as circadian photoentrainment and the pupillary light reflex. Here we review what is known about these novel mammalian photoreceptors. PMID:20959623

  17. Retinal imaging with virtual reality stimulus for studying Salticidae retinas

    NASA Astrophysics Data System (ADS)

    Schiesser, Eric; Canavesi, Cristina; Long, Skye; Jakob, Elizabeth; Rolland, Jannick P.

    2014-12-01

    We present a 3-path optical system for studying the retinal movement of jumping spiders: a visible OLED virtual reality system presents stimulus, while NIR illumination and imaging systems observe retinal movement.

  18. Preclinical Models to Investigate Retinal Ischemia: Advances and Drawbacks

    PubMed Central

    Minhas, Gillipsie; Morishita, Ryuichi; Anand, Akshay

    2012-01-01

    Retinal ischemia is a major cause of blindness worldwide. It is associated with various disorders such as diabetic retinopathy, glaucoma, optic neuropathies, stroke, and other retinopathies. Retinal ischemia is a clinical condition that occurs due to lack of appropriate supply of blood to the retina. As the retina has a higher metabolic demand, any hindrance in the blood supply to it can lead to decreased supply of oxygen, thus causing retinal ischemia. The pathology of retinal ischemia is still not clearly known. To get a better insight into the pathophysiology of retinal ischemia, the role of animal models is indispensable. The standard treatment care for retinal ischemia has limited potential. Transplantation of stem cells provide neuroprotection and to replenish damaged cells is an emerging therapeutic approach to treat retinal ischemia. In this review we provide an overview of major animal models of retinal ischemia along with the current and preclinical treatments in use. PMID:22593752

  19. Retinal Conformation Changes Rhodopsin's Dynamic Ensemble.

    PubMed

    Leioatts, Nicholas; Romo, Tod D; Danial, Shairy Azmy; Grossfield, Alan

    2015-08-01

    G protein-coupled receptors are vital membrane proteins that allosterically transduce biomolecular signals across the cell membrane. However, the process by which ligand binding induces protein conformation changes is not well understood biophysically. Rhodopsin, the mammalian dim-light receptor, is a unique test case for understanding these processes because of its switch-like activity; the ligand, retinal, is bound throughout the activation cycle, switching from inverse agonist to agonist after absorbing a photon. By contrast, the ligand-free opsin is outside the activation cycle and may behave differently. We find that retinal influences rhodopsin dynamics using an ensemble of all-atom molecular dynamics simulations that in aggregate contain 100 μs of sampling. Active retinal destabilizes the inactive state of the receptor, whereas the active ensemble was more structurally homogenous. By contrast, simulations of an active-like receptor without retinal present were much more heterogeneous than those containing retinal. These results suggest allosteric processes are more complicated than a ligand inducing protein conformational changes or simply capturing a shifted ensemble as outlined in classic models of allostery.

  20. Dynamics of retinal photocoagulation and rupture

    NASA Astrophysics Data System (ADS)

    Sramek, Christopher; Paulus, Yannis; Nomoto, Hiroyuki; Huie, Phil; Brown, Jefferson; Palanker, Daniel

    2009-05-01

    In laser retinal photocoagulation, short (<20 ms) pulses have been found to reduce thermal damage to the inner retina, decrease treatment time, and minimize pain. However, the safe therapeutic window (defined as the ratio of power for producing a rupture to that of mild coagulation) decreases with shorter exposures. To quantify the extent of retinal heating and maximize the therapeutic window, a computational model of millisecond retinal photocoagulation and rupture was developed. Optical attenuation of 532-nm laser light in ocular tissues was measured, including retinal pigment epithelial (RPE) pigmentation and cell-size variability. Threshold powers for vaporization and RPE damage were measured with pulse durations ranging from 1 to 200 ms. A finite element model of retinal heating inferred that vaporization (rupture) takes place at 180-190°C. RPE damage was accurately described by the Arrhenius model with activation energy of 340 kJ/mol. Computed photocoagulation lesion width increased logarithmically with pulse duration, in agreement with histological findings. The model will allow for the optimization of beam parameters to increase the width of the therapeutic window for short exposures.

