OCT Risk Factors for Development of Atrophy in Eyes with Intermediate Age-Related Macular Degeneration

Abstract

To determine the frequency of multiple OCT biomarkers of intermediate age-related macular degeneration (iAMD) and their relationship with the development of complete retinal pigment epithelium and outer retinal atrophy (cRORA) after 2 years. Retrospective cohort study. This retrospective analysis included 330 eyes of 330 consecutive patients with iAMD in ≥ 1 eye who had 24 months of follow-up data. Spectralis OCT volume scans (49 B-scans over 6× 6 mm, automatic real time = 6, fovea-centered) at baseline were evaluated for the previously described iAMD biomarkers, including a high-central drusen volume (DV; ≥ 0.03 mm3), intraretinal hyper-reflective foci (IHRF), subretinal drusenoid deposits (SDDs), hypo-reflective drusen cores (hDCs), and a thin or thick (multilayered) double-layer sign (DLS). The age-related macular degeneration (AMD) status in the fellow eye was also assessed and classified as normal or early AMD, iAMD, exudative macular neovascularization, or cRORA. Incidence of cRORA, odds ratio for demographics, and OCT features. At month 24, 16.36% (54/330) of the iAMD eyes developed cRORA. Several baseline features, including high-central DV, IHRF, SDD, hDC, thin DLS, and cRORA in the fellow eye, were associated with a significantly greater risk for development of cRORA at 2 years. The odds ratio, 95% confidence interval, P value, and baseline frequencies of these biomarkers were DV (6.510, 2.467-17.176, P < 0.001, 49.1%), IHRF (12.763, 4.763-34.202, P < 0.001, 38.8%), SDD (2.307, 1.003-5.304, P= 0.049, 34.2%), hDC (3.012, 1.152-7.873, P= 0.024, 13.0%), thin DLS (4.517, 1.555-13.126, P= 0.006, 11.8%), and cRORA in the fellow eye (7.184, 1.938-26.623, P= 0.003, 8.2%). In addition to the 4 previously reported factors that are present in a significant proportion of iAMD (DV, IHRF, hDC, and SDD), a thin DLS and cRORA in the fellow eye were associated with an increased risk of progression to cRORA over 2 years. These biomarkers may aid in prognostication, risk stratification, and selection of patients for clinical trials.