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.

OCTDL: Optical Coherence Tomography Dataset for Image-Based Deep Learning Methods.

Optical coherence tomography (OCT) is a non-invasive imaging technique with extensive clinical applications in ophthalmology. OCT enables the visualization of the retinal layers, playing a vital role in the early detection and monitoring of retinal diseases. OCT uses the principle of light wave interference to create detailed images of the retinal microstructures, making it a valuable tool for diagnosing ocular conditions. This work presents an open-access OCT dataset (OCTDL) comprising over 2000 OCT images labeled according to disease group and retinal pathology. The dataset consists of OCT records of patients with Age-related Macular Degeneration (AMD), Diabetic Macular Edema (DME), Epiretinal Membrane (ERM), Retinal Artery Occlusion (RAO), Retinal Vein Occlusion (RVO), and Vitreomacular Interface Disease (VID). The images were acquired with an Optovue Avanti RTVue XR using raster scanning protocols with dynamic scan length and image resolution. Each retinal b-scan was acquired by centering on the fovea and interpreted and cataloged by an experienced retinal specialist. In this work, we applied Deep Learning classification techniques to this new open-access dataset.

RD-OCT net: hybrid learning system for automated diagnosis of macular diseases from OCT retinal images.

Macular Edema is a leading cause of visual impairment and blindness in patients with ocular fundus diseases. Due to its non-invasive and high-resolution characteristics, optical coherence tomography (OCT) has been extensively utilized for the diagnosis of macular diseases. The manual detection of retinal diseases by clinicians is a laborious process, further complicated by the challenging identification of macular diseases. This difficulty arises from the significant pathological alterations occurring within the retinal layers, as well as the accumulation of fluid in the retina. Deep Learning neural networks are utilized for automatic detection of retinal diseases. This paper aims to propose a lightweight hybrid learning Retinal Disease OCT Net with a reduced number of trainable parameters and enable automatic classification of retinal diseases. A Hybrid Learning Retinal Disease OCT Net (RD-OCT) is utilized for the multiclass classification of major retinal diseases, namely neovascular age-related macular degeneration (nAMD), diabetic macular edema (DME), retinal vein occlusion (RVO), and normal retinal conditions. The diagnosis of retinal diseases is facilitated by the use of hybrid learning models and pre-trained deep learning models in the field of artificial intelligence. The Hybrid Learning RD-OCT Net provides better accuracy of 97.6% for nAMD, 98.08% for DME, 98% for RVO, and 97% for the Normal group. The respective area under the curve values were 0.99, 0.97, 1.0, and 0.99. The utilization of the RD-OCT model will be useful for ophthalmologists in the diagnosis of prevalent retinal diseases, due to the simplicity of the system and reduced number of trainable parameters.

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.

Non-vasogenic cystoid maculopathy in autosomal recessive bestrophinopathy: novel insights from NIR-FAF and OCTA imaging.

BACKGROUND: Autosomal Recessive Bestrophinopathy (ARB) is an inherited retinal disease caused by biallelic mutations in the BEST1 gene. Herein, we report the multimodal imaging findings of ARB presenting with cystoid maculopathy and investigate the short-term response to combined systemic and topical carbonic anhydrase inhibitors (CAIs). MATERIAL AND METHODS: An observational, prospective, case series on two siblings affected by ARB is presented. Patients underwent genetic testing and optical coherence tomography (OCT), blue-light fundus autofluorescence (BL-FAF), near-infrared fundus autofluorescence (NIR-FAF), fluorescein angiography (FA), MultiColor imaging, and OCT angiography (OCTA). RESULTS: Two male siblings, aged 22 and 16, affected by ARB resulting from c.598C>T, p.(Arg200*) and c.728C>A, p.(Ala243Glu) BEST1 compound heterozygous variants, presented with bilateral multifocal yellowish pigment deposits scattered through the posterior pole that corresponded to hyperautofluorescent deposits on BL-FAF. Vice versa, NIR-FAF mainly disclosed wide hypoautofluorescent areas in the macula. A cystoid maculopathy and shallow subretinal fluid were evident on structural OCT, albeit without evidence of dye leakage or pooling on FA. OCTA demonstrated disruption of the choriocapillaris throughout the posterior pole and sparing of intraretinal capillary plexuses. Six months of combined therapy with oral acetazolamide and topical brinzolamide resulted in limited clinical benefit. CONCLUSIONS: We reported two siblings affected by ARB, presenting as non-vasogenic cystoid maculopathy. Prominent alteration of NIR-FAF signal and concomitant choriocapillaris rarefaction on OCTA were noted in the macula. The limited short-term response to combined systemic and topical CAIs might be explained by the impairment of the RPE-CC complex.