  1. Advances in retinal ganglion cell imaging

    PubMed Central

    Balendra, S I; Normando, E M; Bloom, P A; Cordeiro, M F

    2015-01-01

    Glaucoma is one of the leading causes of blindness worldwide and will affect 79.6 million people worldwide by 2020. It is caused by the progressive loss of retinal ganglion cells (RGCs), predominantly via apoptosis, within the retinal nerve fibre layer and the corresponding loss of axons of the optic nerve head. One of its most devastating features is its late diagnosis and the resulting irreversible visual loss that is often predictable. Current diagnostic tools require significant RGC or functional visual field loss before the threshold for detection of glaucoma may be reached. To propel the efficacy of therapeutics in glaucoma, an earlier diagnostic tool is required. Recent advances in retinal imaging, including optical coherence tomography, confocal scanning laser ophthalmoscopy, and adaptive optics, have propelled both glaucoma research and clinical diagnostics and therapeutics. However, an ideal imaging technique to diagnose and monitor glaucoma would image RGCs non-invasively with high specificity and sensitivity in vivo. It may confirm the presence of healthy RGCs, such as in transgenic models or retrograde labelling, or detect subtle changes in the number of unhealthy or apoptotic RGCs, such as detection of apoptosing retinal cells (DARC). Although many of these advances have not yet been introduced to the clinical arena, their successes in animal studies are enthralling. This review will illustrate the challenges of imaging RGCs, the main retinal imaging modalities, the in vivo techniques to augment these as specific RGC-imaging tools and their potential for translation to the glaucoma clinic. PMID:26293138

  2. Protocadherin-17 Function in Zebrafish Retinal Development

    PubMed Central

    Chen, Yun; Londraville, Richard; Brickner, Sarah; El-Shaar, Lana; Fankhauser, Kelsee; Dearth, Cassandra; Fulton, Leah; Sochacka, Alicja; Bhattarai, Sunil; Marrs, James A.; Liu, Qin

    2012-01-01

    Cadherin cell adhesion molecules play crucial roles in vertebrate development including the development of the retina. Most studies have focused on examining functions of classic cadherins (e.g. N-cadherin) in retinal development. There is little information on the function of protocadherins in the development of the vertebrate visual system. We previously showed that protocadherin-17 mRNA was expressed in developing zebrafish retina during critical stages of the retinal development. To gain insight into protocadherin-17 function in the formation of the retina, we analyzed eye development and differentiation of retinal cells in zebrafish embryos injected with protocadherin-17 specific antisense morpholino oligonucleotides (MOs). Protocadherin-17 knockdown embryos (pcdh17 morphants) had significantly reduced eyes due mainly to decreased cell proliferation. Differentiation of several retinal cell types (e.g. retinal ganglion cells) was also disrupted in the pcdh17 morphants. Phenotypic rescue was achieved by injection of protocadherin-17 mRNA. Injection of a vivo-protocadherin-17 MO into one eye of embryonic zebrafish resulted in similar eye defects. Our results suggest that protocadherin-17 plays an important role in the normal formation of the zebrafish retina. PMID:22927092

  3. [Genetic diagnostic testing in inherited retinal dystrophies].

    PubMed

    Kohl, S; Biskup, S

    2013-03-01

    Inherited retinal dystrophies are clinically and genetically highly heterogeneous. They can be divided according to the clinical phenotype and course of the disease, as well as the underlying mode of inheritance. Isolated retinal dystrophies (i.e., retinitis pigmentosa, Leber's congenital amaurosis, cone and cone-rod dystrophy, macular dystrophy, achromatopsia, congenital stationary nightblindness) and syndromal forms (i.e., Usher syndrome, Bardet-Biedl syndrome) can be differentiated. To date almost 180 genes and thousands of distinct mutations have been identified that are responsible for the different forms of these blinding illnesses. Until recently, there was no adequate diagnostic genetic testing available. With the development of the next generation sequencing technologies, a comprehensive genetic screening analysis for all known genes for inherited retinal dystrophies has been established at reasonable costs and in appropriate turn-around times. Depending on the primary clinical diagnosis and the presumed mode of inheritance, different diagnostic panels can be chosen for genetic testing. Statistics show that in 55-80 % of the cases the genetic defect of the inherited retinal dystrophy can be identified with this approach, depending on the initial clinical diagnosis. The aim of any genetic diagnostics is to define the genetic cause of a given illness within the affected patient and family and thereby i) confirm the clinical diagnosis, ii) provide targeted genetic testing in family members, iii) enable therapeutic intervention, iv) give a prognosis on disease course and progression and v) in the long run provide the basis for novel therapeutic approaches and personalised medicine.

