Three-Dimensional Choroidal Vessels Assessment in Age-Related Macular Degeneration.

Abstract

To compare the choroidal vasculature in eyes with early- and intermediate-stage age-related macular degeneration (dAMD) and healthy using a novel three-dimensional algorithm. Patients with dAMD and healthy controls underwent clinical examinations and swept-source optical coherence tomography scans (PlexElite-9000 device) centered on the fovea. Scans with quality scores >6 were included. Eyes with any signs of neovascular AMD or geographic atrophy were excluded. The choroidal layer was segmented using ResUNet model and volumetric smoothing. Phansalkar thresholding was used to binarize the choroidal vasculature. The three-dimensional maps were divided into five sectors. The three largest vessels in each sector were measured to determine the mean choroidal vessel diameter (MChVD) and inter-vessel distance (IVD). Volumetric choroidal thickness (ChT) and vascularity index (CVI) were also calculated. This retrospective cross-sectional study analyzed 60 eyes from 45 dAMD patients (27 early-stage, 33 intermediate-stage) and 26 eyes from 16 healthy controls. The average MChVD was increased in dAMD eyes compared to healthy eyes (239.559 ± 47.058 µm vs. 197.873 ± 49.047 µm, P < 0.001). The average MChVD in each sector increased significantly in eyes with dAMD (P < 0.05). The average IVD was increased significantly in dAMD eyes compared to healthy eyes (234.128 ± 69.537 µm vs. 179.914 ± 49.995 µm, P < 0.001). The average IVD in each sector was significantly increased in eyes with dAMD (P < 0.05). Average ChT and CVI in dAMD were reduced compared to healthy eyes (P < 0.05). Eyes with dAMD demonstrated increased MChVD and IVD and decreased ChT and CVI, possibly related to smaller-vessel atrophy and larger-vessel dilation.