To develop an automated retina layer thickness measurement tool for the ImageJ platform, to quantitate nuclear layers following the retina contour. We developed the ThicknessTool (TT), an automated thickness measurement plugin for the ImageJ platform. To calibrate TT, we created a calibration dataset of mock binary skeletonized mask images with increasing thickness masks and different rotations. Following, we created a training dataset and performed an agreement analysis of thickness measurements between TT and two masked manual observers. Finally, we tested the performance of TT measurements in a validation dataset of retinal detachment images. In the calibration dataset, there were no differences in layer thickness between measured and known thickness masks, with an overall coefficient of variation of 0.00%. Training dataset measurements of immunofluorescence retina nuclear layers disclosed no significant differences between TT and any observer's average outer nuclear layer (ONL) (p = 0.998), inner nuclear layer (INL) (p = 0.807), and ONL/INL ratio (p = 0.944) measurements. Agreement analysis showed that bias between TT vs. observers' mean was lower than between any observers' mean against each other in the ONL (0.77 ± 0.34 µm vs 3.25 ± 0.33 µm) and INL (1.59 ± 0.28 µm vs 2.82 ± 0.36 µm). Validation dataset showed that TT can detect significant and true ONL thinning (p = 0.006), more sensitive than manual measurement capabilities (p = 0.069). ThicknessTool can measure retina nuclear layers thickness in a fast, accurate, and precise manner with multi-platform capabilities. In addition, the TT can be customized to user preferences and is freely available to download.
Dynamic modification of nuclear and cytoplasmic proteins with O-linked β-N-acetylglucosamine (O-GlcNAc) plays an important role in orchestrating the transcriptional activity of eukaryotic cells. Here, we report that the O-GlcNAc modification contributes to maintaining ocular surface epithelial homeostasis by promoting mucin biosynthesis and barrier function. We found that induction of human corneal epithelial cell differentiation stimulated the global transfer of O-GlcNAc to both nuclear and cytosolic proteins. Inflammatory conditions, on the other hand, were associated with a reduction in the expression of O-GlcNAc transferase at the ocular surface epithelia. Loss- and gain-of-function studies using small interfering RNA targeting O-GlcNAc transferase, or Thiamet G, a selective inhibitor of O-GlcNAc hydrolase, respectively, revealed that the presence of O-GlcNAc was necessary to promote glycocalyx barrier function. Moreover, we found that Thiamet G triggered a correlative increase in both surface expression of MUC16 and apical epithelial cell area while reducing paracellular permeability. Collectively, these results identify intracellular protein O-glycosylation as a novel pathway responsible for promoting the terminal differentiation of human corneal epithelial cells.
BACKGROUND: To prevent irreversible vision loss in age-related macular degeneration (AMD), it is critical to detect retinal dysfunction before permanent structural loss occurs. In the current study we evaluated a series of visual function tests to identify potential endpoints to detect visual dysfunction in non-advanced AMD. METHODS: A series of visual function tests were performed on 23 non-advanced AMD subjects (AREDS grade 1-4 on simplified scale) and 34 age-matched normals (AREDS grade 0). Tests included some commonly used endpoints such as ETDRS visual acuity (VA), low luminance (LL) 2.0ND ETDRS VA, MNREAD as well as newly developed tests such as the Ora-VCF™ test, Ora-tablet reading test, color sensitivity etc. Differences between the two groups were compared for each test. Test-retest repeatability and reproducibility was assessed on a subset of subjects and percent agreement was calculated. RESULTS: There was no difference in standard ETDRS VA between non-advanced AMD (0.06 ± 0.02 logMAR) and normal groups (0.04 ± 0.02 logMAR) (p = 0.57). LL 2.0 ETDRS VA and MNREAD showed no difference between the groups (p > 0.05). Ora-VCF™ test was significantly worse in the non-advanced AMD group compared to normals (0.67 ± 0.07 in AMD; 0.45 ± 0.04 in normals, p = 0.005). Non-advanced AMD subjects also had significantly worse reading performance using the Ora-tablet with LL 2.0ND (114.55 ± 11.22 wpm in AMD; 145.17 ± 9.55 wpm in normals p = 0.049). No significant difference between the groups was noted using other tests. Repeatability was 82% for Ora-VCF™ test and 92% for Ora-tablet LL 2.0ND reading. Reproducibility was 89% for both Ora-VCF™ test and Ora-tablet LL 2.0ND reading. CONCLUSION: While there was no significant difference between non-advanced AMD and normal groups using some current common endpoints such as ETDRS VA, LL 2.0 ETDRS VA or MNREAD, Ora-VCF™ test and Ora-tablet LL 2.0ND reading tests were able to identify significant visual dysfunction in non-advanced AMD subjects. These tests show promise as endpoints for AMD studies.
