The 100 most-cited articles in Investigative Ophthalmology & Visual Science, 2016

PURPOSE: To compare performance of a deep-learning enhanced algorithm for automated detection of diabetic retinopathy (DR), to the previously published performance of that algorithm, the Iowa Detection Program (IDP)-without deep learning components-on the same publicly available set of fundus images and previously reported consensus reference standard set, by three US Board certified retinal specialists. METHODS: We used the previously reported consensus reference standard of referable DR (rDR), defined as International Clinical Classification of Diabetic Retinopathy moderate, severe nonproliferative (NPDR), proliferative DR, and/or macular edema (ME). Neither Messidor-2 images, nor the three retinal specialists setting the Messidor-2 reference standard were used for training IDx-DR version X2.1. Sensitivity, specificity, negative predictive value, area under the curve (AUC), and their confidence intervals (CIs) were calculated. RESULTS: Sensitivity was 96.8% (95% CI: 93.3%-98.8%), specificity was 87.0% (95% CI: 84.2%-89.4%), with 6/874 false negatives, resulting in a negative…

PURPOSE: To quantify changes in retinal microvasculature in diabetic retinopathy (DR) by using spectral-domain optical coherence tomography angiography (SD-OCTA). METHODS: Retrospective, cross-sectional, observational study of healthy and diabetic adult subjects with and without DR. Retinal microvascular changes were assessed by using SD-OCTA images and an intensity-based optical microangiography algorithm. A semiautomated program was used to calculate indices of microvascular density and morphology in nonsegmented and segmented SD-OCTA images. Microvascular density was quantified by using skeleton density (SD) and vessel density (VD), while vessel morphology was quantified as fractal dimension (FD) and vessel diameter index (VDI). Statistical analyses were performed by using the Student's t-test or analysis of variance with post hoc Tukey honest significant difference tests for multiple comparisons. RESULTS: Eighty-four eyes with DR and 14 healthy eyes were studied. Spearman's rank test demonstrated a negative correlation between DR severity and SD, VD, and FD, and a positive…

PURPOSE: The purpose of this study was to compare retinal nerve fiber layer (RNFL) thickness and optical coherence tomography angiography (OCT-A) retinal vasculature measurements in healthy, glaucoma suspect, and glaucoma patients. METHODS: Two hundred sixty-one eyes of 164 healthy, glaucoma suspect, and open-angle glaucoma (OAG) participants from the Diagnostic Innovations in Glaucoma Study with good quality OCT-A images were included. Retinal vasculature information was summarized as a vessel density map and as vessel density (%), which is the proportion of flowing vessel area over the total area evaluated. Two vessel density measurements extracted from the RNFL were analyzed: (1) circumpapillary vessel density (cpVD) measured in a 750-μm-wide elliptical annulus around the disc and (2) whole image vessel density (wiVD) measured over the entire image. Areas under the receiver operating characteristic curves (AUROC) were used to evaluate diagnostic accuracy. RESULTS: Age-adjusted mean vessel density was significantly lower in OAG eyes compared with glaucoma suspects and healthy…

This review was written for the special issue of IOVS to describe the history of optical coherence tomography (OCT) and its evolution from a nonscientific, historic perspective. Optical coherence tomography has become a standard of care in ophthalmology, providing real-time information on structure and function - diagnosing disease, evaluating progression, and assessing response to therapy, as well as helping to understand disease pathogenesis and create new therapies. Optical coherence tomography also has applications in multiple clinical specialties, fundamental research, and manufacturing. We review the early history of OCT describing how research and development evolves and the important role of multidisciplinary collaboration and expertise. Optical coherence tomography had its origin in femtosecond optics, but used optical communications technologies and required advanced engineering for early OCT prototypes, clinical feasibility studies, entrepreneurship, and corporate development in order to achieve clinical acceptance and clinical impact. Critical advances were made by early…

Optical coherence tomography angiography (OCTA) is a noninvasive approach that can visualize blood vessels down to the capillary level. With the advent of high-speed OCT and efficient algorithms, practical OCTA of ocular circulation is now available to ophthalmologists. Clinical investigations that used OCTA have increased exponentially in the past few years. This review will cover the history of OCTA and survey its most important clinical applications. The salient problems in the interpretation and analysis of OCTA are described, and recent advances are highlighted.

PURPOSE: To establish a normative database for vascular density (VD) and foveal avascular zone (FAZ) at the superficial (SCP) and deep capillary plexus (DCP) in healthy subjects with optical coherence tomography (OCT) angiography. METHODS: The study was a retrospective chart review of healthy patients who had undergone OCT angiography imaging. A 3- × 3-mm area, centered on the fovea, was scanned for all the study eyes. The automated segmentation allowed separate analysis of the SCP, the DCP, and a comprehensive C-scan including both vascular layers. On the obtained images, VD and FAZ measurements were computed. Interobserver reproducibility and intraobserver repeatability were also assessed. RESULTS: A total of 135 eyes of 70 subjects (51% male) were analyzed. The mean age was 48.3 ± 17.5. We divided patients into group 1, from 20 to 39 years of age; group 2, from 40 to 59 years; and group 3, age 60 years or older. At the level of the SCP, mean VD and mean FAZ ± SD were, respectively, 52.58 ± 3.22% and 0.28 ± 0.1 mm2. At the level of the DCP, mean VD and mean FAZ were 57.87 ± 2.82%…

PURPOSE: The purpose of this study was to quantify retinal capillary density and the foveal avascular zone (FAZ) area in normal subjects according to age, using optical coherence tomography angiography (OCTA). METHODS: All eyes in this cross-sectional study underwent OCTA using RTVue XR Avanti with AngioVue. OCTA scans were analyzed and processed, and vessel density and FAZ dimensions were calculated. RESULTS: A total of 113 normal eyes from 70 subjects were included (30 males, 40 females; mean 48 ± 20 years of age). The mean vessel density and FAZ dimensions were significantly smaller in the superficial retinal capillary plexus (SCP) than in the deep retinal capillary plexus (DCP), using quantitative OCTA analysis (all P< 0.0001). With 3 × 3-mm scans, the mean vessel density was 13.431 ± 1.758 mm-1 in the SCP, 18.812 ± 1.796 mm-1 in the DCP, and 5.913 ± 1.308 mm-1 and 10.447 ± 1.262 mm-1 with 6 × 6-mm scans in the SCP and DCP, respectively. Mean FAZ areas were 0.289 ± 0.108 mm2 at the SCP and 0.614 ± 0.200 mm2 at the DCP. Age was a predictor of SCP and DCP vessel density and FAZ…

PURPOSE: Cataract is the leading cause of blindness and cataract surgical rate (CSR) is used as a proxy indicator of access to cataract services in a country. The aim of this study was to explore the associations between the CSR and the economic development of countries in terms of gross domestic product per capital (GDP/P) and gross national income per capita (GNI/P). METHODS: We systematically searched OVID (Medline and Embase), Pubmed, Embase.com, ISI Web of Science, and Cochrane Library databases, and retrieved additional data from unpublished reports. Cataract surgical rates and economic indicators (GDP/P, GNI/P) were collected for each country from 2005 to 2014. Complete data were used for the 50 largest countries according to World Health Organization (WHO) population estimates. Linear correlations between GDP/P and CSR were calculated. Cataract surgical rate data over two periods were used for analysis: 2005 to 2009 and 2010 to 2014 (CSR in 2009 or nearest year, CSR in 2014 or nearest year). RESULTS: Over the study period, CSR data were available for 152 countries across…

PURPOSE: To characterize the ocular surface microbiome of healthy volunteers using a combination of microbial culture and high-throughput DNA sequencing techniques. METHODS: Conjunctival swab samples from 107 healthy volunteers were analyzed by bacterial culture, 16S rDNA gene deep sequencing (n = 89), and biome representational in silico karyotyping (BRiSK; n = 80). Swab samples of the facial skin (n = 42), buccal mucosa (n = 50), and environmental controls (n = 27) were processed in parallel. 16S rDNA gene quantitative PCR was used to calculate the bacterial load in each site. Bacteria were characterized by site using principal coordinate analysis of metagenomics data. BRiSK data were analyzed for presence of fungi and viruses. RESULTS: Corynebacteria, Propionibacteria, and coagulase-negative Staphylococci were the predominant organisms identified by all three techniques. Quantitative 16S PCR demonstrated approximately 0.1 bacterial 16S rDNA/human actin copy on the ocular surface compared with greater than 10 16S rDNA/human actin copy for facial skin or the buccal mucosa. The…

Advanced macular degeneration is an important cause of vision loss in the United States with over 2 million people affected by the disease. Despite substantial progress in the development of new therapies for wet AMD, the severe visual impairment associated with geographic atrophy in dry AMD or Stargardt disease remains untreatable. Recently, two phase I/II studies involving 18 patients with these diseases have demonstrated that it is possible to safely implant human embryonic stem cell-derived RPE (hESC-RPE) in an attempt to rescue photoreceptors and visual function. The anatomical and functional results are encouraging, with more than half of treated patients experiencing sustained improvements in visual acuity and demonstrating evidence of possible cellular engraftment. However, any conclusions remain tempered by the relatively short follow-up time, lack of a formal control group, poor initial visual acuity, and small number of patients. Aside from an instance of postoperative infectious endophthalmitis, no adverse events related to the cell therapy, such as hyperproliferation,…

PURPOSE: We compared the area of the foveal avascular zone (FAZ) and macular capillary network density at different retinal layers using swept-source optical coherence tomography angiography (OCT-A) in normal individuals and patients with diabetic retinopathy (DR). METHODS: Images (a 3 × 3 mm cube centered on the fovea) were acquired in 40 eyes of 22 normal individuals and 28 eyes of 18 patients with varying levels of DR using a swept-source OCT-A device (central wavelength 1050 nm; A-scan-rate of 100,000 scans per second). En face images of the retinal vasculature were generated from the superficial and deep retinal layers (SRL/DRL). Quantitative analysis of the vessel density (VD) and FAZ area was performed. Vessel density was assessed as the ratio of the retinal area occupied by vessels. RESULTS: Among the DR subjects (mean age, 72 years; 61% male), 35.7% of the eyes had mild, 35.7% moderate, and 7.1% severe nonproliferative DR (NPDR), and 21.4% and proliferative DR (PDR). The mean FAZ area in patients with DR and in normal individuals was 0.518 and 0.339 mm2, respectively, for…

PURPOSE: We used fractal dimensional analysis to analyze retinal vascular disease burden in eyes with diabetic retinopathy using spectral-domain optical coherence tomography angiography (OCTA). METHODS: A retrospective study was performed of 13 eyes with diabetic retinopathy without diabetic macular edema and 56 control eyes. Optical coherence tomography angiography images were acquired using the RTVue XR Avanti. Automated segmentation was obtained through the superficial and deep capillary plexuses for each eye. Grayscale OCTA images were standardized and binarized using ImageJ. Fractal box-counting analyses were performed using Fractalyse. Fractal dimensions (FD) as well as software-generated vascular density analyses of the superficial and deep capillary plexuses were compared between diabetic and control eyes using 2-tailed t-tests and 1-way multivariate ANOVA (MANOVA) analyses. RESULTS: The superficial and deep plexuses from diabetic and control eyes were analyzed. The average FD for diabetic eyes was significantly lower than control eyes for the superficial (P = 4.513 × 10-3)…

PURPOSE: To investigate the contribution of the gut microbiota to the pathogenesis of uveitis. METHODS: Experimental autoimmune uveitis (EAU) in B10.RIII mice was induced using interphotoreceptor binding protein peptide. Mice were treated with oral or intraperitoneal (IP) antibiotics. Effector (Teff) and regulatory (Treg) T lymphocytes were identified using flow cytometry; 16S rRNA gene sequencing and qPCR were performed on gastrointestinal (GI) contents. RESULTS: Broad-spectrum (four antibiotics given simultaneously) oral, but not IP, antibiotics reduced mean uveitis clinical scores significantly compared with water-treated animals (0.5 vs. 3.0, P < 0.0001 for oral; 3.4 vs. 3.4, P > 0.99 for IP). Both oral metronidazole (P = 0.02) and vancomycin (P < 0.0001) alone decreased inflammation, whereas neomycin (P = 0.7) and ampicillin (P = 0.4) did not change mean uveitis scores. Oral broad-spectrum antibiotics increased Tregs in the GI lamina propria of EAU animals at 1 week, and in extraintestinal lymphoid tissues later, whereas Teff and inflammatory cytokines were reduced. 16S…