Foveal cone loss in tamoxifen maculopathy: a case report.

BACKGROUND: Tamoxifen is used in low dose concentrations (20-40 mg per day) as a therapy for breast cancer but is known to have ocular side effects. In this case report, the foveal cone integrity in a tamoxifen-treated patient who complained of a small central scotoma in the left eye while reading was examined using high resolution adaptive optics imaging. CASE PRESENTATION: Both eyes of a 54-year-old Caucasian, non-hispanic female who had been treated with tamoxifen for 1.5 years were examined using various imaging modalities including fundus photography, fundus autofluorescence, fluorescein angiography, spectral-domain optical coherence tomography, and adaptive optics scanning laser ophthalmoscopy. Clinical spectral-domain optical coherence tomography showed a very small disruption to the photoreceptor layer at the fovea in the left eye only. However, adaptive optics scanning laser ophthalmoscopy imaging revealed foveal cone loss in both eyes, but to a lesser extent in the right eye. Inner retinal changes were not observed in either eye. CONCLUSION: The area of cone loss was similar in size to a single newsprint letter when projected onto the retina, matching the patient's description of a scotoma in the left eye. Given the isolated loss of foveal cone photoreceptors with the absence of previously reported inner retinal and vascular changes, our results may indicate the earliest retinal changes associated with tamoxifen retinopathy.

Evaluation of the Performance of a 3D-Printed Smartphone-Based Retinal Imaging Device as a Screening Tool for Retinal Pathology in Mozambique.

Low-income countries carry approximately 90% of the global burden of visual impairment, and up to 80% of this could be prevented or cured. However, there are only a few studies on the prevalence of retinal disease in these countries. Easier access to retinal information would allow differential diagnosis and promote strategies to improve eye health, which are currently scarce. This pilot study aims to evaluate the functionality and usability of a tele-retinography system for the detection of retinal pathology, based on a low-cost portable retinal scanner, manufactured with 3D printing and controlled by a mobile phone with an application designed ad hoc. The study was conducted at the Manhiça Rural Hospital in Mozambique. General practitioners, with no specific knowledge of ophthalmology or previous use of retinography, performed digital retinographies on 104 hospitalized patients. The retinographies were acquired in video format, uploaded to a web platform, and reviewed centrally by two ophthalmologists, analyzing the image quality and the presence of retinal lesions. In our sample there was a high proportion of exudates and hemorrhages-8% and 4%, respectively. In addition, the presence of lesions was studied in patients with known underlying risk factors for retinal disease, such as HIV, diabetes, and/or hypertension. Our tele-retinography system based on a smartphone coupled with a simple and low-cost 3D printed device is easy to use by healthcare personnel without specialized ophthalmological knowledge and could be applied for the screening and initial diagnosis of retinal pathology.

Deep learning for precision medicine: Guiding laser therapy in ischemic retinal diseases.

In this issue of Cell Reports Medicine, Zhao and colleagues1 report a multi-tasking artificial intelligence system that can assist the whole process of fundus fluorescein angiography (FFA) imaging and reduce the reliance on retinal specialists in FFA examination.

Paracentral acute middle maculopathy in a fasting patient after cataract surgery and its response to hyperbaric oxygen therapy.

