Reduced Retinal Vessel Density in Primary Angle Closure Glaucoma: A Quantitative Study Using Optical Coherence Tomography Angiography

Purpose: The purpose of this article is to investigate the changes in the retinal vasculature in different parts of the fundus in eyes with primary angle closure glaucoma (PACG). Methods: Healthy subjects and those with PACG were enrolled. Optical coherence tomography and a split-spectrum amplitude decorrelation angiography algorithm were used to quantify the retinal vessel densities in the parafoveal and peripapillary areas. Results: Thirty-nine eyes from 24 PACG patients and 39 eyes from 20 age-matched and sex-matched healthy subjects were included. The retinal vessel densities in the parafoveal and peripapillary areas and every sector of the 2 areas were significantly lower in the PACG eyes than in the healthy eyes. The difference was greater in the peripapillary area (11.75%) than in the parafoveal area (7.55%, P<0.05). In the PACG eyes, the vessel density in the peripapillary area correlated closely with the intraocular pressure, but that in the parafoveal area did not. When the PACG eyes were divided into groups with well-controlled and not well-controlled intraocular pressure (≤21 mm Hg or not), the vessel density and retinal nerve fiber layer thickness in the peripapillary area were much lower in the not well-controlled eyes (P<0.05), whereas the vessel density in the parafovea and the ganglion cell complex thickness were similar in the 2 subgroups. Conclusion: Retinal vessel density was significantly reduced in PACG eyes. The magnitude of this difference varied between the fundus areas, and was greater in the peripapillary area.