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PurposeThis study aimed to compare a new Artificial Intelligence (AI) method to conventional mathematical warping in accurately overlaying peripheral retinal vessels from two different imaging devices: confocal scanning laser ophthalmoscope (cSLO) wide-field images and SLO ultra-wide field images.MethodsImages were captured using the Heidelberg Spectralis 55-degree field-of-view and Optos ultra-wide field. The conventional mathematical warping was performed using Random Sample Consensus-Sample and Consensus sets (RANSAC-SC). This was compared to an AI alignment algorithm based on a one-way forward registration procedure consisting of full Convolutional Neural Networks (CNNs) with Outlier Rejection (OR CNN), as well as an iterative 3D camera pose optimization process (OR CNN + Distortion Correction [DC]). Images were provided in a checkerboard pattern, and peripheral vessels were graded in four quadrants based on alignment to the adjacent box.ResultsA total of 660 boxes were analysed from 55 eyes. Dice scores were compared between the three methods (RANSAC-SC/OR CNN/OR CNN + DC): 0.3341/0.4665/4784 for fold 1-2 and 0.3315/0.4494/4596 for fold 2-1 in composite images. The images composed using the OR CNN + DC have a median rating of 4 (out of 5) versus 2 using RANSAC-SC. The odds of getting a higher grading level are 4.8 times higher using our OR CNN + DC than RANSAC-SC (p

In this retrospective case series on neovascular age-related macular degeneration (nAMD), we aimed to improve Choroidal Neovascularization (CNV) visualization in Optical Coherence Tomography Angiography (OCTA) scans by addressing segmentation errors. Out of 198 eyes, 73 OCTA scans required manual segmentation correction. We compared uncorrected scans to those with minimal (2 corrections), moderate (10 corrections), and detailed (50 corrections) efforts targeting falsely segmented Bruch's Membrane (BM). Results showed that 55% of corrected OCTAs exhibited improved quality after manual correction. Notably, minimal correction (2 scans) already led to significant improvements, with additional corrections (10 or 50) not further enhancing expert grading. Reduced background noise and improved CNV identification were observed, with the most substantial improvement after two corrections compared to baseline uncorrected images. In conclusion, our approach of correcting segmentation errors effectively enhances image quality in OCTA scans of nAMD. This study demonstrates the efficacy of the method, with 55% of resegmented OCTA images exhibiting enhanced quality, leading to a notable increase in the proportion of high-quality images from 63 to 83%.

BackgroundRetinitis pigmentosa (RP) represents a group of progressive, genetically heterogenous blinding diseases. Recently, relationships between measures of retinal function and structure are needed to help identify outcome measures or biomarkers for clinical trials. The ability to align retinal multimodal images, taken on different platforms, will allow better understanding of this relationship. We investigate the efficacy of artificial intelligence (AI) in overlaying different multimodal retinal images in RP patients.MethodsWe overlayed infrared images from microperimetry on near-infra-red images from scanning laser ophthalmoscope and spectral domain optical coherence tomography in RP patients using manual alignment and AI. The AI adopted a two-step framework and was trained on a separate dataset. Manual alignment was performed using in-house software that allowed labelling of six key points located at vessel bifurcations. Manual overlay was considered successful if the distance between same key points on the overlayed images was ≤1/2°.ResultsFifty-seven eyes of 32 patients were included in the analysis. AI was significantly more accurate and successful in aligning images compared to manual alignment as confirmed by linear mixed-effects modelling (p

ObjectiveTo develop automated algorithms for the detection of posterior vitreous detachment (PVD) using OCT imaging.DesignEvaluation of a diagnostic test or technology.SubjectsOverall, 42 385 consecutive OCT images (865 volumetric OCT scans) obtained with Heidelberg Spectralis from 865 eyes from 464 patients at an academic retina clinic between October 2020 and December 2021 were retrospectively reviewed.MethodsWe developed a customized computer vision algorithm based on image filtering and edge detection to detect the posterior vitreous cortex for the determination of PVD status. A second deep learning (DL) image classification model based on convolutional neural networks and ResNet-50 architecture was also trained to identify PVD status from OCT images. The training dataset consisted of 674 OCT volume scans (33 026 OCT images), while the validation testing set consisted of 73 OCT volume scans (3577 OCT images). Overall, 118 OCT volume scans (5782 OCT images) were used as a separate external testing dataset.Main outcome measuresAccuracy, sensitivity, specificity, F1-scores, and area under the receiver operator characteristic curves (AUROCs) were measured to assess the performance of the automated algorithms.ResultsBoth the customized computer vision algorithm and DL model results were largely in agreement with the PVD status labeled by trained graders. The DL approach achieved an accuracy of 90.7% and an F1-score of 0.932 with a sensitivity of 100% and a specificity of 74.5% for PVD detection from an OCT volume scan. The AUROC was 89% at the image level and 96% at the volume level for the DL model. The customized computer vision algorithm attained an accuracy of 89.5% and an F1-score of 0.912 with a sensitivity of 91.9% and a specificity of 86.1% on the same task.ConclusionsBoth the computer vision algorithm and the DL model applied on OCT imaging enabled reliable detection of PVD status, demonstrating the potential for OCT-based automated PVD status classification to assist with vitreoretinal surgical planning.Financial disclosuresProprietary or commercial disclosure may be found after the references.

