The current study highlights distinct choroidal alterations in primary open-angle and angle-closure glaucoma, underscoring the potential of choroidal vascularity index as a valuable indicator for understanding glaucoma pathogenesis.To evaluate choroidal structural changes in patients with primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) and healthy controls utilizing the choroidal vascularity index (CVI) and subfoveal choroidal thickness (SFCT) by enhanced depth imaging optical coherence tomography (EDI-OCT).This study was cross-sectional. A total of 171 eyes of 171 subjects, comprising 69 eyes with untreated POAG, 58 eyes with untreated PACG and 44 healthy eyes, were enrolled in this study. SFCT, luminal area (LA), stromal area (SA) and total choroidal area (TCA) were measured on EDI-OCT scans. The CVI parameter is calculated as the proportion of LA to TCA.This study included 69 POAG patients with a mean age of 51.4±13.3 years, 58 PACG patients with a mean age of 57.0±7.3 years, and 44 healthy subjects with a mean age of 51.11±10.7 years. The CVI in the POAG and PACG groups was significantly lower than that in the control group (P = 0.001 and P = 0.005, respectively), however not significantly different between the two glaucoma groups (P = 1.000). POAG eyes had significantly lower LA than PACG and controls (P = 0.014 and P = 0.049, respectively), while PACG eyes had significantly greater SA than controls (P = 0.041).The CVI of POAG and PACG eyes was significantly lower than that of normal eyes. A reduced LA was observed mainly in eyes with POAG, and an increased SA was observed mainly in eyes with PACG. The role of the choroid may differ between POAG and PACG eyes.Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.