PURPOSE: To estimate the prevalence of glaucoma in the US population based on optic nerve head photography, to estimate the prevalence of glaucoma awareness, and to identify demographic and ocular risk factors for being unaware of having glaucoma. METHODS: The study included 5746 men and women 40 years of age and older participating in the National Health and Nutrition Examination Survey (NHANES) 2005-2008. Each participant had 45° photographs of the macula and optic disc of both eyes. Fundus photographs were first graded by a reading center, and those with a cup-to-disc ratio (CDR) ≥ 0.6 were regraded by three glaucoma specialists to determine the presence or absence of glaucoma. Analyses were performed using NHANES weights to account for the complex multistage probability sampling design. RESULTS: The estimated overall prevalence of glaucoma in the US civilian, noninstitutionalized population 40 years of age and older was 2.1% (95% confidence interval [CI], 1.7%-2.6%). Glaucoma affected 2.9 million individuals, including 1.4 million women; 1.5 million men; 2.3 million people 60…

PURPOSE: To correlate retinal vascular features with severity and systemic indicators of diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA). METHODS: A total of 209 eyes of 122 type 2 diabetes mellitus patients with DR and 60 eyes of 31 normal Indian subjects underwent OCTA imaging. The diabetic retinopathy patients were graded as having either nonproliferative diabetic retinopathy (NPDR: mild, moderate, and severe NPDR using Early Treatment Diabetic Retinopathy Study classification) or proliferative diabetic retinopathy (PDR). Local fractal analysis was applied to the superficial and deep retinal OCTA images. Foveal avascular zone area (FAZ in mm2); vessel density (%); spacing between large vessels (%); and spacing between small vessels (%) were analyzed. Sensitivity and specificity of vascular parameters were assessed with receiver operating characteristics (ROC) curve. RESULTS: Normal eyes had a significantly lower FAZ area, higher vessel density, and lower spacing between large and small vessels compared with DR grades (P < 0.001). In the superficial…

PURPOSE: Optical coherence tomography (OCT) has enabled "virtual biopsy" of the living human retina, revolutionizing both basic retina research and clinical practice over the past 25 years. For most of those years, in parallel, adaptive optics (AO) has been used to improve the transverse resolution of ophthalmoscopes to foster in vivo study of the retina at the microscopic level. Here, we review work done over the last 15 years to combine the microscopic transverse resolution of AO with the microscopic axial resolution of OCT, building AO-OCT systems with the highest three-dimensional resolution of any existing retinal imaging modality. METHODS: We surveyed the literature to identify the most influential antecedent work, important milestones in the development of AO-OCT technology, its applications that have yielded new knowledge, research areas into which it may productively expand, and nascent applications that have the potential to grow. RESULTS: Initial efforts focused on demonstrating three-dimensional resolution. Since then, many improvements have been made in resolution and…

PURPOSE: To investigate the expression of humanin (HN) in human retinal pigment epithelial (hRPE) cells and its effect on oxidative stress-induced cell death, mitochondrial bioenergetics, and senescence. METHODS: Humanin localization in RPE cells and polarized RPE monolayers was assessed by confocal microscopy. Human RPE cells were treated with 150 μM tert-Butyl hydroperoxide (tBH) in the absence/presence of HN (0.5-10 μg/mL) for 24 hours. Mitochondrial respiration was measured by XF96 analyzer. Retinal pigment epithelial cell death and caspase-3 activation, mitochondrial biogenesis and senescence were analyzed by TUNEL, immunoblot analysis, mitochondrial DNA copy number, SA-β-Gal staining, and p16INK4a expression and HN levels by ELISA. Oxidative stress-induced changes in transepithelial resistance were studied in RPE monolayers with and without HN cotreatment. RESULTS: A prominent localization of HN was found in the cytoplasmic and mitochondrial compartments of hRPE. Humanin cotreatment inhibited tBH-induced reactive oxygen species formation and significantly restored…

PURPOSE: We assessed changes in age-specific prevalence of refractive error at the time of starting school, by comparing preschool and school age cohorts in Shanghai, China. METHODS: A cross-sectional study was done in Jiading District, Shanghai during November and December 2013. We randomly selected 7 kindergartens and 7 primary schools, with probability proportionate to size. Chinese children (n = 8398) aged 3 to 10 years were enumerated, and 8267 (98.4%) were included. Children underwent distance visual acuity assessment and refraction measurement by cycloplegic autorefraction and subjective refraction. RESULTS: The prevalence of uncorrected visual acuity (UCVA), presenting visual acuity, and best-corrected visual acuity in the better eye of ≤20/40 was 19.8%, 15.5%, and 1.7%, respectively. Among those with UCVA ≤ 20/40, 93.2% could achieve visual acuity of ≥20/32 with refraction. Only 28.7% (n = 465) of children with UCVA in the better eye of ≤20/40 wore glasses. Prevalence of myopia (spherical equivalent ≤-0.5 diopters [D] in at least one eye) increased from 1.78% in 3-year-olds…

Purpose: The purpose of this study was to investigate the topographic relationship between the decreased parapapillary retinal microvasculature as assessed by optical coherence tomography angiography (OCTA) and retinal nerve fiber layer (RNFL) defect in eyes with primary open-angle glaucoma (POAG) and a localized RNFL defect. Methods: The peripapillary retinal circulation was evaluated using the OCTA centered on the optic nerve head in 98 POAG eyes having a localized RNFL defect and 45 healthy control eyes. A vascular impairment (VI) was identified in OCTA by the presence of a sign indicating decreased microvasculature. The frequencies of VI were compared between the POAG and control groups, and the topographic correlation between the VI and the RNFL defect identified in red-free fundus photographs was determined in the POAG group. Results: The VI was observed as an area of decreased density of the microvascular network of the retina in 100% of the POAG eyes. The VI exactly coincided with the RNFL defect evident in red-free fundus photographs in terms of both the location and extent…

PURPOSE: Increasing drusen volume was proposed to be a predictor of disease progression in age-related macular degeneration (AMD). In patients with late AMD in one eye, the fellow eyes without neovascularization are known to be at higher risk of developing exudative AMD. We evaluated the relationship between drusen volume in these fellow eyes and their progression to late AMD. METHODS: A retrospective analysis included fellow eyes with drusen associated with nonexudative AMD. All eyes with neovascular AMD were treated with intravitreal ranibizumab, aflibercept, and/or bevacizumab and followed for 2 years. All eyes were scanned with the Cirrus HD-OCT using a 512 × 128 scan pattern. Optical coherence tomography (OCT) data at baseline, month 12, and month 24 were collected using the advanced RPE analysis tool to quantify drusen volume within 3- and 5-mm-diameter circles centered on the fovea. Optical coherence tomography scans were also evaluated for the development of geographic atrophy (GA) or macular neovascularization (MNV). RESULTS: Eighty-nine patients who had neovascular AMD in…

PURPOSE: To evaluate a fully automated local fractal dimension method to quantify vessel density and foveal avascular zone (FAZ) area in optical coherence tomography angiography (OCTA) images. METHODS: Fifty-two healthy Asian Indian eyes underwent imaging prospectively with OCTA system. Superficial and deep retinal vascular plexus was imaged. Local fractal analysis was applied to the OCTA images. A scan area of 3 × 3 mm was selected in the superficial and deep retinal layers. Foveal avascular zone area and vessel density were quantified in circular and sectoral zones around the fovea. A unique contour map of vessel density and dropout zones was developed to perform regional comparisons. RESULTS: Foveal avascular zone of superficial (0.35 ± 0.013 mm2) and deep (0.49 ± 0.012 mm2) retinal vascular plexus was segmented. The agreement between the manually segmented and local fractal dimension segmented FAZ area was 0.97 (95% confidence interval [CI]: 0.94-0.98) and did not change significantly with age (P = 0.94 and 0.21, respectively). The vessel density was greater in the deep than the…

Purpose: To compare perfused peripapillary capillary density in primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), and normal patients using optical coherence tomography angiography (OCT-A). Methods: A retrospective review of POAG, NTG, and normal patients imaged with OCT-A was performed. En face OCT angiograms identifying peripapillary vessels were obtained using a spectral-domain OCT system (Avanti RTVue-XR). A custom image analysis approach identified perfused peripapillary capillaries, quantified perfused capillary density (PCD), and generated color-coded PCD maps for 3.5- and 4.5-mm-diameter scans. We compared PCD values, PCD maps, standard automated perimetry (Humphrey visual field [HVF]) parameters, and OCT retinal nerve fiber layer (RNFL) thickness analyses across all groups. Results: Forty POAG, 26 NTG, and 26 normal patients were included. Annular PCD in POAG (34.24 ± 6.76%) and NTG (37.75 ± 3.52%) patients was significantly decreased compared to normal patients (42.99 ± 1.81%) in 4.5-mm scans (P < 0.01 and P < 0.01, respectively). Similar trends and…

PURPOSE: To determine the size and characteristics of the superficial and deep foveal avascular zone (FAZ) in healthy adults by using optical coherence tomography angiography (OCT-A), and to ascertain the effects of demographic and ocular parameters on the FAZ size. METHODS: In a prospective cohort study of 117 healthy volunteers, foveal-centered 3 × 3-mm OCT-A scans were manually graded by certified graders to determine the size of the superficial and deep FAZ. Multiple linear regression analyses were performed to evaluate the impact of demographics and ocular factors, including central retinal thickness (CRT), choroidal thickness, axial length (AL), and spherical equivalent (SE) on superficial and deep FAZ areas. RESULTS: The mean age of the participants was 22.5 years, with mean AL of 25.4 mm and mean SE of -4.3 diopters. The mean CRT was 262.8 μm (range, 220-316 μm). The mean superficial FAZ area was 0.24 mm2, while the deep FAZ area was 0.38 mm2 (P < 0.001). Females had a larger superficial (P < 0.001) and deep FAZ (P < 0.001). On univariate linear regression, both superficial…

PURPOSE: To study the association between the distributions of microaneurysms detected by en face optical coherence tomography angiography (OCTA) and diabetic macular edema (DME). METHODS: The study design was a retrospective chart review of 27 patients (33 eyes) with DME. The eyes were scanned using OCTA (6 × 6 mm) and spectral-domain (SD) OCT macular cube. Each of the images of the capillary plexus was overlaid onto the image of the topographic map, and the densities of the microaneurysms were measured by ImageJ software. The association between the distribution of microaneurysms and macular edema was evaluated. RESULTS: For microaneurysms in areas with and without edema, 77.3 ± 8.1% of these microaneurysms were located in the deep capillary plexuses (DCP). However, in areas of edema where the retinal thickness was more than 400 μm, 91.3 ± 9.1% of the microaneurysms were found in the DCP. This difference was statistically significant (P < 0.001). In the macular edema area, there was a significantly higher density of microaneurysms in the DCP compared to the superficial capillary…

PURPOSE: To evaluate the perifoveolar retinal capillary network at different depths and to quantify the foveal avascular zone (FAZ) in eyes with retinal vein occlusion (RVO) compared with their fellow eyes and healthy controls using spectral-domain optical coherence tomography angiography (SD-OCTA). METHODS: We prospectively recruited 23 patients with RVO including 15 eyes with central RVO (CRVO) and 8 eyes with branch RVO (BRVO), their fellow eyes, and 8 age-matched healthy controls (8 eyes) for imaging on prototype OCTA software within RTVue-XR Avanti. The 3 × 3 mm and 6 × 6 mm en face angiograms of superficial and deep retinal capillary plexuses were segmented. Perifoveolar retinal capillary network was analyzed and FAZ was quantified. RESULTS: Decrease in vascular perfusion at the deep plexus was observed in all eyes with CRVO (8/8, 100%) and BRVO (6/6, 100%) without cystoid macular edema, and in 8 of 15 (53%) and 2 of 8 (25%) of the fellow eyes, respectively. Vascular tortuosity was observed in 13 of 15 (87%) CRVO and 5 of 8 (63%) BRVO eyes. Collaterals were seen in 10 of 15…

