REGIONAL VARIABILITY IN CHOROIDAL VASCULARITY INDEX AND ASSOCIATION WITH INTERVORTEX ANASTOMOSES IN POLYPOIDAL CHOROIDAL VASCULOPATHY.

Abstract

To evaluate the regional variation in choroidal vascularity index (CVI) in polypoidal choroidal vasculopathy and its association with intervortex anastomosis (IA). Fifty-one eyes with polypoidal choroidal vasculopathy were included. Volumetric optical coherence tomography scans were acquired on a 6 × 6 mm 2 macula area and divided into 36 individual squares. Choroidal vascularity index was calculated using an automated algorithm. The different regions were central, superior-temporal, inferior-temporal (IT), superior-nasal (SN), and inferior-nasal (IN). Intervortex anastomosis was detected using en-face optical coherence tomography. The mean (SD) CVI of the whole macula was 61.01% (1.46), similar to all the other regions (pairwise comparisons, all P > 0.05). Choroidal vascularity index range was 48.75% to 69.48%. The mean (SD) coefficient of variation was 1.9% (1.3). Intervortex anastomosis was present in 64.7% of eyes. Eyes with IA had higher mean (SD) whole macula CVI (61.39% [1.43] vs. 60.30% [1.26], P = 0.01) and subfoveal CT (265.8 µ m [103.4] vs. 190.1 µ m [78.3], P = 0.01) compared to those without, and a lower mean (SD) CVI range (6.08% [2.38] vs. 8.27% [4.13], P = 0.04). Although the mean CVI coefficient of variation was lower in eyes with IA, 1.6% (0.8) versus 2.4% (1.8), this was not statistically significant ( P = 0.14). Regional CVI variability may precede the formation of IA supporting the hypothesis that IA could be a compensatory mechanism for choroidal congestion.