Advances in sickle cell retinopathy screening techniques, tests, and practices: A systematic review.

Sickle cell retinopathy (SCR) is a progressive, sight-threatening ophthalmic complication of sickle cell disease (SCD). Current SCR screening focuses on the detection of pathologic sea fan neovascularization, the first sign of proliferative sickle cell retinopathy (PSR). If untreated, PSR can lead to severe visual impairment and blindness through progression to vitreous hemorrhage and/or retinal detachment. SCR screening with dilated fundus examination (DFE) is recommended every 1-2 years starting at age 10, but data underlying this recommendation are of poor quality and based upon expert consensus. We performed a systematic review to characterize imaging techniques, laboratory-based tests, and clinical practices for SCR screening. This PROSPERO-registered systematic review included relevant texts identified through predetermined searches in online databases. Collected test accuracy data facilitated the calculation of likelihood ratios. Forty-four studies evaluating 4928 patients were included. DFE demonstrated moderate test accuracy (LR+ of 8.0, LR- of 0.3). Ultra-widefield-fundus photography demonstrated superior accuracy (LR+ 32.5, LR- 0.03). Optical coherence tomography angiography applications were highly accurate for PSR identification (machine learning LR+ 32.5, LR- 0.03; human grader LR+ 2.8-213.1, LR- 0.1-0.2). Most techniques and tests were more accurate at detecting PSR than staging SCR or detecting lower-grade SCR. Our findings support the integration of advanced image-based approaches, such as computer-based image analysis and ultra-wide-field fundus imaging, for SCR screening in SCD patients given the superior accuracy in PSR detection compared with the current standard of care. Rigorous SCR screening implementation studies are needed to support evidence-based SCR screening recommendations.

Early diagnosis of sickle cell retinopathy by using ocular coherence tomography in pediatric population (7-18 years) in central India.

BACKGROUND: Sickle cell disease (SCD) is the commonest inherited blood disorder leading to complications occurring due to vaso-occlusion including sight-threatening retinopathy. Retinopathy can be managed if diagnosed early and vision loss can be prevented. Since, very less data are available from India, hence, this study was conducted in children (7-18 years) with SCD to diagnose retinopathy by using ocular coherence tomography (OCT) in subclinical stages. METHODS: This cross sectional single-center study was performed in 7-18 years age group children with SCD without any visual symptoms. Enrolled participants underwent complete ophthalmological examination including macula and optic disc thickness measurements using Cirrus HD-OCT and results were analyzed. RESULTS: Among 55 participants, none had visual impairment. Significant fundoscopy finding (nonproliferative sickle cell retinopathy/NPSR) was found in three patients (5.4%), thinning of central macula in four patients (7.27%), inner macula thinning in eight patients (14.5%), outer macula thinning in one patient (1.81%), retinal nerve fiber layer thinning in five patients (9%), ganglion cell layer to inner plexiform layer thinning in eight patients (14.54%). Overall NPSR was found in 5.4% patients detected with fundoscopy, whereas retinal layer thinning was found in 14 patients (25.4%) using OCT. CONCLUSION: Despite of the significant prevalence of SCR, it is still underdiagnosed complication, leading to thinning of the retina from early ages; thus, its early diagnosis by regular screening using newer diagnostic methods can prevent progression to sight-threatening complications and provide better quality of life for these patients.

Optical Coherence Tomography Angiography of Macular Microangiopathy in Children With Sickle Cell Disease.

