Association of Predominantly Peripheral Lesions on Ultra-Widefield Imaging and the Risk of Diabetic Retinopathy Worsening Over Time

Multimodal imaging in diabetic retinopathy and macular edema: An update about biomarkers

Diabetic macular edema (DME), defined as retinal thickening near, or involving the fovea caused by fluid accumulation in the retina, can lead to vision impairment and blindness in patients with diabetes. Current knowledge of retina anatomy and function and DME pathophysiology has taken great advantage of the availability of several techniques for visualizing the retina. Combining these techniques in a multimodal imaging approach to DME is recommended to improve diagnosis and to guide treatment decisions. We review the recent literature about the following retinal imaging technologies: optical coherence tomography (OCT), OCT angiography (OCTA), wide-field and ultrawide-field techniques applied to fundus photography, fluorescein angiography, and OCTA. The emphasis will be on characteristic DME features identified by these imaging technologies and their potential or established role as diagnostic, prognostic, or predictive biomarkers. The role of artificial intelligence in the assessment and interpretation of retina images is also discussed.

Relationship between macular perfusion and lesion distribution in diabetic retinopathy

BACKGROUND/OBJECTIVES

To assess the relationship between macular vessel density metrics and foveal avascular zone (FAZ) characteristics on optical coherence tomography angiography (OCTA) and lesion distribution in eyes with diabetic retinopathy (DR).

SUBJECTS/METHODS

Patients with DR who underwent both Optos ultrawidefield (UWF) pseudocolor imaging and macular OCTA (Cirrus Angioplex, 6 × 6 mm) were included in this cross-sectional observational study. The distribution of DR lesions was assessed by comparing each of the peripheral ETDRS extended fields (3-7) against their corresponding ETDRS field, hence eyes were defined as either having predominantly peripheral lesions (PPL) or predominantly central lesions (PCL). En face OCTA images from the superficial and deep capillary plexuses (SCP and DCP) were then analysed using Image J software. Perfusion density (PD), vessel length density (VLD), and fractal dimensions (FD) were calculated following binarization and skeletonization of the images.

RESULTS

Out of 344 eyes, 116 (33.72%) eyes had PPL and 228 (66.28%) eyes had PCL. For all DRSS levels, VLD, PD, and FD were not significantly different between eyes with PPL and PCL. The FAZ in eyes with PPL, however, was found to be more circular in shape compared to eyes with PCL (p = 0.037).

CONCLUSION

Although the presence of PPL has been associated with a higher risk for diabetic retinopathy progression, the macular perfusion is similar in eyes with PPL and PCL. The FAZ is more circular in eyes with PPL, but the clinical relevance of this difference remains to be defined.

Ultra-Widefield and Early Treatment Diabetic Retinopathy Study 7-Field Grading of Diabetic Retinopathy

Importance

High concordance in diabetic retinopathy (DR) outcomes between 7-field (7F) and ultra-widefield (UWF) images would allow for combining longitudinal assessments based on the 2 modalities both in clinical studies and clinical care.

Objective

To compare 7F and UWF imaging with regard to DR severity and the associations of DR severity with risk factors, such as hemoglobin A1c, age, diabetes duration, and sex.

Design, Setting, and Participants

This cross-sectional study describes the outcomes of the randomized clinical Diabetes Control and Complications Trial (DCCT) and its subsequent observational study, the Epidemiology of Diabetes Interventions and Complications (EDIC) study. Of the 1441 participants with type 1 diabetes in the DCCT, 1375 were enrolled in the EDIC study. Of the 1171 participants who were active between March 2019 and December 2021, 200° UWF color imaging and 7F fundus photographs were obtained for 785 participants once at the same visit. Central graders assessed 7F-UWF with a 7F template masking the retinal periphery and the full UWF image (UWF-global). Data were analyzed from January 2022 to March 2023.

Exposures

Hemoglobin A1c was assessed quarterly during the DCCT and annually during the EDIC study using high-performance liquid chromatography.

Main Outcomes and Measures

Retinopathy was determined independently for all imaging as mild, moderate, or severe nonproliferative DR (SNPDR) using the Early Treatment Diabetic Retinopathy Study (ETDRS) grading scale for the 7F images and the global ETDRS grading scale for the UWF images. Panretinal and focal photocoagulation were self-reported or based on scarring location and pattern observed during grading. Proliferative DR (PDR) was defined by observed neovascularization or evidence of panretinal photocoagulation.

Results

Among the 785 participants included in this study, 420 (53%) were male and 365 (47%) were female. The mean (SD) age was 61 (7) years. DR grading between UWF-7F and 7F imaging was correlated for all outcomes, including for severe outcomes, such as SNPDR (κ, 0.73; concordance, 96%), PDR (κ, 0.74; concordance, 97%), scatter photocoagulation (κ, 0.97; concordance, 99%), and focal photocoagulation (κ, 0.71; concordance, 98%). Most DR severity scores were within 1 step (1410 of 1529 [92%]), and 3% (51 of 1529) were more than 2 steps apart (κ, 0.45; 95% CI, 0.42-0.49; weighted κ, 0.63; 95% CI, 0.60-0.67) on the ETDRS severity scale. DR severity assessed within the UWF-global area was higher compared to 7F (median [IQR] UWF-global score, 3 [2-3] vs median 7F level score, 2.0 [1-3]; P < .001), although the 2 modalities were correlated (1225 of 1508 [81%] 1-step agreement; weighted κ, 0.41).

Conclusions and Relevance

Standard ETDRS 7F and UWF evaluations of DR were comparable for ETDRS severity levels as previously reported by Diabetic Retinopathy Clinical Research Retina Network reports. In addition, these evaluations of DR were comparable for DCCT/EDIT study outcomes and major study conclusions, suggesting that use of UWF imaging is not likely to introduce relevant measurement biases in future longitudinal studies.