INTRODUCTION: Paracentral acute middle maculopathy (PAMM) is a structural optical coherence tomography (OCT) sign secondary to ischemia in the intermediate and deep retinal vascular network, characterized by hyperreflectivity in the inner nuclear layer (INL). AIM: Our objective is to demonstrate PAMM development following uncomplicated cataract surgery, possibly triggered by fasting and dehydration. We also aim to emphasize the potential role of hyperbaric oxygen therapy in treating PAMM. CASE PRESENTATION: A 66-year-old man with a past medical history of Neurofibromatosis type 1 and cardiovascular disease underwent uncomplicated cataract surgery in the left eye. The patient was also fasting due to Ramadan. The patient complained of very low vision during the routine postoperative examination on the third day. His-best-corrected visual acuity (BCVA) was counting fingers at 1 meter. His-anterior and posterior segment examination was unremarkable. In infrared imaging, a large hyporeflective area was observed in the parafoveal region, and structural OCT also showed increased hyperreflectivity in the middle retinal layers corresponding to the junction of INL and outer plexiform layer (OPL) involving the entire INL which suggested PAMM. Following 14 sessions of hyperbaric oxygen therapy, the patient's BCVA increased to 0.9 on the 14th day of diagnosing PAMM. CONCLUSION: To the best of our knowledge, this is the first case representing a patient with  PAMM triggered by fasting and cataract surgery who responded positively to hyperbaric oxygen therapy. However, triggering of PAMM by fasting is entirely unproven and that this observation occurred in a highly complex case with many other possible contributing factors. Also, the triggering of PAMM by some manipulation during surgery is equally unproven.

Radiation chorioretinopathy: unusual occurrence of intervortex venous anastomosis.

A woman in her 60s presented with vision blur in both eyes, a year post-radiotherapy for oral cancer. The best corrected visual acuity was 20/40 in both eyes. Posterior segment examination was remarkable for a unilateral intervortex venous anastomosis in choroid in her right eye, on the side of her face that had received radiation. Ultra-wide field indocyanine green angiography complimented the clinical findings. We discuss the ramifications of detection of this entity and suggest non-invasive methods of detection.

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.

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.

The role of near-infrared reflectance imaging in retinal disease: A systematic review.

Near-infrared reflectance (NIR) retinal imaging aids in a better visualization of structures at the level of outer retina, retinal pigment epithelium, and choroid. It has multiple advantages, including easy acquisition in association with structural spectral domain optical coherence tomography, more comfort for patients, and enhanced contrast and spatial resolution. It helps in the diagnosis of chorioretinal diseases that present with minimal funduscopic findings and can be used to follow up many chorioretinal conditions. We describe the chorioretinal NIR imaging appearance and the clinical role of NIR imaging in ocular inflammatory disease, vascular and acquired disease, degenerative disease, tumors, associated systemic condition, toxic and traumatic disease, optic nerve head conditions, and physiological findings.

Ultra-Widefield OCT Angiography.

Optical Coherence Tomography Angiography (OCTA), a functional extension of OCT, has the potential to replace most invasive fluorescein angiography (FA) exams in ophthalmology. So far, OCTA's field of view is however still lacking behind fluorescence fundus photography techniques. This is problematic, because many retinal diseases manifest at an early stage by changes of the peripheral retinal capillary network. It is therefore desirable to expand OCTA's field of view to match that of ultra-widefield fundus cameras. We present a custom developed clinical high-speed swept-source OCT (SS-OCT) system operating at an acquisition rate 8-16 times faster than today's state-of-the-art commercially available OCTA devices. Its speed allows us to capture ultra-wide fields of view of up to 90 degrees with an unprecedented sampling density and hence extraordinary resolution by merging two single shot scans with 60 degrees in diameter. To further enhance the visual appearance of the angiograms, we developed for the first time a three-dimensional deep learning based algorithm for denoising volumetric OCTA data sets. We showcase its imaging performance and clinical usability by presenting images of patients suffering from diabetic retinopathy.