PURPOSE: To investigate the retinal vascular network alterations in highly myopic eyes. METHODS: Thirty-three highly myopic eyes from 21 subjects and 47 mildly myopic or emmetropic eyes from 24 healthy control subjects were enrolled. Optical coherence tomography angiography (OCTA) was used to image the superficial, deep, and whole retinal vascular plexuses at the macular region. Highly myopic eye images were analyzed after adjusting the ocular magnification using Bennett's formula. Fractal analysis (box counting method, Dbox) representing vessel density was performed in different annular and quadrantile zones of both large vessels and microvessels. Correlations between the vascular density, axial length, and spherical equivalent refractive error were analyzed. RESULTS: The average density (Dbox) of the superficial retinal annular zone (0.6-2.5 mm) microvessels was 1.741 ± 0.018 in highly myopic eyes and was shown to be significantly lower than that of the controls (1.773 ± 0.010, P < 0.001). Individual annular zone (bandwidth of 0.16 mm) analysis of highly myopic eyes revealed a…

PURPOSE: Netarsudil is a Rho kinase/norepinephrine transporter inhibitor currently in phase 3 clinical development for glaucoma treatment. We investigated the effects of its active metabolite, netarsudil-M1, on outflow facility (C), outflow hydrodynamics, and morphology of the conventional outflow pathway in enucleated human eyes. METHODS: Paired human eyes (n = 5) were perfused with either 0.3 μM netarsudil-M1 or vehicle solution at constant pressure (15 mm Hg). After 3 hours, fluorescent microspheres were added to perfusion media to trace the outflow patterns before perfusion-fixation. The percentage effective filtration length (PEFL) was calculated from the measured lengths of tracer distribution in the trabecular meshwork (TM), episcleral veins (ESVs), and along the inner wall (IW) of Schlemm's canal after global and confocal imaging. Morphologic changes along the trabecular outflow pathway were investigated by confocal, light, and electron microscopy. RESULTS: Perfusion with netarsudil-M1 significantly increased C when compared to baseline (51%, P < 0.01) and to paired controls…

Purpose: To characterize the morphology of neovascularization at the disc (NVD) and neovascularization elsewhere (NVE) in treatment-naïve or previously treated proliferative diabetic retinopathy (PDR) patients using optical coherence tomography (OCT) angiography. Methods: En face OCT angiograms of NVD/NVE in 40 eyes of 33 patients with PDR were acquired using RTVue XR Avanti OCT. The morphology of NVD/NVE on OCT angiograms was evaluated, and the activity was determined by biomicroscopy and fluorescein angiography (FA). In 12 eyes that were treated or treatment-naïve, changes in the morphology and vessel area of NVD/NVE before and after panretinal photocoagulation (PRP) were investigated. Results: Twenty eyes had treatment-naïve PDR, whereas 20 eyes were previously treated with PRP. All treatment-naïve NVD/NVE had remarkable (i.e., active) leakage in early-phase FA. Ninety-five percent of treatment-naïve NVD/NVE observed by OCT angiography had exuberant vascular proliferation (EVP), identified as irregular proliferation of fine (smaller-caliber) new vessels; whereas, the presence of…

PURPOSE: To investigate the vascular microcirculation changes in the retinal nerve fiber layer (RNFL) in normal, glaucoma suspect, and open-angle glaucoma (OAG) groups using optical coherence tomography-based microangiography (OMAG). METHODS: One eye from each subject was scanned with a Cirrus HD-OCT 5000-based OMAG prototype system montage scanning protocol centered at the optic nerve head (ONH). Blood flow signals were extracted using OMAG algorithm. Retinal nerve fiber layer vascular microcirculation was measured by calculating the blood flux index and vessel area density within a 1.2-mm width annulus centered at the ONH with exclusion of big retinal vessels. One-way ANOVA were performed to analyze the RNFL microcirculation among groups. Linear-regression models were constructed to analyze the correlation between RNFL microcirculation and clinical parameters. Discrimination capabilities of the flow metrics were assessed with the area under the receiver operating characteristic curve (AROC). RESULTS: Twenty normal, 26 glaucoma suspect, and 42 OAG subjects were enrolled. Eyes from…

PURPOSE: To investigate retinal ganglion cell (RGC) survival and activation of caspase 3 after optic nerve crush (ONC) or transection (ONT) and treatment with brain-derived neurotrophic factor (BDNF) or Z-DEVD_fmk. METHODS: In albino Swiss mice, the left optic nerve was severed or crushed at 0.5 mm from the optic head and retinas were analyzed from 1 to 10 days. Additional groups were treated intravitreally with a single injection of BDNF (2.5 μg) or Z-DEVD_fmk (125 ng) right after injury, or with Z-DEVD_fmk at day 2, or with multiple injections of Z-DEVD_fmk. As controls intact or vehicle-treated retinas were used. In all retinas, Brn3a (RGCs) and cleaved-caspase 3 (c-casp3) were immunodetected and their numbers quantified. In an additional group, c-casp3 expression was assessed in RGCs retrogradely labeled before axotomy. RESULTS: The temporal loss of RGCs was the same after ONC or ONT and occurred in two phases with 65% loss during the first 7 days and an additional 4% loss from day 7 to 10. The appearance of c-casp3+RGCs is Gaussian, peaking at 4 days and declining thereafter.…

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…

PURPOSE: Human limbal palisade of Vogt is an ideal model for studying and practicing regenerative medicine due to their accessibility. Nonresolving inflammation is a common manifestation of limbal stem cell deficiency, which is the major cause of corneal blindness, and presents as a threat to the success of transplanted limbal epithelial stem cells. Clinical studies have shown that the efficacy of transplantation of limbal epithelial stem cells can be augmented by transplantation of cryopreserved human amniotic membrane (AM), which exerts anti-inflammatory, antiscarring, and antiangiogenic action to promote wound healing. METHODS: Review of published data to determine the molecular action mechanism explaining how AM exerts the aforementioned therapeutic actions. RESULTS: From the water-soluble extract of cryopreserved AM, we have biochemically purified one novel matrix component termed heavy chain (HC)-hyaluronan (HA)/pentraxin 3 (PTX3) as the key relevant tissue characteristic responsible for the aforementioned AM's efficacy. Heavy chain-HA is a complex formed by a covalent linkage…

PURPOSE: The aim of this study was to quantify the relationship between categories of body mass index (BMI) and age-related macular degeneration (AMD) risk in different stages. METHODS: MEDLINE, EMBASE, and ISI Web of Science were searched for all eligible studies on the relationship between BMI and incident early or late AMD. The analyses were based on data extracted from study reports. The pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated to evaluate the strength of this association, and dose-response relationship was assessed by restricted cubic spline. RESULTS: Seven prospective cohort studies with 1613 cases identified among 31,151 subjects were included. For overweight, the relationship remained insignificant for its association with both early AMD (RR = 0.92, 95% CI: 0.68-1.15; P = 0.54) and late AMD (RR = 1.09, 95% CI: 0.93-1.25; P = 0.18). A marked 32% increase in the risk of developing late AMD was noted among obese individuals (RR = 1.32, 95% CI: 1.11-1.53, P < 0.01), while obesity showed no significant association with early AMD (RR = 0.91,…

PURPOSE: To examine the relationships between axial length and foveal and peripheral retinal thickness. METHODS: Using optical coherence tomography, foveal retinal thickness was measured in participants of the population-based Beijing Eye Study without optic nerve or macula diseases. Inner and outer nuclear layer thickness as surrogate for retinal thickness was assessed in the fundus periphery in human globes enucleated due to malignant uveal melanoma or painful glaucoma. RESULTS: The study included 1117 individuals with a mean age of 64.2 ± 9.7 years (range: 50-93 years) and mean axial length of 23.4 ± 1.04 mm (range: 20.29-28.68 mm). In multivariate analysis, thicker central foveal thickness was associated with male sex (P < 0.001; standardized regression coefficient beta: -0.13; nonstandardized regression coefficient B: -5.84; 95% confidence interval (CI): -8.56, -3.13); urban region of habitation (P = 0.02; beta: 0.07; B: 3.56; 95% CI: 0.55, 6.57); thinner lens thickness (P = 0.01; beta: -0.08; B: -5.11; 95% CI: -9.01, -1.21); thinner subfoveal choroidal thickness (P = 0.04;…

PURPOSE: We combined finite element (FE) analysis and dynamic magnetic resonance imaging (MRI) to estimate optic nerve head (ONH) strains during horizontal eye movements, and identified factors influencing such strains. We also compared ONH strains (prelamina, lamina cribrosa, and retrolamina strains) induced by eye movements to those induced by IOP. METHODS: The ocular globes and orbits of a healthy subject were visualized during horizontal eye movements (up to 13°), using dynamic MRI. A baseline FE model of one eye was reconstructed in the primary gaze position, including details from the orbital and ONH tissues. Finite element-derived ONH strains induced by eye movements were compared to those resulting from an IOP of 50 mm Hg. Finally, a FE sensitivity study was performed, in which we varied the stiffness of all ONH connective tissues, to understand their influence on ONH strains. RESULTS: Our models predicted that, during horizontal eye movements, the optic nerve pulled the ONH posteriorly. Optic nerve head strains following a lateral eye movement of 13° were large and higher…

PURPOSE: Ripasudil (Glanatec), a selective rho-associated coiled coil-containing protein kinase (ROCK) inhibitor, was approved as a glaucoma and ocular hypertension treatment in Japan in 2014. The purpose of this study was to investigate the feasibility of using ripasudil eye drops to treat corneal endothelial injuries. METHODS: Cultured human corneal endothelial cells (HCECs) were treated with ripasudil, and 5-bromo-2'-deoxyuridine (BrdU) incorporation was evaluated by ELISA. A rabbit corneal endothelial damage model was also created by mechanically scraping the corneal endothelium, followed by topical ripasudil eye drop application for 2 weeks. The anterior segment was evaluated by slit-lamp microscopy, and central corneal thickness was measured by ultrasound pachymetry. Corneal specimens were evaluated by phalloidin staining and immunohistochemical analysis using antibodies against Ki67, N-cadherin, and Na+/K+-ATPase. RESULTS: Many more BrdU-positive cells were observed among the HCECs treated with ripasudil (0.3-30 μM) than among the control HCECs. Ripasudil-treated eyes in a…

PURPOSE: To evaluate how metrics used to describe the cone mosaic change in response to simulated photoreceptor undersampling (i.e., cell loss or misidentification). METHODS: Using an adaptive optics ophthalmoscope, we acquired images of the cone mosaic from the center of fixation to 10° along the temporal, superior, inferior, and nasal meridians in 20 healthy subjects. Regions of interest (n = 1780) were extracted at regular intervals along each meridian. Cone mosaic geometry was assessed using a variety of metrics - density, density recovery profile distance (DRPD), nearest neighbor distance (NND), intercell distance (ICD), farthest neighbor distance (FND), percentage of six-sided Voronoi cells, nearest neighbor regularity (NNR), number of neighbors regularity (NoNR), and Voronoi cell area regularity (VCAR). The "performance" of each metric was evaluated by determining the level of simulated loss necessary to obtain 80% statistical power. RESULTS: Of the metrics assessed, NND and DRPD were the least sensitive to undersampling, classifying mosaics that lost 50% of their coordinates…

PURPOSE: The purpose of this study was to evaluate an automated algorithm for detecting avascular area (AA) in optical coherence tomography angiograms (OCTAs) separated into three individual plexuses using a projection-resolved technique. METHODS: A 3 × 3 mm macular OCTA was obtained in 13 healthy and 13 mild nonproliferative diabetic retinopathy (NPDR) participants. A projection-resolved algorithm segmented OCTA into three vascular plexuses: superficial, intermediate, and deep. An automated algorithm detected AA in each of the three plexuses that were segmented and in the combined inner-retinal angiograms. We assessed the diagnostic accuracy of extrafoveal and total AA using segmented and combined angiograms, the agreement between automated and manual detection of AA, and the within-visit repeatability. RESULTS: The sum of extrafoveal AA from the segmented angiograms was larger in the NPDR group by 0.17 mm2 (P < 0.001) and detected NPDR with 94.6% sensitivity (area under the receiver operating characteristic curve [AROC] = 0.99). In the combined inner-retinal angiograms, the…