Trial Registration

ClinicalTrials.gov Identifiers: NCT00360815.

The role of nutritional factors in transitioning between early, mid, and late stages of age-related macular degeneration: prospective longitudinal analysis

BACKGROUND

Transitions between different stages of age-related macular degeneration (AMD) are not completely captured by traditional survival models with an end point of advanced AMD.

OBJECTIVES

This study aimed to explore the transitions from early and intermediate AMD to higher nonadvanced and advanced stages and determine the contributions of nutritional factors to these outcomes.

METHODS

Eyes with early or intermediate AMD at baseline, classified according to the Age-Related Eye Disease Study severity score, were included in this prospective longitudinal analysis. Foods and the biologically active nutrients associated with AMD [green leafy vegetables, fish, lutein/zeaxanthin (LZ), and ω-3 (n-3) fatty acids] were determined by a baseline food frequency questionnaire. Progression was defined as eyes transitioning to higher severity groups including nonadvanced and advanced stages over 5 y, confirmed at 2 consecutive visits. Cox proportional hazards models for foods and nutrients were analyzed adjusting for demographics, lifestyle, baseline macular status, a family history of AMD, caloric intake, and genetic risk.

RESULTS

Among 2697 eyes, 616 (23%) progressed to higher severity groups. In the food group model, higher intake of green leafy vegetables reduced incidence of transitions {hazard ratio [HR] (≥2.7 servings/wk compared with none): 0.75; 95% confidence interval [CI]: 0.59, 0.96; P = 0.02}. Higher fish intake was also protective [HR (greater than two 4-ounce servings/wk compared with <2): 0.79; 95% CI: 0.65, 0.95; P = 0.01]. In the nutrient model, LZ intake was protective [HR (≥2 mg/d compared with <2): 0.76; 95% CI: 0.60, 0.96; P = 0.02]. Higher intake of ω-3 fatty acids also tended to be beneficial [HR (≥0.7 g/wk compared with <0.7): 0.85; 95% CI: 0.71, 1.01; P = 0.06].

CONCLUSIONS

Increased consumption of green leafy vegetables, LZ, and fish nutritionally rich in ω-3 fatty acids during the initial stages of AMD may reduce rates of progression to higher severity of this debilitating disease. This trial was registered at clinicaltrials.gov as NCT00594672.

RELIABILITY OF CLINICAL GRADING OF DIABETIC RETINOPATHY COMPARED WITH GRADING OF ULTRA-WIDEFIELD IMAGES

PURPOSE

To evaluate the reliability of clinical grading of diabetic retinopathy (DR) severity compared with grading on ultra-widefield pseudocolor fundus (UWF-CF) and ultra-widefield fluorescein angiography (UWF-FA) images and their relative detection of sight-threatening DR and referable DR.

METHODS

A total of 184 diabetic eyes were analyzed. UWF-CF and UWF-FA images were graded based on the International Clinical Diabetic Retinopathy severity scale. Agreement between clinical and UWF-based severity grading was evaluated using Cohen's kappa coefficient. The rate of sight-threatening DR and referable DR was evaluated for each grading method.

RESULTS

Moderate agreement was found between clinical grading and UWF-CF (k = 0.456, P < 0.001) and between UWF-CF and UWF-FA (k = 0.443, P < 0.001). The agreement between clinical grading and UWF-FA was fair (k = 0.397, P < 0.001). UWF-based grading identified a higher DR grade in 56 eyes (30%) on UWF-CF and 85 eyes (46.2%) on UWF-FA. Compared with clinical grading, UWF-FA detected a higher rate of sight-threatening DR (44%; 81/184 vs. 22.3%; 41/184), while UWF-CF detected more referable eyes (58.1%; 107/184 vs. 45.65%; 84/184).

CONCLUSION

Ultra-widefield pseudocolor fundus is a valuable tool for identifying referable eyes and can be a useful, noninvasive adjunct to clinical grading. The results suggest that UWF-FA is particularly useful for detecting unsuspected sight-threatening DR in eyes with clinically referable DR.

Microaneurysm detection using high-speed megahertz optical coherence tomography angiography in advanced diabetic retinopathy

PURPOSE

To compare detection rates of microaneurysms (MAs) on high-speed megahertz optical coherence tomography angiography (MHz-OCTA), fluorescein angiography (FA) and colour fundus photography (CF) in patients with diabetic retinopathy (DR).

METHODS

For this exploratory cross-sectional study, MHz-OCTA data were acquired with a swept-source OCT prototype (A-scan rate: 1.7 MHz), and FA and CF imaging was performed using Optos® California. MA count was manually evaluated on en face MHz-OCTA/FA/CF images within an extended ETDRS grid. Detectability of MAs visible on FA images was evaluated on corresponding MHz-OCTA and CF images. MA distribution and leakage were correlated with detectability on OCTA and CF imaging.

RESULTS

47 eyes with severe DR (n = 12) and proliferative DR (n = 35) were included. MHz-OCTA and CF imaging detected on average 56% and 36% of MAs, respectively. MHz-OCTA detection rate was significantly higher than CF (p < 0.01). The combination of MHz-OCTA and CF leads to an increased detection rate of 70%. There was no statistically significant association between leakage and MA detectability on OCTA (p = 0.13). For CF, the odds of detecting leaking MAs were significantly lower than non-leaking MAs (p = 0.012). Using MHz-OCTA, detection of MAs outside the ETDRS grid was less likely than MAs located within the ETDRS grid (outer ring, p < 0.01; inner ring, p = 0.028). No statistically significant difference between rings was observed for CF measurements.

