Ultra-wide field retinal imaging: A wider clinical perspective

Prospective validation of a virtual post-operative clinic in vitreoretinal surgery

PURPOSE

To evaluate the clinical efficacy and safety of asynchronous virtual post-operative assessments following vitreoretinal surgery and procedures compared to traditional face-to-face assessments in a high-volume tertiary eye centre.

METHODS

Prospective comparative clinical series study of patients who had undergone vitreoretinal surgery or post-laser retinopexy. Patients received both virtual and face-to-face assessments. The virtual assessment included clinical questions, visual acuity measurement, and virtual retinal imaging using ultra-wide field (UWF) imaging and macular optical coherence tomography (OCT). Face-to-face assessments involved standard clinical examinations.

RESULTS

We included 142 patients undergoing a variety of vitreoretinal procedures. We showed comparable results between virtual and face-to-face assessments in both, post-operative and post-laser treatments. UWF imaging with macular OCT demonstrated potential for effective virtual post-operative assessment. The virtual assessment has a sensitivity of 91% and specificity of 100% for detecting retinal detachments with 100% specificity and 100% sensitivity for detecting new retinal tears or insufficient laser treatment.

CONCLUSIONS

The implementation of asynchronous virtual post-operative assessments following a variety of vitreoretinal procedures is a promising alternative to traditional face-to-face assessments. Virtual assessments using UWF imaging and macular OCT showed high sensitivity and specificity. Virtual post-operative clinics offer the potential to improve patient access and decrease the clinical burden, especially with the continuing evolution of telemedicine technologies and imaging modalities.

Artificial Intelligence, Digital Imaging, and Robotics Technologies for Surgical Vitreoretinal Diseases

OBJECTIVE

To review recent technological advancement in imaging, surgical visualization, robotics technology, and the use of artificial intelligence in surgical vitreoretinal (VR) diseases.

BACKGROUND

Technological advancements in imaging enhance both preoperative and intraoperative management of surgical VR diseases. Widefield imaging in fundal photography and OCT can improve assessment of peripheral retinal disorders such as retinal detachments, degeneration, and tumors. OCT angiography provides a rapid and noninvasive imaging of the retinal and choroidal vasculature. Surgical visualization has also improved with intraoperative OCT providing a detailed real-time assessment of retinal layers to guide surgical decisions. Heads-up display and head-mounted display utilize 3-dimensional technology to provide surgeons with enhanced visual guidance and improved ergonomics during surgery. Intraocular robotics technology allows for greater surgical precision and is shown to be useful in retinal vein cannulation and subretinal drug delivery. In addition, deep learning techniques leverage on diverse data including widefield retinal photography and OCT for better predictive accuracy in classification, segmentation, and prognostication of many surgical VR diseases.

CONCLUSION

This review article summarized the latest updates in these areas and highlights the importance of continuous innovation and improvement in technology within the field. These advancements have the potential to reshape management of surgical VR diseases in the very near future and to ultimately improve patient care.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Analysis of the Retinal and Choroidal Vasculature Using Ultrawidefield Fundus Imaging in Mild Cognitive Impairment and Normal Cognition

Purpose

To utilize ultrawidefield (UWF) imaging to evaluate retinal and choroidal vasculature and structure in individuals with mild cognitive impairment (MCI) compared with that of controls with normal cognition.

Design

Prospective cross sectional study.

Participants

One hundred thirty-one eyes of 82 MCI patients and 230 eyes of 133 cognitively normal participants from the Eye Multimodal Imaging in Neurodegenerative Disease Study.

Methods

A scanning laser ophthalmoscope (California, Optos Inc) was used to obtain UWF fundus color images. Images were analyzed with the Vasculature Assessment Platform for Images of the Retina UWF (VAMPIRE-UWF 2.0, Universities of Edinburgh and Dundee) software.

Main outcome measures

Imaging parameters included vessel width gradient, vessel width intercept, large vessel choroidal vascular density, vessel tortuosity, and vessel fractal dimension.

Results

Both retinal artery and vein width gradients were less negative in MCI patients compared with controls, demonstrating decreased rates of vessel thinning at the periphery (P < 0.001; P = 0.027). Retinal artery and vein width intercepts, a metric that extrapolates the width of the vessel at the center of the optic disc, were smaller in MCI patients compared with that of controls (P < 0.001; P = 0.017). The large vessel choroidal vascular density, which quantifies the vascular area versus the total choroidal area, was greater in MCI patients compared with controls (P = 0.025).