PURPOSE: To compare the use of optical coherence tomography angiography (OCTA) and adaptive optics scanning light ophthalmoscope fluorescein angiography (AOSLO FA) for characterizing the foveal microvasculature in healthy and vasculopathic eyes. METHODS: Four healthy controls and 11 vasculopathic patients (4 diabetic retinopathy, 4 retinal vein occlusion, and 3 sickle cell retinopathy) were imaged with OCTA and AOSLO FA. Foveal perfusion maps were semiautomatically skeletonized for quantitative analysis, which included foveal avascular zone (FAZ) metrics (area, perimeter, acircularity index) and vessel density in three concentric annular regions of interest. On each set of OCTA and AOSLO FA images, matching vessel segments were used for lumen diameter measurement. Qualitative image comparisons were performed by visual identification of microaneurysms, vessel loops, leakage, and vessel segments. RESULTS: Adaptive optics scanning light ophthalmoscope FA and OCTA showed no statistically significant differences in FAZ perimeter, acircularity index, and vessel densities. Foveal avascular…

PURPOSE: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) has recently been adapted to enable efficient editing of the mammalian genome, opening novel avenues for therapeutic intervention of inherited diseases. In seeking to disrupt yellow fluorescent protein (YFP) in a Thy1-YFP transgenic mouse, we assessed the feasibility of utilizing the adeno-associated virus 2 (AAV2) to deliver CRISPR/Cas for gene modification of retinal cells in vivo. METHODS: Single guide RNA (sgRNA) plasmids were designed to target YFP, and after in vitro validation, selected guides were cloned into a dual AAV system. One AAV2 construct was used to deliver Streptococcus pyogenes Cas9 (SpCas9), and the other delivered sgRNA against YFP or LacZ (control) in the presence of mCherry. Five weeks after intravitreal injection, retinal function was determined using electroretinography, and CRISPR/Cas-mediated gene modifications were quantified in retinal flat mounts. RESULTS: Adeno-associated virus 2-mediated in vivo delivery of SpCas9 with sgRNA targeting YFP…

PURPOSE: Dysfunction of the retinal pigment epithelium (RPE) underlies numerous retinal pathologies, but biomarkers sensitive to RPE change at the cellular level are limited. In this study, we used adaptive optics optical coherence tomography (AO-OCT) in conjunction with organelle motility as a novel contrast mechanism to visualize RPE cells and characterize their 3-dimensional (3D) reflectance profile. METHODS: Using the Indiana AO-OCT imaging system (λc = 790 nm), volumes were acquired in the macula of six normal subjects (25-61 years). Volumes were registered in 3D with subcellular accuracy, layers segmented, and RPE and photoreceptor en face images extracted and averaged. Voronoi and two-dimensional (2D) power spectra analyses were applied to the images to quantify RPE and cone packing and cone-to-RPE ratio. RESULTS: Adaptive optics OCT revealed two distinct reflectance patterns at the depth of the RPE. One is characterized by the RPE interface with rod photoreceptor tips, the second by the RPE cell nuclei and surrounding organelles, likely melanin. Increasing cell contrast by…

PURPOSE: To determine the sensitivity of the combination of optical coherence tomography angiography (OCTA) and structural optical coherence tomography (OCT) for detecting type 1 neovascularization (NV) and to determine significant factors that preclude visualization of type 1 NV using OCTA. METHODS: Multicenter, retrospective cohort study of 115 eyes from 100 patients with type 1 NV. A retrospective review of fluorescein (FA), OCT, and OCTA imaging was performed on a consecutive series of eyes with type 1 NV from five institutions. Unmasked graders utilized FA and structural OCT data to determine the diagnosis of type 1 NV. Masked graders evaluated FA data alone, en face OCTA data alone and combined en face OCTA and structural OCT data to determine the presence of type 1 NV. Sensitivity analyses were performed using combined FA and OCT data as the reference standard. RESULTS: A total of 105 eyes were diagnosed with type 1 NV using the reference. Of these, 90 (85.7%) could be detected using en face OCTA and structural OCT. The sensitivities of FA data alone and en face OCTA data…

PURPOSE: To investigate the entire nerve architecture and content of the two main sensory neuropeptides in mouse cornea to determine if it is a good model with similarities to human corneal innervation. METHODS: Mice aged 1 to 24 weeks were used. The corneas were stained with neuronal-class βIII-tubulin, calcitonin gene-related peptide (CGRP), and substance P (SP) antibodies; whole-mount images were acquired to build an entire view of corneal innervation. To test the origin of CGRP and SP, trigeminal ganglia (TG) were processed for immunofluorescence. Relative corneal nerve fiber densities or neuron numbers were assessed by computer-assisted analysis. RESULTS: Between 1 and 3 weeks after birth, mouse cornea was mainly composed of a stromal nerve network. At 4 weeks, a whorl-like structure (or vortex) appeared that gradually became more defined. By 8 weeks, anatomy of corneal nerves had reached maturity. Epithelial bundles converged into the central area to form the vortex. The number and pattern of whorl-like structures were different. Subbasal nerve density and nerve terminals were…

PURPOSE: The purpose of this study was to compare optical coherence tomography (OCT) angiography to standard fluorescein angiography (FA) in the grading of diabetic macular ischemia. METHODS: In our study, OCT angiography and traditional FA images were acquired from 24 diabetic patients. The level of diabetic macular ischemia in the superficial capillary plexus was graded with standard Early Treatment Diabetic Retinopathy Study (ETDRS) protocols and a comparison between conventional FA and OCT angiography was performed. The deep vascular plexus and choriocapillaris were also graded for macular ischemia. Additionally, flow indices were analyzed for all OCT angiography images. RESULTS: We identified moderate agreement between diabetic macular ischemia grades for conventional FA and OCT angiography (weighted κ of 0.53 and 0.41). In addition, the intergrader agreement for the superficial, deep, and choriocapillaris scores was substantial (weighted κ of 0.65, 0.61, and 0.65, respectively). Finally, the parafoveal flow indices were shown to have a statistically significant relationship…

PURPOSE: In this study, we elucidated the differential expression of a set of local molecular factors in ectatic cone area of the cornea to uncover a functional cause for focal corneal weakening characteristic of the keratoconus (KC) disease. METHODS: All human corneal samples were collected after approval of Institutional Ethics Committee and informed consent. Keratoconus patients were classified based on clinical parameters, topographical features, and structural deformity. Epithelial cells were collected from KC patients (n = 66) undergoing corneal cross-linking procedures from cone apex and periphery. Nonectatic refractive surgery patients (n = 23) served as controls. The ratio of epithelial gene expression in cone and periphery of each eye was estimated by quantitative PCR and correlated with clinical data. Similar cone versus periphery analysis was done from the KC stroma and from KC patients with Bowman's layer (BL) breach observed by anterior segment optical coherence tomography (OCT). RESULTS: Epithelium from the cone apex of KC patients had elevated levels of inflammatory…

PURPOSE: The optic nerve (ON) sheath's role in limiting duction has been previously unappreciated. This study employed magnetic resonance imaging (MRI) to demonstrate this constraint on adduction. METHODS: High-resolution, surface coil axial MRI was obtained in 11 normal adults, 14 subjects with esotropia (ET) having normal axial length (AL) < 25.8 mm, 13 myopic subjects with ET and mean AL 29.3 ± 3.3 (SD) mm, and 7 subjects with exotropia (XT). Gaze angles and ON lengths were measured for scans employing eccentric lateral fixation in which an ON became completely straightened. RESULTS: In all groups, ON straightening occurred only in the adducting, not abducting, eye. Adduction at ON straightening was 26.0 ± 8.8° in normal subjects, not significantly different from XT at 22.2 ± 11.8°. However, there was significant increase in comparable adduction in ET to 36.3 ± 9.3°, and in myopic ET to 33.6 ± 10.7° (P < 0.04). Optic nerve length at straightening was 27.6 ± 2.7 mm in normals, not significantly different from 28.2 ± 2.8 mm in ET and 27.8 ± 2.7 mm in XT. In myopic ET, ON length at…

PURPOSE: Müller cells (MCs) are a major source of VEGF in diabetic retinopathy (DR). Vascular endothelial growth factor is the main therapeutic target for treating DR. This study aimed to investigate whether autophagy is involved in MC response under high glucose (HG). METHODS: Rat retinal Müller cells (rMCs) were exposed to normal or high glucose in and out of presence of pharmacologic inhibitors and activators and small interfering RNA (siRNA) for p62/SQTSM1 for 24 hours. RESULTS: High glucose induces increase of early and late autophagic markers, accumulation of p62/SQTSM1 and endoplasmic reticulum (ER) stress response associated with apoptosis augmentation (P < 0.01). The inhibition of autophagy in HG leads to higher rMC apoptotic rate (P < 0.001). By silencing the p62/SQTSM1, ER stress is ameliorated (p<0.0001), preventing apoptosis. Retinal MCs in HG treated with rapamycin (mTOR inhibitor) show autophagy machinery activation and reestablishment of cargo degradation, protecting cells from apoptosis (P < 0.0001). Rapamycin improves lysosomal proteolytic activity by improving…

PURPOSE: To examine associations between corneal mechanical thresholds and metrics of dry eye. METHODS: This was a cross-sectional study of individuals seen in the Miami Veterans Affairs eye clinic. The evaluation consisted of questionnaires regarding dry eye symptoms and ocular pain, corneal mechanical detection and pain thresholds, and a comprehensive ocular surface examination. The main outcome measures were correlations between corneal thresholds and signs and symptoms of dry eye and ocular pain. RESULTS: A total of 129 subjects participated in the study (mean age 64 ± 10 years). Mechanical detection and pain thresholds on the cornea correlated with age (Spearman's ρ = 0.26, 0.23, respectively; both P < 0.05), implying decreased corneal sensitivity with age. Dry eye symptom severity scores and Neuropathic Pain Symptom Inventory (modified for the eye) scores negatively correlated with corneal detection and pain thresholds (range, r = -0.13 to -0.27, P < 0.05 for values between -0.18 and -0.27), suggesting increased corneal sensitivity in those with more severe ocular complaints.…

PURPOSE: Congenital achromatopsia (ACHM) is an autosomal recessive disorder in which cone function is absent or severely reduced. Gene therapy in animal models of ACHM have shown restoration of cone function, though translation of these results to humans relies, in part, on the presence of viable cone photoreceptors at the time of treatment. Here, we characterized residual cone structure in subjects with CNGB3-associated ACHM. METHODS: High-resolution imaging (optical coherence tomography [OCT] and adaptive optics scanning light ophthalmoscopy [AOSLO]) was performed in 51 subjects with CNGB3-associated ACHM. Peak cone density and inter-cone spacing at the fovea was measured using split-detection AOSLO. Foveal outer nuclear layer thickness was measured in OCT images, and the integrity of the photoreceptor layer was assessed using a previously published OCT grading scheme. RESULTS: Analyzable images of the foveal cones were obtained in 26 of 51 subjects, with nystagmus representing the major obstacle to obtaining high-quality images. Peak foveal cone density ranged from 7,273 to…

PURPOSE: To investigate the appearance of choriocapillaris (CC) flow under drusen by comparing long-wavelength (1050 nm) swept-source optical coherence tomography (SS-OCT) angiography with shorter-wavelength (840 nm) spectral-domain (SD) OCT angiography. METHODS: Patients with drusen imaged on both devices on the same day were selected and graded. Ambiguous OCT angiography (OCTA) signal loss was defined as low OCTA signal on the en face OCTA CC image that also had low OCT signal in the corresponding area on the en face OCT CC image and OCT B-scans. Unambiguous OCTA signal loss was defined as low OCTA signal on the en face OCTA CC image that did not have low OCT signal in the corresponding area on the en face OCT CC image and OCT B-scans. False-positive flow impairment on SS-OCTA was defined as ambiguous OCTA signal loss on SS-OCTA but no OCTA signal loss on SD-OCTA. False-positive flow impairment on SD-OCTA was defined as ambiguous OCTA signal loss on SD-OCTA but no OCTA signal loss on SS-OCTA. RESULTS: Nine eyes from seven patients were enrolled, 23 drusen were analyzed. On 840-nm…