CONCLUSIONS

More MAs were detected on MHz-OCTA than on CF imaging. Detection rate was lower for MAs located outside the macular region with MHz-OCTA and for leaking MAs with CF imaging. Combining both non-invasive modalities can improve MA detection.

Quantitative Biomarkers of Diabetic Retinopathy Using Ultra-Widefield Fluorescein Angiography

Introduction

Diabetic retinopathy (DR) is a leading cause of blindness. Retinal imaging is an important tool to monitor the progression of DR. While seven-standard retinal fields are the traditional method for evaluating DR, ultra-widefield (UWF) imaging allows for improved visualization of peripheral areas of nonperfusion (NP) and neovascularization (NV), which could be used as biomarkers to monitor and predict progression of DR.

Methods

A retrospective, cross-sectional study was conducted on 651 eyes from 363 patients diagnosed with type 1 or type 2 diabetes who received UWF-FA over 10 years. Fluorescein Angiography (FA) images were segmented, and surface areas of NP and NV were analyzed using multivariate regression to determine if biomarkers of DR and DR severity are associated with increasing areas of NP and NV.

Results

Each additional year with a diagnosis of DR was associated with a 10.75 mm2 increase in the total NP (95% CI, 1.94-19.56; P = 0.02) and 7.87 mm2 increase in NP far-periphery (95% CI, 1.62-14.13; P = 0.01). A one-unit change in severity as defined by the Early Treatment of Diabetic Retinopathy Study (ETDRS) classification was associated with a 25.75 mm2 increase in total NP (95% CI, 11.16-40.33; P = 0.001), a 13.15 mm2 increase in mid-periphery NP (95% CI, 6.93-19.38; P < 0.0001), and a 12.29 mm2 increase in far-periphery NP (95% CI, 3.62-20.97; P = 0.01).

Discussion

Biomarkers identified through UWF imaging such as total and regional areas of NP can be used to monitor and predict the progression of DR. This may provide a quantitative method for prognostication in patients with DR.

Imaging Modalities for Assessing the Vascular Component of Diabetic Retinal Disease: Review and Consensus for an Updated Staging System

Purpose

To review the evidence for imaging modalities in assessing the vascular component of diabetic retinal disease (DRD), to inform updates to the DRD staging system.

Design

Standardized narrative review of the literature by an international expert workgroup, as part of the DRD Staging System Update Effort, a project of the Mary Tyler Moore Vision Initiative. Overall, there were 6 workgroups: Vascular Retina, Neural Retina, Systemic Health, Basic and Cellular Mechanisms, Visual Function, and Quality of Life.

Participants

The Vascular Retina workgroup, including 16 participants from 4 countries.

Methods

Literature review was conducted using standardized evidence grids for 5 modalities: standard color fundus photography (CFP), widefield color photography (WFCP), standard fluorescein angiography (FA), widefield FA (WFFA), and OCT angiography (OCTA). Summary levels of evidence were determined on a validated scale from I (highest) to V (lowest). Five virtual workshops were held for discussion and consensus.

Main Outcome Measures

Level of evidence for each modality.

Results

Levels of evidence for standard CFP, WFCP, standard FA, WFFA, and OCTA were I, II, I, I, and II respectively. Traditional vascular lesions on standard CFP should continue to be included in an updated staging system, but more studies are required before they can be used in posttreatment eyes. Widefield color photographs can be used for severity grading within the area covered by standard CFPs, although these gradings may not be directly interchangeable with each other. Evaluation of the peripheral retina on WFCP can be considered, but the method of grading needs to be clarified and validated. Standard FA and WFFA provide independent prognostic value, but the need for dye administration should be considered. OCT angiography has significant potential for inclusion in the DRD staging system, but various barriers need to be addressed first.

Conclusions

This study provides evidence-based recommendations on the utility of various imaging modalities for assessment of the vascular component of DRD, which can inform future updates to the DRD staging system. Although new imaging modalities offer a wealth of information, there are still major gaps and unmet research needs that need to be addressed before this potential can be realized.

Financial Disclosures

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

American Society of Retina Specialists Clinical Practice Guidelines on Multimodal Imaging for Retinal Disease

Purpose: Advancements in retinal imaging have augmented our understanding of the pathology and structure-function relationships of retinal disease. No single diagnostic test is sufficient; rather, diagnostic and management strategies increasingly involve the synthesis of multiple imaging modalities. Methods: This literature review and editorial offer practical clinical guidelines for how the retina specialist can use multimodal imaging to manage retinal conditions. Results: Various imaging modalities offer information on different aspects of retinal structure and function. For example, optical coherence tomography (OCT) and B-scan ultrasonography can provide insights into the microstructural anatomy; fluorescein angiography (FA), indocyanine green angiography (ICGA), and OCT angiography (OCTA) can reveal vascular integrity and perfusion status; and near-infrared reflectance and fundus autofluorescence (FAF) can characterize molecular components within tissues. Managing retinal vascular diseases often includes fundus photography, OCT, OCTA, and FA to evaluate for macular edema, retinal ischemia, and the secondary complications of neovascularization (NV). OCT and FAF play a key role in diagnosing and treating maculopathies. FA, OCTA, and ICGA can help identify macular NV, posterior uveitis, and choroidal venous insufficiency, which guides treatment strategies. Finally, OCT and B-scan ultrasonography can help with preoperative planning and prognostication in vitreoretinal surgical conditions. Conclusions: Today, the retina specialist has access to numerous retinal imaging modalities that can augment the clinical examination to help diagnose and manage retinal conditions. Understanding the capabilities and limitations of each modality is critical to maximizing its clinical utility.