Conclusions

When compared with controls with normal cognition, MCI patients had thinner retinal vasculature manifested in both the retinal arteries and the veins. In MCI, these thinner arteries and veins attenuated at a lower rate when traveling toward the periphery. MCI patients also had increased choroidal vascular density.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Computational single fundus image restoration techniques: a review

Fundus cameras are widely used by ophthalmologists for monitoring and diagnosing retinal pathologies. Unfortunately, no optical system is perfect, and the visibility of retinal images can be greatly degraded due to the presence of problematic illumination, intraocular scattering, or blurriness caused by sudden movements. To improve image quality, different retinal image restoration/enhancement techniques have been developed, which play an important role in improving the performance of various clinical and computer-assisted applications. This paper gives a comprehensive review of these restoration/enhancement techniques, discusses their underlying mathematical models, and shows how they may be effectively applied in real-life practice to increase the visual quality of retinal images for potential clinical applications including diagnosis and retinal structure recognition. All three main topics of retinal image restoration/enhancement techniques, i.e., illumination correction, dehazing, and deblurring, are addressed. Finally, some considerations about challenges and the future scope of retinal image restoration/enhancement techniques will be discussed.

FQ-UWF: Unpaired Generative Image Enhancement for Fundus Quality Ultra-Widefield Retinal Images

Ultra-widefield (UWF) retinal imaging stands as a pivotal modality for detecting major eye diseases such as diabetic retinopathy and retinal detachment. However, UWF exhibits a well-documented limitation in terms of low resolution and artifacts in the macular area, thereby constraining its clinical diagnostic accuracy, particularly for macular diseases like age-related macular degeneration. Conventional supervised super-resolution techniques aim to address this limitation by enhancing the resolution of the macular region through the utilization of meticulously paired and aligned fundus image ground truths. However, obtaining such refined paired ground truths is a formidable challenge. To tackle this issue, we propose an unpaired, degradation-aware, super-resolution technique for enhancing UWF retinal images. Our approach leverages recent advancements in deep learning: specifically, by employing generative adversarial networks and attention mechanisms. Notably, our method excels at enhancing and super-resolving UWF images without relying on paired, clean ground truths. Through extensive experimentation and evaluation, we demonstrate that our approach not only produces visually pleasing results but also establishes state-of-the-art performance in enhancing and super-resolving UWF retinal images. We anticipate that our method will contribute to improving the accuracy of clinical assessments and treatments, ultimately leading to better patient outcomes.

Wide-field imaging with smartphone based fundus camera: grading of severity of diabetic retinopathy and locating peripheral lesions in diabetic retinopathy

AIM

To assess the performance of smartphone based wide-field retinal imaging (WFI) versus ultra-wide-field imaging (UWFI) for assessment of sight-threatening diabetic retinopathy (STDR) as well as locating predominantly peripheral lesions (PPL) of DR.

METHODS

Individuals with type 2 diabetes with varying grades of DR underwent nonmydriatic UWFI with Daytona Plus camera followed by mydriatic WFI with smartphone-based Vistaro camera at a tertiary care diabetes centre in South India in 2021-22. Grading of DR as well as identification of PPL (DR lesions beyond the posterior pole) in the retinal images of both cameras was performed by senior retina specialists. STDR was defined by the presence of severe non-proliferative DR, proliferative DR or diabetic macular oedema (DME). The sensitivity and specificity of smartphone based WFI for detection of PPL and STDR was assessed. Agreement between the graders for both cameras was compared.

RESULTS

Retinal imaging was carried out in 318 eyes of 160 individuals (mean age 54.7 ± 9 years; mean duration of diabetes 16.6 ± 7.9 years). The sensitivity and specificity for detection of STDR by Vistaro camera was 92.7% (95% CI 80.1-98.5) and 96.6% (95% CI 91.5-99.1) respectively and 95.1% (95% CI 83.5-99.4) and 95.7% (95% CI 90.3-98.6) by Daytona Plus respectively. PPL were detected in 89 (27.9%) eyes by WFI by Vistaro camera and in 160 (50.3%) eyes by UWFI. However, this did not translate to any significant difference in the grading of STDR between the two imaging systems. In both devices, PPL were most common in supero-temporal quadrant (34%). The prevalence of PPL increased with increasing severity of DR with both cameras (p < 0.001). The kappa comparison between the 2 graders for varying grades of severity of DR was 0.802 (p < 0.001) for Vistaro and 0.753 (p < 0.001) for Daytona Plus camera.

