Optical Coherence Tomography Biomarkers for Conversion to Exudative Neovascular Age-related Macular Degeneration

Morph-SSL: Self-Supervision With Longitudinal Morphing for Forecasting AMD Progression From OCT Volumes

The lack of reliable biomarkers makes predicting the conversion from intermediate to neovascular age-related macular degeneration (iAMD, nAMD) a challenging task. We develop a Deep Learning (DL) model to predict the future risk of conversion of an eye from iAMD to nAMD from its current OCT scan. Although eye clinics generate vast amounts of longitudinal OCT scans to monitor AMD progression, only a small subset can be manually labeled for supervised DL. To address this issue, we propose Morph-SSL, a novel Self-supervised Learning (SSL) method for longitudinal data. It uses pairs of unlabelled OCT scans from different visits and involves morphing the scan from the previous visit to the next. The Decoder predicts the transformation for morphing and ensures a smooth feature manifold that can generate intermediate scans between visits through linear interpolation. Next, the Morph-SSL trained features are input to a Classifier which is trained in a supervised manner to model the cumulative probability distribution of the time to conversion with a sigmoidal function. Morph-SSL was trained on unlabelled scans of 399 eyes (3570 visits). The Classifier was evaluated with a five-fold cross-validation on 2418 scans from 343 eyes with clinical labels of the conversion date. The Morph-SSL features achieved an AUC of 0.779 in predicting the conversion to nAMD within the next 6 months, outperforming the same network when trained end-to-end from scratch or pre-trained with popular SSL methods. Automated prediction of the future risk of nAMD onset can enable timely treatment and individualized AMD management.

Risk factors for development of hyper-reflective foci overlying drusen in eyes with intermediate age-related macular degeneration

AIMS

The aim of this study is to assess baseline characteristics of drusen preceding the development of intraretinal hyper-reflective foci (IHRF) in eyes with intermediate age-related macular degeneration (AMD).

METHODS

In this retrospective case-control study, longitudinal optical coherence tomography (OCT) volume data from eyes with intermediate AMD in a retina clinic population were screened. All drusen that developed overlying IHRF were marked. A random number generator was used to select for further grading three drusen that did not develop IHRF.

RESULTS

Ninety eyes (from 72 patients), including 140 drusen with overlying IHRF and 270 IHRF- drusen, were analysed. Greater drusen height, basal drusen width and overlying ellipsoid zone (EZ) and external limiting membrane disruption were associated with a significantly greater risk for IHRF development (p≤0.001). Regression analysis revealed EZ disruption increased these odds by 4.1 (p≤0.001). Each 10-µm increase in drusen height and width increased the odds by 34% (p≤0.001) and 3% (p: 0.005), respectively. Each 100-µm increase in distance from the fovea decreased the odds by 10% (p: 0.013).

CONCLUSIONS

The presence of overlying EZ disruption and a greater drusen height substantially increased the risk for IHRF development, whereas drusen further from the fovea indicated reduced risk. Given the importance of IHRF as a biomarker for AMD progression, these findings may be of value in defining patient populations for future early intervention trials.

Predict and Protect: Evaluating the Double-Layer Sign in Age-Related Macular Degeneration

INTRODUCTION

Advanced age-related macular degeneration (AMD) is a major cause of vision loss. Therefore, there is interest in precursor lesions that may predict or prevent the onset of advanced AMD. One such lesion is a shallow separation of the retinal pigment epithelium (RPE) and Bruch's membrane (BM), which is described by various terms, including double-layer sign (DLS).

METHODS

In this article, we aim to examine and clarify the different terms referring to shallow separation of the RPE and BM. We also review current evidence on the outcomes associated with DLS: firstly, whether DLS is predictive of exudative neovascular AMD; and secondly, whether DLS has potential protective properties against geographic atrophy.

RESULTS

The range of terms used to describe a shallow separation of the RPE and BM reflects that DLS can present with different characteristics. While vascularised DLS appears to protect against atrophy but can progress to exudation, non-vascularised DLS is associated with an increased risk of atrophy. Optical coherence tomography (OCT) angiography (OCTA) is the principal method for identifying and differentiating various forms of DLS. If OCTA is unavailable or not practically possible, simplified classification of DLS as thick or thin, using OCT, enables the likelihood of vascularisation to be approximated. Research is ongoing to automate DLS detection by applying deep-learning algorithms to OCT scans.