Age-related macular degeneration (AMD) is the most common cause of irreversible blindness and visual impairment in individuals over the age of 50 years in western societies. More than 25 million people currently suffer from this illness in the world, with an additional 500 000 every year, approximately. It is a multifactorial ocular disease that affects the maculae due to a late-onset progressive neurodegeneration and dysfunction of photoreceptors and retinal pigment epithelium (RPE). There are many subtypes of AMD but basically two broad forms: the nonneovascular (dry, nonexudative) and neovascular (wet, exudative). Exudative AMD is the less common form (about 15%) but tends to progress more rapidly. At the moment, wet AMD is treated primarily on the basis of anti-vascular endothelial growth factor (VEGF) agents, which have led to massive improvement in the prognosis of the disease since they were first introduced. This article focuses on the latest treatment approaches to neovascular AMD. An extensive literature review was performed in order to illustrate the effectiveness of current and future anti-VEGF agents as well as the landmark clinical studies that have been carried out to establish these drugs as a gold standard in the therapy of wet AMD.
On the occasion of being awarded the Prentice Medal, I was asked to summarize my translational journey. Here I describe the process of becoming a low-vision rehabilitation clinician and researcher, frustrated by the unavailability of effective treatments for some conditions. This led to decades of working to understand patients' needs and the complexities and subtleties of their visual systems and conditions. It was followed by many iterations of developing vision aids and the techniques needed to objectively evaluate their benefit. I specifically address one path: the invention and development of peripheral prisms to expand the visual fields of patients with homonymous hemianopia, leading to our latest multiperiscopic prism (mirror-based design) with its clear 45° field-of-view image shift.
: Overview of the evolving epidemiology of human immunodeficiency virus (HIV)-related ocular disease over time. : Narrative review. : HIV enhances susceptibility to opportunistic eye infections, has direct pathogenic effects, and places patients at risk of immune recovery inflammatory syndromes in previously infected eyes after starting highly-active antiretroviral therapy (HAART). Widespread availability of HAART has resulted in a decrease of infectious ocular conditions such as cytomegalovirus retinitis, toxoplasmic retinitis, squamous cell carcinoma of the conjunctiva, and microvascular retinopathy. However, large coexisting burdens of tuberculosis, herpesvirus infection and syphilis (among others) continue to contribute to the burden of ocular disease, especially in low-resource settings. Growing risks of cataract, retinopathy and retinal nerve fiber thinning can affect patients with chronic HIV on HAART; thought due to chronic inflammation and immune activation. : The changing epidemic of ocular disease in HIV-infected patients warrants close monitoring and identification of interventions that can help reduce the imminent burden of disease.
Corneal stiffness plays a critical role in shaping the cornea with respect to intraocular pressure and physical interventions. However, it remains difficult to measure the mechanical properties noninvasively. Here, we report the first measurement of shear modulus in human corneas in vivo using optical coherence elastography (OCE) based on surface elastic waves. In a pilot study of 12 healthy subjects aged between 25 and 67, the Rayleigh-wave speed was 7.86 ± 0.75 m/s, corresponding to a shear modulus of 72 ± 14 kPa. Our data reveal two unexpected trends: no correlation was found between the wave speed and IOP between 13-18 mmHg, and shear modulus decreases with age (- 0.32 ± 0.17 m/s per decade). We propose that shear stiffness is governed by the interfibrillar matrix, whereas tensile strength is dominated by collagen fibrils. Rayleigh-wave OCE may prove useful for clinical diagnosis, refractive surgeries, and treatment monitoring.
