Percentage of Foveal versus Total Macular Geographic Atrophy as a Predictor of Visual Acuity in Age-related Macular Degeneration

Abstract

ObjectivesTo investigate the relationship between visual acuity (VA), total area of geographic atrophy (GA) and percentage of foveal GA. MethodsMulticenter, retrospective cross-sectional study of patients with GA due to age-related macular degeneration. Demographics, VA, fundus autofluorescence (FAF) and optical coherence tomography (OCT) images were collected. Using FAF images aided by OCT, foveal sparing status, GA pattern, total GA size, and percentage of GA covering the foveal area - area within a 1.5 mm diameter circle centered on the fovea centralis - were assessed. Univariable and multiple linear regression analyses were performed. Results54 eyes (mean age 78.7 {+/-}7.7 (SD), 60.0% female) were studied. Mean VA was 0.8 {+/-} 0.6 logMAR, mean total GA 8.8 {+/-} 6.7 mm2 and mean percentage of foveal GA was 71.5 {+/-} 30.9%. Of all assessed eyes, 48.2% (n = 26) presented with multifocal GA, and 18.5% (n = 10) had foveal sparing. Multiple regression analysis revealed that, controlling for age and GA pattern, the percentage of foveal GA presented a statistically significant association with VA ({beta} = 0.41, P = 0.004). No significant associations were observed with mean total GA size, while controlling for the same variables ({beta} = 0.010, P = 0.440). ConclusionPercentage of foveal GA was significantly associated with VA impairment, while the same was not verified for total GA area. These findings suggest that percentage of foveal GA may represent a more useful tool for assessing the impact of GA on VA. Further validation is needed in larger cohorts.