Purpose: We generate a renewable supply of corneal endothelial cells (CEC) from human pluripotent stem cells (PSCs) under defined culture conditions. Methods: Corneal endothelial cell induction was driven by small molecules in a stepwise fashion of lineage specification. During the initial phase, PSC fate was restricted to the eye field-like state and became eye field stem cells (EFSCs). In the second phase, PSC-derived EFSCs were further directed toward either neural crest lineage or retinal lineage. The CECs were directly induced from ocular neural crest stem cells (NCSCs) by suppressing TGF-β and ROCK signaling. Results: Under chemically defined conditions, PSCs were massively converted into EFSCs and subsequently NCSCs. Eye field cell identity was characterized by the expression of key fate restriction factors for early eye field cells, such as PAX6, LHX2, and VSX2. The induction of ocular NCSCs was initiated by promoting WNT signaling in EFSCs. Within 2 weeks of induction, the majority of cells expressed the typical neural crest markers p75NTR and HNK-1. Eye field stem…

PURPOSE: To compare the diagnostic value of Bruch's membrane opening minimum rim width (BMO-MRW) and retinal nerve fiber layer thickness (RNFLT) in patients with ocular hypertension, preperimetric, and perimetric glaucoma. METHODS: One hundred eighty-one eyes consisting of 40 healthy controls, 41 ocular hypertensive subjects, 50 subjects with preperimetric glaucoma and 50 with perimetric glaucoma were included. One randomly selected eye was included. All patients underwent slit-lamp examination, funduscopy, achromatic perimetry, and 24-hour IOP profile. Bruch's membrane opening-MRW and RNFLT (3 peripapillary circle scans, 12°/14°/16°) data were obtained using spectral domain optical coherence tomography. Areas under the receiver operating characteristics curves (AUROC) as well as sensitivity at fixed specificity were computed globally and for six vertical split sectors. Venn diagrams were plotted to identify patients that were diagnosed by one of the two parameters only. RESULTS: For RNFLT the smallest circle diameter showed highest diagnostic accuracy and was used for comparison…

PURPOSE: The high-performance visual function associated with central vision is mediated by the macula (the central retina), which accumulates three diet-derived pigments (the carotenoids lutein [L], zeaxanthin [Z], and meso-zeaxanthin [MZ]). Our study sought to investigate the impact on visual function, including contrast sensitivity (CS), of supplementation with these naturally occurring carotenoids, in individuals with low retinal concentrations. METHODS: Subjects consumed daily a formulation containing 10 mg L, 2 mg Z, and 10 mg MZ (active group; n = 53) or placebo (n = 52) for a period of 12 months. Study visits were at baseline, 3, 6, and 12 months. Contrast sensitivity at 6 cycles per degree (cpd) was the primary outcome measure (POM). Secondary outcome measures included CS at other spatial frequencies, best-corrected visual acuity (BCVA), glare disability, photostress recovery, and light scatter. Macular pigment optical density (MPOD) was measured using dual-wavelength autofluorescence, and serum carotenoid concentrations were analyzed using high performance liquid…

PURPOSE: To investigate the relationship between best-corrected visual acuity (BCVA) and the foveal avascular zone (FAZ) in patients with central retinal vein occlusion (CRVO) evaluated with optical coherence angiography (OCT-A). METHODS: The study was a prospective consecutive case series including 24 patients with CRVO. All patients received either aflibercept or ranibizumab intravitreal injections prior to analysis. Best-corrected visual acuity and FAZ were evaluated in eyes without macular edema. The FAZ areas were evaluated with OCT-A in both the superficial and deep capillary plexus layers by using 3 × 3-mm images of the macula. Disruption of the ellipsoid zone (EZ) was also analyzed. RESULTS: The mean superficial FAZ area measured 0.76 mm2 (95% confidence interval [CI] 0.50-1.13). The mean deep FAZ area measured 1.12 mm2 (95% CI 0.77-1.47). In a multivariable analysis a negative correlation was found between the BCVA and the superficial FAZ area (r = -0.54, P = 0.03). The correlation between the BCVA and deep FAZ area did not meet statistical significance (r = -0.43, P =…

PURPOSE: The purpose of this study was to examine cone photoreceptor structure in retinitis pigmentosa (RP) and Usher syndrome using confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). METHODS: Nineteen subjects (11 RP, 8 Usher syndrome) underwent ophthalmic and genetic testing, spectral-domain optical coherence tomography (SD-OCT), and AOSLO imaging. Split-detector images obtained in 11 subjects (7 RP, 4 Usher syndrome) were used to assess remnant cone structure in areas of altered cone reflectivity on confocal AOSLO. RESULTS: Despite normal interdigitation zone and ellipsoid zone appearance on OCT, foveal and parafoveal cone densities derived from confocal AOSLO images were significantly lower in Usher syndrome compared with RP. This was due in large part to an increased prevalence of non-waveguiding cones in the Usher syndrome retina. Although significantly correlated to best-corrected visual acuity and foveal sensitivity, cone density can decrease by nearly 38% before visual acuity becomes abnormal. Aberrantly waveguiding cones were…

PURPOSE: Increasing evidence suggests a role for macrophages in the pathogenesis of age-related macular degeneration (AMD). This study examined choroidal macrophages and their activation in postmortem eyes from subjects with and without AMD. METHODS: Choroids were incubated with anti-ionized calcium-binding adapter molecule 1 (anti-IBA1) to label macrophages, anti-human leukocyte antigen-antigen D-related (anti-HLA-DR) as a macrophage activation marker, and Ulex europaeus agglutinin lectin to label blood vessels. Whole mounts were imaged using confocal microscopy. IBA1- and HLA-DR-positive (activated) cells were counted in submacula, paramacula, and nonmacula, and cell volume and sphericity were determined using computer-assisted image analysis. RESULTS: In aged control eyes, the mean number of submacular IBA1+ and HLA-DR+ macrophages was 433/mm2 and 152/mm2, respectively. In early AMD eyes, there was a significant increase in IBA1+ and HLA-DR+ cells in submacula compared to those in controls (P = 0.0015 and P = 0.008, respectively). In eyes with neovascular AMD, there were…

Purpose: To explore the role of Rho-associated kinases (ROCK) in corneal physiology and regeneration, and the effects of suppressing its activity in stimulating corneal endothelial cell proliferation and migration in vitro and in vivo. Methods: Immunohistochemistry was performed to detect RhoA and ROCK-1 and ROCK-2 in human corneal tissue. Adult porcine corneal endothelial cells (CECs) were isolated, grown to confluence, and further characterized. Under the treatment of ROCK inhibitors, changes in the cellular distribution profile of ZO-1 and F-actin were examined by immunofluorescence staining. Corneal endothelial cells migration was evaluated by scratch assay and analyzed with Axiovision software. Cell proliferation was quantified using Click-iT EdU HCS Assay. In vivo, the corneal endothelia of rabbits were surgically injured and H-1152 was topically applied for 10 days. Progress of wound healing was evaluated daily by monitoring corneal edema, inflammation, and thickness using slit-lamp examination, photography, and pachymetry. Rabbits were euthanized and enucleated for further…

Optical coherence tomography (OCT) has established itself as the dominant imaging modality in the management of glaucoma and retinal diseases, providing high-resolution visualization of ocular microstructures and objective quantification of tissue thickness and change. This article reviews the history of OCT imaging with a specific focus on glaucoma. We examine the clinical utility of OCT with respect to diagnosis and progression monitoring, with additional emphasis on advances in OCT technology that continue to facilitate glaucoma research and inform clinical management strategies.

PURPOSE: The aim of the study was to understand natural changes of meibomian glands (MG) that occur with aging in the absence of any ocular pathology or ocular discomfort symptoms, to differentiate between "age normal" and pathologic or dysfunctional changes of the MG. METHODS: A total of 185 subjects (109 females) with no pre-existing ocular and systemic abnormalities were recruited and divided into four age groups: 25 to 34, 35 to 44, 45 to 54, and 55 to 66 years. At a single visit, the following MG measures were collected: meibum quality (MQ) and MG expressibility (MGE) of the lower lid, and MG drop-out score (meiboscale) using infrared meibography of the upper and lower lids. Assessments of anterior eye, tear function variables, noninvasive and invasive tear breakup time (TBUT), corneal integrity, and lid wiper epitheliopathy were also performed during the visit. An Ocular Surface Disease Index (OSDI) questionnaire was used to record dry eye symptoms. Meibum lipids samples were collected and analyzed. RESULTS: A majority of the study population (61%) was asymptomatic. There was…

PURPOSE: The continuous-text reading-acuity test MNREAD is designed to measure the reading performance of people with normal and low vision. This test is used to estimate maximum reading speed (MRS), critical print size (CPS), reading acuity (RA), and the reading accessibility index (ACC). Here we report the age dependence of these measures for normally sighted individuals, providing baseline data for MNREAD testing. METHODS: We analyzed MNREAD data from 645 normally sighted participants ranging in age from 8 to 81 years. The data were collected in several studies conducted by different testers and at different sites in our research program, enabling evaluation of robustness of the test. RESULTS: Maximum reading speed and reading accessibility index showed a trilinear dependence on age: first increasing from 8 to 16 years (MRS: 140-200 words per minute [wpm]; ACC: 0.7-1.0); then stabilizing in the range of 16 to 40 years (MRS: 200 ± 25 wpm; ACC: 1.0 ± 0.14); and decreasing to 175 wpm and 0.88 by 81 years. Critical print size was constant from 8 to 23 years (0.08 logMAR), increased…

PURPOSE: To assess the reactive changes of the corneal epithelial thickness (ET) profile induced by small incision lenticule extraction (SMILE) for treatment of myopia. METHODS: This prospective observational study included 46 eyes of 23 patients that were scheduled for myopic SMILE. High-resolution spectral-domain optical coherence tomography (SD-OCT) and a custom image segmentation algorithm were applied to measure corneal ET at multiple time points within the central 5-mm zone. Postoperative ET alterations were correlated with treatment parameters and refractive outcomes. RESULTS: Mean age was 33 ± 6 years and mean spherical equivalent of surgical refractive correction was -4.78 ± 1.75 diopters. The average ET (averaged over the central 5-mm zone) increased from 52.3 ± 3.6 μm preoperatively to 57.7 ± 5.1 μm 6 months postoperatively (P < 0.01). Average ET was 101.9% of the preoperative thickness at 24 hours postoperatively, 103.2% at 1 week, 106.7% at 6 weeks, 109.3% at 3 months, and 110.4% at 6 months postoperatively. The epithelial thickening response could be modeled by an…

PURPOSE: We quantitatively analyzed the features of a radial peripapillary capillary (RPC) network visualized using wide-field montage optical coherence tomography (OCT) angiography in healthy human eyes. METHODS: Twenty eyes of 20 healthy subjects were recruited. En face 3 × 3-mm OCT angiograms of multiple locations in the posterior pole were acquired using the RTVue XR Avanti, and wide-field montage images of the RPC were created. To evaluate the RPC density, the montage images were binarized and skeletonized. The correlation between the RPC density and the retinal nerve fiber layer (RNFL) thickness measured by an OCT circle scan was investigated. RESULTS: The RPC at the temporal retina was detected as far as 7.6 ± 0.7 mm from the edge of the optic disc but not around the perifoveal area within 0.9 ± 0.1 mm of the fovea. Capillary-free zones beside the first branches of the arterioles were significantly (P < 0.0001) narrower than those beside the second ones. The RPC densities at 0.5, 2.5, and 5 mm from the optic disc edge were 13.6 ± 0.8, 11.9 ± 0.9, and 10.4 ± 0.9 mm-1. The RPC…

PURPOSE: Retinal photocoagulation and nondamaging laser therapy are used for treatment of macular disorders, without understanding of the response mechanism and with no rationale for dosimetry. To establish a proper titration algorithm, we measured the range of tissue response and damage threshold. We then evaluated safety and efficacy of nondamaging retinal therapy (NRT) based on this algorithm for chronic central serous chorioretinopathy (CSCR) and macular telangiectasia (MacTel). METHODS: Retinal response to laser treatment below damage threshold was assessed in pigmented rabbits by expression of the heat shock protein HSP70 and glial fibrillary acidic protein (GFAP). Energy was adjusted relative to visible titration using the Endpoint Management (EpM) algorithm. In clinical studies, 21 eyes with CSCR and 10 eyes with MacTel were treated at 30% EpM energy with high spot density (0.25-diameter spacing). Visual acuity, retinal and choroidal thickness, and subretinal fluid were monitored for 1 year. RESULTS: At 25% EpM energy and higher, HSP70 was expressed acutely in RPE, and GFAP…

