Prevalence and characteristics of pseudodrusen subtypes in advanced age-related macular degeneration

Purpose The purpose of our study was to investigate the clinical and genetic characteristics of pseudodrusen subtypes and their incidence in advanced age-related macular degeneration (AMD). Methods We studied 84 eyes from 84 patients with pseudodrusen associated with advanced AMD, including typical AMD, polypoidal choroidal vasculopathy (PCV), retinal angiomatous proliferation (RAP), and geographic atrophy (GA). Multiple imaging modalities, including color fundus photography, spectral-domain optical coherence tomography (SD-OCT), near-infrared reflectance, and fundus autofluorescence, were employed to diagnose pseudodrusen and its subtypes. Subfoveal choroidal thickness was measured using SD-OCT. Subject eyes were classified into two subtypes, dot-dominant or ribbon-dominant, according to the maximum length of ribbon pseudodrusen. Genotyping was performed for ARMS2 A69S (rs10490924) and CFH I62V (rs800292) variants. Results The percentage of ribbon-dominant type pseudodrusen was significantly higher in eyes with RAP (69.6%) and GA (78.6%) compared with those with typical AMD (31.1%) ( p = .0025 and .0017, respectively). Multivariate logistic regression analysis disclosed that incidence of female patients and coexisting large soft drusen was significantly higher in ribbon- than dot-dominant types ( P = 0.014 and P = 0.008, respectively), while age, subfoveal choroidal thickness, and risk allele frequency for both ARMS2 A69S (rs10490924) and CFH I62V (rs800292) were not different between the two pseudodrusen subtypes. Conclusions Among eyes with advanced AMD associated with pseudodrusen, ribbon-dominant type pseudodrusen were more prevalent in eyes with GA or RAP and were associated with large soft drusen and female patients.