The role of ultra-widefield imaging with navigated central and peripheral cross-sectional and three-dimensional swept source optical coherence tomography in ophthalmology: Clinical applications

PURPOSE

To assess central and peripheral retinal and choroidal diseases using ultra-widefield (UWF) fundus imaging in combination with navigated central and peripheral cross-sectional and three-dimensional (3D) swept source optical coherence tomography (SS-OCT) scans.

METHODS

Retrospective study involving 332 consecutive patients, with a nearly equal distribution of males and females. The mean age of patients was 52 years (range 18-92 years). Average refractive error was -3.80 D (range +7.75 to -20.75 D).

RESULTS

The observations in this study demonstrate the efficacy of peripheral navigated SS-OCT in assessing various ocular conditions. The technology provides high-quality images of the peripheral vitreous, vitreoretinal interface, retina, and choroid, enabling visualization of vitreous floaters and opacities, retinal holes and tears, pigmented lesions, and peripheral retinal degenerations. 3D OCT scans enhance the visualization of these abnormalities and improve diagnostic and therapeutic decisions.

CONCLUSION

Navigated central and peripheral cross-sectional and 3D SS-OCT scans offer significant complementary benefits in the assessment and management of retinal diseases. Their addition to UWF imaging provides a comprehensive view of central and peripheral ocular structures, aiding in early detection, precise anatomical measurements, and objective monitoring of disease progression. In addition, this technology serves as a valuable tool for patient education, a teaching tool for trainees, and documentation for medico-legal purposes.

Ultra-wide field and new wide field composite retinal image registration with AI-enabled pipeline and 3D distortion correction algorithm

PURPOSE

This study aimed to compare a new Artificial Intelligence (AI) method to conventional mathematical warping in accurately overlaying peripheral retinal vessels from two different imaging devices: confocal scanning laser ophthalmoscope (cSLO) wide-field images and SLO ultra-wide field images.

METHODS

Images were captured using the Heidelberg Spectralis 55-degree field-of-view and Optos ultra-wide field. The conventional mathematical warping was performed using Random Sample Consensus-Sample and Consensus sets (RANSAC-SC). This was compared to an AI alignment algorithm based on a one-way forward registration procedure consisting of full Convolutional Neural Networks (CNNs) with Outlier Rejection (OR CNN), as well as an iterative 3D camera pose optimization process (OR CNN + Distortion Correction [DC]). Images were provided in a checkerboard pattern, and peripheral vessels were graded in four quadrants based on alignment to the adjacent box.

RESULTS

A total of 660 boxes were analysed from 55 eyes. Dice scores were compared between the three methods (RANSAC-SC/OR CNN/OR CNN + DC): 0.3341/0.4665/4784 for fold 1-2 and 0.3315/0.4494/4596 for fold 2-1 in composite images. The images composed using the OR CNN + DC have a median rating of 4 (out of 5) versus 2 using RANSAC-SC. The odds of getting a higher grading level are 4.8 times higher using our OR CNN + DC than RANSAC-SC (p < 0.0001).

CONCLUSION

Peripheral retinal vessel alignment performed better using our AI algorithm than RANSAC-SC. This may help improve co-localizing retinal anatomy and pathology with our algorithm.

Peripheral retinal lesions in diabetic retinopathy on ultra-widefield imaging

Peripheral retinal imaging plays a crucial role in the diagnosis, management, and prognosis of diabetic retinopathy (DR). Traditional fundus imaging techniques have limited coverage of the retina, resulting in missed peripheral lesions. The advent of ultra-widefield (UWF) imaging has revolutionized the assessment of the peripheral retina. UWF imaging modalities provide comprehensive visualization of the retina, enabling the detection of peripheral lesions without the need for mydriasis. Integration of UWF imaging with other modalities, including fluorescein angiography (FA), indocyanine green angiography, pseudocolor imaging, and fundus autofluorescence, further enhances our understanding of peripheral retinal lesions. UWF imaging has demonstrated improved detection of DR lesions and presumably more accurate management of DR compared to traditional fundus photography and dilated fundus examination. UWF-FA and UWF-optical coherence tomography angiography have emerged as valuable tools for assessing retinal and choroidal vascular abnormalities, nonperfusion areas, neovascularization, and microvascular abnormalities. The presence and increasing extent of predominantly peripheral lesions detected using UWF FA are associated with a higher risk of DR progression and proliferative DR. UWF imaging provides a comprehensive evaluation of DR severity, aiding in more accurate risk stratification and treatment decision-making. Overall, UWF imaging modalities have significantly advanced our understanding of peripheral retinal lesions in DR, facilitating early detection and targeted management for better visual outcomes.

The clinical evaluation of a widefield lens to expand the field of view in optical coherence tomography (OCT-A)

This study aimed to evaluate the clinical benefits of incorporating a widefield lens (WFL) in optical coherence tomography angiography (OCT-A) in patients with retinal vascular diseases in comparison to standard single-shot OCT-A scans. Sixty patients with retinal vascular diseases including diabetic retinopathy (DR) and retinal vein occlusion (RVO) were recruited. OCT-A imaging (PlexElite 9000) with and without WFL was performed in randomized order. The assessment included patient comfort, time, field of view (FoV), image quality and pathology detection. Statistical analysis included paired t-tests, Mann-Whitney U-tests and Bonferroni correction for multiple tests, with inter-grader agreement using the kappa coefficient. Using a WFL did not lead to statistically significant differences in DR and RVO group test times. Patient comfort remained high, with similar responses for WFL and non-WFL measurements. The WFL notably expanded the scan field (1.6× FoV increase), enhancing peripheral retinal visibility. However, image quality varied due to pathology and eye dominance, affecting the detection of peripheral issues in RVO and DR cases. The use of a WFL widens the scan field, aiding vascular retinal disease imaging with minor effects on comfort, time, and image quality. Further enhancements are needed for broader view angles, enabling improved quantification of non-perfused areas and more reliable peripheral proliferation detection.