CONCLUSION

Mydriatic smartphone-based widefield imaging has high sensitivity and specificity for detecting STDR and can be used to screen for peripheral retinal lesions beyond the posterior pole in individuals with diabetes.

Reduced Retinal Vascular Density and Skeleton Length in Amblyopia

Purpose

This study aimed to investigate the possible relationship between retinal vascular abnormalities and amblyopia by analyzing vascular structures of fundus images.

Methods

In this observational study, retinal fundus images were collected from 36 patients with unilateral amblyopia, 33 patients with bilateral amblyopia, and 36 healthy control volunteers. We developed a customized training algorithm based on U-Net to digitalize the vasculature in the fundus images to quantify vascular density (area and fractal dimension), skeleton length, and number of bifurcation points. For statistical comparisons, this study divided participants into two groups. The amblyopic eyes and the fellow eyes of patients with unilateral amblyopia formed the paired group, while bilateral amblyopic patients and healthy controls formed the independent group.

Results

In the paired group, the vascular area (P = 0.007), vascular fractal dimension (P = 0.007), and vascular skeleton length (P = 0.002) of the amblyopic eyes were significantly smaller than those of the fellow eyes. In the independent group, significant decreases in the vascular fractal dimension (P = 0.006) and skeleton length (P = 0.048) were observed in bilateral amblyopia compared to control. The vascular area was also significantly correlated with best-corrected visual acuity in amblyopic eyes.

Conclusions

This study demonstrated that retinal vascular density and skeleton length in amblyopic eyes were significantly smaller compared to control, indicating an association between the changes in retinal vascular features and the state of amblyopia.

Translational Relevance

Our algorithm presents amblyopic retinal vascular changes that are more biologically interpretable for both clinicians and researchers.

Comparison of B-Scan ultrasonography, ultra-widefield fundus imaging, and indirect ophthalmoscopy in detecting retinal breaks in cataractous eyes

BACKGROUND/OBJECTIVES

To evaluate the diagnostic performance of B-scan kinetic ultrasonography (USG), standard ultra-widefield (UWF) imaging, and indirect ophthalmoscopy (IDO) in retinal break detection in cataractous eyes.

SUBJECTS/METHODS

We consecutively enrolled 126 cataract patients (including 246 eyes) with no comorbidities that could decrease best corrected visual acuity (BCVA). Three index tests (USG, nonmydriatic UWF, and mydriatic IDO) were performed preoperatively to screen for retinal breaks. One week after cataract extraction, a dilated IDO examination was repeated for the definitive diagnosis of retinal break as the reference standard. The sensitivity, specificity, Youden index (YI), and predictive values of each index test were calculated according to postoperative ophthalmoscopic findings. A deep-learning nomogram was developed to quantify the risk of retinal break presence using patients' baseline data and findings reported from preoperative ophthalmic tests.

RESULTS

Fifty-two eyes (21%) were excluded from appropriate preoperative UWF imaging because of massive lens opacity. The BCVA cutoff point with maximum YI indicating UWF applicability was 0.6 logMAR (YI = 0.3; area under curve [AUC] = 0.7). Among all 246 eyes, preoperative IDO, USG, and UWF showed fair interobserver agreement (all κ > 0.2). According to postoperative IDO findings, the index tests with the highest sensitivity and specificity were USG (100%) and preoperative IDO (99%), respectively.

CONCLUSIONS

For cataractous eyes without vision-impairing comorbidities, a BCVA better than 0.6 logMAR (Snellen acuity, 20/80) allows for appropriate nonmydriatic standard UWF imaging. In a high-volume clinic equipped with skilled ophthalmic examiners, screening with USG followed by directed IDO allows the efficient identification of retinal breaks in cataractous eyes.