In this study, we identified the presence of sickle cell maculopathy and determined correlations between hemolysis indicators and systemic and ocular manifestations in children with sickle cell disease (SCD). Thirty-three patients with SCD 5 to 18 years of age underwent optical coherence tomography angiography (OCTA) as part of a thorough eye examination. The hematological indices and clinical data (hemoglobin, fetal hemoglobin, mean corpuscular volume, and frequency of sickle cell-associated complications and therapy) were collected. The SCD group contained 33 patients (66 eyes), and the control group contained 36 healthy participants (72 eyes). The SCD group had significantly thinner parafoveal thickness ( P =0.041) and significantly smaller parafoveal volume ( P =0.041) than the controls. The SCD group had lower deep capillary plexus density than the controls ( P =0.029). The SCD group had significantly smaller flow areas than the controls ( P <0.001). The foveal avascular zone (FAZ) perimeter, foveal density, and FAZ area in the entire retina did not differ significantly between the groups ( P >0.05). The platelet level was negatively correlated with parafoveal and perifoveal thickness and density. OCTA detected early macular microvascular changes in children and adolescents with asymptomatic SCD.

DIRECTIONAL OPTICAL COHERENCE TOMOGRAPHY IMAGING OF MACULAR PATHOLOGY.

PURPOSE: To survey the impact of directional reflectivity on structures within optical coherence tomography images in retinal pathology. METHODS: Sets of commercial optical coherence tomography images taken from multiple pupil positions were analyzed. These directional optical coherence tomography sets revealed directionally reflective structures within the retina. After ensuring sufficient image quality, resulting hybrid and composite images were characterized by assessing the Henle fiber layer, outer nuclear layer, ellipsoid zone, and interdigitation zone. Additionally, hybrid images were reviewed for novel directionally reflective pathological features. RESULTS: Cross-sectional directional optical coherence tomography image sets were obtained in 75 eyes of 58 patients having a broad range of retinal pathologies. All cases showed improved visualization of the outer nuclear layer/Henle fiber layer interface, and outer nuclear layer thinning was, therefore, more apparent in several cases. The ellipsoid zone and interdigitation zone also demonstrated attenuation where a geometric impact of underlying pathology affected their orientation. Misdirected photoreceptors were also noted as a consistent direction-dependent change in ellipsoid zone reflectivity between regions of normal and absent ellipsoid zone. CONCLUSION: Directional optical coherence tomography enhances the understanding of retinal anatomy and pathology. This optical contrast yields more accurate identification of retinal structures and possible imaging biomarkers for photoreceptor-related pathology.

Alignment, calibration, and validation of an adaptive optics scanning laser ophthalmoscope for high-resolution human foveal imaging.

In prior art, advances in adaptive optics scanning laser ophthalmoscope (AOSLO) technology have enabled cones in the human fovea to be resolved in healthy eyes with normal vision and low to moderate refractive errors, providing new insight into human foveal anatomy, visual perception, and retinal degenerative diseases. These high-resolution ophthalmoscopes require careful alignment of each optical subsystem to ensure diffraction-limited imaging performance, which is necessary for resolving the smallest foveal cones. This paper presents a systematic and rigorous methodology for building, aligning, calibrating, and testing an AOSLO designed for imaging the cone mosaic of the central fovea in humans with cellular resolution. This methodology uses a two-stage alignment procedure and thorough system testing to achieve diffraction-limited performance. Results from retinal imaging of healthy human subjects under 30 years of age with refractive errors of less than 3.5 diopters using either 680 nm or 840 nm light show that the system can resolve cones at the very center of the fovea, the region where the cones are smallest and most densely packed.

Importance of optical coherence tomography before cataract surgery.

