Quantitative Assessment of Choriocapillaris Flow Deficits in Eyes with Advanced Age-Related Macular Degeneration Versus Healthy Eyes

Abstract Purpose To compare choriocapillaris (CC) flow deficits in eyes with geographic atrophy (GA) or choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) and age-matched healthy control subjects. Design Cross-sectional study. Methods Patients with GA due to AMD, CNV due to AMD, and age-matched healthy subjects presenting to the Doheny-UCLA Eye Centers were enrolled in this cross-sectional IRB-approved study. Swept-source optical coherence tomography angiography (SS-OCTA) was performed using a Zeiss PLEX Elite instrument with a 6 × 6 mm scan pattern centered on the fovea. Two repeated volume scans were acquired to allow for image averaging. The instrument pre-defined en face slab of the CC was used to isolate and display the CC. Both the structural and OCTA slabs from this location were exported for averaging and signal compensation using Image J. The resultant image was then binarized. The CC flow deficit percentage (FD %) was computed in four peripheral 1 mm × 1 mm squares located at the corners of the images to allow comparison between equidistant regions unaffected by atrophy or CNV. Results Twenty eyes of twenty subjects were enrolled in each of the three groups (CNV, GA, normal) for this study. The average CC FD % of the 4 peripheral squares was 17.24% ± 2.86% in GA eyes, 15.55% ± 1.03% in CNV eyes, and 15.31% ± 0.93% in healthy controls of a similar age. The FD% in GA eyes was significantly greater than in both normal eyes and eyes with CNV ( p = 0.012 and 0.038 respectively). The difference in FD% was not significantly different between CNV eyes and normal eyes for the tested peripheral macular regions ( p = 0.678). Conclusions The choriocapillaris in peripheral macular regions in eyes with GA shows greater impairment than in eyes with CNV.