Retinal detachment

Retinal detachment (RD) occurs when the neurosensory retina, the neurovascular tissue responsible for phototransduction, is separated from the underlying retinal pigment epithelium (RPE). Given the importance of the RPE for optimal retinal function, RD invariably leads to decreased vision. There are three main types of RD: rhegmatogenous, tractional and exudative (also termed serous) RD. In rhegmatogenous RD, one or more retinal breaks enable vitreous fluid to enter the subretinal space and separate the neurosensory retina from the RPE. In tractional RD, preretinal, intraretinal or subretinal membranes contract and exert tangential forces and elevate the retina from the underlying RPE. Finally, in exudative RD, an underlying inflammatory condition, vascular abnormality or the presence of a tumour causes exudative fluid to accumulate in the subretinal space, exceeding the osmotic pump function of the RPE. The surgical management of RD usually involves pars plana vitrectomy, scleral buckling or pneumatic retinopexy. The approach taken often depends on patient characteristics as well as on practitioner experience and clinical judgement. Advances in surgical technology and continued innovation have improved outcomes for many patients. However, even if retinal re-attachment is achieved, some patients still experience decreased vision or other visual symptoms, such as metamorphopsia, that diminish their quality of life. Continued research in the areas of neuroprotection and retinal biology as well as continued surgical innovation are necessary to enhance therapeutic options and outcomes for these patients.

Prevalence of peripheral retinal findings in retinal patients using ultra-widefield pseudocolor fundus imaging

Ultra-widefield retinal imaging is increasingly used in ophthalmology and optometry practices to image patients identifying peripheral abnormalities. However, the clinical relevance of these peripheral retinal abnormalities is unclear. This cross-sectional study aims to firstly validate a new grading system, secondly, assess the prevalence of peripheral retinal abnormalities in retinal patients, and finally understand how peripheral findings may associate with retinal disease. Ultra-widefield pseudocolor fundus images were taken from the eyes of clinic patients. Demographic data and clinical diagnosis for each patient was noted. The grading system was validated using masked retinal specialists. Logistic regression identified associations between retinal disease and peripheral retinal findings. Using the grading system, inter-observer agreement was 76.1% with Cohen's Kappa coefficient 0.542 (p < 0.0001) and the test-retest agreement was 95.1% with Kappa 0.677(p < 0.0001). 971 images were included, with 625 eyes (64.4%) having peripheral abnormalities. Peripheral drusen was the most common abnormality (n = 221, 22.76%) and correlated with age-related macular degeneration (p < 0.001). Novel correlations were also identified between diabetic retinopathy and retinal pigmentation as well as pigmentary degeneration. This study provides a validated system for identifying peripheral abnormalities and adds to literature highlighting peripheral retinal associations with retinal disease which would benefit from further study.

The Sensitivity of Ultra-Widefield Fundus Photography Versus Scleral Depressed Examination for Detection of Retinal Horseshoe Tears

PURPOSE

Ultra-widefield (UWF) imaging is commonly used in ophthalmology in tandem with scleral depressed examinations (SDE) to evaluate peripheral retinal disease. Because of the increased reliance on this technology in tele-ophthalmology, it is critical to evaluate its efficacy for detecting the peripheral retina when performed in isolation. Therefore, we sought to evaluate UWF imaging sensitivity in detecting retinal horseshoe tears (HSTs).

STUDY DESIGN

Retrospective clinical validity and reliability study.

METHODS

A single-institutional retrospective analysis was performed on patients at the Shiley Eye Institute, University of California, San Diego. Patients with HSTs seen on SDE who underwent treatment with laser were included in the study. A total of 140 patients with HSTs in the right and/or left eyes met the inclusion criteria. Those with concomitant ruptured globes, retinal detachments, and vitreous hemorrhages were excluded. A total of 123 patients with 135 HSTs were included in the final analysis. The primary outcome was the number of HSTs detected by UWF imaging. A secondary outcome was HST location. Sensitivity was measured with respect to HST location, and statistical significance was calculated by Fisher exact testing.

RESULTS

A total of 69 (51.1%) HSTs were visualized on UWF images and 66 (48.9%) were not visualized. The sensitivity of UWF imaging in capturing HSTs was 7 of 41 (17.1%), 8 of 25 (32.0%), 7 of 14 (50.0%), and 47 of 55 (85.5%) for the superior, inferior, nasal, and temporal quadrants, respectively. Sensitivities between HST visibility and location were statistically significant (P < .001).

CONCLUSIONS

Nearly half of HSTs were missed by UWF imaging. This study demonstrates that UWF imaging alone is not sufficiently sensitive to exclude the presence of HSTs.

Vision degrading myodesopsia assessed with optos ultra-widefield scanning laser ophthalmoscope

BACKGROUND

To investigate the diagnostic sensitivity of Optos imaging for vision degrading myodesopsia (VDM).

