Assessment of Ocular Flow Area and Vessel Density by Optical Coherence Tomography Angiography across the Primary Angle Closure Disease Spectrum

Abstract

Purpose : To assess the ocular microvasculature across the primary angle closure disease (PACD) spectrum using optical coherence tomography angiography (OCTA).

Methods : Two hundred and forty-one eyes with PACD including primary angle closure suspect (PACS, n=46), primary angle closure (PAC, n=93), primary angle closure glaucoma (PACG, n=77) and those with history of previous acute primary angle closure (APAC, n=25) underwent OCTA (AngioVue, Fremont, CA). Flow area (FA) and vessel density (VD) in the optic nerve head (ONH), the radial peripapillary capillary (RPC) network and the superficial and deep capillary plexuses of the macula were calculated and compared across the PACD using linear regression models with generalized estimating equation after adjusting for inter-eye correlation.

Results : Smaller FA was observed in the ONH (1.35±0.02mm²), the vitreous (0.8±0.02mm²), the RPC (0.78±0.04mm²) and the superficial retinal layer (1.08±0.03mm²⁾ of eyes with PACG when compared to other subgroups (all P<0.05). Lesser VD was also observed in the “whole image”, “inside disc” and “peripapillary” of the ONH and RPC and the “whole image” and “parafoveal” of the superficial retinal layer in the PACG group when compared with other subgroups (all P<0.05). No significant difference was found among other groups (all P>0.05). The lesser VD in the ONH, RPC and superficial retinal layer was significantly correlated with worse visual field loss in PACG eyes (all P<0.05).

Conclusions : The ocular microvasculature in the disc and macula was significantly reduced in PACG eyes but not in other groups. The lesser VD in the PACG group may contribute disease severity.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.