  4. Electron detachment from negative ions in a short laser pulse

    NASA Astrophysics Data System (ADS)

    Shearer, S. F. C.; Smyth, M. C.; Gribakin, G. F.

    2011-09-01

    We present an efficient and accurate method to study electron detachment from negative ions by a few-cycle linearly polarized laser pulse. The adiabatic saddle-point method of Gribakin and Kuchiev [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.55.3760 55, 3760 (1997)] is adapted to calculate the transition amplitude for a short laser pulse. Its application to a pulse with N optical cycles produces 2(N+1) saddle points in complex time, which form a characteristic “smile.” Numerical calculations are performed for H- in a 5-cycle pulse with frequency 0.0043 a.u. and intensities of 1010, 5×1010, and 1011 W/cm2, and for various carrier-envelope phases. We determine the spectrum of the photoelectrons as a function of both energy and emission angle, as well as the angle-integrated energy spectra and total detachment probabilities. Our calculations show that the dominant contribution to the transition amplitude is given by 5-6 central saddle points, which correspond to the strongest part of the pulse. We examine the dependence of the photoelectron angular distributions on the carrier-envelope phase and show that measuring such distributions can provide a way of determining this phase.

  5. Electron detachment from negative ions in a short laser pulse

    SciTech Connect

    Shearer, S. F. C.; Smyth, M. C.; Gribakin, G. F.

    2011-09-15

    We present an efficient and accurate method to study electron detachment from negative ions by a few-cycle linearly polarized laser pulse. The adiabatic saddle-point method of Gribakin and Kuchiev [Phys. Rev. A 55, 3760 (1997)] is adapted to calculate the transition amplitude for a short laser pulse. Its application to a pulse with N optical cycles produces 2(N+1) saddle points in complex time, which form a characteristic 'smile.' Numerical calculations are performed for H{sup -} in a 5-cycle pulse with frequency 0.0043 a.u. and intensities of 10{sup 10}, 5x10{sup 10}, and 10{sup 11} W/cm{sup 2}, and for various carrier-envelope phases. We determine the spectrum of the photoelectrons as a function of both energy and emission angle, as well as the angle-integrated energy spectra and total detachment probabilities. Our calculations show that the dominant contribution to the transition amplitude is given by 5-6 central saddle points, which correspond to the strongest part of the pulse. We examine the dependence of the photoelectron angular distributions on the carrier-envelope phase and show that measuring such distributions can provide a way of determining this phase.

  6. Plasma Detachment Studies in the VASIMR Magnetic Nozzle

    NASA Astrophysics Data System (ADS)

    Tarditi, Alfonso G.; Shebalin, John

    2004-11-01

    Two important issues related to the VASIMR (Variable Specific Impulse Magnetoplasma Rocket, [1]) experiment are the plasma detachment and the collimation of the plume in the magnetic nozzle. These issues are being investigated both through theory/simulation studies and now also experimentally. A 3D, nonlinear MHD/2-fluid model of the magnetic nozzle has been implemented with the NIMROD code. The model has been run both with the actual VASIMR geometry and for an ideal De Laval nozzle configuration. The simulations indicate a distortion of the external field due to the plasma exhaust flow (carrying an azimuthal diamagnetic current) that may to lead to plasma detachment through the formation of magnetic islands. This is also being investigated experimentally. A Hall-effect, one-axis, gaussmeter has shown the local low-frequency magnetic field fluctuations during a plasma pulse. A 2D array of 3-axis "B-dot" probes is being developed for a fast mapping of the field perturbations in the nozzle (on the order of the Alfven time). Finally, a Rogowski coil probe is being designed to measure the azimuthal current profile in the exhaust plasma. [1] F. R. Chang-Diaz et al, Scientific American, p. 90, Nov. 2000

  7. X-ray Characterization of Detached-Grown Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Schweizer, M.; Raghothamachar, B.; Dudley, M.; Szoke, J.; Cobb, S. D.; Szofran, F. R.

