Foveolar Choroidal Blood Flow in Patients with Age–related Macular Degeneration (AMD)

Abstract

Abstract: : Purpose: We have previously reported that foveolar choroidal blood flow is decreased in patients with AMD and drusen. We have now investigated the relationship between choroidal blood flow changes and fundus features associated with increased risk for choroidal neovascularization (CNV). Methods:This study included 23 control eyes of 15 normal subjects and 148 eyes with early AMD characteristics of 96 AMD patients. AMD eyes were divided into 3 groups according to increasing risk for the development of CNV: 1)drusen ≥63µ in study eye and no CNV in the fellow eye, 2)drusen ≥63µ and RPE hypertrophy in study eye and no CNV in fellow eye, and 3) eyes with CNV in the fellow eye. Visual acuity was 20/40 or better in the study eye. Following pupillary dilatation, laser Doppler flowmetry (Oculix) was used to assess relative choroidal blood velocity (ChB Vel), volume (ChB Vol) and flow (ChB Flow) in the center of the fovea of the study eyes. Differences in the mean circulatory parameters between groups of eyes were assessed using analysis of variance (ANOVA) and a test of linear trend, with adjustment for the correlation between eyes. Results:As shown in the table, mean ChB Vel, ChB Vol and ChB Flow decreased with increased risk for CNV (linear trend, P–values <0.05). Similar trends for ChBVel and ChB Flow were seen after adjustment for age, IOP, perfusion pressure and refractive error. 

Conclusions:There is a systematic decrease in choroidal circulatory parameters with an increase in the severity of AMD features associated with risk for the development of CNV, suggesting a role for ischemia in the development of CNV.

Keywords: age–related macular degeneration • blood supply • ischemia