Purpose: This article describes the clinical and multimodal imaging characteristics of subthreshold exudative choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD). Methods: Among 3773 patients with AMD, 8 eyes (6 patients) were identified with the clinical phenotype of interest. Dilated fundus examinations, color fundus photography, fluorescein angiography (FA), indocyanine green angiography (ICGA), optical coherence tomography (OCT), and OCT angiography (OCTA) were performed. Results: OCT typically showed a moderately reflective irregular pigment epithelial detachment with overlying subretinal fluid (SRF). Traditional FA did not show leakage and ICGA showed no definitive neovascular network or hot spots. However, OCTA clearly demonstrated a CNV within the pigment epithelial detachment. The majority of our cases (7 of 8) did not receive antivascular endothelial growth factor (anti-VEGF) injections, and visual acuity remained stable over the available follow-up period of I to 10 years. Conclusions: CNV is often associated with SRF and vision loss in AMD, usually requiring frequent anti-VEGF injections. OCTA allowed us to better identify CNV not readily detected on FA and ICGA. Although some have suggested early clinical intervention with anti-VEGF injections in any case with fluid and confirmed CNV on OCTA, we describe a subset of AMD patients with SRF who may be better managed by observation. These cases may represent a more indolent, mature, and stable vascular network.
PURPOSE: To determine whether a quantitative approach to assessment of the severity of diabetic retinopathy (DR) lesions on ultrawide field (UWF) images can provide new parameters to predict progression to proliferative diabetic retinopathy (PDR). METHODS: One hundred forty six eyes from 73 participants with DR and 4 years of follow-up data were included in this post hoc analysis, which was based on a cohort of 100 diabetic patients enrolled in a previously published prospective, comparative study of UWF imaging at the Joslin Diabetes Center. Diabetic Retinopathy Severity Score level was determined at baseline and 4-year follow-up visits using mydriatic 7-standard field Early Treatment Diabetic Retinopathy Study (ETDRS) photographs. All individual DR lesions (hemorrhage [H], microaneurysm [ma], cotton wool spot [CWS], intraretinal microvascular abnormality [IRMA]) were manually segmented on stereographic projected UWF. For each lesion type, the frequency/number, surface area, and distances from the optic nerve head (ONH) were computed. These quantitative parameters were compared between eyes that progressed to PDR in 4 years and eyes that did not progress. Univariable and multivariable logistic regression analyses were performed to identify parameters that were associated with an increased risk for progression to PDR. RESULTS: A total of 146 eyes of 73 subjects were included in the final analysis. The mean age of the study cohort was 53.1 years, and 42 (56.8%) subjects were female. The number and surface area of H/ma's and CWSs were significantly (P ≤ .05) higher in eyes that progressed to PDR compared with eyes that did not progress by 4 years. Similarly, H/ma's and CWSs were located further away from the ONH (ie, more peripheral) in eyes that progressed (P < .05). DR lesion parameters that conferred a statistically significant increased risk for proliferative diabetic retinopathy in the multivariate model included hemorrhage area (odds ratio [OR], 2.63; 95% confidence interval [CI], 1.25-5.53), and greater distance of hemorrhages from the ONH (OR, 1.24; 95% CI, 0.97-1.59). CONCLUSIONS: Quantitative analysis of DR lesions on UWF images identifies new risk parameters for progression to PDR including the surface area of hemorrhages and the distance of hemorrhages from the ONH. Although these risk factors will need to be confirmed in larger, prospective studies, they highlight the potential for quantitative lesion analysis to inform the design of a more precise and complete staging system for diabetic retinopathy severity in the future. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.