PURPOSE: To examine whether Nrf2-regulated antioxidant defense and p53 are activated in human corneal endothelial cells (CEnCs) by environmental levels of ultraviolet A (UV-A), a known stimulator of oxidative stress. METHODS: Immortalized human CEnCs (HCEnCi) were exposed to UV-A fluences of 2.5, 5, 10, or 25 J/cm2, then allowed to recover for 3 to 24 hours. Control HCEnCi did not receive UV-A. Reactive oxygen species (ROS) were measured using H2DCFDA. Cell cytotoxicity was evaluated by lactate dehydrogenase (LDH) release. Levels of Nrf2, HO-1, NQO-1, p53, and caspase3 were detected by immunnoblotting or real-time PCR. Activated caspase3 was measured by immunoblotting and a fluorescence assay. RESULTS: Exposure of HCEnCi to 5, 10, and 25 J/cm2 UV-A increased ROS levels compared with controls. Nrf2, HO-1, and NQO-1 mRNA increased 1.7- to 3.2-fold at 3 and 6 hours after irradiation with 2.5 and 5 J/cm2 UV-A. At 6 hours post irradiation, UV-A (5 J/cm2) enhanced nuclear Nrf2 translocation. At 24 hours post treatment, UV-A (5, 10, and 25 J/cm2) produced a 1.8- to 2.8-fold increase in…

PURPOSE: To develop a tear molecule level-based predictive model based on a panel of tear cytokines and their correlation with clinical features in ocular chronic graft versus host disease (cGVHD). METHODS: Twenty-two ocular cGVHD patients and 21 healthy subjects were evaluated in a controlled environmental research laboratory (CERLab). Clinical parameters were recorded, and tears were collected. Levels of 15 molecules (epidermal growth factor [EGF], IL receptor antagonist [IL-1Ra], IL-1β, IL-2, IL-6, IL-8/CXCL8, IL-10, IL-12p70, IL-17A, interferon inducible protein [IP]-10/CXCL10, IFN-γ, VEGF, TNF-α, eotaxin 1, and regulated on activation normal T cell expressed and secreted [RANTES]) were measured by multiplex-bead assay and correlated with clinical parameters. Logistic regression was used to develop a predictive model. Leave-one-out cross-validation was applied. Classification capacity was evaluated in a cohort of individuals with dry eye (DE) of other etiologies different from GVHD. RESULTS: Epidermal growth factor and IP-10/CXCL10 levels were significantly decreased in ocular…

Purpose: To evaluate the efficacy and safety of SYL1001, a short interfering (si) RNA targeting the transient receptor potential cation channel subfamily V member 1 (TRPV1), for the treatment of dry eye disease (DED). Methods: This study combines a phase I and two phase II clinical trials to test different doses of SYL1001 in a total of 156 healthy subjects and patients with DED. After 10 days of treatment, the primary efficacy endpoints were the effect on (1) the scoring in the Visual Analogue Scale (VAS) and Ocular Surface Disease Index (OSDI) questionnaires, and (2) ocular tolerance evaluated by corneal fluorescein staining and conjunctival hyperemia. Secondary endpoints included the assessment of systemic and local tolerance. Results: Topical administration of SYL1001 1.125% once daily produced a significant decrease in VAS scores compared with placebo from day 4 until the end of treatment (change from baseline at day 10: -1.73 ± 0.32 vs. -0.91 ± 0.34; P = 0.013). For all treatments, OSDI scores were significantly reduced compared to their respective baseline values (P < 0.01),…

PURPOSE: To determine the feasibility of a 49-channel suprachoroidal-transretinal stimulation (STS) retinal prosthesis that was implanted for 1 year. METHODS: Three patients with advanced retinitis pigmentosa (RP) and with less than or equal to hand motion (HM) vision were studied. A 49-channel STS system was implanted in a scleral pocket, and the stability of the prosthesis, adverse events, and its efficacy were investigated. RESULTS: The electrode array was implanted in a scleral pocket located under the parafoveal area through a scleral incision at 14 mm in patient (Pt) 1, 16 mm in Pt 2, and 18 mm in Pt 3 from the sclerocorneal limbus. No complications occurred during surgery in all cases. During the follow-up period, iridocyclitis developed in Pt 2 and Pt 3, which was successfully treated with topical medications. The implanted devices continued functioning and elicited phosphenes in all cases. The results of localization tests (P < 0.05) and table tests (P < 0.05) were significantly better with the prosthesis turned on than turned off in Pt 3. The deviations of the walking…

PURPOSE: To analyze the age dependence of the longitudinal modulus of the crystalline lens in vivo using Brillouin scattering data in healthy subjects. METHODS: Brillouin scans were performed along the crystalline lens in 56 eyes from 30 healthy subjects aged from 19 to 63 years. Longitudinal elastic modulus was acquired along the sagittal axis of the lens with a transverse and axial resolution of 4 and 60 μm, respectively. The relative lens stiffness was computed, and correlations with age were analyzed. RESULTS: Brillouin axial profiles revealed nonuniform longitudinal modulus within the lens, increasing from a softer periphery toward a stiffer central plateau at all ages. The longitudinal modulus at the central plateau showed no age dependence in a range of 19 to 45 years and a slight decrease with age from 45 to 63 years. A significant intersubject variability was observed in an age-matched analysis. Importantly, the extent of the central stiff plateau region increased steadily over age from 19 to 63 years. The slope of change in Brillouin modulus in the peripheral regions were…

PURPOSE: The purpose of this study was to describe autofluorescence lifetime characteristics in Stargardt disease (STGD) using fluorescence lifetime imaging ophthalmoscopy (FLIO) and to investigate potential prognostic markers for disease activity and progression. METHODS: Fluorescence lifetime data of 16 patients with STGD (mean age, 40 years; range, 22-56 years) and 15 age-matched controls were acquired using a fluorescence lifetime imaging ophthalmoscope based on a Heidelberg Engineering Spectralis system. Autofluorescence was excited with a 473-nm laser, and decay times were measured in a short (498-560 nm) and long (560-720 nm) spectral channel. Clinical features, autofluorescence lifetimes and intensity, and corresponding optical coherence tomography images were analyzed. One-year follow-up examination was performed in eight STGD patients. Acquired data were correlated with in vitro measured decay times of all-trans retinal and N-retinylidene-N-retinylethanolamine. RESULTS: Patients with STGD displayed characteristic autofluorescence lifetimes within yellow flecks (446 ps)…

PURPOSE: To assess the effect of dry eye disease on work productivity and performance of non-work-related activities, and patients' satisfaction with over-the-counter (OTC) dry eye treatments. METHODS: In this prospective, noninterventional, cross-sectional study, conducted at 10 U.S. optometry/ophthalmology practices, 158 symptomatic dry eye patients naïve to prescription medication underwent standard dry eye diagnostic tests and completed Work Productivity and Activity Impairment (WPAI) and Ocular Surface Disease Index (OSDI) questionnaires. Use of OTC dry eye medication, and satisfaction with OTC medication and symptom relief were also assessed. RESULTS: On average, dry eye resulted in loss of 0.36% of work time (∼5 minutes over 7 days) and ∼30% impairment of workplace performance (presenteeism), work productivity, and non-job-related activities. Presenteeism and productivity impairment scores showed significant correlation with OSDI total (r = 0.55) and symptom domain (r = 0.50) scores, but not with dry eye clinical signs. Activity impairment score showed stronger correlation…

PURPOSE: Oxidative stress and metabolic dysregulation of the RPE have been implicated in AMD; however, the molecular regulation of RPE metabolism remains unclear. The transcriptional coactivator, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) is a powerful mediator of mitochondrial function. This study examines the ability of PGC-1α to regulate RPE metabolic program and oxidative stress response. METHODS: Primary human fetal RPE (hfRPE) and ARPE-19 were matured in vitro using standard culture conditions. Mitochondrial mass of RPE was measured using MitoTracker staining and citrate synthase activity. Expression of PGC-1 isoforms, RPE-specific genes, oxidative metabolism proteins, and antioxidant enzymes was analyzed by quantitative PCR and Western blot. Mitochondrial respiration and fatty-acid oxidation were monitored using the Seahorse extracellular flux analyzer. Expression of PGC-1α was increased using adenoviral delivery. ARPE-19 were exposed to hydrogen peroxide to induce oxidative stress. Reactive oxygen species were measured by CM-H2DCFDA…

Purpose: To evaluate the global patterns in health burden of uncorrected refractive error (URE) by year, age and sex, region, and socioeconomic status, using disability-adjusted life years (DALYs). Methods: Global, regional, or national DALY numbers, crude DALY rates, and age-standardized DALY rates caused by URE, by year, or age and sex, were obtained from the Global Burden of Disease Study 2013. Human development index (HDI) in 2013 as a national socioeconomic indicator was obtained from the Human Development Report. Kruskal-Wallis test and linear regression were performed to explore the association between age-standardized DALY rates and HDI. Results: From 1990 to 2013, global DALY numbers caused by URE rose by 43.8%, crude rates remained relatively constant, and age-standardized rates fell by 8.8%. Global DALY rates increased with age, and older females had higher DALY numbers and rates than males of the same age. Age-standardized DALY rates in Eastern Mediterranean, South-East Asia, and Africa were higher than that at a global level. Multiple comparisons indicated higher…

PURPOSE: To measure lamina cribrosa (LC) strains (deformations) following abduction and adduction in healthy subjects and to compare them with those resulting from a relatively high acute intraocular pressure (IOP) elevation. METHODS: A total of 16 eyes from 8 healthy subjects were included. Among the 16 eyes, 11 had peripapillary atrophy (PPA). For each subject, both optic nerve heads (ONHs) were imaged using optical coherence tomography (OCT) at baseline (twice), in different gaze positions (adduction and abduction of 20°) and following an acute IOP elevation of approximately 20 mm Hg from baseline (via ophthalmodynamometry). Strains of LC for all loading scenarios were mapped using a three-dimensional tracking algorithm. RESULTS: In all 16 eyes, LC strains induced by adduction and abduction were 5.83% ± 3.78% and 3.93% ± 2.57%, respectively, and both significantly higher than the control strains measured from the repeated baseline acquisitions (P < 0.01). Strains of LC in adduction were on average higher than those in abduction, but the difference was not statistically…

PURPOSE: We observed and analyzed the morphologic characteristics of polypoidal lesions and abnormal branching vascular network (BVN) in patients with polypoidal choroidal vasculopathy (PCV) by optical coherence tomography angiography (OCTA). METHODS: A retrospective observational case series was done of patients with PCV. All patients were scanned with a 70-kHz spectral-domain OCT system using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm to distinguish blood flow from static tissue. The OCTA images of these patients were compared to those from indocyanine green angiography (ICGA). Semiautomated segmentation was used to further analyze the polypoidal lesion and the BVN. RESULTS: We studied 13 eyes of 13 patients 51 to 69 years old. A total of 11 patients were treatment-naive. Two patients had multiple anti-VEGF injections and one underwent photodynamic therapy (PDT). Optical coherence tomography angiography was able to detect the BVN in all cases. Using cross-sectional OCTA, BVN locations were shown to be in the space between the RPE and Bruch's membrane.…

PURPOSE: To investigate the relationship between retinal perfusion and retinal thickness in the peripapillary and macular areas of healthy subjects. METHODS: Using spectral-domain optic coherence tomography and split-spectrum amplitude decorrelation angiography (SSADA) algorithm, retinal perfusion and retinal thicknesses in the macular and peripapillary areas were measured in healthy volunteers, and correlations among these variables were analyzed. RESULTS: Overall, 64 subjects (121 eyes) including 28 males and 36 females with a mean ± SD age of 38 ± 13 years participated. Linear mixed-models showed that vessel area density was significantly correlated with the inner retinal thickness (from the inner limiting membrane to the outer border of the inner nucleus layer; P < 0.05), but not with the thickness of the full retina (P > 0.05) in the parafoveal area. The area of the foveal capillary-free zone was negatively correlated with the inner and full foveal thicknesses (all P < 0.001). In the peripapillary area, the vessel area density was positively correlated with the thickness of the…