    2005-01-01

    Germanium (111)-oriented crystals have been grown by the vertical Bridgman technique, in both detached and attached configurations. Microstructural characterization of these crystals has been performed using synchrotron white beam x-ray topography (SWBXT) and double axis x-ray diffraction. Dislocation densities were measured from x-ray topographs obtained using the reflection geometry. For detached-grown crystals, the dislocation density is 4-6 x 10(exp 4) per square centimeter in the seed region, and decreases in the direction of growth to less than 10(exp 3) per square centimeter, and in some crystals reaches less than 10(exp 2) per square centimeter. For crystals grown in the attached configuration, dislocation densities were on the order of 10(exp 4) per square centimeter in the middle of the crystals, increasing to greater than 10(exp 5) per square centimeter near the edge. The measured dislocation densities are in excellent agreement with etch pit density results. The rocking curve linewidths were relatively insensitive to the dislocation densities. However, broadening and splitting of the rocking curves were observed in the vicinity of subgrain boundaries identified by x-ray topography in some of the attached-grown crystals.

  8. Predictive Computer Models for Biofilm Detachment Properties in Pseudomonas aeruginosa

    PubMed Central

    Cogan, Nick G.; Harro, Janette M.; Stoodley, Paul

    2016-01-01

    ABSTRACT Microbial biofilm communities are protected against environmental extremes or clearance by antimicrobial agents or the host immune response. They also serve as a site from which microbial populations search for new niches by dispersion via single planktonic cells or by detachment by protected biofilm aggregates that, until recently, were thought to become single cells ready for attachment. Mathematically modeling these events has provided investigators with testable hypotheses for further study. Such was the case in the recent article by Kragh et al. (K. N. Kragh, J. B. Hutchison, G. Melaugh, C. Rodesney, A. E. Roberts, Y. Irie, P. Ø. Jensen, S. P. Diggle, R. J. Allen, V. Gordon, and T. Bjarnsholt, mBio 7:e00237-16, 2016, http://dx.doi.org/10.1128/mBio.00237-16), in which investigators were able to identify the differential competitive advantage of biofilm aggregates to directly attach to surfaces compared to the single-celled planktonic populations. Therefore, as we delve deeper into the properties of the biofilm mode of growth, not only do we need to understand the complexity of biofilms, but we must also account for the properties of the dispersed and detached populations and their effect on reseeding. PMID:27302761

  9. Effects of crop canopies on rain splash detachment.

    PubMed

    Ma, Bo; Yu, Xiaoling; Ma, Fan; Li, Zhanbin; Wu, Faqi

    2014-01-01

    Crops are one of the main factors affecting soil erosion in sloping fields. To determine the characteristics of splash erosion under crop canopies, corn, soybean, millet, and winter wheat were collected, and the relationship among splash erosion, rainfall intensity, and throughfall intensity under different crop canopies was analyzed through artificial rainfall experiments. The results showed that, the mean splash detachment rate on the ground surface was 390.12 g/m2 · h, which was lower by 67.81% than that on bare land. The inhibiting effects of crops on splash erosion increased as the crops grew, and the ability of the four crops to inhibit splash erosion was in the order of winter wheat>corn>soybeans>millet. An increase in rainfall intensity could significantly enhance the occurrence of splash erosion, but the ability of crops to inhibit splash erosion was 13% greater in cases of higher rainfall intensity. The throughfall intensity under crop canopies was positively related to the splash detachment rate, and this relationship was more significant when the rainfall intensity was 40 mm/h. Splash erosion tended to occur intensively in the central row of croplands as the crop grew, and the non-uniformity of splash erosion was substantial, with splash erosion occurring mainly between the rows and in the region directly under the leaf margin. This study has provided a theoretical basis for describing the erosion mechanisms of cropland and for assisting soil erosion prediction as well as irrigation and fertilizer management in cultivated fields.