This cross-sectional study aimed to investigate the hypothesis that permanent capillary damage may underlie the long-term COVID-19 sequela by quantifying the retinal vessel integrity. Participants were divided into three subgroups; Normal controls who had not been affected by COVID-19, mild COVID-19 cases who received out-patient care, and severe COVID-19 cases requiring intensive care unit (ICU) admission and respiratory support. Patients with systemic conditions that may affect the retinal vasculature before the diagnosis of COVID-19 infection were excluded. Participants underwent comprehensive ophthalmologic examination and retinal imaging obtained from Spectral-Domain Optical Coherence Tomography (SD-OCT), and vessel density using OCT Angiography. Sixty-one eyes from 31 individuals were studied. Retinal volume was significantly decreased in the outer 3 mm of the macula in the severe COVID-19 group (p = 0.02). Total retinal vessel density was significantly lower in the severe COVID-19 group compared to the normal and mild COVID-19 groups (p = 0.004 and 0.0057, respectively). The intermediate and deep capillary plexuses in the severe COVID-19 group were significantly lower compared to other groups (p

Multi-modal retinal image registration plays an important role in the ophthalmological diagnosis process. The conventional methods lack robustness in aligning multi-modal images of various imaging qualities. Deep-learning methods have not been widely developed for this task, especially for the coarse-to-fine registration pipeline. To handle this task, we propose a two-step method based on deep convolutional networks, including a coarse alignment step and a fine alignment step. In the coarse alignment step, a global registration matrix is estimated by three sequentially connected networks for vessel segmentation, feature detection and description, and outlier rejection, respectively. In the fine alignment step, a deformable registration network is set up to find pixel-wise correspondence between a target image and a coarsely aligned image from the previous step to further improve the alignment accuracy. Particularly, an unsupervised learning framework is proposed to handle the difficulties of inconsistent modalities and lack of labeled training data for the fine alignment step. The proposed framework first changes multi-modal images into a same modality through modality transformers, and then adopts photometric consistency loss and smoothness loss to train the deformable registration network. The experimental results show that the proposed method achieves state-of-the-art results in Dice metrics and is more robust in challenging cases.

We previously identified a homozygous G178R mutation in human ASRGL1 (hASRGL1) through whole-exome analysis responsible for early onset retinal degeneration (RD) in patients with cone-rod dystrophy. The mutant G178R ASRGL1 expressed in Cos-7 cells showed altered localization, while the mutant ASRGL1 in E. coli lacked the autocatalytic activity needed to generate the active protein. To evaluate the effect of impaired ASRGL1 function on the retina in vivo, we generated a mouse model with c.578_579insAGAAA (NM_001083926.2) mutation (Asrgl1mut/mut) through the CRISPR/Cas9 methodology. The expression of ASGRL1 and its asparaginase activity were undetectable in the retina of Asrgl1mut/mut mice. The ophthalmic evaluation of Asrgl1mut/mut mice showed a significant and progressive decrease in scotopic electroretinographic (ERG) response observed at an early age of 3 months followed by a decrease in photopic response around 5 months compared with age-matched wildtype mice. Immunostaining and RT-PCR analyses with rod and cone cell markers revealed a loss of cone outer segments and a significant decrease in the expression of Rhodopsin, Opn1sw, and Opn1mw at 3 months in Asrgl1mut/mut mice compared with age-matched wildtype mice. Importantly, the retinal phenotype of Asrgl1mut/mut mice is consistent with the phenotype observed in patients harboring the G178R mutation in ASRGL1 confirming a critical role of ASRGL1 in the retina and the contribution of ASRGL1 mutations in retinal degeneration.

Multi-modal retinal image registration between 2D Ultra-Widefield (UWF) and narrow-angle (NA) images has not been well-studied, since most existing methods mainly focus on NA image alignment. The stereographic projection model used in UWF imaging causes strong distortions in peripheral areas, which leads to inferior alignment quality. We propose a distortion correction method that remaps the UWF images based on estimated camera view points of NA images. In addition, we set up a CNN-based registration pipeline for UWF and NA images, which consists of the distortion correction method and three networks for vessel segmentation, feature detection and matching, and outlier rejection. Experimental results on our collected dataset shows the effectiveness of the proposed pipeline and the distortion correction method.

Optical Coherence Tomography (OCT) is a powerful technique for non-invasive 3D imaging of biological tissues at high resolution that has revolutionized retinal imaging. A major challenge in OCT imaging is the motion artifacts introduced by involuntary eye movements. In this paper, we propose a convolutional neural network that learns to correct axial motion in OCT based on a single volumetric scan. The proposed method is able to correct large motion, while preserving the overall curvature of the retina. The experimental results show significant improvements in visual quality as well as overall error compared to the conventional methods in both normal and disease cases.

Comparing automated retinal layer segmentation using proprietary software (Heidelberg Spectralis HRA + OCT) and cross-platform Optical Coherence Tomography (OCT) segmentation software (Orion). Image segmentations of normal and diseased (iAMD, DME) eyes were performed using both softwares and then compared to the 'gold standard' of manual segmentation. A qualitative assessment and quantitative (layer volume) comparison of segmentations were performed. Segmented images from the two softwares were graded by two masked graders and in cases with difference, a senior retina specialist made a final independent decisive grading. Cross-platform software was significantly better than the proprietary software in the segmentation of NFL and INL layers in Normal eyes. It generated significantly better segmentation only for NFL in iAMD and for INL and OPL layers in DME eyes. In normal eyes, all retinal layer volumes calculated by the two softwares were moderate-strongly correlated except OUTLY. In iAMD eyes, GCIPL, INL, ONL, INLY, TRV layer volumes were moderate-strongly correlated between softwares. In eyes with DME, all layer volume values were moderate-strongly correlated between softwares. Cross-platform software can be used reliably in research settings to study the retinal layers as it compares well against manual segmentation and the commonly used proprietary software for both normal and diseased eyes.

