Cross-Sectional Study of Cone Function in Age-Related Macular Degeneration Subjects With Non-foveal Nascent Geographic Atrophy

Abstract

To determine photoreceptor function in subjects with drusen only and non-foveal nascent geographic atrophy (nGA) intermediate age-related macular degeneration. In this cross-sectional study, 60 eyes from 33 subjects, 30 with drusen only and 30 with non-foveal nGA determined by spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) underwent testing for best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), and qCSF algorithm (area under log contrast sensitivity function [AULCSF]) under both standard photopic and low-luminance (LL AULCSF) conditions. Areas of nGA-associated hypo-autofluorescence (hypo-AF) were graded. In the drusen group, visual acuity (VA)=81 letters ± 3 (mean ± SD), LLVA=65 letters ± 4, AULCSF=0.99 ± 0.0.5, and LL AULCSF=0.38 ± 0.04, whereas in the nGA group, VA=77 ± 4 letters, LLVA=61± 4, AULCSF=0.87 ± 0.09, and LL AULCSF=0.28 ± 0.06. Multivariate analysis of variance among the LLVA, AULCSF, and LL AULCSF did not demonstrate a statistical difference (P=.167), whereas LL AULCSF analyzed by analysis of variance demonstrated a significant difference between the 2 groups (P=.037). Linear regressions demonstrated significant relationships between BCVA and AULCSF in both the drusen and nGA groups (r=0.83, P < 10-9 and r=0.61, P=.0004) but did not correlate with AULCSF under low-luminance conditions (r=2.9, P=.13) in the nGA group. The total area of hypo-AF was negatively associated with poorer visual functions. The use of LL AULCSF and certain features of FAF should be considered in clinical trials of intermediate age-related macular degeneration. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.