NINE-YEAR PROGRESSION OF PENTOSAN MACULOPATHY WITH MULTIMODAL RETINAL IMAGING.

BACKGROUND/PURPOSE: The purpose of this study was to describe the characteristic pattern of progression of pentosan polysulfate (PPS) maculopathy with multimodal retinal imaging in two patients, including one with over 9 years of follow-up. METHODS: Two patients with PPS maculopathy were sequentially evaluated with near-infrared reflectance (NIR) and optical coherence tomography. RESULTS: Near-infrared reflectance showed characteristic centrifugal progression of the parafoveal hyperreflective lesions toward the vascular arcades with the development of hyporeflective areas in both cases. Optical coherence tomography demonstrated focal retinal pigment epithelium (RPE) thickening that corresponded to the hyperreflective lesions on NIR. On subsequent optical coherence tomography scans, the hyperreflective areas resolved with the development of ellipsoid zone attenuation, RPE disruption, and atrophy, which colocalized with hyporeflectivity on NIR. CONCLUSION: This report describes the progression of pentosan polysulfate maculopathy over almost 10 years of PPS treatment and highlights the importance of NIR as a tool for the diagnosis and monitoring of PPS maculopathy. Pentosan polysulfate lesions present as areas of focal RPE thickening with ensuing development of ellipsoid zone loss and RPE drop-out. The pathophysiology of PPS toxicity is unknown and may either result from primary RPE or choroidal toxicity.

Ultra-wide-field fundus photography compared to ophthalmoscopy in diagnosing and classifying major retinal diseases.

To analyze the performance of ultra-wide-field (UWF) fundus photography compared with ophthalmoscopy in identifying and classifying retinal diseases. Patients examined for presumed major retinal disorders were consecutively enrolled. Each patient underwent indirect ophthalmoscopic evaluation, with scleral depression and/or fundus biomicroscopy, when clinically indicated, and mydriatic UWF fundus imaging by means of CLARUS 500™ fundus camera. Each eye was classified by a clinical grader and two image graders in the following groups: normal retina, diabetic retinopathy, vascular abnormalities, macular degenerations and dystrophies, retinal and choroidal tumors, peripheral degenerative lesions and retinal detachment and myopic alterations. 7024 eyes of new patients were included. The inter-grader agreement for images classification was perfect (kappa = 0.998, 95% Confidence Interval (95%CI) = 0.997-0.999), as the two methods concordance for retinal diseases diagnosis (kappa = 0.997, 95%CI = 0.996-0.999) without statistically significant difference. UWF fundus imaging might be an alternative to ophthalmoscopy, since it allows to accurately classify major retinal diseases, widening the range of disorders possibly diagnosed with teleophthalmology. Although the clinician should be aware of the possibility that a minority of the most peripheral lesions may be not entirely visualized, it might be considered a first line diagnostic modality, in the context of a full ophthalmological examination.

Comparison of the proposed DCNN model with standard CNN architectures for retinal diseases classification.

Deep learning in medical image analysis has indicated increasing interest in the classification of signs of abnormalities. In this study, a new convolutional neural network (CNN) architecture (MIDNet18) Medical Image Detection Network was proposed for the classification of retinal diseases using optical coherence tomography (OCT) images. The model consists of 14 convolutional layers, seven Max Pooling layers, four dense layers, and one classification layer. A multi-class classification layer in the MIDNet18 is used to classify the OCT images into either normal or any of the three abnormal types: Choroidal Neovascularization (CNV), Drusen, and Diabetic Macular Edema (DME). The dataset consists of 83,484 training images, 41,741 validation images, and 968 test images. According to the experimental results, MIDNet18 obtains an accuracy of 98.86%, and their performances are compared with other standard CNN models; ResNet-50 (83.26%), MobileNet (93.29%) and DenseNet (92.5%). Also, MIDNet18 with a p-value < 0.001 has been proved to be statistically significant than other standard CNN architectures in classifying retinal diseases using OCT images.

Update on the utility of en face optical coherence tomography in the assessment of vitreoretinal diseases.