PurposeThe purpose of this study was to evaluate the ability to align two types of retinal images taken on different platforms; color fundus (CF) photographs and infrared scanning laser ophthalmoscope (IR SLO) images using mathematical warping and artificial intelligence (AI).MethodsWe collected 109 matched pairs of CF and IR SLO images. An AI algorithm utilizing two separate networks was developed. A style transfer network (STN) was used to segment vessel structures. A registration network was used to align the segmented images to each. Neither network used a ground truth dataset. A conventional image warping algorithm was used as a control. Software displayed image pairs as a 5 × 5 checkerboard grid composed of alternating subimages. This technique permitted vessel alignment determination by human observers and 5 masked graders evaluated alignment by the AI and conventional warping in 25 fields for each image.ResultsOur new AI method was superior to conventional warping at generating vessel alignment as judged by masked human graders (P < 0.0001). The average number of good/excellent matches increased from 90.5% to 94.4% with AI method.ConclusionsAI permitted a more accurate overlay of CF and IR SLO images than conventional mathematical warping. This is a first step toward developing an AI that could allow overlay of all types of fundus images by utilizing vascular landmarks.Translational relevanceThe ability to align and overlay imaging data from multiple instruments and manufacturers will permit better analysis of this complex data helping understand disease and predict treatment.

PurposeTo assess early retinal microvascular and functional changes in diabetic patients without clinical evidence of diabetic retinopathy with optical coherence tomography angiography and central visual analyzer.MethodsThis was an observational case-control study of diabetic patients without diabetic retinopathy and nondiabetic controls. Patients underwent optical coherence tomography angiography imaging and visual acuity testing using the central visual analyzer. The foveal avascular zone area and the capillary density in the superficial and deep capillary plexuses were measured manually by a masked grader.ResultsSixty eyes from 35 diabetic patients were included in the study group, and 45 eyes from 31 nondiabetic patients were included in the control group. The foveal avascular zone area was not significantly different between the diabetic group and controls (both P > 0.05). The mean capillary density in the deep capillary plexus was significantly lower in diabetic eyes compared with control eyes (P = 0.04). The mean visual acuity in all central visual analyzer modules was significantly decreased in diabetic patients compared with controls (all P < 0.05).ConclusionOptical coherence tomography angiography was able to detect retinal microvascular changes in the deep capillary plexus, and the central visual analyzer showed signs of decreased visual acuity under conditions simulating suboptimal contrast and glare in diabetic patients without diabetic retinopathy.

PurposeSubretinal prostheses are a novel technology for restoring useful vision in patients with retinitis pigmentosa or age-related macular degeneration. We characterize the surgical implantation technique and functional time window of an acute rabbit eye model for testing of human subretinal prostheses.MethodsRetinal prostheses were implanted subretinally in 26 rabbits using a two-step technique. Fundus imaging, fluorescein fundus angiography, and optical coherence topography (OCT) were conducted postoperatively from days 1 to 21 to monitor prosthesis positioning and retinal anatomic changes.ResultsSuccessful implantation and excellent retina apposition were achieved in 84.6% of the rabbits. OCTs showed the overlying retina at full thickness for the first 2 days after implantation. Histology confirmed intact inner layers of the overlying retina until day 3. Progressive atrophy of the overlying retina was revealed by repeated OCTs; approximately 40% of the retina thickness remained on postoperative days 5 and 6.ConclusionsThe two-step implantation technique works well for the rabbit eye model with human prostheses. Rabbit retina may be used for acute electrophysiologic testing of a retinal prosthesis, but is unsuitable for chronic studies due to the merangiotic retina and its limited time window of validity.Translational relevanceThe improved efficacy in prosthesis surgery using this technique will circumvent the challenges in animal models that provide human-like features critical for the transition into human clinical trials.

PurposeTo evaluate depth of field, lateral resolution, and image quality of a heads-up 3D visualization system for vitreoretinal surgery using physician survey and optical measurement outcomes.MethodsDepth of field and lateral resolution were compared between the standard ocular viewing system and the digital 3D system at ×5, ×13, and ×18 magnification by 6 retinal surgeons. Optical techniques were used as well as a survey of surgeon impression. Surgeon impression surveys were performed after 6 weeks of surgical use of the device.ResultsPhysician questionnaire survey scores for depth of field at high magnification were better for the digital 3D system and equivalent for all other categories. Measured lateral resolution was 36.7 mm and 16.6 mm at ×5 magnification (P < 0.001), 14.3 mm and 6.4 mm at ×13 magnification (P < 0.001), and 9.8 mm and 4.2 mm (P < 0.001) at ×18 magnification for the digital 3D and oculars, respectively. Measured depth of field was 4.00 mm and 6.78 mm at ×5 magnification (P = 0.027), 0.72 mm and 0.86 mm at ×13 (P = 0.311), and 0.28 mm and 0.40 mm at ×18 magnification (P = 0.235) for the oculars and digital 3D, respectively.ConclusionLateral resolution of the digital 3D system was half that of the ocular viewing system and there was some improvement in depth of field with the digital system. Surgeon impression suggested that the digital system was superior when evaluating depth of field at high magnification.