  10. Electric Field Effect on Bubble Detachment in Variable Gravity Environment

    NASA Technical Reports Server (NTRS)

    Iacona, Estelle; Herman, Cila; Chang, Shinan

    2003-01-01

    The subject of the present study, the process of bubble detachment from an orifice in a plane surface, shows some resemblance to bubble departure in boiling. Because of the high heat transfer coefficients associated with phase change processes, boiling is utilized in many industrial operations and is an attractive solution to cooling problems in aerospace engineering. In terrestrial conditions, buoyancy is responsible for bubble removal from the surface. In space, the gravity level being orders of magnitude smaller than on earth, bubbles formed during boiling remain attached at the surface. As a result, the amount of heat removed from the heated surface can decrease considerably. The use of electric fields is proposed to control bubble behavior and help bubble removal from the surface on which they form. The objective of the study is to investigate the behavior of individual air bubbles injected through an orifice into an electrically insulating liquid under the influence of a static electric field. Bubble cycle life were visualized in terrestrial conditions and for several reduced gravity levels. Bubble volume, dimensions and contact angle at detachment were measured and analyzed for different parameters as gravity level and electric field magnitude. Situations were considered with uniform or non-uni form electric field. Results show that these parameters significantly affect bubble behavior, shape, volume and dimensions.

  11. Amitraz: a tick and flea repellent and tick detachment drug.

    PubMed

    Folz, S D; Ash, K A; Conder, G A; Rector, D L

    1986-06-01

    A topical formulation of amitraz (Mitaban Liquid Concentrate, The Upjohn Company, Kalamazoo, Michigan, U.S.A.) was evaluated as a tick repellent and detachment agent, and flea repellent. The diluted liquid concentrate (250 p.p.m. active drug) was topically applied as a single treatment to dogs; the concentration was identical to the rate recommended for treatment of demodicosis and scabies. Brown dog tick (Rhipicephalus sanguineus) and American dog tick (Dermacentor variabilis) populations were eliminated and repelled. Repellent activity (92-95%) was observed against R. sanguineus for 2 weeks post-treatment; the treatment was moderately active (63%) during the third week, and at 4 weeks post-treatment the drug was inactive. Established R. sanguineus populations were also treated, and the diluted liquid concentrate had 100% tick-detachment efficacy. Repellent activity (99%) was also detected against D. variabilis; the activity was monitored for only 7 days. The ectoparasiticide had low to moderate flea (Ctenocephalides felis) repellent activity (42%) for 4 days post-treatment; thereafter the treatment was ineffective. Side-effects were not observed in any of the dogs treated with amitraz, or the placebo.

  12. Predictive Computer Models for Biofilm Detachment Properties in Pseudomonas aeruginosa.

    PubMed

    Cogan, Nick G; Harro, Janette M; Stoodley, Paul; Shirtliff, Mark E

    2016-01-01

    Microbial biofilm communities are protected against environmental extremes or clearance by antimicrobial agents or the host immune response. They also serve as a site from which microbial populations search for new niches by dispersion via single planktonic cells or by detachment by protected biofilm aggregates that, until recently, were thought to become single cells ready for attachment. Mathematically modeling these events has provided investigators with testable hypotheses for further study. Such was the case in the recent article by Kragh et al. (K. N. Kragh, J. B. Hutchison, G. Melaugh, C. Rodesney, A. E. Roberts, Y. Irie, P. Ø. Jensen, S. P. Diggle, R. J. Allen, V. Gordon, and T. Bjarnsholt, mBio 7:e00237-16, 2016, http://dx.doi.org/10.1128/mBio.00237-16), in which investigators were able to identify the differential competitive advantage of biofilm aggregates to directly attach to surfaces compared to the single-celled planktonic populations. Therefore, as we delve deeper into the properties of the biofilm mode of growth, not only do we need to understand the complexity of biofilms, but we must also account for the properties of the dispersed and detached populations and their effect on reseeding. PMID:27302761

  13. Aerosols optical properties in Titan's Detached Haze Layer

    NASA Astrophysics Data System (ADS)

