Correlation Between Localized Choriocapillaris Perfusion and Macular Function in Eyes with Geographic Atrophy: Choriocapillaris Flow Relates to Macular Function in AMD with GA

PURPOSE To test the hypothesis that choriocapillaris perfusion correlates with visual function in geographic atrophy (GA). DESIGN Cross-sectional, single-center study Methods: We imaged choriocapillaris flow using 6mm x 6mm swept-source optical coherence tomography angiography (OCTA) scans and measured retinal sensitivity using fundus-guided microperimetry in the central 20° in 18 eyes of 12 subjects with GA and 7 eyes of 4 normal subjects. OCTA scans were divided into a grid and microperimetry results were superimposed using retinal vascular landmarks. The main outcome measure correlated choriocapillaris flow deficit with retinal sensitivity at each localized region. Robust linear mixed effects regression compared flow deficit or sensitivity with distance from the fovea. The Pearson ρ correlation described the relationship between flow deficit or retinal sensitivity and distance from the GA border. RESULTS Choriocapillaris flow deficit was significantly greater in GA than normal (mean ± standard deviation 24.2 ± 7.9% vs 7.9 ± 2.3%, P = 0.0015), while retinal sensitivity was significantly lower in GA than normal (mean difference -17.0 ± 1.2 dB, P<0.001). In GA, choriocapillaris flow deficit decreased (ρ= -0.40, 95% CI: -0.54 to -0.27), while retinal sensitivity increased (ρ= + 0.63, 95% CI: 0.30 to 0.81) with distance from the GA margin. Choriocapillaris flow deficits inversely correlated with retinal sensitivity (ρ = -0.61, 95% CI: -0.75 to -0.42). CONCLUSION Choriocapillaris flow and retinal sensitivity improved with distance from the GA margin. Choriocapillaris flow deficit was inversely correlated with sensitivity, supporting the hypothesis that choriocapillaris perfusion correlated with macular function.