PurposeTo compare retinal pathology visualization in multispectral scanning laser ophthalmoscope imaging between the Spectralis and Optos devices.MethodsThis retrospective cross-sectional study included 42 eyes from 30 patients with age-related macular degeneration (19 eyes), diabetic retinopathy (10 eyes), and epiretinal membrane (13 eyes). All patients underwent retinal imaging with a color fundus camera (broad-spectrum white light), the Spectralis HRA-2 system (3-color monochromatic lasers), and the Optos P200 system (2-color monochromatic lasers). The Optos image was cropped to a similar size as the Spectralis image. Seven masked graders marked retinal pathologies in each image within a 5 × 5 grid that included the macula.ResultsThe average area with detected retinal pathology in all eyes was larger in the Spectralis images compared with Optos images (32.4% larger, P < 0.0001), mainly because of better visualization of epiretinal membrane and retinal hemorrhage. The average detection rate of age-related macular degeneration and diabetic retinopathy pathologies was similar across the three modalities, whereas epiretinal membrane detection rate was significantly higher in the Spectralis images.ConclusionSpectralis tricolor multispectral scanning laser ophthalmoscope imaging had higher rate of pathology detection primarily because of better epiretinal membrane and retinal hemorrhage visualization compared with Optos bicolor multispectral scanning laser ophthalmoscope imaging.

Patients harboring homozygous c.498_499insC mutations in MFRP demonstrate hyperopia, microphthalmia, retinitis pigmentosa, retinal pigment epithelial atrophy, variable degrees of foveal edema, and optic disc drusen. The disease phenotype is variable, however, with some patients maintaining good central vision and cone function till late in the disease. A knock-in mouse model with the c.498_499insC mutation in Mfrp (Mfrp KI/KI) was developed to understand the effects of these mutations in the retina. The model shares many of the features of human clinical disease, including reduced axial length, hyperopia, retinal degeneration, retinal pigment epithelial atrophy, and decreased electrophysiological responses. In addition, the eyes of these mice had a significantly greater refractive error (p

PurposeFor more than 20 years, there has been an international, multidisciplinary effort to develop retinal prostheses to restore functional vision to patients blinded by retinal degeneration. We developed a novel subretinal prosthesis with 1512 optically addressed silicon nanowire photodiodes, which transduce incident light into an electrical stimulation of the remaining retinal circuitry. This study was conducted to evaluate the efficacy of optically driving the subretinal prosthesis to produce visual cortex activation via electrical stimulation of the retina.MethodsWe measured electrically evoked potential responses (EEPs) in rabbit visual cortex in response to illumination of the subretinal nanowire prosthesis with pulsed 852-nm infrared (IR) light. We compared the EEP responses to visually evoked potential responses (VEPs) to pulsed 532-nm visible light (positive control) and pulsed 852-nm IR light (negative control).ResultsActivating the devices with IR light produced EEP responses with a significantly higher trough-to-peak amplitude (54.17 ± 33.4 μV) than IR light alone (24.07 ± 22.1 μV) or background cortical activity (23.22 ± 17.2 μV). EEP latencies were significantly faster than focal VEP latencies. Focal VEPs produced significantly higher amplitudes (94.88 ± 43.3 μV) than EEPs. We also demonstrated how an electrode placed on the cornea can be used as a noninvasive method to monitor the function of the implant.ConclusionsThese results show that subretinal electrical stimulation with nanowire electrodes can elicit EEPs in the visual cortex, providing evidence for the viability of a subretinal nanowire prosthetic approach for vision restoration.

PurposeGeographic atrophy (GA) is the sequelae of macular degeneration. Automated inner retinal analysis using optical coherence tomography is flawed because segmentation software is calibrated for normal eyes. The purpose of this study is to determine whether ganglion cell layer (GCL) volume is reduced in GA using manual analysis.MethodsNineteen eyes with subfoveal GA and 22 controls were selected for morphometric analyses. Heidelberg scanning laser ophthalmoscope optical coherence tomography images of the optic nerve and macula were obtained, and the Viewing Module was used to manually calibrate retinal layer segmentation. Retinal layer volumes in the central 3-mm and surrounding 6-mm diameter were measured. Linear mixed models were used for statistics.ResultsThe GCL volume in the central 3 mm of the macula is less (P = 0.003), and the retinal nerve fiber layer volume is more (P = 0.02) in patients with GA when compared with controls. Ganglion cell layer volume positively correlated with outer nuclear layer volume (P = 0.020).ConclusionThe patients with geographic atrophy have a small significant loss of the GCL. Ganglion cell death may precede axonal loss, and increased macular retinal nerve fiber layer volumes are not indicative of GCL volume. Residual ganglion cell stimulation by interneurons may enable vision in patients with GA.