PURPOSE: To determine the importance of optical coherence tomography (OCT) in patients scheduled for cataract surgery who present with no pathologies in biomicroscopic fundus examination. DESIGN: Retrospective study. METHODS: In this study, the routine ophthalmologic examination of patients who were recommended cataract surgery was performed.Occult retinal pathologies were evaluated using OCT in patients without any pathologies in biomicroscopic fundus examination.According to whether retinal pathologies were detected on OCT, the patients were divided into two groups: normal and abnormal OCT.The findings of patients with retinal pathologies on OCT and their distribution according to age were also evaluated. RESULTS: A total of 271 eyes from 271 patients were evaluated.The number of patients with retinal pathologies on OCT despite normal fundoscopic examination findings was 38(14.0%).Of these patients,15(39.4%) had an epiretinal membrane,10(26.3%) had age-related macular degeneration, eight(21%) had vitreomacular traction, two(5.2%) had a lamellar hole, and 1(2.6%) patient each had a full-thickness macular hole, an intraretinal cyst, and photoreceptor layer damage.The age distribution of the patients with retinal pathologies was as follows: two patients,<60 years; six patients,60-70 years;14 patients,70-80 years; and 16 patients,>80 years.The rate of patients aged > 70 years and above was 78.9%.There was no statistically significant difference between the normal and abnormal OCT groups in terms of age, gender, the presence of systemic diseases, visual acuity, central macular thickness, and cataract type or density(p > 0.05 for all). CONCLUSION: In one of seven patients evaluated, retinal pathologies were detected on OCT despite normal fundoscopic examination findings.OCT can be used to detect occult retinal pathologies that cannot be detected by biomicroscopic fundus examination before cataract surgery.

Recent advances in the use of optical coherence tomography in neuro-ophthalmology: A review.

Optical coherence tomography (OCT) is an in vivo imaging modality that provides non-invasive, high resolution and fast cross-sectional images of the optic nerve head, retina and choroid. OCT angiography (OCTA) is an emerging tool. It is a non-invasive, dye-free imaging approach of visualising the microvasculature of the retina and choroid by employing motion contrast imaging for blood flow detection and is gradually receiving attention for its potential roles in various neuro-ophthalmic and retinal conditions. We will review the clinical utility of the OCT in the management of various common neuro-ophthalmic and neurological disorders. We also review some of the OCTA research findings in these conditions. Finally, we will discuss the limitations of OCT as well as introduce other emerging technologies.

Uncovering Language Disparity of ChatGPT on Retinal Vascular Disease Classification: Cross-Sectional Study.

BACKGROUND: Benefiting from rich knowledge and the exceptional ability to understand text, large language models like ChatGPT have shown great potential in English clinical environments. However, the performance of ChatGPT in non-English clinical settings, as well as its reasoning, have not been explored in depth. OBJECTIVE: This study aimed to evaluate ChatGPT's diagnostic performance and inference abilities for retinal vascular diseases in a non-English clinical environment. METHODS: In this cross-sectional study, we collected 1226 fundus fluorescein angiography reports and corresponding diagnoses written in Chinese and tested ChatGPT with 4 prompting strategies (direct diagnosis or diagnosis with a step-by-step reasoning process and in Chinese or English). RESULTS: Compared with ChatGPT using Chinese prompts for direct diagnosis that achieved an F1-score of 70.47%, ChatGPT using English prompts for direct diagnosis achieved the best diagnostic performance (80.05%), which was inferior to ophthalmologists (89.35%) but close to ophthalmologist interns (82.69%). As for its inference abilities, although ChatGPT can derive a reasoning process with a low error rate (0.4 per report) for both Chinese and English prompts, ophthalmologists identified that the latter brought more reasoning steps with less incompleteness (44.31%), misinformation (1.96%), and hallucinations (0.59%) (all P<.001). Also, analysis of the robustness of ChatGPT with different language prompts indicated significant differences in the recall (P=.03) and F1-score (P=.04) between Chinese and English prompts. In short, when prompted in English, ChatGPT exhibited enhanced diagnostic and inference capabilities for retinal vascular disease classification based on Chinese fundus fluorescein angiography reports. CONCLUSIONS: ChatGPT can serve as a helpful medical assistant to provide diagnosis in non-English clinical environments, but there are still performance gaps, language disparities, and errors compared to professionals, which demonstrate the potential limitations and the need to continually explore more robust large language models in ophthalmology practice.

The Framework of Quantifying Biomarkers of OCT and OCTA Images in Retinal Diseases.