PURPOSE: To describe a spectral imaging system for small animal studies based on noninvasive endoscopy of the retina, and to present time-resolved spectral changes from live Alzheimer's mice prior to cognitive decline, corroborating our previous in vitro findings. METHODS: Topical endoscope fundus imaging was modified to use a machine vision camera and tunable wavelength system for acquiring monochromatic images across the visible to near-infrared spectral range. Alzheimer's APP/PS1 mice and age-matched, wild-type mice were imaged monthly from months 3 through 8 to assess changes in the fundus reflection spectrum. Optical changes were fit to Rayleigh light scatter models as measures of amyloid aggregation. RESULTS: Good quality spectral images of the central retina were obtained. Short-wavelength reflectance from Alzheimer's mice retinae showed significant reduction over time compared to wild-type mice. Optical changes were consistent with an increase in Rayleigh light scattering in neural retina due to soluble Aβ1-42 aggregates. The changes in light scatter showed a monotonic…

PURPOSE: We determined the intraocular pharmacokinetic properties of intravitreally injected aflibercept (Eylea) in a rabbit model. METHODS: Aflibercept was injected intravitreally in 21 eyes from New Zealand White rabbits. The eyes were enucleated 1, 24, 48, 120, 216, 360, and 720 hours (1, 2, 5, 9, 15, and 30 days, respectively) after injection and immediately frozen at -80°C. The concentrations of aflibercept in the vitreous, aqueous humor, and retina/choroid were determined by performing an indirect enzyme-linked immunosorbent assay, and analyzed to understand the pharmacokinetic properties of the drug. RESULTS: The maximum concentration of aflibercept was observed 1, 48 (2 days), and 24 (1 day) hours after intravitreal administration in the vitreous, aqueous humor, and retina/choroid, respectively. The one-compartment model was selected as the final model for all three ocular tissues. In the vitreous, aqueous humor, and retina/choroid, the estimated half-lives of aflibercept were 94.1, 48.0, and 58.2 hours, and the estimated mean residence times (MRTs) were 135.8, 69.2, and…

Purpose: To compare the thickness of all retinal layers between a nondiabetic group and diabetic patients without diabetic retinopathy (DR). Methods: Cross-sectional study, in which all subjects underwent an ophthalmic examination including optical coherence tomography. After automatic retinal segmentation, each retinal layer thickness (eight separate layers and overall thickness) was calculated in all nine Early Treatment Diabetic Retinopathy Study (ETDRS) areas. The choroidal thickness (CT) also was measured at five locations. Generalized additive regression models were used to analyze the data. Results: A total of 175 patients were recruited, 50 nondiabetic subjects and 125 diabetic patients without DR, stratified into three groups according to diabetes duration: group I (<5 years, n = 55), group II (5-10 years, n = 39), and group III (>10 years, n = 31). Overall, groups I and III of diabetic patients had a decrease in the photoreceptor layer (PR) thickness, when compared with the nondiabetic subjects in six ETDRS areas (P < 0.0007). Patients with more recent diagnosis (group I)…

PURPOSE: To determine the effects of clinical variables, including age, sex, history of refractive or cataract surgery, contact lens use, and ocular surface and meibomian gland parameters on the lipid layer thickness (LLT) in normal subjects and patients with dry eye syndrome (DES). METHODS: A total of 64 normal subjects and 326 patients with DES were enrolled, and they underwent measurements of LLT with a LipiView interferometer and tear meniscus height using optical coherence tomography, tear film break-up time (TBUT) determination, ocular surface staining, Schirmer's test, examination of the lid margins and meibomian glands, and assessment using the Ocular Surface Disease Index (OSDI). RESULTS: In normal subjects, the median (range) LLT was 67 (33-100) nm, and age was the only factor that was significantly associated with LLT (β = 0.678, P = 0.028). In patients with DES, the median (range) LLT was 84 (20-100) nm, and 79.0% of the participants fulfilled the diagnostic criteria for meibomian gland dysfunction (MGD). In a multivariate analysis, increased age and female sex were…

PURPOSE: To compare spectral-domain optical coherence tomography (SD-OCT) standard structural measures and a new three-dimensional (3D) volume optic nerve head (ONH) change detection method for detecting change over time in severely advanced-glaucoma (open-angle glaucoma [OAG]) patients. METHODS: Thirty-five eyes of 35 patients with very advanced glaucoma (defined as a visual field mean deviation < -21 dB) and 46 eyes of 30 healthy subjects to estimate aging changes were included. Circumpapillary retinal fiber layer thickness (cpRNFL), minimum rim width (MRW), and macular retinal ganglion cell-inner plexiform layer (GCIPL) thicknesses were measured using the San Diego Automated Layer Segmentation Algorithm (SALSA). Progression was defined as structural loss faster than 95th percentile of healthy eyes. Three-dimensional volume ONH change was estimated using the Bayesian-kernel detection scheme (BKDS), which does not require extensive retinal layer segmentation. RESULTS: The number of progressing glaucoma eyes identified was highest for 3D volume BKDS (13, 37%), followed by GCPIL (11,…

PURPOSE: Optical coherence tomography (OCT) has revolutionized the diagnosis and management of adult retinal and optic nerve disease. Children were deprived of this technology until the recent development of handheld spectral-domain OCT (HH-SDOCT). In this article, we review the applications of OCT imaging in pediatric ophthalmology. METHODS: This study was a review of the literature. RESULTS: The acquisition and interpretation of pediatric tomograms differ significantly from those for adults, with adjustments needed to account for the shorter axial lengths, higher refractive errors, and ongoing retinal and optic nerve development in the pediatric eye. Handheld SDOCT is increasingly being used as an adjunctive diagnostic tool in retinopathy of prematurity (ROP) and nonaccidental injury (NAI) by providing additional morphologic information that is not normally clinically discernible. The role of HH-SDOCT in streamlining diagnosis in infantile nystagmus syndrome, retinal dystrophies, and degenerations has been established. Optical coherence tomography can also help differentiate…

PURPOSE: To explain the pivotal role optical coherence tomography (OCT) imaging had in the development of antiangiogenic therapies for the treatment of neovascular age-related macular degeneration (nvAMD). METHODS: A historical literature review was combined with personal perspectives from the introduction of OCT imaging and the early clinical use of vascular endothelial growth factor (VEGF) inhibitors. RESULTS: At the time that OCT emerged, the gold standard for imaging of nvAMD was fluorescein angiography (FA), a time-consuming, dye-based, invasive technique that provided en face images of the retina and was used to characterize leakage, perfusion status, and the types of macular neovascularization (MNV). In comparison, OCT imaging was a fast, safe, noninvasive technique that complemented FA imaging by providing cross-sectional images of the macula. OCT was able to visualize and quantify the macular fluid that was associated with the presence of excess VEGF, which was identified by intraretinal fluid, subretinal fluid, and fluid under the retinal pigment epithelium (RPE).…

PURPOSE: Scleral stiffening has been proposed as a treatment for glaucoma to protect the lamina cribrosa (LC) from excessive intraocular pressure-induced deformation. Here we experimentally evaluated the effects of moderate stiffening of the peripapillary sclera on the deformation of the LC. METHODS: An annular sponge, saturated with 1.25% glutaraldehyde, was applied to the external surface of the peripapillary sclera for 5 minutes to stiffen the sclera. Tissue deformation was quantified in two groups of porcine eyes, using digital image correlation (DIC) or computed tomography imaging and digital volume correlation (DVC). In group A (n = 14), eyes were subjected to inflation testing before and after scleral stiffening. Digital image correlation was used to measure scleral deformation and quantify the magnitude of scleral stiffening. In group B (n = 5), the optic nerve head region was imaged using synchrotron radiation phase-contrast microcomputed tomography (PC μCT) at an isotropic spatial resolution of 3.2 μm. Digital volume correlation was used to compute the full-field…

PURPOSE: To determine risk factors for glaucoma in a population-based study in the United States. METHODS: Participants age 40 and older from the National Health and Nutrition Examination Survey underwent questionnaires, physical examination, laboratory tests, and vision tests including fundus imaging. Glaucoma was determined based on expert grading of fundus photographs. Regression modeling of glaucoma risk factors was performed. RESULTS: Participants with glaucoma (172) were older (mean age 68.1 [95% confidence interval (CI) 65.6-70.7] vs. 56.4 years [95% CI 55.6-57.2, P < 0.001]), likely to have less than high school education (25.1% vs. 18.1%, P = 0.05), to have diabetes (23.1% vs. 10.8%, P < 0.001), to have central obesity (72.5% vs. 60.7%, P = 0.01), to have systolic hypertension (30.3% vs. 20.1%, P = 0.01), to have diastolic hypotension (30.3% vs. 13.9%, P < 0.001), and to be nonsmokers (91.0% vs. 79.3%, P = 0.002). Sex, poverty, access to health care, fasting glucose, insulin dependence, body mass index, cholesterol levels, diastolic hypertension, systolic hypotension,…

PURPOSE: To compensate for reflectance variation when quantifying vessel density by optical coherence tomography angiography (OCTA). METHODS: Healthy participants received 6×6-mm macular and 4.5×4.5-mm optic nerve head (ONH) angiography scans on a 70-kHz spectral-domain optical coherence tomography system. The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to compute the OCTA signal. Mean reflectance projection and maximum decorrelation projection were used to create en face OCT and OCTA images. Background OCTA noise in static tissue was evaluated in the foveal avascular zone (FAZ). Vessel density was calculated from en face retinal OCTA that was binarized according to a decorrelation threshold. RESULTS: The average retinal decorrelation noise in the FAZ was linearly related to the average logarithmic-scale OCT reflectance signal. Based on this relationship, a reflectance-adjusted decorrelation threshold equation was developed to filter out 97.5% of background OCTA noise. A fixed threshold was also used for comparison. The superficial vascular complex…

PURPOSE: Visual impairment and intracranial pressure (VIIP) syndrome is a health concern for long-duration spaceflight, and a proposed risk factor is elevation of intracranial pressure (ICP). Our goal was to use finite element modeling to simulate how elevated ICP and interindividual differences affect tissue deformation within the optic nerve head (ONH). METHODS: We considered three ICP conditions: the upright and supine position on earth and an elevated ICP assumed to occur in chronic microgravity. Within each condition we used Latin hypercube sampling to consider a range of pressures and ONH tissue mechanical properties, determining the influence of each input on the following outcome measures: peak strains in the prelaminar tissue, lamina cribrosa, and retrolaminar optic nerve. Elevated strains can alter cell phenotype and induce tissue remodeling. RESULTS: Elevating ICP increased the strains in the retrolaminar optic nerve. Variations in IOP, ICP, and in optic nerve and lamina cribrosa stiffness had the strongest influence on strains within the ONH. We predicted that 5% to 47%…

PURPOSE: The purpose of this study was to determine whether reduced fine motor skills in children with amblyopia improve after binocular treatment and whether improvements are sustained once treatment has ceased. METHODS: Fine motor skills (FMS [Bruininks-Oseretsky Test of Motor Proficiency]), visual acuity (VA [Early Treatment of Diabetic Retinopathy Study chart]) and level of binocular function (BF [Randot preschool stereoacuity and Worth 4 Dot]) were measured in children with amblyopia (n = 20; age: 8.5 ± 1.3 years; 11 anisometropic; 5 strabismic; 4 mixed) and in a group of visually normal children (n = 10; age: 9.63 ± 1.6 years). Eighteen children with amblyopia subsequently completed 5 weeks of binocular treatment provided by home-based dichoptic iPod game play. FMS, VA, and BF were retested at the end of treatment and 12 weeks after treatment cessation. All visually normal children also completed FMS measurements at baseline and 5 weeks later to assess test-retest variability of the FMS scores. RESULTS: Prior to treatment, FMS scores in children with amblyopia were poorer than…

PURPOSE: The purpose of this study was to evaluate the effect of disease severity and number of tests acquired during follow-up on the relative odds of identifying progression by structural or functional tests in glaucoma. METHODS: This was an observational cohort study involving 462 eyes of 305 patients with glaucoma and 62 eyes of 49 healthy subjects. Glaucoma patients and healthy subjects were followed for an average of 3.6 ± 0.9 and 3.8 ± 0.9 years, with a median (interquantile range) of 8 (6-9) and 7 (6-8) visits, respectively. At each visit, subjects underwent visual field assessment with standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) evaluation by spectral-domain optical coherence tomography (SD-OCT). Slopes of change in SAP mean sensitivity and OCT RNFL thickness over time were estimated by linear regression using progressively cumulative visits over time. Cutoff values for age-related expected rates of change for each test were obtained from the healthy group. Progression by SD-OCT and/or SAP was determined if the slope of change was statistically…