Visualizing features with wide-field volumetric OCT angiography

Optical coherence tomography (OCT) and its extension OCT angiography (OCTA) have become essential clinical imaging modalities due to their ability to provide depth-resolved angiographic and tissue structural information non-invasively and at high resolution. Within a field of view, the anatomic detail available is sufficient to identify several structural and vascular pathologies that are clinically relevant for multiple prevalent blinding diseases, including age-related macular degeneration (AMD), diabetic retinopathy (DR), and vein occlusions. The main limitation in contemporary OCT devices is that this field of view is limited due to a fundamental trade-off between system resolution/sensitivity, sampling density, and imaging window dimensions. Here, we describe a swept-source OCT device that can capture up to a 12 × 23-mm field of view in a single shot and show that it can identify conventional pathologic features such as non-perfusion areas outside of conventional fields of view. We also show that our approach maintains sensitivity sufficient to visualize novel features, including choriocapillaris morphology beneath the macula and macrophage-like cells at the inner limiting membrane, both of which may have implications for disease.

Advantages of the Utilization of Wide-Field OCT and Wide-Field OCT Angiography in Clinical Practice

Wide-field (WF) retinal imaging is becoming a standard diagnostic tool for diseases involving the peripheral retina. Technological progress elicited the advent of wide-field optical coherence tomography (WF-OCT) and WF-OCT angiography (WF-OCTA) examinations. This review presents the results of studies that analyzed the implementation of these procedures in clinical practice and refers to them as traditional and ultra-wide-field fluorescein angiography (UWF-FA). A PUBMED search was performed using the terms WF-OCT OR WF-OCTA OR UWF-FA AND the specific clinical entity, and another search for diabetic retinopathy (DR), retinal vein occlusion (RVO), Coats disease, peripheral retinal telangiectasia, peripheral retinal degeneration, lattice degeneration, and posterior vitreous detachment. The analysis only included the studies in which the analyzed field of view for the OCT or OCTA exam was larger than 55 degrees. The evaluation of the extracted studies indicates that WF imaging with OCT and OCTA provides substantial information on retinal disorders involving the peripheral retina. Vascular diseases, such as DR or RVO, can be reliably evaluated using WF-OCTA with results superior to standard-field fluorescein angiography. Nevertheless, UWF-FA provides a larger field of view and still has advantages over WF-OCTA concerning the evaluation of areas of non-perfusion and peripheral neovascularization. Detailed information on the vascular morphology of peripheral changes should be obtained via WF-OCTA and not angiographic examinations. WF-OCT can serve as a valuable tool for the detection and evaluation of vitreoretinal traction, posterior vitreous detachment, and peripheral retinal degeneration, and guide therapeutic decisions on a patient's eligibility for surgical procedures.

Optical coherence tomography angiography in diabetic retinopathy

There remain many unanswered questions on how to assess and treat the pathology and complications that arise from diabetic retinopathy (DR). Optical coherence tomography angiography (OCTA) is a novel and non-invasive three-dimensional imaging method that can visualize capillaries in all retinal layers. Numerous studies have confirmed that OCTA can identify early evidence of microvascular changes and provide quantitative assessment of the extent of diseases such as DR and its complications. A number of informative OCTA metrics could be used to assess DR in clinical trials, including measurements of the foveal avascular zone (FAZ; area, acircularity, 3D para-FAZ vessel density), vessel density, extrafoveal avascular zones, and neovascularization. Assessing patients with DR using a full-retinal slab OCTA image can limit segmentation errors and confounding factors such as those related to center-involved diabetic macular edema. Given emerging data suggesting the importance of the peripheral retinal vasculature in assessing and predicting DR progression, wide-field OCTA imaging should also be used. Finally, the use of automated methods and algorithms for OCTA image analysis, such as those that can distinguish between areas of true and false signals, reconstruct images, and produce quantitative metrics, such as FAZ area, will greatly improve the efficiency and standardization of results between studies. Most importantly, clinical trial protocols should account for the relatively high frequency of poor-quality data related to sub-optimal imaging conditions in DR and should incorporate time for assessing OCTA image quality and re-imaging patients where necessary.

Comparison of 50° handheld fundus camera versus ultra-widefield table-top fundus camera for diabetic retinopathy detection and grading

OBJECTIVES

To compare the performance of a handheld fundus camera with standard 50° visual field to ultra-widefield (UWF) table-top fundus camera in diabetic retinopathy (DR) detection and grading.

METHODS

Patients affected by diabetes mellitus and referred to our diabetic retinopathy clinic were enroled and underwent fundus photography in mydriasis. All photos were taken using the ultra-widefield table-top fundus camera Zeiss Clarus™ 500 (four fields per eye) and the Optomed Aurora® handheld fundus camera (3 fields per eye). The following parameters were analysed: the gradability of the images, the grade of DR, and diabetic maculopathy (DM), the presence of hypertensive retinopathy (HR) and the presence of other ocular diseases.

RESULTS

We enroled 759 eyes of 384 diabetic patients and analysed 5313 fundus photos. The handheld fundus camera obtained a sensitivity of 84.2% and specificity of 95.4% for referable cases. Moreover, it obtained, compared to UWF, an almost perfect agreement with linear weighting for DR, DM and HR (k = 0.877, k = 0.854, and k = 0.961, respectively). The lowest sensitivity was achieved for proliferative DR (58.7% sensitivity, 100% specificity).

CONCLUSIONS

Optomed Aurora® handheld fundus camera imaging showed a strong agreement compared to UWF in grading DR, considering all DR and DM grades, in mydriasis. However, the use of UWF imaging increases the detection of referable eyes.