Despite the significant advancements facilitated by previous research in introducing a plethora of retinal biomarkers, there is a lack of research addressing the clinical need for quantifying different biomarkers and prioritizing their importance for guiding clinical decision making in the context of retinal diseases. To address this issue, our study introduces a novel framework for quantifying biomarkers derived from optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images in retinal diseases. We extract 452 feature parameters from five feature types, including local binary patterns (LBP) features of OCT and OCTA, capillary and large vessel features, and the foveal avascular zone (FAZ) feature. Leveraging this extensive feature set, we construct a classification model using a statistically relevant p value for feature selection to predict retinal diseases. We obtain a high accuracy of 0.912 and F1-score of 0.906 in the task of disease classification using this framework. We find that OCT and OCTA's LBP features provide a significant contribution of 77.12% to the significance of biomarkers in predicting retinal diseases, suggesting their potential as latent indicators for clinical diagnosis. This study employs a quantitative analysis framework to identify potential biomarkers for retinal diseases in OCT and OCTA images. Our findings suggest that LBP parameters, skewness and kurtosis values of capillary, the maximum, mean, median, and standard deviation of large vessel, as well as the eccentricity, compactness, flatness, and anisotropy index of FAZ, may serve as significant indicators of retinal conditions.

Gold Nanoparticles for Retinal Molecular Optical Imaging.

The incorporation of gold nanoparticles (GNPs) into retinal imaging signifies a notable advancement in ophthalmology, offering improved accuracy in diagnosis and patient outcomes. This review explores the synthesis and unique properties of GNPs, highlighting their adjustable surface plasmon resonance, biocompatibility, and excellent optical absorption and scattering abilities. These features make GNPs advantageous contrast agents, enhancing the precision and quality of various imaging modalities, including photoacoustic imaging, optical coherence tomography, and fluorescence imaging. This paper analyzes the unique properties and corresponding mechanisms based on the morphological features of GNPs, highlighting the potential of GNPs in retinal disease diagnosis and management. Given the limitations currently encountered in clinical applications of GNPs, the approaches and strategies to overcome these limitations are also discussed. These findings suggest that the properties and efficacy of GNPs have innovative applications in retinal disease imaging.

A fusion of deep neural networks and game theory for retinal disease diagnosis with OCT images.

Retinal disorders pose a serious threat to world healthcare because they frequently result in visual loss or impairment. For retinal disorders to be diagnosed precisely, treated individually, and detected early, deep learning is a necessary subset of artificial intelligence. This paper provides a complete approach to improve the accuracy and reliability of retinal disease identification using images from OCT (Retinal Optical Coherence Tomography). The Hybrid Model GIGT, which combines Generative Adversarial Networks (GANs), Inception, and Game Theory, is a novel method for diagnosing retinal diseases using OCT pictures. This technique, which is carried out in Python, includes preprocessing images, feature extraction, GAN classification, and a game-theoretic examination. Resizing, grayscale conversion, noise reduction using Gaussian filters, contrast enhancement using Contrast Limiting Adaptive Histogram Equalization (CLAHE), and edge recognition via the Canny technique are all part of the picture preparation step. These procedures set up the OCT pictures for efficient analysis. The Inception model is used for feature extraction, which enables the extraction of discriminative characteristics from the previously processed pictures. GANs are used for classification, which improves accuracy and resilience by adding a strategic and dynamic aspect to the diagnostic process. Additionally, a game-theoretic analysis is utilized to evaluate the security and dependability of the model in the face of hostile attacks. Strategic analysis and deep learning work together to provide a potent diagnostic tool. This suggested model's remarkable 98.2% accuracy rate shows how this method has the potential to improve the detection of retinal diseases, improve patient outcomes, and address the worldwide issue of visual impairment.

Assessment of retinal atrophy in mixed breed dogs using spectral domain optical coherence tomography (SD-OCT) and electroretinography.