    Seignovert, Benoit; Rannou, Pascal; Lavvas, Panayotis; West, Robert

    2016-10-01

    Titan's Detached Haze Layer (DHL) was first observed in 1983 by Rages and Pollack during the Voyager 2 is a consistent spherical haze feature surrounding Titan's upper atmosphere and detached from the main haze. Since 2005, the Imaging Science Subsystem (ISS) instrument on board the Cassini mission performs a continuous survey of the Titan's atmosphere and confirmed its persistence at 500 km up to the equinox (2009) before its drop and disappearance in 2012 (West et al. 2011). Previous analyses showed, that this layer corresponds to the transition area between small spherical aerosols and large fractal aggregates and play a key role in the aerosols formation in Titan's atmosphere (Rannou et al. 2000, Lavvas et al. 2009, Cours et al. 2011).In this talk we will present the UV photometric analyses based on radiative transfer inversion to retrieve aerosols particles properties in the DHL (bulk and monomer radius and local density) performed on ISS observations taken from 2005 to 2007.References:- Rages and Pollach, Icarus 55 (1983)- West, et al., Icarus 38 (2011)- Rannou, et al., Icarus 147 (2000)- Lavvas, et al., Icarus 201 (2009)- Cours, et al., ApJ Lett. 741 (2015)

  14. Recognizing detachment-mode seafloor spreading in the deep geological past.

    PubMed

    Maffione, Marco; Morris, Antony; Anderson, Mark W

    2013-01-01

    Large-offset oceanic detachment faults are a characteristic of slow- and ultraslow-spreading ridges, leading to the formation of oceanic core complexes (OCCs) that expose upper mantle and lower crustal rocks on the seafloor. The lithospheric extension accommodated by these structures is now recognized as a fundamentally distinct "detachment-mode" of seafloor spreading compared to classical magmatic accretion. Here we demonstrate a paleomagnetic methodology that allows unequivocal recognition of detachment-mode seafloor spreading in ancient ophiolites and apply this to a potential Jurassic detachment fault system in the Mirdita ophiolite (Albania). We show that footwall and hanging wall blocks either side of an inferred detachment have significantly different magnetizations that can only be explained by relative rotation during seafloor spreading. The style of rotation is shown to be identical to rolling hinge footwall rotation documented recently in OCCs in the Atlantic, confirming that detachment-mode spreading operated at least as far back as the Jurassic.

  15. Recognizing detachment-mode seafloor spreading in the deep geological past.

    PubMed

    Maffione, Marco; Morris, Antony; Anderson, Mark W

    2013-01-01

    Large-offset oceanic detachment faults are a characteristic of slow- and ultraslow-spreading ridges, leading to the formation of oceanic core complexes (OCCs) that expose upper mantle and lower crustal rocks on the seafloor. The lithospheric extension accommodated by these structures is now recognized as a fundamentally distinct "detachment-mode" of seafloor spreading compared to classical magmatic accretion. Here we demonstrate a paleomagnetic methodology that allows unequivocal recognition of detachment-mode seafloor spreading in ancient ophiolites and apply this to a potential Jurassic detachment fault system in the Mirdita ophiolite (Albania). We show that footwall and hanging wall blocks either side of an inferred detachment have significantly different magnetizations that can only be explained by relative rotation during seafloor spreading. The style of rotation is shown to be identical to rolling hinge footwall rotation documented recently in OCCs in the Atlantic, confirming that detachment-mode spreading operated at least as far back as the Jurassic. PMID:23903780

  16. Recognizing detachment-mode seafloor spreading in the deep geological past

    PubMed Central

    Maffione, Marco; Morris, Antony; Anderson, Mark W.

    2013-01-01

    Large-offset oceanic detachment faults are a characteristic of slow- and ultraslow-spreading ridges, leading to the formation of oceanic core complexes (OCCs) that expose upper mantle and lower crustal rocks on the seafloor. The lithospheric extension accommodated by these structures is now recognized as a fundamentally distinct “detachment-mode” of seafloor spreading compared to classical magmatic accretion. Here we demonstrate a paleomagnetic methodology that allows unequivocal recognition of detachment-mode seafloor spreading in ancient ophiolites and apply this to a potential Jurassic detachment fault system in the Mirdita ophiolite (Albania). We show that footwall and hanging wall blocks either side of an inferred detachment have significantly different magnetizations that can only be explained by relative rotation during seafloor spreading. The style of rotation is shown to be identical to rolling hinge footwall rotation documented recently in OCCs in the Atlantic, confirming that detachment-mode spreading operated at least as far back as the Jurassic. PMID:23903780

  17. Detachment and steep normal faulting in Atlantic oceanic crust west of Africa

    USGS Publications Warehouse

    Reston, T.J.; Ruoff, O.; McBride, J.H.; Ranero, C.R.; White, Robert S.