Comparisons of handheld retinal imaging devices with ultrawide field images for determining diabetic retinopathy severity

PURPOSE

To compare diabetic retinopathy (DR) severity identified on handheld retinal imaging with ultrawide field (UWF) images.

METHODS

Mydriatic images of 225 eyes of 118 diabetic patients were prospectively imaged with the Aurora (AU) handheld retinal camera [5-field protocol (macula-centred, disc-centred, temporal, superior, inferior)] and compared with UWF images. Images were classified based on the international classification for DR. Sensitivity, specificity, kappa statistics (K/Kw) were calculated on an eye and person-level.

RESULTS

Distribution of DR severity by AU/UWF images (%) by eye was no DR 41.3/36.0, mild non-proliferative DR (NPDR) 18.7/17.8, moderate 10.2/10.7, severe 16.4/15.1, proliferative DR (PDR) 13.3/20.4. Agreement between UWF and AU was exact in 64.4%, within 1-step 90.7%, k = 0.55 (95% CI:0.45-0.65), and kw = 0.79 (95% CI:0.73-0.85) by eye, and exact in 68%, within 1-step 92.9%, k = 0.58 (95% CI:0.50-0.66), and kw = 0.76 (95% CI:0.70-0.81) by person. Sensitivity/specificity for any DR, refDR, vtDR and PDR were as follows: 0.90/0.83, 0.90/0.97, 0.82/0.95 and 0.69/1.00 by person and 0.86/0.90, 0.84/0.98, 0.75/0.95 and 0.63/0.99 by eye. Handheld imaging missed 37% (17/46) eyes and 30.8% (8/26) persons with PDR. Only 3.9% (1/26) persons or 6.5% (3/46) eyes with PDR were missed if a referral threshold of moderate NPDR was used.

CONCLUSIONS

Data from this study show that comparing UWF and handheld images, when PDR was the referral threshold for handheld devices, 37.0% of eyes or 30.8% of patients with PDR were missed. Due to the identification of neovascular lesions outside of the handheld fields, lower referral thresholds are needed if handheld devices are used.

Clinical utility of ultra-widefield fluorescein angiography and optical coherence tomography angiography for retinal vein occlusions

Retinal vein occlusions (RVOs) are the second most common retinal vascular disease after diabetic retinopathy, and are a significant cause of visual impairment, especially in the elderly population. RVOs result in visual loss due to macular ischemia, cystoid macular edema (CME), and complications related to neovascularization. Vascular assessment in RVOs traditionally relies on standard fluorescein angiography (FA) for assessment of macular and retinal ischemia, which aids in prognostication and guides intervention. Standard FA has significant limitations-it is time-consuming, requires invasive dye administration, allows for limited assessment of the peripheral retina, and is usually evaluated semi-qualitatively, by ophthalmologists with tertiary expertise. More recently, the introduction of ultra-widefield FA (UWF FA) and optical coherence tomography angiography (OCTA) into clinical practice has changed the tools available for vascular evaluation in RVOs. UWF FA allows for evaluation of peripheral retinal perfusion, and OCTA is non-invasive, rapidly-acquired, and provides more information on capillary perfusion. Both modalities can be used to provide more quantitative parameters related to retinal perfusion. In this article, we review the clinical utility and impact of UWF FA and OCTA in the evaluation and management of patients with RVOs.

Deep learning for automated detection of neovascular leakage on ultra-widefield fluorescein angiography in diabetic retinopathy

Diabetic retinopathy is a leading cause of blindness in working-age adults worldwide. Neovascular leakage on fluorescein angiography indicates progression to the proliferative stage of diabetic retinopathy, which is an important distinction that requires timely ophthalmic intervention with laser or intravitreal injection treatment to reduce the risk of severe, permanent vision loss. In this study, we developed a deep learning algorithm to detect neovascular leakage on ultra-widefield fluorescein angiography images obtained from patients with diabetic retinopathy. The algorithm, an ensemble of three convolutional neural networks, was able to accurately classify neovascular leakage and distinguish this disease marker from other angiographic disease features. With additional real-world validation and testing, our algorithm could facilitate identification of neovascular leakage in the clinical setting, allowing timely intervention to reduce the burden of blinding diabetic eye disease.

Peripheral retinal vessel whitening in patients with diabetes mellitus

This study aimed to identify retinal vessel whitening outside the standard Early Treatment Diabetic Retinopathy Study (ETDRS) fields and to correlate the findings with vision and severity of diabetic retinopathy. Patients with diabetes mellitus who were seen in the retinal clinic to assess diabetic retinopathy status were included. Retinal vessel whitening was identified using ultra-widefield imaging. Four hundred and forty-five eyes of 260 patients were included. Thirty-five eyes in 24 patients (7.9%) were noted to have peripheral retinal vessel whitening. Thirty-one eyes with peripheral retinal vessel whitening did not have vessel whitening within the standard 7 ETDRS fields (p < 0.001). The proportion of whitening increased as DR severity increased, from 4.0% for patients with no DR (OR 0.249) to 33.3% for those with severe NPDR and PDR (OR 6.430 and 7.232, respectively). In addition, patients with peripheral retinal vessel whitening had worse visual acuity (logMAR = 0.34) compared to those without (logMAR = 0.15) (p < 0.001). In conclusion, we found an association between peripheral retinal vessel whitening in diabetic patients which correlated with diabetic retinopathy severity. Additionally, we found an association between vessel whitening and reduced vision, suggesting that vessel whitening identified using ultra-widefield imaging may be a prognostic indicator of vision in diabetic retinopathy.