The aim of the study was to characterize retinal atrophy (RA) with progressive retinal atrophy symptoms in mixed breed dogs using ophthalmoscopy, spectral domain optical coherence tomography (SD-OCT) and electroretinography (ERG).The study was performed on 13 mixed breed dogs affected by retinal atrophy (11 males and 2 females that were 1.5-14 years old). Depending on the advancement of RA, SD-OCT examinations identified retinal abnormalities ranging from layer disorganisation to advanced atrophy. The most advanced RA occurred ventral to the optic disc. Total retinal thickness in both eyes (mean ± SD) was lower in dogs with RA compared to controls dorsally (77.7 ± 39.5 µm vs 173.5 ± 13.3 µm), ventrally (33.4 ± 29.9 µm vs 139.5 ± 10.8 µm), nasally (65.0 ± 34.5 µm vs 163.9 ± 11.0 µm) and temporally (61.8 ± 41.7 µm vs 171.9 ± 11.1 µm) to the optic disc. In dogs with locally normal architecture of inner retina, loss of definition of outer retinal layers occurred in many regions. Dark and light-adapted ERGs were reduced in 2 dogs with RA and were unrecordable in 11 dogs. Lesions evident in SD-OCT scans of mixed breed dogs affected with retinal atrophy initially appear ventrally to the optic disc and ventro-dorsally in advanced RA. In all mixed breed dogs with retinal atrophy, clinical signs and SD-OCT results correlate with ERG findings.

[Can ultra-widefield optical coherence tomography angiography replace traditional fundus angiography].

Fundus imaging plays a pivotal role in diagnosing retinal and choroidal diseases. Optical coherence tomography angiography (OCTA), by capturing signals to reconstruct vascular structures, offers a clear depiction of retinal vasculature with notable advantages such as rapid scanning and non-invasiveness. Although OCTA, due to its underlying principles, cannot dynamically assess vascular function, exploring its future applications and potential to eventually replace traditional fundus angiography remains a key focus in the medical community. OCTA provides multiple parameters that conventional fundus angiography cannot obtain. With the expanding coverage area of OCTA scans and improvements in artifact elimination, the detection rate of various retinal and choroidal diseases has significantly increased, making the widespread clinical application of OCTA an inevitable trend. Although ultra-widefield OCTA cannot yet fully replace angiography in clinical practice, with continued clinical practice, expanded clinical research, and ongoing technological innovation, OCTA is expected to gradually replace fundus angiography in the future.

[Terminology of quantitative optical coherence tomography angiography metrics]. / Osobennosti terminologii kolichestvennykh pokazatelei opticheskoi kogerentnoi tomografii-angiografii.

This review is devoted to the English- and Russian-language terminology of quantitative metrics that are used in the evaluation of images obtained by optical coherence tomography angiography (OCT-A). The paper presents an analysis of the use of terms characterizing intraretinal blood flow (vascular density, perfusion density, skeletonized density, etc.), area and shape of the foveal avascular zone, and choriocapillaris blood flow. The factors causing the heterogeneity of OCT-A terminology are described, including the lack of a unified international nomenclature for OCT-A, features of their Russian translation, inconsistency of the parameters in optical coherence tomography systems of different manufacturers. The article also considers ways to standardize the terminology.

Retinal imaging technologies in cerebral malaria: a systematic review.

BACKGROUND: Cerebral malaria (CM) continues to present a major health challenge, particularly in sub-Saharan Africa. CM is associated with a characteristic malarial retinopathy (MR) with diagnostic and prognostic significance. Advances in retinal imaging have allowed researchers to better characterize the changes seen in MR and to make inferences about the pathophysiology of the disease. The study aimed to explore the role of retinal imaging in diagnosis and prognostication in CM; establish insights into pathophysiology of CM from retinal imaging; establish future research directions. METHODS: The literature was systematically reviewed using the African Index Medicus, MEDLINE, Scopus and Web of Science databases. A total of 35 full texts were included in the final analysis. The descriptive nature of the included studies and heterogeneity precluded meta-analysis. RESULTS: Available research clearly shows retinal imaging is useful both as a clinical tool for the assessment of CM and as a scientific instrument to aid the understanding of the condition. Modalities which can be performed at the bedside, such as fundus photography and optical coherence tomography, are best positioned to take advantage of artificial intelligence-assisted image analysis, unlocking the clinical potential of retinal imaging for real-time diagnosis in low-resource environments where extensively trained clinicians may be few in number, and for guiding adjunctive therapies as they develop. CONCLUSIONS: Further research into retinal imaging technologies in CM is justified. In particular, co-ordinated interdisciplinary work shows promise in unpicking the pathophysiology of a complex disease.