METHODS

A total of 420 eyes from 345 patients with VDM were collected in this cross-sectional study. All eyes were classified as having posterior vitreous detachment (PVD) or not having PVD. The sensitivity of Optos imaging for the visibility of vitreous floaters was evaluated. The associated factors with the visibility of vitreous floaters on Optos images were analyzed in univariate and multivariate logistic regression analyses.

RESULTS

The mean age of all patients was 56.19 ± 13.89 years old, and 66.67% of patients were female. The vitreous floaters were visible on the ultrasound B scan in all eyes, but only in 47.62% of Optos images (55.29% in eyes with PVD and 15% in eyes without PVD). In the multiple binary logistic regression analysis, age (OR = 1.094, 95%CI = 1.063-1.125, P < 0.001), spherical equivalent (OR = 0.869, 95%CI = 0.791-0.955, P = 0.004) and the distance of the floaters from the retina (OR = 1.191, 95%CI = 1.059-1.339, P = 0.003) were significantly correlated with the visibility of vitreous floaters on Optos images. On Optos images, 25.71% of VDM eyes presented additional retinal abnormalities.

CONCLUSIONS

Optos imaging has a low sensitivity for vitreous floaters, particularly in eyes without PVD. On Optos imaging, floaters were more visible in older patients, eyes with greater myopia, and floaters that were further from the retina.

Discriminative-Region Multi-Label Classification of Ultra-Widefield Fundus Images

Ultra-widefield fundus image (UFI) has become a crucial tool for ophthalmologists in diagnosing ocular diseases because of its ability to capture a wide field of the retina. Nevertheless, detecting and classifying multiple diseases within this imaging modality continues to pose a significant challenge for ophthalmologists. An automated disease classification system for UFI can support ophthalmologists in making faster and more precise diagnoses. However, existing works for UFI classification often focus on a single disease or assume each image only contains one disease when tackling multi-disease issues. Furthermore, the distinctive characteristics of each disease are typically not utilized to improve the performance of the classification systems. To address these limitations, we propose a novel approach that leverages disease-specific regions of interest for the multi-label classification of UFI. Our method uses three regions, including the optic disc area, the macula area, and the entire UFI, which serve as the most informative regions for diagnosing one or multiple ocular diseases. Experimental results on a dataset comprising 5930 UFIs with six common ocular diseases showcase that our proposed approach attains exceptional performance, with the area under the receiver operating characteristic curve scores for each class spanning from 95.07% to 99.14%. These results not only surpass existing state-of-the-art methods but also exhibit significant enhancements, with improvements of up to 5.29%. These results demonstrate the potential of our method to provide ophthalmologists with valuable information for early and accurate diagnosis of ocular diseases, ultimately leading to improved patient outcomes.

Ultra-Widefield Imaging of Presumed Vitreous Base-Associated Vasculopathy: Assessment of Peripheral Retinal Hemorrhages and Microaneurysms

Purpose: To describe cases of asymptomatic peripheral retinal hemorrhage attributed to presumed vitreous base traction seen on ultra-widefield (UWF) imaging. Methods: This retrospective consecutive series comprised asymptomatic patients with peripheral retinal hemorrhages, microaneurysms, or both. Imaging included UWF fundus photography, fundus autofluorescence, fluorescein angiography (FA), optical coherence tomography (OCT), or a combination. Results: The series included 9 adult patients. The findings were observed on a routine eye examination or as an incidental finding in the contralateral eye of patients presenting with a retinal break or detachment. On UWF imaging, the distinguishing features of the peripheral retinal hemorrhages and microaneurysms presumably caused by vitreous base traction were their pinpoint shape and location at the vitreous base, in particular in the far temporal and superior retinal periphery. UWF FA showed punctate hyperfluorescent spots with no leakage. OCT showed signs of evolving posterior vitreous detachment. Management was limited to observation; with time, the microaneurysms were stable and the hemorrhages resolved. Conclusions: UWF imaging has led to the identification of presumed vitreous base vasculopathy. After a targeted workup is unrevealing, observation is appropriate.

New Imaging Technology for Simultaneous Multiwavelength-UWF Fundus Fluorescein Angiography and Indocyanine Green Angiography With Navigated Central and Peripheral SS-OCT

OBJECTIVE

Our aim was to assess central and peripheral retinal and choroidal diseases using novel simultaneous multiwavelength-ultra-widefield (MW-UWF) fundus fluorescein angiography (FFA)/indocyanine green angiography (ICGA) with navigated central and peripheral swept-source optical coherence tomography (SS-OCT) technology.