PurposeTo characterize inner retinal damage in patients with dry age-related macular degeneration (AMD) using high-resolution spectral domain optical coherence tomography images.MethodsSixty eyes of 60 patients with AMD were categorized using the Age-Related Eye Disease Study (AREDS) severity scale. Spectral domain optical coherence tomography images of these patients were quantified by manually correcting the segmentation of each retinal layer, including the retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer to ensure accurate delineation of layers. The mean ganglion cell complex thickness values (ganglion cell layer + inner plexiform layer + retinal nerve fiber layer) were compared with 30 eyes of 30 healthy subjects.ResultsNinety percent of eyes (81 eyes) required manual correction of segmentation. Compared with healthy subjects, mean ganglion cell complex thicknesses significantly decreased in more advanced dry AMD eyes, and this decrease was predominantly related to a change in inner plexiform layer thickness. There was no significant difference in thickness-related measurements between milder dry AMD (AREDS-2) eyes and healthy eyes (P > 0.05).ConclusionIn patients with dry AMD, automatic optical coherence tomography segmentation algorithms may be erroneous. As the severity of dry AMD increases, the inner plexiform layer layer becomes thinned, suggesting that transsynaptic degeneration may be occurring, as the photoreceptor layer is affected by AMD.

PurposeOur purpose was to compare the characteristics of the retinal and choroidal lesions including choroidal nevus, choroidal melanoma and congenital hypertrophy of the retina pigment epithelium using conventional color fundus photography (CFP) and multicolor imaging (MCI).MethodsThe paired images of patients with retinal or choroidal lesions were assessed for the visibility of lesion's border, halo and drusen using a grading scale (0-2). The area of the lesion was measured on both imaging modalities. The same grading was also done on the individual color channels of MCI for a further evaluation.ResultsThirty-three eyes of 33 patients were included. There were no significant differences in the mean border, drusen and halo visibility scores between the two imaging modalities (p = 0.12, p = 0.70, p = 0.35). However, the mean area of the lesion was significantly smaller on MCI than that on CFP (14.9±3.3 versus 18.7±3.4 mm2, p = 0.01).ConclusionThe appearance of choroidal and/ or retinal lesions on MCI may be different than that on CFP. Though MCI can provide similar information with CFP for the features of retinal and/ or choroidal lesions including border, halo and drusen; the infrared light reflection on MCI underestimates the extent of the choroidal lesion by 33%.

PurposeTo compare the visualization of the epiretinal membrane (ERM) using multicolor imaging (MCI) (Heidelberg Engineering, Carlsbad, CA) and conventional white light flood color fundus photography (FP) (Topcon).MethodsThe paired images of patients with ERM who underwent same-day MCI and FP examinations were reviewed. Visibility of the ERM was graded using a scale (0: not visible, 1: barely visible, and 2: clearly visible) by masked readers, and surface folds were counted to quantify the membrane visibility for each method. Images from individual color channels in MCI (green, blue, and infrared) were also graded using the same method to further investigate MCI images.ResultsForty-eight eyes of 42 patients were included. The average ERM visibility score was 1.8 ± 0.37 for MCI and 1.01 ± 0.63 for FP (P < 0.001). The number of the surface folds detected per quadrant was signifi8cantly higher in MCI than that in FP (6.79 ± 3.32 vs. 2.85 ± 2.81, P < 0.001). The ERM was graded with similar scores on the two modalities in 43.8% of the eyes; in 56.2%, the ERM was better visualized on MCI than that on FP. Conventional FP failed to detect ERM in 11.4% of eyes when the mean central retinal thickness was

PurposeMacular pigment, composed of lutein, zeaxanthin, and meso-zeaxanthin, is postulated to protect against age-related macular degeneration, likely because of filtering blue light and its antioxidant properties. Macular pigment optical density (MPOD) is reported to be associated with macular function evaluated by visual acuity and multifocal electroretinogram. Given the importance of macular pigment, reliable and accurate measurement methods are important. The main purpose of this study is to determine the reproducibility of MPOD measurement by two-wavelength autofluorescence method using scanning laser ophthalmoscopy.MethodsSixty-eight eyes of 39 persons were enrolled in the study, including 11 normal eyes, 16 eyes with wet age-related macular degeneration, 16 eyes with dry age-related macular degeneration, 11 eyes with macular edema due to diabetic mellitus, branch retinal vein occlusion or macular telangiectasia, and 14 eyes with tractional maculopathy, including vitreomacular traction, epiretinal membrane, or macular hole. MPOD was measured with a two-wavelength (488 and 514 nm) autofluorescence method with the Spectralis HRA + OCT after pupil dilation. The measurement was repeated for each eye 10 minutes later. The analysis of variance and Bland-Altman plot were used to assess the reproducibility between the two measurements.ResultsThe mean MPOD at eccentricities of 1° and 2° was 0.36 ± 0.17 (range: 0.04-0.69) and 0.15 ± 0.08 (range: -0.03 to 0.35) for the first measurement and 0.35 ± 0.17 (range: 0.02-0.68) and 0.15 ± 0.08 (range: -0.01 to 0.33) for the second measurement, respectively. The difference between the 2 measurements was not statistically significant, and the Bland-Altman plot showed 7.4% and 5.9% points outside the 95% limits of agreement, indicating an overall excellent reproducibility. Similarly, there is no significant difference between the first and second measurements of MPOD volume within eccentricities of 1°, 2°, and 6° radius, and the Bland-Altman plot showed 8.8%, 2.9%, and 4.4% points outside the 95% limits of agreement, respectively. The data for the reproducibility did not differ significantly among the various disease and normal eyes.ConclusionUnder routine examination conditions with pupil dilation, MPOD measurement by two-wavelength autofluorescence method showed a high reproducibility.