Optical coherence tomography angiography in neuro-ophthalmology.

PURPOSE OF REVIEW: Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging technique, which provides depth resolved visualization of microvasculature of the retina and choroid. Although OCTA has been widely used for the evaluation of a number of retinal diseases, its use in the field of neuro-ophthalmology has been less studied. In this review, we provide an update on the utility of OCTA in neuro-ophthalmic conditions. RECENT FINDINGS: Peripapillary and macular microvasculature analyses have indicated that OCTA can be a promising tool for early detection of a number of neuro-ophthalmic diseases, differential diagnosis, and monitoring of disease progression. Recent studies have demonstrated that structural and functional impairment can develop at early stages in some conditions such as in multiple sclerosis and Alzheimer's disease even in the absence of overt clinical symptoms. Furthermore, this dye-less technique can be a valuable adjunct tool in the detection of complications commonly seen in some congenital entities such optic disc drusen. SUMMARY: Since its introduction, OCTA has emerged as an important imaging approach shedding light on unrevealed pathophysiological mechanisms of several ocular diseases. The use of OCTA as a biomarker in the field of neuro-ophthalmology has recently gained considerable attention with studies supporting its role in clinical setting while larger studies are warranted for correlating these findings with traditional diagnostic procedures and clinical features and outcomes.

Case Report: Recurrent Acute Macular Neuroretinopathy-Monitoring Recovery with Multimodal Imaging.

SIGNIFICANCE: Acute macular neuroretinopathy (AMN) is a rare, nonprogressive condition affecting the outer retina that can be diagnosed clinically using widely available multimodal imaging techniques. This case report presents an exceedingly rare same-eye recurrence of AMN and describes the characteristic imaging findings of this unique, not fully understood clinical entity. PURPOSE: The following report provides a detailed account of recurrent AMN from 4 hours of symptom onset to 4 months with repeat multimodal imaging captured at different visits. This report also devotes some discussion to the current understanding of its pathophysiology, associations, management, and imaging characteristics. CASE REPORT: A 32-year-old woman with unilateral recurrent AMN was monitored frequently with various multimodal imaging from 4 hours after onset of new scotoma to 4 months. The primary finding in the acute stage was a hyperreflective lesion of the outer nuclear and outer plexiform layers followed by disruption of underlying external limiting membrane, ellipsoid zone, and photoreceptors. This resolved into stable outer nuclear layer thinning and subtle disruption of the deeper layers after 1 week. Fundus photography revealed a red-brown petaloid lesion adjacent to the fovea, and optical coherence tomography angiography revealed subtle decreased perfusion of the choriocapillaris layer throughout follow-up. CONCLUSIONS: Acute macular neuroretinopathy is a rare nonprogressive condition of the outer retina most often affecting otherwise healthy young female individuals and is most associated with recent flu-like illness and oral contraceptives. The underlying mechanism of AMN remains unknown, but modern imaging techniques have elucidated the disease locus to be choroidal and/or deep capillary plexus. It is important for eye care providers to recognize AMN as a clinical entity distinct from other retinal conditions that require different management.

