The Discrepancy Between Visual Acuity Decline and Foveal Involvement in Geographic Atrophy

Abstract

To investigate the discrepancy between visual acuity (VA) decline and foveal involvement in geographic atrophy (GA) secondary to non-exudative age-related macular degeneration (AMD), and to explore how early retinal changes impact the progression of visual impairment. Retrospective, longitudinal cohort study. This study evaluated 80 eyes from 60 patients (mean age 74.2±10 years) with progressing non-neovascular AMD using blue-light fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT). The study monitored the onset of foveal involvement and analyzed VA changes over an average follow-up of 60±26.4 months, encompassing 785 observations. Mixed-effects models with natural splines assessed the effects of demographic and ocular characteristics on baseline VA and its rate of decline. Survival analyses compared the timing of anatomical changes with the most rapid functional declines, indicated by the highest first derivative of VA trajectories. Discrepancies between visual and anatomical changes were explored using generalized linear mixed-effects models. VA declined consistently by an average of 0.010 LogMAR per month (SE: 0.0003, p<0.001). The onset of foveal involvement significantly exacerbated this decline, adding an average loss of 0.15 LogMAR (SE: 0.02, p<0.001). Stabilization of VA typically occurred around 41 months post-foveal involvement. Significant factors associated with worse baseline VA were older age, female gender, unifocal GA morphology, and drusen-associated forms of GA (p<0.05). The most rapid declines in VA typically occurred about 9 months (IQR 0-27 months) prior to detectable subfoveal changes. The reticular FAF pattern (27/46 [59%] vs. 2/13 [15%], p=0.02) and smaller baseline GA lesions (p=0.01) were associated with faster deterioration preceding visible foveal damage. This study demonstrates that significant VA loss in GA can precede detectable foveal involvement, suggesting a window for early interventions to slow the progression of visual impairment. Identifying specific GA characteristics and FAF patterns as predictors of rapid VA decline supports the need for personalized treatment strategies to optimize outcomes for patients with non-exudative AMD.