PurposeTo compare the real-time visualization of vitreoretino-choroidal structures using full-depth imaging (FDI) spectral domain optical coherence tomography (SD-OCT) and swept-source (SS)-OCT.MethodsFoveal scans using both FDI SD-OCT (Heidelberg Spectralis) and SS-OCT (Topcon Deep Range Imaging-OCT-1) were obtained in 40 normal eyes, 40 eyes with macular pathologies, and 40 eyes with glaucoma. Full-depth imaging SD-OCT images were obtained by manually enhancing the vitreoretinal interface first and then the choroid while averaging each OCT B-scan 100 times. Swept-source-OCT images were obtained by averaging each B-scan 96 times. After masking and randomly mixing the original OCT images, two independent physicians graded visualization of the premacular bursa, interdigitation zone line, and chorioscleral boundary, and also sharpness of choroidal structures.ResultsA real-time full-depth image of vitreoretino-choroidal structures was successfully achieved with FDI SD-OCT in 118 cases (98.3%) and with SS-OCT in 45 cases (37.5%, P < 0.001). Full-depth imaging SD-OCT imaging was superior to SS-OCT imaging in visualizing the anterior border of the premacular bursa in 109 eyes (90.8%), with average grading of 1.63 ± 0.53 for the FDI SD-OCT and 0.39 ± 0.52 for the SS-OCT (P < 0.001). Swept-source-OCT was similar to FDI SD-OCT in visualizing the chorioscleral boundary in 108 eyes (90.0%), with average grading of 1.81 ± 0.39 for the SS-OCT and 1.78 ± 0.38 for the FDI-OCT (P = 0.566). The visualization of the interdigitation zone line was identical in the 2 imaging instruments (P = 1.000). The sharpness of the choroidal structures was greater with SS-OCT than with FDI-OCT (P < 0.001).ConclusionManual double-enhancing FDI technique using SD-OCT provided a good compromise between vitreous and retinochoroidal structures visualization in real time during scanning procedure. In contrast, SS-OCT imaged well details of choroidal sublayers. Appropriate OCT technology and software should be selected according to its application in clinical settings.

PurposeA spontaneous frameshift mutation, c.3481delC, in the Crb1 gene is the underlying cause of dysplasia and retinal degeneration in rd8 mice. The rd8 mutation is found in C57BL/6N but not in C57BL/6J mouse sub-strains. The development of ocular pathology in single knockout Ccl2-/-, Cx3cr1-/- and in double knockout Ccl2-/-, Cx3cr1-/- mice raised on a C57BL/6 background has been reported to depend on the presence of a rd8 mutation. In this study, we investigated the influence of the rd8 mutation on the retinal pathology that we previously described in the late-onset retinal degeneration (L-ORD) mouse model with a heterozygous S163R mutation in the C1q-tumor necrosis factor-related protein-5Ctrp5+/- gene that was generated on a C57BL/6J background.MethodsMouse lines carrying the Ctrp5 S163R and rd8 mutations (Ctrp5+/-;rd8/rd8), corresponding controls without the rd8 mutation (Ctrp5+/-;wt/wt), and wild-type mice with and without the rd8 mutation (Wtrd8/rd8 and Wtwt/wt, respectively) were generated by systematic breeding of mice in our L-ORD mouse colony. Genotyping the mice for the rd8 (del C at nt3481 in Crb1) and Ctrp5 S163R mutations was performed with allelic PCR or sequencing. Retinal morphology was studied with fundus imaging, histology, light microscopy, electron microscopy, and immunohistochemistry.ResultsGenotype analysis of the mice in L-ORD mouse colony detected the rd8 mutation in the homozygous and heterozygous state. Fundus imaging of wild-type mice without the rd8 mutation (Wtwt/wt) revealed no autofluorescence (AF) spots up to 6-8 months and few AF spots at 21 months. However, the accumulation of AF lesions accelerated with age in the Ctrp5+/- mice that lack the rd8 mutation (Ctrp5+/-;wt/wt). The number of AF lesions was significantly increased (p

PurposeTo determine the presence of structural changes in HIV retinae (i.e., photoreceptor density and retinal thickness in the macula) compared with age-matched HIV-negative controls.MethodsCohort of patients with known HIV under CART (combination Antiretroviral Therapy) treatment were examined with a flood-illuminated retinal AO camera to assess the cone photoreceptor mosaic and spectral-domain optical coherence tomography (SD-OCT) to assess retinal layers and retinal thickness.ResultsTwenty-four eyes of 12 patients (n = 6 HIV-positive and 6 HIV-negative) were imaged with the adaptive optics camera. In each of the regions of interest studied (nasal, temporal, superior, inferior), the HIV group had significantly less mean cone photoreceptor density compared with age-matched controls (difference range, 4,308-6,872 cones/mm2). A different subset of forty eyes of 20 patients (n = 10 HIV-positive and 10 HIV-negative) was included in the retinal thickness measurements and retinal layer segmentation with the SD-OCT. We observed significant thickening in HIV positive eyes in the total retinal thickness at the foveal center, and in each of the three horizontal B-scans (through the macular center, superior, and inferior to the fovea). We also noted that the inner retina (combined thickness from ILM through RNFL to GCL layer) was also significantly thickened in all the different locations scanned compared with HIV-negative controls.ConclusionOur present study shows that the cone photoreceptor density is significantly reduced in HIV retinae compared with age-matched controls. HIV retinae also have increased macular retinal thickness that may be caused by inner retinal edema secondary to retinovascular disease in HIV. The interaction of photoreceptors with the aging RPE, as well as possible low-grade ocular inflammation causing diffuse inner retinal edema, may be the key to the progressive vision changes in HIV-positive patients without overt retinitis.

