Natural history of incomplete retinal pigment epithelial and outer retinal atrophy in age-related macular degeneration

Objective: To assess the time course and risk factors for conversion of incomplete retinal pigment epithelium and outer retina atrophy (iRORA) to complete retinal pigment epithelium and outer retina atrophy (cRORA) in eyes with non-neovascular intermediate age-related macular degeneration (iAMD), using optical coherence tomography (OCT) analysis. Design: Retrospective survival study. Participants: Tracked structural Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) volume datasets from 2 retinal specialists at the University of California–Los Angeles were retrospectively screened to identify consecutive participants with non-neovascular iAMD without signs of atrophy or macular neovascularization in either eye at baseline. Methods: In the first stage of selection, 321 consecutive iAMD eyes were screened for onset of iRORA. Eyes that developed iRORA within the first 24 months were followed for an additional 24 months to assess the rate of conversion to cRORA. A Kaplan-Meier survival curve was formulated to illustrate the conversion from iRORA to cRORA. Results: Among 321 baseline participants with iAMD, 87 incident iRORA lesions (50 eyes, 42 participants) were included in the conversion analysis. Eighty-one iRORA lesions (93.1%) converted to cRORA within 24 months (median 14 months). Multivariate binary logistic regression analysis indicated that intraretinal hyperreflective foci and extrafoveal iRORA location at baseline were associated with a faster rate of progression to cRORA (model R² = 0.816, p < 0.05). Conclusions: The majority of incident iRORA lesions progress to cRORA within a 24-month period. These findings may be of value in the design of early intervention trials for risk stratification and prognostication but need to be validated with a prospective analysis.