METHODS

Retrospective evaluation was carried out of 30 consecutive patients (60 eyes) who underwent UWF red/green (RG), infrared (IR), FFA and ICGA with simultaneous navigated SS-OCT using Optos Silverstone (Optos PLC). Angiographic retinal and choroidal findings in vascular pathologies and their relationship with the vitreoretinal interface (VRI) were assessed.

RESULTS

Simultaneous FFA with navigated SSOCT was performed in all patients and simultaneous FFA-ICGA with SS-OCT in 18 eyes (30%). Cross-sectional central and peripheral changes in the retina, choroid, and VRI corresponding with angiographic findings in several diseases were imaged.

CONCLUSION

First-in-human study of a new technology providing UWF RG/FFA/ICGA with simultaneous navigated central and peripheral SS-OCT can guide clinical management and provide new insights and understanding of central and peripheral retinal and choroidal disease. [Ophthalmic Surg Lasers Imaging Retina 2023;54:xx-xx.].

[Comparison of available clinical and imaging tools to assess good positioning of a fluocinolone acetonide implant (Iluvien®) in the vitreous cavity after injection]

INTRODUCTION

Sustained-release corticosteroid implants are injected into the vitreous cavity using preloaded pens. The fluocinolone (FAc) implant is approximately half the size of the dexamethasone implant (Dex-I). It is simply introduced in the vitreous base rather than propelled into the vitreous cavity as is Dex-I. Verification of its positioning after injection is thus difficult by indirect ophthalmoscopy. The goal of our study is to compare the performance of available clinical and imaging tools to confirm the presence of the FAc in the vitreous cavity following injection.

METHODS

Twelve eyes of 12 consecutive patients were included in a retrospective, single-center, observational study carried out at the Bordeaux University Hospital, France. All patients were injected with the FAc after pupil dilation, and presence of the implant was immediately checked by indirect biomicroscopy, wide-field retinography (Clarus®, Carl-Zeiss-Meditec, Dublin, CA, USA) and ultra-wide-field retinography (California®, Optos, Edinburgh, United-Kingdom). Seven days later, a B-mode ultrasonography (10MHz, AVISO, Quantel-medical, France) and an UBM ultrasonography (50MHz, AVISO, Quantel-medical, France) were performed.

RESULTS

Indirect biomicroscopy and wide-field retinography detected 4/12 implants (33.3%). Ultra-wide-field retinophotography detected 6/12 implants (50%). All the implants seen using indirect biomicroscopy and wide-field retinography were also visualized with ultra-wide-field. B-mode ultrasonography showed 5/12 implants (41.6%) and UBM 9/12 implants (75%). Finally, one implant dislocated into the anterior chamber and was seen in the iridocorneal angle on gonioscopy.

CONCLUSION

Objective confirmation of the proper positioning of the FAc implant in the vitreous cavity is mandatory. If both indirect ophthalmoscopy and anterior examination fail to detect it, ultra-wide field retinography along with UBM ultrasonography, if necessary, appear to be the two best imaging modalities to use.

Widefield and Ultra-Widefield Retinal Imaging: A Geometrical Analysis

Diabetic retinopathy (DR) often causes a wide range of lesions in the peripheral retina, which can be undetected when using a traditional fundus camera. Widefield (WF) and Ultra-Widefield (UWF) technologies aim to significantly expand the photographable retinal field. We conducted a geometrical analysis to assess the field of view (FOV) of WF and UWF imaging, comparing it to the angular extension of the retina. For this task, we shot WF images using the Zeiss Clarus 500 fundus camera (Carl Zeiss Meditec, Jena, Germany). Approximating the ocular bulb to an ideal sphere, the angular extension of the theoretically photographable retinal surface was 242 degrees. Performing one shot, centered on the macula, it was possible to photograph a retinal surface of ~570 mm², with a FOV of 133 degrees. Performing four shots with automatic montage, we obtained a retinal surface area of ~1100 mm² and an FOV of 200 degrees. Finally, performing six shots with semi-automatic montage, we obtained a retinal surface area of ~1400 mm² and an FOV of 236.27 degrees, which is close to the entire surface of the retina. WF and UWF imaging allow the detailed visualization of the peripheral retina, with significant impact on the diagnosis and management of DR.