PurposeTo use novel confocal scanning ophthalmoscopy technology to test hypothesis that HIV-seropositive patients without history of retinitis with a history of a low CD4 count are more likely to have damage to their retinal nerve fiber layer (RNFL) when compared to patients with high CD4 count. In addition, we compared optic disc morphologic changes with glaucoma.DesignCross-sectional study.Participants and controls171 patients were divided into four groups. The control group consisted of 40 eyes of 20 HIV-seronegative patients. The second group consisted of 80 eyes of 41 HIV-positive patients whose CD4 cell count never dropped below 100 (1.0 x 10(9)/L). The third group consisted of 44 eyes of 26 HIV-positive patients with a history of low CD4 counts

PurposeTo compare laser photocoagulation plans for diabetic macular edema (DME) using fluorescein angiography (FA) versus optical coherence tomography (OCT) thickness map superimposed on the retina.MethodsFourteen eyes with DME undergoing navigated laser photocoagulation with navigated photocoagulator had FA taken using the same instrument. Optical coherence tomography central retinal thickness map was imported to the photocoagulator and with same magnification aligned onto the retina. Three retina specialists placed laser spot marks separately on FA and OCT image in a masked fashion. The spots placed by each physician were compared between FA and OCT and among physicians. The area of dye leakage on FA and increased central retinal thickness on OCT of the same eye were also compared.ResultsThe average number of spots using FA and OCT template was 36.64 and 40.61, respectively (P = 0.0201). The average area of dye leakage was 7.45 mm, whereas the average area of increased central retinal thickness on OCT of the same eye was 10.92 mm (P = 0.013).ConclusionThere is variability in the treatment planning for macular photocoagulation with a tendency to place more spots when guided by OCT than by FA. Integration of OCT map aligned to the retina may have an impact on treatment plan once such information is available.

PurposeTo evaluate the morphologic restoration of retinal anatomy after surgery for epiretinal membrane (ERM) peeling using spectral domain optical coherence tomography. Correlation of retinal structure with visual outcome.DesignRetrospective consecutive case series.MethodsThirty-four consecutive eyes with ERM underwent surgery with 1 year follow-up examination. Spectral domain optical coherence tomography scans were analyzed preoperatively and 1, 3, 6, 9, and 12 months postoperative. Best-corrected visual acuity (BCVA) using Early Treatment Diabetic Retinopathy Study charts was measured at each visit.ResultsAll eyes showed a significant improvement of BCVA after ERM peeling (P = 0.002). The time point of BCVA and retinal restoration seen on spectral domain optical coherence tomography occurred simultaneously and varied between individuals (occurrence of BCVA: mean, 4.82 months; retinal restoration: mean, 4.24 months). At 3 months, the retinal anatomical restoration rate was 70% and 88% at 6 months.ConclusionRestoration of the retinal anatomical structure predominantly occurs within the first 3 months post-ERM peeling. An improvement of BCVA and anatomical retinal restoration after ERM removal varies in individuals. If retinal layers fully restore in their anatomical structure, BCVA improves at the same time point.

Visual function abnormalities are common in people living with HIV disease (PLWH) without retinitis, even after improvement in immune status. Abnormalities such as reduced contrast sensitivity, altered color vision, peripheral visual field loss, and electrophysiological changes are related to a combination of retinal dysfunctions, involving inner and outer retinal structures. The standard protocol for testing vision performance in clinical practice is the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. However, this method poorly correlates with activities of daily living that require patients to assess visual stimuli in multiple light/contrast conditions, and with limited time. We utilized a novel interactive computer program (Central Vision Analyzer) to analyze vision performance in PLWH under a variety of light/contrast conditions that simulate stressful and real-world environments. The program tests vision in a time-dependent way that we believe better correlates with daily living activities than the non-timed ETDRS chart. We also aimed to correlate visual scores with retinal neuro-fiber layer thickness on optical coherence tomography. Here we show that visual acuity is more affected in PLWH in comparison to HIV-seronegative controls in varying contrast and luminance, especially if the nadir CD4+ T-cell count was lower than 100 cells/mm3. Visual impairment reflects the loss of retinal nerve fiber layer thickness especially of the temporal-inferior sector. In PLWH the ETDRS chart test led to better visual acuity compared to the Central Vision Analyzer equivalent test, likely because patients had indefinite time to guess the letters. This study confirms and strengthens the finding that visual function is affected in PLWH even in absence of retinitis, since we found that the HIV serostatus is the best predictor of visual loss. The Central Vision Analyzer may be useful in the diagnosis of subclinical HIV-associated visual loss in multiple light/contrast conditions, and may offer better understanding of this entity called "neuroretinal disorder".

