Optical coherence tomography angiography microvascular changes in the macular region in open-angle glaucoma

Introduction/Objective. Glaucoma is the leading cause of irreversible blindness worldwide. It is hypothesized that glaucomatous microvascular changes in the superficial capillary plexus (SCP) may lead to early structural damage and correlate with visual field defects. The aim of this study was to quantitatively analyze microvascular characteristics of the SCP in the macular region of healthy eyes and in eyes with varying severity of open-angle glaucoma (OAG) using optical coherence tomography angiography (OCT-A). Methods. A total of 144 eyes were included in this cross-sectional study, including 109 eyes with confirmed OAG and 35 healthy eyes. Based on the Hodapp–Anderson–Parrish classification, patients were categorized into early, moderate, and severe stage glaucoma. All subjects underwent visual field, optical coherence tomography, and OCT-A examinations. Results. Significant reductions were observed in macular vessel density across glaucoma stages. Foveal vessel density decreased from 23 ± 1.9% in normal eyes to 13.9 ± 1.8% in severe glaucoma eyes. Foveal and parafoveal vessel densities were significantly reduced even in early-stage glaucoma. OCT parameters progressively decreased with glaucoma severity. Total ganglion cell complex thickness decreased from 108.5 ± 5.6 μm in healthy eyes to 61.2 ± 6.9 μm in severe glaucoma eyes. Total peripapillary retinal nerve fiber layer thickness decreased from 106.2 ± 7.9 μm in healthy eyes to 48.7 ± 7.5 μm in severe glaucoma. Conclusion. Our findings support the hypothesis that macular vessel density decreases progressively with glaucoma severity. These results reinforce the potential clinical utility of OCT-A in detecting early glaucoma and monitoring disease progression.