Association between geographic atrophy progression and reticular pseudodrusen in eyes with dry age-related macular degeneration

Purpose. To evaluate geographic atrophy (GA) progression in eyes with dry AMD and to determine factors related to GA expansion, notably reticular pseudodrusen (RPD), also known as subretinal drusenoid deposits (SDD) or reticular macular disease (RMD). Methods. This was a retrospective cohort study of patients with dry AMD who were diagnosed with GA in at least one eye and were imaged with sequential fundus autofluorescence (FAF) and/or near infrared reflectance (NIR-R) imaging. Images were analyzed for the presence of GA within the macular region. Geographic atrophy progression was measured in the fields of a modified Wisconsin grid and spatially correlated with RPD. Factors also evaluated for association with GA progression included initial GA size and pattern. Results. The study sample included 126 eyes of 92 patients, with an average follow up of 20.4 months (SD = 11.7). At baseline, 93.6% of eyes had RPD, and the average GA area was 2.8 mm² (SD = 2.9). The average GA progression rate was 0.8 mm²/y (SD = 0.6), with a statistically significant difference between the unilobular and multilobular phenotype groups (0.3 mm²/y vs. 0.9 mm²/y, P = 0.02). Patients in the lower 50th percentile of initial GA area had a lower progression rate than patients in the upper 50th percentile (0.6 mm²/y vs. 1.1 mm²/y, P < 0.001). Geographic atrophy progression was more frequent in fields with RPD than in those without RPD (74.2% vs. 41.7%, P < 0.001). Conclusions. The high correlation between the presence of RPD (also known as SDD or RMD) and the presence of GA, and the expansion of GA into areas with these lesions suggest that they are an early manifestation of the process leading to GA.