PurposeTo evaluate the safety of oral fluorescein angiography (FA) and to compare its efficacy in detection of macular edema (ME) with spectral-domain optical coherence tomography (SD-OCT).MethodsResults of imaging studies for 1,928 eyes of 1,019 patients who had simultaneously undergone both oral FA and SD-OCT by a confocal laser ophthalmoscope were reviewed. Sensitivity in detecting ME, discrepancy rate, and "kappa" agreement were determined for both the techniques and with eyes stratified by disease diagnosis.ResultsNo allergic reactions occurred after oral FA. Mild gastric discomfort was noted in

PurposeTo evaluate temporal changes and predictors of accuracy in the alignment between simultaneous near-infrared image and optical coherence tomography (OCT) scan on the Heidelberg Spectralis using a model eye.DesignLaboratory investigation.MethodsAfter calibrating the device, 6 sites performed weekly testing of the alignment for 12 weeks using a model eye. The maximum error was compared with multiple variables to evaluate predictors of inaccurate alignment. Variables included the number of weekly scanned patients, total number of OCT scans and B-scans performed, room temperature and its variation, and working time of the scanning laser. A 4-week extension study was subsequently performed to analyze short-term changes in the alignment.ResultsThe average maximum error in the alignment was 15 ± 6 μm; the greatest error was 35 μm. The error increased significantly at week 1 (P = .01), specifically after the second imaging study (P < .05); reached a maximum after the eighth patient (P < .001); and then varied randomly over time. Predictors for inaccurate alignment were temperature variation and scans per patient (P < .001). For each 1 unit of increase in temperature variation, the estimated increase in maximum error was 1.26 μm. For the average number of scans per patient, each increase of 1 unit increased the error by 0.34 μm.ConclusionOverall, the accuracy of the Heidelberg Spectralis was excellent. The greatest error happened in the first week after calibration, and specifically after the second imaging study. To improve the accuracy, room temperature should be kept stable and unnecessary scans should be avoided. The alignment of the device does not need to be checked on a regular basis in the clinical setting, but it should be checked after every other patient for more precise research purposes.

HIV retinopathy is the most common non-infectious complication in the eyes of HIV-positive individuals. Oncotic lesions in the retinal nerve fiber layer, referred to as cotton wool spots (CWS), and intraretinal (IR) hemorrhages are frequently observed but are not unique to this pathology. HIV-positive patients have impaired color vision and contrast sensitivity, which worsens with age. Evidence of inner-retinal lesions and damage have been documented ophthalmoscopically, however their long term structural effect has not been investigated. It has been hypothesized that they may be partially responsible for loss of visual function and visual field. In this study we utilized clinical data, retinal imaging and transcriptomics approaches to comprehensively interrogate non-infectious HIV retinopathy. The methods employed encompassed clinical examinations, fundus photography, indirect ophthalmoscopy, Farmsworth-Munsell 100 hue discrimination testing and Illumina BeadChip analyses. Here we show that changes in the outer retina, specifically in the retinal pigment epithelium (RPE) and photoreceptor outer segments (POS) contribute to vision changes in non-infectious HIV retinopathy. We find that in HIV-positive retinae there is an induction of rhodopsin and other transcripts (including PDE6A, PDE6B, PDE6G, CNGA1, CNGB1, CRX, NRL) involved in visual transduction, as well as structural components of the rod photoreceptors (ABCA4 and ROM1). This is consistent with an increased rate of renewal of rod outer segments induced via increased phagocytosis by HIV-infected RPE previously reported in culture. Cone-specific transcripts (OPN1SW, OPN1LW, PDE6C, PDE6H and GRK7) are uniformly downregulated in HIV positive retina, likely due to a partial loss of cone photoreceptors. Active cotton wool spots and intraretinal hemorrhages (IRH) may not affect photoreceptors directly and the interaction of photoreceptors with the aging RPE may be the key to the progressive vision changes in HIV-positive patients.

The rs1061170T/C variant encoding the Y402H change in complement factor H (CFH) has been identified by genome-wide association studies as being significantly associated with age-related macular degeneration (AMD). However, the precise mechanism by which this CFH variant impacts the risk of AMD remains largely unknown. Oxidative stress plays an important role in many aging diseases, including cardiovascular disease and AMD. A large amount of oxidized phospholipids (oxPLs) are generated in the eye because of sunlight exposure and high oxygen content. OxPLs bind to the retinal pigment epithelium and macrophages and strongly activate downstream inflammatory cascades. We hypothesize that CFH may impact the risk of AMD by modulating oxidative stress. Here we demonstrate that CFH binds to oxPLs. The CFH 402Y variant of the protective rs1061170 genotype binds oxPLs with a higher affinity and exhibits a stronger inhibitory effect on the binding of oxPLs to retinal pigment epithelium and macrophages. In addition, plasma from non-AMD subjects with the protective genotype has a lower level of systemic oxidative stress measured by oxPLs per apolipoprotein B (oxPLs/apoB). We also show that oxPL stimulation increases expression of genes involved in macrophage infiltration, inflammation, and neovascularization in the eye. OxPLs colocalize with CFH in drusen in the human AMD eye. Subretinal injection of oxPLs induces choroidal neovascularization in mice. In addition, we show that the CFH risk allele confers higher complement activation and cell lysis activity. Together, these findings suggest that CFH influences AMD risk by modulating oxidative stress, inflammation, and abnormal angiogenesis.