Progression of geographic atrophy and impact of fundus autofluorescence patterns in age-related macular degeneration

Abstract

Purpose: To test if fundus autofluorescence (FAF) patterns around geographic atrophy (GA) have an impact on GA progression rates over time in atrophic age-related macular degeneration (AMD).

Design: Prospective longitudinal multicenter natural history study.

Methods: Standardized digital FAF images were obtained from 195 eyes of 129 patients with GA using confocal scanning laser ophthalmoscopy (excitation 488 nm, emission >500 nm). Areas of GA were quantified and patterns of abnormal FAF in the junctional zone were classified. Repeated FAF images were obtained over a median follow-up period of 1.80 years (interquartile range [IQR], 1.28 to 3.34).

Results: Areas of GA (median, 7.04 mm(2) at baseline; IQR, 3.12 to 10.0) showed a median enlargement of 1.52 mm(2)/year (IQR, 0.81 to 2.33). Progression rates in eyes with the banded (median 1.81 mm(2)/year) and the diffuse FAF pattern (1.77 mm(2)/year) were significantly higher compared to eyes without FAF abnormalities (0.38 mm(2)/year) and focal FAF patterns (0.81 mm(2)/year, P < .0001). Within the group of the diffuse pattern, eyes with a diffuse trickling pattern could be identified that exhibited an even higher spread rate (median 3.02 mm(2)/year) compared to the other diffuse types (1.67 mm(2)/year, P = .001).

Conclusions: The results indicate that distinct phenotypic FAF patterns have an impact on disease progression in eyes with atrophic AMD and may therefore serve as prognostic determinants. The findings underscore the relevance of FAF imaging and the pathogenetic role of excessive retinal pigment epithelium (RPE) lipofuscin (LF) accumulation in GA. Natural history data and identification of high-risk characteristics will be helpful to design interventional studies aiming at slowing the spread of atrophy.