En face optical coherence tomography (EF-OCT) is a rapid, non-invasive, high-resolution imaging technique that has evolved in recent years to be a routine examination for the assessment and follow-up of various vitreoretinal diseases. With the introduction of swept-source OCT (SS-OCT), which can achieve up to 100,000 A-scans per second and better-quality imaging of deeper structures using a longer wavelength (1050nm), EF-OCT reconstruction can produce high-resolution frontal images of the retina and choroid (C-Scans) that give an overview of disease extent. These images allow a more accurate study of vitreoretinal interface pathologies such as epiretinal membranes, macular holes, and vitreomacular traction. They also provide key information in the study of various retinal vascular diseases and the differential diagnosis of cystic macular edema. EF-OCT provides valuable information about the severity of vitreoretinal interface alterations and precisely assesses the choriocapillaris and choroidal vasculature in pachychoroid disorders. Finally, this technique provides valuable information about atrophic and neovascular age-related macular degeneration and various uveitic entities. This review aims to describe the current clinical applications of EF-OCT in various vitreoretinal diseases as well as the latest findings and future perspectives.

Automated image quality appraisal through partial least squares discriminant analysis.

PURPOSE: Automatic retinal fundus image quality analysis is one of the most essential preliminary stages in automatic computer-aided retinal disease diagnosis system, which allows good-quality fundus images for accurate disease prediction through localization and segmentation of retinal regions. This paper presents new feature extraction methods using full-reference and no-reference image quality metrics for image quality classification. METHODS: Basic image features, reference and no-reference features are extracted from the fundus image and applied through different classification techniques to determine the image quality for further diagnosis. In this paper, human-made categorization including good and non-good-quality fundus image classification is constructed by considering major features of retinal fundus images are illumination, clarity, image intensity, contrast and region visibility. The proposed system presented fundus image quality classification by automatic extraction of features from fundus images through image processing techniques and automatic classification of image quality through different classification algorithm. RESULTS: This system was thoroughly investigated on 2674 retinal fundus images from publically available datasets, namely MESSIDOR, Drishti-GS1, DRIVE, HRF, DRIONS-DB, DIARETDB0, DIARETDB1, IDRiD, INSPIRE-AVR, CHASE-DB1, ONHSD, DRIMDB and e-ophtha-EX with better performance results in terms of sensitivity, accuracy, precision and F1 score of 99.36%, 96.79%, 96.29% and 97.79%, respectively. CONCLUSION: The proposed system results were compared to the existing state-of-the-art approaches and outperform existing methods for image quality assessment representing the efficiency and robustness of our system is most suitable for automatic image analysis during retinal disease diagnosis.

Redefining the Koizumi model of mouse cerebral ischemia: A comparative longitudinal study of cerebral and retinal ischemia in the Koizumi and Longa middle cerebral artery occlusion models.

Cerebral and retinal ischemia share similar pathogenesis and epidemiology, each carrying both acute and prolonged risk of the other and often co-occurring. The most used preclinical stroke models, the Koizumi and Longa middle cerebral artery occlusion (MCAO) methods, have reported retinal damage with great variability, leaving the disruption of retinal blood supply via MCAO poorly investigated, even providing conflicting assumptions on the origin of the ophthalmic artery in rodents. The aim of our study was to use longitudinal in vivo magnetic resonance assessment of cerebral and retinal vascular perfusion after the ischemic injury to clarify whether and how the Koizumi and Longa methods induce retinal ischemia and how they differ in terms of cerebral and retinal lesion evolution. We provided anatomical evidence of the origin of the ophthalmic artery in mice from the pterygopalatine artery. Following the Koizumi surgery, retinal responses to ischemia overlapped with those in the brain, resulting in permanent damage. In contrast, the Longa method produced only extensive cerebral lesions, with greater tissue loss than in the Koizumi method. Additionally, our data suggests the Koizumi method should be redefined as a model of ischemia with chronic hypoperfusion rather than of ischemia and reperfusion.