CONCLUSIONS

The term DLS remains applicable for describing shallow separation of the RPE and BM. Detection and classification of this feature provides valuable information regarding the risk of progression to advanced AMD. However, the appearance of DLS and its value in predicting AMD progression can vary between patients. With further research, individualised risks can be confirmed to inform appropriate treatment.

Associations of drusen location with risk factors and incidence of late age-related macular degeneration in the Alienor study

PURPOSE

To test the hypothesis that central drusen location is strongly linked with known Age-related Macular Degeneration (AMD) risk factors and risk of incident late AMD.

METHODS

The Alienor study is a prospective population-based cohort study of residents of Bordeaux, France, followed from 2009 to 2017. On retinal photographs, we defined central drusen as at least one soft drusen (>63 μm) within 500 μm from fovea and pericentral drusen as at least one drusen 500-3000 μm from fovea, in the absence of any central drusen. Late AMD (atrophic and/or neovascular) was diagnosed using multimodal imaging. In total, 481 eyes were included in the analysis: 160 central and 321 pericentral. We investigated associations with systemic (age, sex, smoking, medical prescriptions, plasma concentrations of lipids and nutrients, UV exposure, blood pressure), ocular (retinal thickness, cataract extraction) and genetic risk scores (GRS).

RESULTS

In multivariate logistic regression central drusen were associated with smoking (OR, 2.95 for smoking more than 20 pack-years, p = 0.02), HDL-cholesterol (OR, 1.57 for 1 standard deviation (SD) increase, p = 0.0048), pulse pressure (OR, 0.77 for 1 SD increase, p = 0.04), Age-Related Maculopathy Susceptibility 2 (ARMS2) GRS (OR, 1.42; 95% CI, 1.11-1.83) and complement GRS (OR, 1.55; 95% CI, 1.15-2.10). In Cox modelling, the central location of drusen (at baseline or during the follow-up) was associated with a 4.41-fold increased risk (95% CI,1.98-9.81) for an incident late AMD.

CONCLUSION

Central drusen were strongly associated with AMD risk factors and incident late AMD, suggesting that it represents a key marker for AMD progression.

Microperimetry and Structural Risk Factors on OCT in Intermediate Age-Related Macular Degeneration

PURPOSE

To determine the relationship between structural biomarkers on OCT that increase the risk of disease progression and microperimetric retinal sensitivity in patients with intermediate age-related macular degeneration (iAMD).

DESIGN

Prospective cross-sectional, observational study.

PARTICIPANTS

Forty-five eyes of 23 patients with iAMD.

METHODS

Patients underwent OCT and microperimetry. OCT scans were evaluated for the risk factors intraretinal hyperreflective foci (HRF), hyporeflectivity within drusenoid lesions (HRDL), subretinal drusenoid deposits, double-layer sign (DLS), and drusen volume. Microperimetric retinal sensitivity was analyzed with a 33-point grid covering the macula. With a novel method of determining what part of the retina corresponded to each microperimetry point, a Voronoi diagram was constructed, dividing the macula in cells consisting of the region nearer to each point than any other. The Voronoi diagram was superimposed on the OCT, making it possible to determine the point-to-point location of the OCT risk factors. Univariable and multivariable linear mixed-effect models were used for analysis.

MAIN OUTCOME MEASURES

Association between microperimetric retinal sensitivity and OCT risk factors at individual measuring points.

RESULTS

One thousand four hundred seventy-nine points of retinal sensitivity and corresponding structural area on OCT were included in this study. Retinal sensitivity was significantly decreased with presence of the OCT risk factors HRF, HRDL, DLS, and drusen volume (all P < 0.001) when analyzed with the univariable linear mixed-effect model. The multivariable model showed a significant decrease of retinal sensitivity with presence of HRF (P < 0.001), DLS (P = 0.025), and greater drusen volume (P < 0.001).

CONCLUSIONS

Presence of HRF, DLS, and greater drusen volume, all of which increase the risk of disease progression, is significantly and independently associated with decreased microperimetric retinal sensitivity in patients with iAMD.

FINANCIAL DISCLOSURE(S)

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

Pachy-Reticular Pseudodrusen

PURPOSE

To characterize the features of a peculiar association between reticular pseudodrusen (RPD) and pachychoroid (pachy-RPD) and to compare them with eyes affected by RPD and normal/leptochoroid.

DESIGN

Observational, retrospective, case-control study.

PARTICIPANTS

Among a cohort of patients with intermediate age-related macular degeneration (AMD), we selected eyes with RPD and pachychoroid (i.e., choroidal thickness of >50 μm). A control group of RPD eyes but without pachychoroid (i.e., a choroidal thickness of <250 μm) was included.