PURPOSE: This study evaluated the risk and risk factors for exudative retinal detachment (ERD) in ocular inflammatory diseases. DESIGN: Retrospective cohort study. METHODS: Patients with noninfectious ocular inflammation had been followed longitudinally between 1978 and 2007 at 4 US subspecialty uveitis centers. The main outcome measurements were occurrences of ERD and predictive factors. RESULTS: A total of 176 of 14,612 eyes with ocular inflammation presented with ERD. Among uveitis cases, Vogt-Koyanagi-Harada syndrome (VKH) (odds ratio [OR] = 109), undifferentiated choroiditis (OR = 9.18), sympathetic ophthalmia (OR = 8.43), primary or secondary panuveitis (OR = 7.09), multifocal choroiditis with panuveitis (OR = 4.51), and "other" forms of posterior uveitis (OR = 16.9) were associated with a higher prevalence of ERD. Among the 9,209 uveitic or scleritic eyes initially free of ERD and followed, 137 incident ERD cases were observed over 28,949 eye-years at risk (incidence rate = 0.47% [0.40%-0.56%/eye-year]). VKH (HR = 13.2), sympathetic ophthalmia (HR = 5.82), undifferentiated choroiditis (HR = 6.03), primary or secondary panuveitis (HR = 4.21), and rheumatoid arthritis (HR = 3.30) were significantly associated with incident ERD. A significant dose-response relationship with the prevalence and incidence of ERD were observed for AC cells and vitreous cell activity. African Americans had significantly higher prevalence and incidence of ERD. CONCLUSIONS: Other ocular inflammatory conditions in addition to VKH syndrome and posterior scleritis were associated with increased risk of ERD, indicating that ERD does not necessarily dictate a diagnosis of VKH or posterior scleritis. In addition, the relationship between ERD and inflammatory severity factors implies that inflammation is a key predictive factor associated with developing ERD and requires early and vigorous control.
We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School's teaching hospital, the Massachusetts Eye and Ear-and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.
PURPOSE: To establish the prevalence, clinical characteristics, and risk factors for persistent corneal epithelial defects (PED) in patients with chronic ocular graft-versus-host disease (oGVHD) and to determine visual outcomes after healing. DESIGN: Retrospective cohort study. METHODS: A chart review was conducted of patients in whom chronic oGVHD was diagnosed between January 2011 and December 2018 and their demographic and clinical characteristics were collected. Data were analyzed to determine prevalence of PED, and multivariate logistic regression was performed to determine the risk factors associated with it. RESULTS: A total of 405 patients at a mean age of 60 ± 13 years in whom chronic oGVHD was diagnosed; 58% were men. The prevalence of PED was 8.1%. The median time for PED development after hematopoietic stem cell transplantation was approximately 24 months. Median time to PED resolution was 4.5 weeks after starting therapy. The mean best-corrected visual acuity declined by 2 lines post-PED resolution. The prevalence rates of corneal ulcer and perforation were 6.2% and 4.0%, respectively, over 8 years. Logistic regression analysis, used to determine factors associated with PED, showed diabetes (P = .006), limbal stem cell deficiency (LSCD) (P = .02), filamentary keratitis (P = .02), subconjunctival fibrosis (P = .02), and a higher National Institutes of Health (NIH) oGVHD score (P = .01) were significant risk factors for PED development. CONCLUSIONS: The study found the prevalence rate of PED, corneal ulceration, and corneal perforation in chronic oGVHD to be 8.1%, 6.2%, and 4%, respectively. Analysis showed that oGVHD patients with diabetes, LSCD, filamentary keratitis, subconjunctival fibrosis, and a high NIH score were at higher risk of developing severe corneal disease.
Amiodarone is an anti-arrhythmic drug that was approved by the US Food and Drug Administration (FDA) in 1985. Pre-clinical studies suggest that Amiodarone induces cytotoxicity in several types of cancer cells, thus making it a potential candidate for use as an anti-cancer treatment. However, it is also known to cause a variety of severe side effects. We hypothesized that in addition to the cytotoxic effects observed in cancer cells Amiodarone also has an indirect effect on angiogensis, a key factor in the tumor microenvironment. In this study, we examined Amiodarone's effects on a murine tumor model comprised of U-87 MG glioblastoma multiforme (GBM) cells, known to form highly vascularized tumors. We performed several in vitro assays using tumor and endothelial cells, along with in vivo assays utilizing three murine models. Low dose Amiodarone markedly reduced the size of GBM xenograft tumors and displayed a strong anti-angiogenic effect, suggesting dual cancer fighting properties. Our findings lay the ground for further research of Amiodarone as a possible clinical agent that, used in safe doses, maintains its dual properties while averting the drug's harmful side effects.