PURPOSE: To assess the genotoxic effect of airborne particulate matter on corneal epithelial cells and investigate the role of reactive oxygen species (ROS) formation in this process. METHODS: Immortalized human corneal epithelial cells (HCECs) and primary bovine corneal epithelial cells were exposed to airborne particulate matter collected from Guangzhou for 24 hours. The cell viability and toxicity were measured by the CCK-8 test and lactate dehydrogenase (LDH) release, respectively. The DNA breaks and DNA repair were examined by alkaline comet assay and by immunofluorescence staining of the phosphorylated histone variant H2AX (γH2AX), respectively. Reactive oxygen species production was assessed by the fluorescent probe, CM-H2DCFDA. Cell senescence was evaluated with senescence-associated β-Galactosidase staining, and cell ultrastructure was observed with transmission electron microscopy. RESULTS: Exposure to PM2.5 at the concentration of 20 μg/mL to 200 μg/mL decreased cell viability and increased LDH release. Remarkably increased DNA double-stand breaks, increased expression of…

PURPOSE: The parapapillary gamma zone has been defined as the parapapillary region without Bruch's membrane. We examined which morphologic parameters are associated with the presence and size of the parapapillary gamma zone. METHODS: Using fundus photographs and spectral-domain optical coherence tomographic images of the optic nerve head in the population-based Beijing Eye Study, we determined parapapillary gamma zone width, macular Bruch's membrane length, optic disc-fovea distance, the angle of horizontal optic disc rotation, the angle of vertical optic disc rotation, and the ratio of the vertical-to-horizontal disc diameter. RESULTS: The study included 2068 individuals with a mean age of 63.0 ± 9.0 years (range, 50-91 years), and mean axial length was 23.2 ± 1.0 mm (range, 18.96-28.87 mm). In multivariate analysis, larger width of parapapillary gamma zone was associated with more marked vertical optic disc rotation (P < 0.001; standardized correlation coefficient β, 0.15; nonstandardized correlation coefficient B, 0.02; 95% confidence interval [CI], 0.02, 0.03), more marked…

Purpose: To investigate correlations among macular ganglion cell complex (GCC) layer thickness, macular capillary density, and macular function in patients affected by retinitis pigmentosa (RP). Methods: Fourteen patients (28 eyes) with previous diagnosis of RP were enrolled. The diagnosis of these conditions was made based on both clinical features and electrophysiological examination. All patients underwent a complete ophthalmologic examination, including optical coherence tomography angiography (OCTA) and multifocal electroretinogram (mfERG). Main outcome measures were macular GCC layer thickness; superficial capillary plexus (SCP) vessel density; deep capillary plexus (DCP) vessel density; choriocapillaris plexus (CCP) vessel density; and amplitudes of mfERG N1 and P1 waves. Results: Average GCC thickness was significantly thinner in RP patients (76.0 ± 25.1 and 109.2 ± 17.5 μm, P = 0.028). Superficial capillary plexus density was 42.2 ± 3.4% in the RP group and 51.4 ± 2.3% in the control group (P < 0.001). Deep capillary plexus density was reduced in RP patients (42.7 ± 6.2%)…

PURPOSE: The contrast sensitivity function (CSF) provides a detailed description of an individual's spatial-pattern detection capability. We tested the hypothesis that the CSFs of people with low vision differ from a "normal" CSF only in their horizontal and vertical positions along the spatial frequency (SF) and contrast sensitivity (CS) axes. METHODS: Contrast sensitivity for detecting horizontal sinewave gratings was measured with a two temporal-interval forced-choice staircase procedure, for a range of SFs spanning 5 to 6 octaves, for 20 low-vision observers and five adults with normal vision. An asymmetric parabolic function was used to fit the aggregate data of the normal-vision observers, yielding the "normal template." Each of the 20 low-vision CSFs was fit in two ways, by using a shape-invariant version of the normal template (with the width parameters fixed) that was shifted along the log-SF and log-CS axes, and by an unconstrained asymmetric parabolic function ("free-fit"). RESULTS: The two fitting methods yielded values of the peak CS, the SF corresponding to peak CS,…

PURPOSE: To determine the discriminant function of optical coherence tomography angiography (OCTA) by disease severity in glaucoma. METHODS: In this prospective, observational cross-sectional study, all subjects underwent visual fields, retinal nerve fiber layer (RNFL) measurements, and OCTA imaging. Local fractal analysis was applied to OCTA images (radial peripapillary capillaries [RPC] layer). Vessel density en face and inside the disc and spacing between large and small vessels were quantified. Stepwise logistic regression was performed and a glaucoma severity score (range, 0-1: 0, normal; 1, severe glaucoma) was developed by using global and regional (superotemporal [ST], inferotemporal [IT], temporal, superonasal [SN], inferonasal, and nasal) vascular parameters. Glaucoma severity score was compared with visual field and RNFL indices. RESULTS: One hundred ninety-nine eyes (112 subjects) with glaucoma (28 eyes preperimetric; 83 early, 43 moderate, and 45 severe glaucoma) and 74 normal (54 subjects) eyes were enrolled. Preperimetric and glaucomatous eyes had significantly…

Purpose: To assess whether tear hyperosmolarity, being diagnostic of dry eye disease (DED), is associated with specific alterations to the cytokine content of human tears that may provide a biomarker for DED. Methods: In this prospective, cross-sectional, clinical study, participants (n = 77) were recruited from a single clinical site and categorized into groups based upon tear osmolarity status (n = 62 hyperosmolar, n = 15 normo-osmolar). Comprehensive anterior eye clinical assessments were undertaken. Concentrations of seven cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, and TNF-α) in basal tears were assayed using multiplex cytometric bead array. The main outcome measure was difference in cytokine concentration between groups. Group comparisons were undertaken using 2-tailed t-tests. Cohen's effect size was calculated for each finding. Spearman correlations between cytokine concentrations, clinical symptoms, and clinical parameters of DED were calculated. Results: Tear hyperosmolarity was specifically associated with increased tear IFN-γ levels (13.3 ± 2.0 vs. 4.4 ± 1.4…

PURPOSE: To evaluate the relationships between RPE, photoreceptor, and choroidal degeneration in choroideremia. METHODS: Enhanced-depth imaging optical coherence tomography (EDI-OCT), scanning laser ophthalmoscopy (SLO), and autofluorescence (AF) were performed on 39 patients (78 eyes) with choroideremia. The edges of surviving outer retina on OCT and residual AF were aligned. The distribution of outer retinal tubulations was mapped over a range of ages (16-71 years), and comparison made between pre- and postsubretinal gene therapy. Subfoveal choroidal thickness (SFCT) was compared between 23 choroideremia patients (42 eyes) and 20 age- and refraction-matched male controls (40 eyes). RESULTS: The edges of RPE AF aligned with a reduction in outer nuclear layer thickness (Spearman's rho = 0.9992). Correlation was also found between the quality of AF and integrity of ellipsoid zone within islands of surviving retina. Tubulations existed in 71 of 78 (91%) eyes with choroideremia and remained stable following gene therapy. Subfoveal choroidal thickness was reduced at baseline in…

PURPOSE: Preclinical studies on photoreceptor transplantation provided evidence for restoration of visual function with pluripotent stem cells considered as a potential source for sufficient amounts of donor material. Adequate preclinical models representing retinal disease conditions of potential future patients are needed for translation research. Here we compared transplant integration in mouse models with mild (prominin1-deficient; Prom1-/-) or severe (cone photoreceptor function loss 1/rhodopsin-deficient double-mutant; Cpfl1/Rho-/-) cone-rod degeneration. METHODS: For photoreceptor transplant production, we combined the mouse embryonic stem cell retinal organoid system with rhodopsin-driven GFP cell labeling by recombinant adeno-associated virus (AAV). Organoid-derived photoreceptors were enriched by CD73-based magnetic-activated cell sorting (MACS) and transplanted subretinally into wild-type, Prom1-/- and Cpfl1/Rho-/- hosts. The survival, maturation, and synapse formation of donor cells was analyzed by immunohistochemistry. RESULTS: Retinal organoids yielded high…

PURPOSE: Recent studies suggest that photoreceptor cells regulate local inflammation in the retina in diabetes. The purpose of this study was to determine if photoreceptor cells themselves produce inflammatory proteins in diabetes and if soluble factors released by photoreceptors in elevated glucose induce inflammatory changes in nearby cells. METHODS: Laser capture microdissection was used to isolate the outer retina (photoreceptors) from the inner retina in nondiabetic and diabetic mice. Diabetes-induced changes in the expression of inflammatory targets were assessed by reverse transcription polymerase chain reaction and immunohistochemistry. Cell culture experiments were carried out to determine if photoreceptors in vitro and ex vivo release soluble mediators that can stimulate nearby cells. Photoreceptor contribution to leukocyte-mediated endothelial cell death was tested using coculture models. RESULTS: Messenger ribonucleic acid and protein expression levels for inflammatory proteins intercellular adhesion molecule 1 (ICAM1), inducible nitric oxide synthase (iNOS), and…

PURPOSE: To describe prevalence and associations of anisometropia in children. METHODS: The cross-sectional school-based study included children aged 4 to 18 years. RESULTS: The study included 6025 (94.7%) of 6364 eligible children. Mean refractive anisometropia was 0.37 ± 0.57 diopters (median: 0.25 diopters; range: 0-7.88 diopters; prevalence [≥1 diopter]: 7.0% ± 0.3%). In multivariate analysis (regression coefficient r: 0.66), higher refractive anisometropia was associated with older age (P < 0.001; β: 0.07; B: 0.01; 95% CI: 0.01-0.02), higher maternal education level (P < 0.001; β: 0.04; B: 0.02; 95% CI: 0.01-0.03), more total time spent indoors reading or writing (P = 0.001; β: 0.04; B: 0.01; 95% CI: 0.01-0.02), larger intereye difference in axial length (P < 0.001; β: 0.57; B: 1.20; 95% CI: 1.15-1.24), shorter mean axial length of both eyes (P = 0.03; β: -0.03; B: -0.02; 95% CI: -0.03 to -0.001), larger intereye difference in best corrected visual acuity (BCVA) (P < 0.001; β: 0.14; B: 1.83; 95% CI: 1.54-2.12), and lower stereoacuity (P < 0.001; β: 0.08; B: 0.31; 95% CI:…

PURPOSE: In Denmark, the occurrence of Leber hereditary optic neuropathy (LHON) has continuously been monitored since 1944. We provide here a summary of 70 years of data collection including registered lines and subjects by the end of 2012. METHODS: Affected individuals were identified from a national register of hereditary eye diseases at the National Eye Clinic (NEC), a tertiary low vision rehabilitation center for the entire Danish population. The assembling of LHON pedigrees was based on the reconstruction of published families and newly diagnosed cases from 1980 to 2012 identified in the files of NEC. Genealogic follow-up on the maternal ancestry of all affected individuals was performed to identify a possible relation to an already known maternal line. A full genotypic characterization of the nation-based LHON cohort is provided. RESULTS: Forty different lines were identified. The number of live affected individuals with a verified mitochondrial DNA mutation was 104 on January 1, 2013, which translates to a prevalence rate of 1:54,000 in the Danish population. CONCLUSIONS:…

PURPOSE: To analyze visual outcome, effectiveness of various modes of antibiotic treatment, and prognostic factors in patients with serologically proven syphilitic uveitis. METHODS: The clinical records of 85 patients (139 eyes) diagnosed with syphilitic uveitis between 1984 and 2013 at tertiary centers in The Netherlands were retrospectively analyzed. RESULTS: Mean age was 47 years (range, 27-73 years), 82.4% were male. HIV positivity was found in 28 (35.9%) patients; 13 were newly diagnosed. Most patients had pan (45.9%) or posterior (31.8%) uveitis. On average, logMAR visual acuity (VA) improved significantly from 0.55 at the start of syphilis treatment to 0.34 at 1 month and to 0.27 at 6 months follow-up. Most patients (86.7%) reached disease remission. No differences in efficacy between the various treatment regimens were found. A high logMAR VA at the start of syphilis treatment and a treatment delay of more than 12 weeks were prognostic for a high logMAR VA at 6 months follow-up. Chronicity was not related to any form of treatment, HIV status, or Venereal Disease Research…