METHODS

Number and stages of RPD were evaluated in each ETDRS subfield. Furthermore, choroidal perfusion was investigated using the choroidal vascularity index (CVI), and choriocapillaris perfusion density (PD) on structural OCT and OCT angiography.

MAIN OUTCOME MEASURES

Description of the multimodal imaging features of pachy-RPD and differences with RPD associated with normal/leptochoroid.

RESULTS

Among 111 RPD eyes, 37 were included in the pachy-RPD group and 74 in the control group. Patients with pachy-RPD were significantly younger than patients with RPD and normal/leptochoroid (mean age, 75 ± 16 and 82 ± 7 years, respectively; P = 0.002). Total RPD number was comparable between the 2 groups (P = 0.220). However, pachy-RPD eyes showed a significantly higher number of stage 1 RPD in comparison to the controls (P < 0.001), and a lower number of stage 3 (P < 0.001) and stage 4 RPD (P = 0.052). The CVI and choriocapillaris PD were greater in pachy-RPD than in the control group (P < 0.001 and P= 0.010, respectively).

CONCLUSIONS

Pachy-RPD are characterized by a different distribution of RPD stages (i.e., more early stages and fewer advanced stages) in comparison to RPD with normal/leptochoroid. Furthermore, pachy-RPD eyes showed greater perfusion indices of the choroid. These features suggest that the presence of pachychoroid could be a protective factor in the RPD evolution to the advanced AMD forms.

FINANCIAL DISCLOSURE(S)

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

Atrophic Lesions Associated with Age-Related Macular Degeneration: High-Resolution versus Standard OCT

OBJECTIVE

The objective of this study was to determine whether high-resolution OCT (HR-OCT) could enhance the identification and classification of atrophic features in age-related macular degeneration (AMD) compared with standard resolution OCT.

DESIGN

Prospective, observational, cross-sectional study.

SUBJECTS

The study included 60 eyes from 60 patients > 60 years of age with a diagnosis of AMD.

METHODS

The participants underwent volume OCT scanning using HR-OCT and standard resolution OCT devices. Trained graders reviewed and graded the scans, identifying specific regions of interest for subsequent analysis.

MAIN OUTCOME MEASURES

The study focused on identifying and classifying complete retinal pigment epithelium (RPE) and outer retinal atrophy (cRORA), incomplete RORA (iRORA), and other nonatrophic AMD features. Additionally, qualitative and quantitative features associated with atrophy were assessed.

RESULTS

The agreement among readers for classifying atrophic lesions was substantial to perfect for both HR-OCT (0.88) and standard resolution OCT(0.82). However, HR-OCT showed a higher accuracy in identifying iRORA lesions compared with standard OCT. Qualitative assessment of features demonstrated higher agreement for HR-OCT, particularly in identifying external limiting membrane (ELM) (0.95) and ellipsoid zone (EZ) disruption (0.94). Quantitative measurements of features such as hypertransmission defects, RPE attenuation/disruption, EZ disruption width, and ELM disruption width showed excellent interreader agreement with HR-OCT (> 0.90 for all features) but only moderate agreement with standard OCT (0.51-0.60).

CONCLUSIONS

The study results suggest that HR-OCT improves the accuracy and reliability of classifying and quantifying atrophic lesions associated with AMD compared with standard resolution OCT. The quantitative findings in particular may have implications for future research and clinical practice, especially with the availability of therapeutic agents for treating geographic atrophy and the development of commercially available HR-OCT devices.

FINANCIAL DISCLOSURE(S)

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

Optical coherence tomography biomarkers in early and intermediate age-related macular degeneration: A clinical guide

Advanced forms of age-related macular degeneration (AMD), characterised by atrophic and neovascular changes, are a leading cause of vision loss in the elderly population worldwide. Prior to the development of advanced AMD, a myriad of risk factors from the early and intermediate stages of AMD have been published in the scientific literature over the last years. The ability to precisely recognise structural and anatomical changes in the ageing macula, altogether with the understanding of the individual risk implications of each one of them is key for an accurate and personalised diagnostic assessment. The present review aims to summarise updated evidence of the relative risk conferred by diverse macular signs, commonly seen on optical coherence tomography, in terms of progression to geographic atrophy or macular neovascularization. This information may also serve as a basis for tailored follow-up monitoring visits.