Purpose: To identify factors affecting family members' decision whether to donate eye organs. Methods: A community-based case-control study based on in-home interviews with families of deceased individuals who had or had not donated eye organs, in Madurai district, Tamil Nadu, India. Data collected were knowledge and awareness of eye donations, whether the deceased individual had expressed or pledged willingness to donate, and family members' attitudes and willingness to donate their own eye organs. Results: Seventy-six families of donors and 256 families of non-donors completed the survey. Multivariable analysis showed that the following variables were significantly associated with a donation: age, whether the deceased had registered for eye donation, pre-expressed willingness of deceased to donate, whether family members personally know beneficiaries of eye donations, and higher score on a scale evaluating knowledge and awareness about eye donation. The majority of donors' families (71%) had been encouraged by someone to donate. Among non-donor families, a substantially larger fraction (52.8%) indicated they would have donated had someone reminded or encouraged them to do so, in comparison with those who indicated lack of awareness or knowledge (14.5%). Conclusion: Community programs are likely to be effective if they encourage individuals to pledge their eyes or express their willingness to donate their eyes to family members in advance of death; they increase public awareness of the value of eye donation. A friend, family member, neighbor or counselor approaching bereaved families and having a dialogue about eye donation would substantially increase the probability of a decision to donate.
This article was withdrawn on October 15, 2020, at the request of the journal editors, with agreement from the authors, owing to a substantial amount of unattributed or improperly cited text overlap with other sources. In accordance with Annual Reviews' commitment to transparency, the original PDF of the article remains available for download at .
Phase unwrapping is one of the major challenges in multiple branches of science that extract three-dimensional information of objects from wrapped signals. In several applications, it is important to extract the unwrapped information with minimal signal resolution degradation. However, most of the denoising techniques for unwrapping are designed to operate on the entire phase map to remove a limited number of phase residues, and therefore they significantly degrade critical information contained in the image. In this paper, we present a novel, smart, and automatic filtering technique for locally minimizing the number of phase residues in noisy wrapped holograms, based on the phasor average filtering (PAF) of patches around each residue point. Both patch sizes and PAF filters are increased in an iterative algorithm to minimize the number of residues and locally restrict the artifacts caused by filtering to the pixels around the residue pixels. Then, the improved wrapped phase can be unwrapped using a simple phase unwrapping technique. The feasibility of our method is confirmed by filtering, unwrapping, and enhancing the quality of a noisy hologram of neurons; the intensity distribution of the spatial frequencies demonstrates a 40-fold improvement, with respect to previous techniques, in preserving the higher frequencies.
: Uveitis is an important cause of blindness and ocular morbidity in the world. The patterns of uveitis have not been well characterized in sub-Saharan Africa. : To describe the characteristics of uveitis among patients presenting to Jimma University Department of Ophthalmology (JUDO) from July 2013 to December 2014. : This hospital-based prospective cross-sectional study included all new uveitis patients visiting JUDO outpatient department during the study period. : Among 98 patients diagnosed with uveitis, anterior uveitis was found in 74.5% of patients. Majority of the patients, 83.7%, had unilateral uveitis. A uveitis syndrome was identified in 22.5% of cases; of these 15 (68.2%) were infectious. Herpes simplex uveitis was the commonest infectious cause (53.3%) while Toxoplasmosis was the most common cause of posterior uveitis (60%). : Anterior uveitis was the most common pattern found among uveitis patients. Herpes simplex and toxoplasmic chorioretinitis were the most common-identified infectious causes.
Diabetic retinopathy (DR) is an eye condition that develops after chronically poorly-managed diabetes, and is presently the main cause for blindness on a global scale. Current treatments for DR such as laser photocoagulation, topical injection of corticosteroids, intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents and vitreoretinal surgery are only applicable at the late stages of DR and there are possibilities of significant adverse effects. Moreover, the forms of treatment available for DR are highly invasive to the eyes. Safer and more effective pharmacological treatments are required for DR treatment, in particular at an early stage. In this review, we cover recently investigated promising oral pharmacotherapies, the methods of which are safer, easier to use, patient-friendly and pain-free, in clinical studies. We especially focus on peroxisome proliferator-activator receptor alpha (PPARα) agonists in which experimental evidence suggests PPARα activation may be closely related to the attenuation of vascular damages, including lipid-induced toxicity, inflammation, an excess of free radical generation, endothelial dysfunction and angiogenesis. Furthermore, oral administration of selective peroxisome proliferator-activated receptor alpha modulator (SPPARMα) agonists may induce hepatic fibroblast growth factor 21 expression, indirectly resulting in retinal protection in animal studies. Our review will enable more comprehensive approaches for understanding protective roles of PPARα for the prevention of DR development.