Proliferative Sickle Cell Retinopathy in the Retinal Periphery Detected by Ultra-Widefield Imaging: A Case Report

Sickle cell proliferative retinopathy usually presents first in the peripheral retina and the ability to extend and enhance our visualization of the peripheral retina would allow for superior clinical decision-making. In our practice, we had a 28-year-old patient diagnosed with major sickle cell disease of the homozygous type SS (HbSS) that presented with sickle cell proliferative retinopathy detected by ultra-widefield imaging in the nasal side of the left fundus. At follow-up, neovascularization was detected in the extreme nasal periphery of the left eye by ultra-widefield imaging fluorescein angiography with right gaze. The case was graded as Goldberg stage 3, and the patient was administered photocoagulation treatment. With further advancements in the quality and modality of peripheral retinal imaging, novel proliferative lesions can be detected and appropriately managed much earlier than was previously possible. Ultra-widefield imaging allows for the visualization of the central 200 degrees of the retina but, with gaze view, peripheral retina beyond 200 degrees can be reached.

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.

Step-wise diagnostic approach for patients with uveitis - Experts consensus in Taiwan

Uveitis is a sight-threatening disease that can be associated with many different etiologies. Successful treatment of uveitis relies on accurate diagnosis and prompt efficient therapy. History taking, physical and ocular examinations, systemic evaluations, and response to treatment provide crucial information to differentiate possible etiologies involved in the pathophysiology of intraocular inflammation. This article provides recommendations for a step-wise approach to patients with uveitis in Taiwan based on an expert meeting and consensus. Systemic evaluations for uveitis should be performed step-by-step and include investigation of patients' general systemic conditions, ruling out infectious etiologies, and obtaining evidential biomarkers to diagnose a specific disease entity.

Deep learning for ultra-widefield imaging: a scoping review

PURPOSE

This article is a scoping review of published and peer-reviewed articles using deep-learning (DL) applied to ultra-widefield (UWF) imaging. This study provides an overview of the published uses of DL and UWF imaging for the detection of ophthalmic and systemic diseases, generative image synthesis, quality assessment of images, and segmentation and localization of ophthalmic image features.

METHODS

A literature search was performed up to August 31st, 2021 using PubMed, Embase, Cochrane Library, and Google Scholar. The inclusion criteria were as follows: (1) deep learning, (2) ultra-widefield imaging. The exclusion criteria were as follows: (1) articles published in any language other than English, (2) articles not peer-reviewed (usually preprints), (3) no full-text availability, (4) articles using machine learning algorithms other than deep learning. No study design was excluded from consideration.

RESULTS

A total of 36 studies were included. Twenty-three studies discussed ophthalmic disease detection and classification, 5 discussed segmentation and localization of ultra-widefield images (UWFIs), 3 discussed generative image synthesis, 3 discussed ophthalmic image quality assessment, and 2 discussed detecting systemic diseases via UWF imaging.

CONCLUSION

The application of DL to UWF imaging has demonstrated significant effectiveness in the diagnosis and detection of ophthalmic diseases including diabetic retinopathy, retinal detachment, and glaucoma. DL has also been applied in the generation of synthetic ophthalmic images. This scoping review highlights and discusses the current uses of DL with UWF imaging, and the future of DL applications in this field.

Correlation between ultrawide-field fluorescence contrast results and white blood cell indexes in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes. DR involves a state of systemic inflammation, and chronic inflammation can promote microvascular and macrovascular diseases in diabetic patients and accelerate disease progression. Ultrawide-field FFA (UWFA) systems are increasingly being used to examine a wider retina. The aim of this study was to explore the correlation between the different manifestations of retinopathy under UWFA and the systemic indicators of white blood cells in patients with diabetic retinopathy.

METHODS

This retrospective study included the hospitalized DR patients in the Department of Ophthalmology and Endocrinology of the Affiliated Hospital 2 of Nantong University between January 2016 and March 2019. This study examined the correlations between the UWFA examination results and glycated hemoglobin (HbA1c), routine blood tests,and the neutrophil-to-lymphocyte ratio of patients with clinically diagnosed DR during hospitalization.