PREVALENCE AND PERSISTENCE OF HYPERTRANSMISSION DEFECTS OF VARIOUS SIZES IN EYES WITH INTERMEDIATE AGE-RELATED MACULAR DEGENERATION

PURPOSE

To determine the prevalence and rate of persistence over 2 years of various-sized hypertransmission defects (hyperTDs) in eyes with intermediate age-related macular degeneration.

METHODS

Retrospective analysis of optical coherence tomography data from consecutive intermediate age-related macular degeneration patients. Choroidal en face optical coherence tomography images were evaluated for the presence and number of hyperTDs of three different sizes based on greatest linear dimension (small, 63-124 µ m; medium, 125-249 µ m; large, ≥250 µ m) at baseline and at the 2-year follow-up. Interreader agreement was determined by Gwet's agreement coefficient. Disagreements between graders were resolved by the senior investigator to yield a single consensus for all cases.

RESULTS

From 273 intermediate age-related macular degeneration eyes (247 patients), 72 and 76 hyperTD lesions were independently identified by two graders at baseline and overall agreement coefficient was 0.89 (95% CI, 0.86-0.93). After adjudication by the senior grader, the final consensus yielded 78 hyperTD lesions from 46 eyes (16.8%) of 42 patients (17.0%) in this study cohort. Among eyes with follow-up optical coherence tomography, 32 of 45 hyperTD lesions (71.1%) persisted. The rates of persistence were 100.0%, 72.7%, and 53.3% in large, medium, and small hyperTD sizes, respectively.

CONCLUSION

HyperTDs were present in a significant proportion of intermediate age-related macular degeneration eyes. Acceptable interreader agreement was demonstrated in identifying hyperTD. Larger hyperTD lesions were more likely to persist over 2 years.

Pushing Retinal Imaging Forward: Innovations and Their Clinical Meaning - The 2022 Ophthalmologica Lecture

Retinal imaging has greatly expanded our understanding of various pathological conditions. This article presents a summary of the key points covered during the 2022 Ophthalmologica Lecture held at the Euretina Congress in Hamburg. The first part of the article focuses on the use of optical coherence tomography angiography to examine and comprehend the choroid in age-related macular degeneration (AMD). Subsequently, we delve into the discussion of the "postreceptor neuronal loss" theory in AMD, which was studied using en face structural optical coherence tomography (OCT). Following that, we explore pertinent findings obtained through cross-sectional OCT in retinal and optic nerve diseases, such as AMD, diabetic macular edema, pathologic myopia, central serous chorioretinopathy, and Leber's hereditary optic neuropathy.

Spatial Cluster Patterns of Retinal Sensitivity Loss in Intermediate Age-Related Macular Degeneration Features

Purpose

To examine spatial patterns of retinal sensitivity loss in the three key features of intermediate age-related macular degeneration (iAMD).

Methods

One-hundred individuals (53 iAMD, 47 normal) underwent 10-2 mesopic microperimetry testing in one eye. Pointwise sensitivities (dB) were corrected for age, sex, iAMD status, and co-presence of co-localized key iAMD features: drusen load, pigmentary abnormalities, and reticular pseudodrusen (RPD). Clusters (labeled by ranks of magnitude C-2, C-1, C0) were derived from pointwise sensitivities and then assessed by quadrants and eccentricity/rings.

Results

Two clusters of decreased sensitivities were evident in iAMD versus normal: C-2, -1.67 dB (95% CI (confidence intervals), -2.36 to -0.98; P < 0.0001); C-1, -0.93 dB (95% CI, -1.5 to -0.36; P < 0.01). One cluster of decreased sensitivity was independently associated each with increased drusen load (13.57 µm increase per -1 dB; P < 0.0001), pigmentary abnormalities (C-1: -2.23 dB; 95% CI, -3.36 to -1.1; P < 0.01), and RPD (C-1: -1.07 dB; 95% CI, -2 to -0.14; P < 0.01). Sensitivity loss in iAMD was biased toward the superior and central macula (P = 0.16 to <0.0001), aligning with structural distributions of features. However, sensitivity loss associated with drusen load also extended to the peripheral macula (P < 0.0001) with paracentral sparing, which was discordant with the central distribution of drusen.

Conclusions

Drusen load, pigmentary abnormalities, and RPD are associated with patterns of retinal sensitivity loss commonly demonstrating superior and central bias. Results highlighted that a clinical focus on these three key iAMD features using structural measures alone does not capture the complex, spatial extent of vision-related functional impairment in iAMD.

Translational Relevance

Defining the spatial patterns of retinal sensitivity loss in iAMD can facilitate a targeted visual field protocol for iAMD assessment.