Optical Coherence Tomography Angiography in Retinal Vascular Disorders

Traditionally, abnormalities of the retinal vasculature and perfusion in retinal vascular disorders, such as diabetic retinopathy and retinal vascular occlusions, have been visualized with dye-based fluorescein angiography (FA). Optical coherence tomography angiography (OCTA) is a newer, alternative modality for imaging the retinal vasculature, which has some advantages over FA, such as its dye-free, non-invasive nature, and depth resolution. The depth resolution of OCTA allows for characterization of the retinal microvasculature in distinct anatomic layers, and commercial OCTA platforms also provide automated quantitative vascular and perfusion metrics. Quantitative and qualitative OCTA analysis in various retinal vascular disorders has facilitated the detection of pre-clinical vascular changes, greater understanding of known clinical signs, and the development of imaging biomarkers to prognosticate and guide treatment. With further technological improvements, such as a greater field of view and better image quality processing algorithms, it is likely that OCTA will play an integral role in the study and management of retinal vascular disorders. Artificial intelligence methods-in particular, deep learning-show promise in refining the insights to be gained from the use of OCTA in retinal vascular disorders. This review aims to summarize the current literature on this imaging modality in relation to common retinal vascular disorders.

Recent advances in the management of proliferative diabetic retinopathy

PURPOSE OF REVIEW

The prevalence of diabetic retinopathy continues to rise. This review highlights advances in imaging, medical, and surgical management of proliferative diabetic retinopathy (PDR) in recent years.

RECENT FINDINGS

Ultra-widefield fluorescein angiography has been shown to better characterize which patients have predominantly peripheral lesions and who may advance to more advanced forms of diabetic retinopathy. This was well demonstrated in DRCR Retina Network's Protocol AA. Protocol S demonstrated that antivascular endothelial growth factor (VEGF) treatment alone can be useful in the management of select PDR patients - particularly those without high-risk features. However, a growing body of literature highlights how lapse in care is a significant concern in PDR patients, and tailoring one's approach to treatment based on patient needs is recommended. In patients with high-risk features or where there is concern for lost-to-follow-up, incorporation of panretinal photocoagulation in the treatment paradigm is recommended. Protocol AB highlighted how patients with more advanced disease may benefit from earlier surgical intervention for earlier visual recovery but that continued anti-VEGF treatment may result in similar visual outcomes over a longer period. Finally, earlier surgical intervention for PDR without vitreous hemorrhage (VH) or retinal detachment is being considered a potential option to minimize treatment burden.

SUMMARY

Recent advances in imaging, as well as medical and surgical treatment options for PDR, have provided a deeper understanding of PDR management, which can be optimized for the individual patient.

Incidence and Progression of Diabetic Retinopathy in American Indian and Alaska Native Individuals Served by the Indian Health Service, 2015-2019

Importance

Estimates of diabetic retinopathy (DR) incidence and progression in American Indian and Alaska Native individuals are based on data from before 1992 and may not be informative for strategizing resources and practice patterns.

Objective

To examine incidence and progression of DR in American Indian and Alaska Native individuals.

Design, Setting, and Participants

This was a retrospective cohort study conducted from January 1, 2015, to December 31, 2019, and included adults with diabetes and no evidence of DR or mild nonproliferative DR (NPDR) in 2015 who were reexamined at least 1 time during the 2016 to 2019 period. The study setting was the Indian Health Service (IHS) teleophthalmology program for diabetic eye disease.

Exposure

Development of new DR or worsening of mild NPDR in American Indian and Alaska Native individuals with diabetes.

Main Outcomes and Measures

Outcomes were any increase in DR, 2 or more (2+) step increases, and overall change in DR severity. Patients were evaluated with nonmydriatic ultra-widefield imaging (UWFI) or nonmydriatic fundus photography (NMFP). Standard risk factors were included.

Results

The total cohort of 8374 individuals had a mean (SD) age of 53.2 (12.2) years and a mean (SD) hemoglobin A1c level of 8.3% (2.2%) in 2015, and 4775 were female (57.0%). Of patients with no DR in 2015, 18.0% (1280 of 7097) had mild NPDR or worse in 2016 to 2019, and 0.1% (10 of 7097) had PDR. The incidence rate from no DR to any DR was 69.6 cases per 1000 person-years at risk. A total of 6.2% of participants (441 of 7097) progressed from no DR to moderate NPDR or worse (ie, 2+ step increase; 24.0 cases per 1000 person-years at risk). Of patients with mild NPDR in 2015, 27.2% (347 of 1277) progressed to moderate NPDR or worse in 2016 to 2019, and 2.3% (30 of 1277) progressed to severe NPDR or worse (ie, 2+ step progression). Incidence and progression were associated with expected risk factors and evaluation with UWFI.

Conclusions and Relevance

In this cohort study, the estimates of DR incidence and progression were lower than those previously reported for American Indian and Alaska Native individuals. The results suggest extending the time between DR re-evaluations for certain patients in this population, if follow-up compliance and visual acuity outcomes are not jeopardized.

Ethnic Variation in Diabetic Retinopathy Lesion Distribution on Ultra-widefield Imaging

PURPOSE

To evaluate whether the distribution of diabetic retinopathy (DR) lesions differs among various ethnicities.

DESIGN

Multi-center, retrospective cohort study.

METHODS

We accrued a cohort of 226 eyes with DR consisting of 51 East Asian eyes, 102 South Asian eyes, 30 Caucasian eyes, and 43 Latino eyes, all evaluated with ultrawide field pseudocolor images. Images were manually annotated for DR lesions and were classified as having predominantly peripheral lesions (PPL) or predominantly central lesions (PCL) using 4 quantitative methods. The percent distribution of PCL to PPL was compared among different ethnicities.