2022 Prentice Award Lecture: Advancing Retinal Imaging and Visual Function in Patient Management and Disease Mechanisms.

SIGNIFICANCE: Patient-based research plays a key role in probing basic visual mechanisms. Less-well recognized is the role of patient-based retinal imaging and visual function studies in elucidating disease mechanisms, which are accelerated by advances in imaging and function techniques and are most powerful when combined with the results from histology and animal models.A patient's visual complaints can be one key to patient management, but human data are also key to understanding disease mechanisms. Unfortunately, pathological changes can be difficult to detect. Before advanced retinal imaging, the measurement of visual function indicated the presence of pathological changes that were undetectable with existing clinical examination. Over the past few decades, advances in retinal imaging have increasingly revealed the unseen. This has led to great strides in the management of many diseases, particularly diabetic retinopathy and macular edema, and age-related macular degeneration. It is likely widely accepted that patient-based research, as in clinical trials, led to such positive outcomes. Both visual function measures and advanced retinal imaging have clearly demonstrated differences among retinal diseases. Contrary to initial thinking, sight-threatening damage in diabetes occurs to the outer retina and not only to the inner retina. This has been clearly indicated in patient results but has only gradually entered the clinical classifications and understanding of disease etiology. There is strikingly different pathophysiology for age-related macular degeneration compared with photoreceptor and retinal pigment epithelial genetic defects, yet research models and even some treatments confuse these. It is important to recognize the role that patient-based research plays in probing basic visual mechanisms and elucidating disease mechanisms, combining these findings with the concepts from histology and animal models. Thus, this article combines sample instrumentation from my laboratory and progress in the fields of retinal imaging and visual function.

"En Face" Spectral-Domain Optical Coherence Tomography versus Multifocal Electroretinogram in Hydroxychloroquine Retinopathy Screening.

INTRODUCTION: The performance of "en face" optical coherence tomography (OCT) in screening for chloroquine (CQ) or hydroxychloroquine (HCQ) retinopathy has not been largely explored. The aim of this study was to determine the concordance of "en face" OCT with multifocal electroretinography (mfERG) in screening for CQ/HCQ retinopathy. METHODS: This is a prospective cohort study conducted at the Rothschild Foundation Hospital, Paris, between August 2016 and February 2021. Patients taking HCQ were followed up over 2 consecutive years and received an "en face" OCT and a mfERG on each visit. RESULTS: A total of 91 patients (182 eyes) were analyzed. mfERG and "en face" OCT were concordant in 147 eyes (86.3%). Cohen's kappa coefficient for concordance between mfERG and "en face" OCT was considered weak with a value 0.61 (95% CI: 0.50-0.72). The sensitivity and specificity of "en face" OCT were 70% (95% CI: 59-79%) and 91% (95% CI: 83-96%), respectively, relatively to mfERG. Proportion of abnormal R2/R5 and R3/R5 ratios did not differ between patients with normal and abnormal "en face" OCT (p = 0.2). DISCUSSION: "En face" OCT and mfERG have low concordance and cannot be used interchangeably as each investigation evaluates a different facet of CQ/HCQ retinopathy. "En face" OCT could be used as a complement in screening for CQ/HCQ retinal toxicity if the anomalies detected on "en face" OCT are confirmed by B-scan OCT sections.

A connectomics approach to understanding a retinal disease.

Macular telangiectasia type 2 (MacTel), a late-onset macular degeneration, has been linked to a loss in the retina of Müller glial cells and the amino acid serine, synthesized by the Müller cells. The disease is confined mainly to a central retinal region called the MacTel zone. We have used electron microscopic connectomics techniques, optimized for disease analysis, to study the retina from a 48-y-old woman suffering from MacTel. The major observations made were specific changes in mitochondrial structure within and outside the MacTel zone that were present in all retinal cell types. We also identified an abrupt boundary of the MacTel zone that coincides with the loss of Müller cells and macular pigment. Since Müller cells synthesize retinal serine, we propose that a deficiency of serine, required for mitochondrial maintenance, causes mitochondrial changes that underlie MacTel development.