    1996-01-01

    Improved images of the internal structure of Early Cretaceous North Atlantic crust reveal both probable detachment faults and more steeply dipping normal faults. The detachment faults occur as subhorizontal structures passing ???1.5 km beneath fault blocks without offset; several steeper block-bounding faults appear to detach onto these structures. However, the detachments are bounded to the west (ridgeward) by presumably younger, more steeply west-dipping normal faults. In one possible interpretation, the detachment and the steep faults belong to the same "rolling-hinge" extension system. An intriguing alternative is that a phase of detachment faulting, perhaps related to increased magmatic activity, was succeeded by localized amagmatic extension along steeper and more deeply penetrating faults.

  18. The influence of the radial particle transport on the divertor plasma detachment

    NASA Astrophysics Data System (ADS)

    Hoshino, K.; Shimizu, K.; Takizuka, T.; Asakura, N.; Nakano, T.

    2015-08-01

    Divertor plasma detachment is the most promising candidate to reduce the divertor heat load in fusion reactors. Present understanding of detachment physics is not sufficient to adequately reproduce experimental observations. Understanding and control of detachment physics is indispensable to design the divertor in future machines. To improve the quality of divertor modeling and reveal limitations of the detachment physics built into state-of-the-art codes, an integrated divertor code SONIC has been applied to modeling of the JT-60U detached divertor plasma. In this study, the radial diffusion coefficient in the private region or the far SOL region is increased to investigate the influence of radial plasma transport on detachment characteristics. Saturation of the reduction in ion flux after roll-over is improved by the radial transport enhancement, while the radial profile at the mid-plane agreed with the experimental data.

  19. Experimental study of a fiber optically guided CO2 laser probe for intraocular surgery: measurement of the immediate retinal adhesion force

    NASA Astrophysics Data System (ADS)

    DeRowe, Ari; Bartov, Elisha; Triester, G.; Belkin, Michael; Katzir, Abraham

    1992-08-01

    Using an experimental fiberoptically guided CO2 laser system, we performed lesions on fresh bovine retinas. These lesions were shown to achieve measurable immediate chorioretinal adhesion. This model implies the feasibility of utilizing a fiberoptic CO2 laser probe in intraocular surgery for retinal detachment. The advantages of using CO2 laser energy are minimal damage surrounding the desired lesion and its versatility as a coagulator and cutter. With further research we believe that the technical problem of delivery can be solved. The CO2 endolaser holds promise for intraocular surgery.

  20. Enzymatic Detachment of Therapeutic Mesenchymal Stromal Cells Grown on Glass Carriers in a Bioreactor

    PubMed Central

    Salzig, Denise; Schmiermund, Alexandra; P. Grace, Pablo; Elseberg, Christiane; Weber, Christian; Czermak, Peter

    2013-01-01

    Cell therapies require the in vitro expansion of adherent cells such as mesenchymal stromal cells (hMSCs) in bioreactor systems or other culture environments, followed by cell harvest. As hMSCs are strictly adherent cells, cell harvest requires cell detachment. The use of hMSCs for cell therapy requires GMP production in accordance with the guidelines for advanced therapeutic medical products. Therefore, several GMP-conform available proteolytic enzymes were investigated for their ability to promote hMSC detachment. An allogeneic hMSC cell line (hMSC-TERT) that is used in clinical trials in the form of alginate cell capsules was chosen as a model. This study investigated the influence of several factors on the outcome of proteolytic hMSC-TERT detachment. Therefore, hMSC-TERT detachment was analyzed in different cultivation systems (static, dynamic) and in combination with further cell processing including encapsulation. Only two of the commercially available enzymes (AccutaseTM, TrypZeanTM) that fulfill all process requirements (commercial availability, cost, GMP conditions during manufacturing and non-animal origin) are found to be generally suitable for detaching hMSC-TERT. Combining cell detachment with encapsulation demonstrated a high impact of the experimental set up on cell damage. It was preferable to reduce the temperature during detachment and limit the detachment time to a maximum of 20 minutes. Cell detachment in static systems was not comparable with detachment in dynamic systems. Detachment yields in dynamic systems were lower and cell damage was higher for the same experimental conditions. Finally, only TrypZeanTM seemed to be suitable for the detachment of hMSC-TERT from dynamic reactor systems. PMID:24478807