RESULTS

Using a single-field lesion frequency-based method, East Asian eyes more frequently demonstrated a PPL distribution (86.3%), whereas South Asian eyes more frequently demonstrated a PCL distribution (64.7%). These findings were also observed when considering only the subset of treatment-naïve eyes. Furthermore, in treatment-naïve eyes without proliferative DR, the percent distribution of PPL to PCL in East Asian eyes was significantly different when compared to other ethnicities (P < .0001 South Asian, P = .035 Caucasian, P = .0003 Latino). The majority of patients (60%-78%) in all ethnic groups had moderate nonproliferative diabetic retinopathy(NPDR), and the same difference between East Asian and South Asian eyes was observed in this subgroup.

CONCLUSIONS

The distribution of DR lesions appears to vary among different ethnicities. DR lesions tend to be distributed more peripherally in East Asian eyes compared to other ethnic groups, particularly South Asian eyes, which tend to have more central disease. The prognostic implications of these ethnic differences in DR lesion distribution require further investigation.

Imaging in retinal vascular disease: A review

Retinal vascular diseases represent a broad field of ocular pathologies. Retinal imaging is an important tool for diagnosis, prognosis and follow up of retinal vascular diseases. It includes a wide variety of imaging techniques ranging from colour fundus photography and optical coherence tomography to dynamic diagnostic options such as fluorescein angiography, and optical coherence tomography angiography. The newest developments in respective imaging techniques include widefield imaging to assess the retinal periphery, which is of especial interest in retinal vascular diseases. Automatic image analysis and artificial intelligence may support the image analysis and may prove valuable for prognostic purposes. This review provides a broad overview of the imaging techniques that have been used in the past, today and maybe in the future to stage and monitor retinal vascular disease with focus on the main disease entities including diabetic retinopathy, retinal vein occlusion, and retinal artery occlusion.

Association of Ultra-Widefield Fluorescein Angiography-Identified Retinal Nonperfusion and the Risk of Diabetic Retinopathy Worsening Over Time

Importance

Presence of predominantly peripheral diabetic retinopathy (DR) lesions on ultra-widefield fluorescein angiography (UWF-FA) was associated with greater risk of DR worsening or treatment over 4 years. Whether baseline retinal nonperfusion assessment is additionally predictive of DR disease worsening is unclear.

Objective

To assess whether the extent and location of retinal nonperfusion identified on UWF-FA are associated with worsening in Diabetic Retinopathy Severity Scale (DRSS) score or DR treatment over time.

Design, Setting, and Participants

This cohort study was a prospective, multicenter, longitudinal observational study with data for 508 eyes with nonproliferative DR and gradable nonperfusion on UWF-FA at baseline. All images were graded at a centralized reading center; 200° ultra-widefield (UWF) color images were graded for DR at baseline and annually for 4 years. Baseline 200° UWF-FA images were graded for nonperfused area, nonperfusion index (NPI), and presence of predominantly peripheral lesions on UWF-FA (FA PPL).

Interventions

Treatment of DR or diabetic macular edema was at investigator discretion.

Main Outcomes and Measures

Association of baseline UWF-FA nonperfusion extent with disease worsening, defined as either 2 or more steps of DRSS worsening within Early Treatment Diabetic Retinopathy Study fields on UWF-color images or receipt of DR treatment.

Results

After adjusting for baseline DRSS, the risk of disease worsening over 4 years was higher in eyes with greater overall NPI (hazard ratio [HR] for 0.1-unit increase, 1.11; 95% CI, 1.02-1.21; P = .02) and NPI within the posterior pole (HR for 0.1-unit increase, 1.35; 95% CI, 1.17-1.56; P < .001) and midperiphery (HR for 0.1-unit increase, 1.08; 95% CI, 1.00-1.16; P = .04). In a multivariable analysis adjusting for baseline DRSS score and baseline systemic risk factors, greater NPI (HR, 1.11; 95% CI, 1.02-1.22; P = .02) and presence of FA PPL (HR, 1.89; 95% CI, 1.35-2.65; P < .001) remained associated with disease worsening.

Conclusions and Relevance

This 4-year longitudinal study has demonstrated that both greater baseline retinal nonperfusion and FA PPL on UWF-FA are associated with higher risk of disease worsening, even after adjusting for baseline DRSS score and known systemic risk. These associations between disease worsening and retinal nonperfusion and FA PPL support the increased use of UWF-FA to complement color fundus photography in future efforts for DR prognosis, clinical care, and research.

Diabetic retinopathy: Looking forward to 2030

Diabetic retinopathy (DR) is the major ocular complication of diabetes mellitus, and is a problem with significant global health impact. Major advances in diagnostics, technology and treatment have already revolutionized how we manage DR in the early part of the 21^st century. For example, the accessibility of imaging with optical coherence tomography, and the development of anti-vascular endothelial growth factor (VEGF) treatment are just some of the landmark developments that have shaped the DR landscape over the last few decades. Yet, there are still more exciting advances being made. Looking forward to 2030, many of these ongoing developments are likely to further transform the field. First, epidemiologic projections show that the global burden of DR is not only increasing, but also shifting from high-income countries towards middle- and low-income areas. Second, better understanding of disease pathophysiology is placing greater emphasis on retinal neural dysfunction and non-vascular aspects of diabetic retinal disease. Third, a wealth of information is becoming available from newer imaging modalities such as widefield imaging systems and optical coherence tomography angiography. Fourth, artificial intelligence for screening, diagnosis and prognostication of DR will become increasingly accessible and important. Fifth, new pharmacologic agents targeting other non-VEGF-driven pathways, and novel therapeutic strategies such as gene therapy are being developed for DR. Finally, the classification system for diabetic retinal disease will need to be continually updated to keep pace with new developments. In this article, we discuss these major trends in DR that we expect to see in 2030 and beyond.