RESULTS

A total of 115 patients with DR (53 females and 62 males) were included (199 eyes: 102 right eyes and 97 left eyes). UWFA revealed that most eyes (77.4%) had grade 4 microvascular leakage, 52.8% had grade 0 capillary non-perfusion area, 59.3% had grade 0 neovascularization, and 92.0% had grade 0 fibrous proliferative membranes. Microvascular leakage was correlated with the NLR (r = 0.186, P = 0.027). Capillary non-perfusion area was correlated with the monocyte ratio (r = 0.144, P = 0.042) and the eosinophil ratio (r = 0.123, P = 0.044). Neovascularization was correlated to the monocyte ratio (r = 0.324, P = 0.018). Finally, the fibrous proliferative membrane was correlated to the monocyte ratio (r = 0.418, P = 0.002). Only the eosinophil ratio was independently associated with proliferative DR (odds ratio = 1.25, 95% confidence interval: 1.04-1.51, P = 0.018).

CONCLUSION

The results of UWFA imaging in patients with DR are correlated with white blood cell population indexes. The eosinophil ratio was independently associated with proliferative DR.

Fundus Autofluorescence Imaging in Patients with Choroidal Melanoma

Simple Summary

The ocular fundus contains molecules that emit fluorescence when excited with light of an appropriate wavelength. Fundus autofluorescence imaging is based on the in vivo detection of intrinsic fluorescence and results in topographic autofluorescence mapping of the ocular fundus. In contrast to fluorescence angiography, where the fluorescing agents need to be administered intravenously, autofluorescence imaging is a non-invasive technique. Even though choroidal melanomas do not contain significant autofluorescent molecules themselves, they may lead to secondary alterations in neighbouring tissues with an impact on the autofluorescence signal recording. Fundus autofluorescence imaging in the context of choroidal melanoma is helpful for differential diagnosis and for monitoring variations over time in affected patients before and after treatment.

Abstract

Choroidal melanocytic lesions require reliable and precise clinical examination and diagnosis to differentiate benign choroidal nevi from choroidal melanoma, as the latter may become life-threatening through metastatic disease. To come to an accurate diagnosis, as well as for monitoring, and to assess the efficacy of therapy, various imaging modalities may be used, one of which is non-invasive fundus autofluorescence (FAF) imaging using novel high-resolution digital imaging technology. FAF imaging is based on the visualization of intrinsic fluorophores in the ocular fundus. Lipofuscin and melanolipofuscin within the postmitotic retinal pigment epithelium (RPE) cells represent the major fluorophores that contribute to the FAF signal. In addition, the presence or loss of absorbing molecular constituents may have an impact on the FAF signal. A choroidal melanoma can cause secondary retinal and RPE alterations that affect the FAF signal (e.g., occurrence of orange pigment). Therefore, FAF imaging supports multimodal imaging and gives additional information over and above conventional imaging modalities regarding retinal metabolism and RPE health status. This article summarises the features of FAF imaging and the role of FAF imaging in the context of choroidal melanoma, both before and following therapeutic intervention.

A Novel, Smartphone-Based, Teleophthalmology-Enabled, Widefield Fundus Imaging Device With an Autocapture Algorithm

Purpose

Widefield imaging can detect signs of retinal pathology extending beyond the posterior pole and is currently moving to the forefront of posterior segment imaging. We report a novel, smartphone-based, telemedicine-enabled, mydriatic, widefield retinal imaging device with autofocus and autocapture capabilities to be used by non-specialist operators.

Methods

The Remidio Vistaro uses an annular illumination design without cross-polarizers to eliminate Purkinje reflexes. The measured resolution using the US Air Force target test was 64 line pairs (lp)/mm in the center, 57 lp/mm in the middle, and 45 lp/mm in the periphery of a single-shot retinal image. An autocapture algorithm was developed to capture images automatically upon reaching the correct working distance. The field of view (FOV) was validated using both model and real eyes. A pilot study was conducted to objectively assess image quality. The FOVs of montaged images from the Vistaro were compared with regulatory-approved widefield and ultra-widefield devices.

Results

The FOV of the Vistaro was found to be approximately 65° in one shot. Automatic image capture was achieved in 80% of patient examinations within an average of 10 to 15 seconds. Consensus grading of image quality among three graders showed that 91.6% of the images were clinically useful. A two-field montage on the Vistaro was shown to exceed the cumulative FOV of a seven-field Early Treatment Diabetic Retinopathy Study image.

Conclusions

A novel, smartphone-based, portable, mydriatic, widefield imaging device can view the retina beyond the posterior pole with a FOV of 65° in one shot.

Translational Relevance

Smartphone-based widefield imaging can be widely used to screen for retinal pathologies beyond the posterior pole.