Purpose: To investigate retinal sensitivity in the junctional zone of geographic atrophy (GA), with variations in fundus autofluorescence (FAF) in patients with advanced age-related macular degeneration (AMD).
Methods: The spatial distribution and intensity of FAF were recorded with a confocal scanning laser ophthalmoscope (SLO). Eyes had normal background FAF (group 1) or increased FAF (group 2) surrounding the atrophic patches. Retinal sensitivity was assessed by applying light stimuli with static automated full-threshold fundus perimetry with a modified SLO. Threshold sensitivities were compared with age-matched normal sensitivities.
Results: Thirty-nine eyes of 39 patients with GA were included. Group 2 had a higher percentage of all test points outside the GA area, with decreased retinal sensitivity (44.9% +/- 28.7%) compared with group 1 (20.7% +/- 12.7%; P = 0.0063; multiple regression model; outcome variable is retinal sensitivity; covariates are group affiliation and GA area). Within group 2, the average percentage of stimuli in areas of normal FAF with reduced sensitivity was 38.0% +/- 33.0%, whereas the average percentage of stimuli in areas of elevated FAF with reduced sensitivity was 52.6% +/- 29.7% (P = 0.023, Wilcoxon signed rank test).
Conclusions: Areas of increased FAF outside GA may be associated with variable degrees of loss of retinal sensitivity and suggest a functional correlate of excessive accumulation of retinal pigment epithelium lipofuscin in AMD. Combining in vivo recording of FAF and retinal sensitivity, using SLO technology, may give important clues in the understanding of mechanisms of disease.