The Role of Optical Coherence Tomography Angiography (OCTA) in the Early Diagnosis of Primary Open-Angle Glaucoma

Background: Primary Open-Angle Glaucoma (POAG) is one of the leading causes of irreversible blindness in the world and is characterized by the gradual loss of retinal ganglion cells and damage of the optic nerve. The process of preventing irreversible visual damage means that it must be identified early. It is now possible to visualize the microvasculature of the retina and optic nerve head with a non-invasive imaging technique called optical coherence tomography angiography (OCTA) that can help detect glaucoma in its early stages before a permanent loss of visual field is observed. Objective: To determine the contribution of OCTA in the early detection of POAG by comparing retinal and peripapillary microvascular parameters of early POAG and healthy controls. Methods: This cross-sectional research was carried out between September 2024 and May 2025 at Gulab Devi Hospital and Ghurki Trust Teaching Hospital in Punjab. Twenty-five early POAG patients and twenty-five age- and sex-matched healthy controls made up the 50 participants in total. Every subject had OCTA imaging and a thorough ophthalmologic examination. Measured and statistically examined were the foveal avascular zone (FAZ) area, radial peripapillary capillary (RPC) density, and vessel densities in the macular and peripapillary areas. Results: POAG patients showed significantly reduced peripapillary vessel density (41.2% vs. 48.6%, p < 0.001), RPC density (39.8% vs. 46.9%, p < 0.001), and macular superficial vessel density (43.1% vs. 49.4%, p < 0.001) compared to controls. RNFL thickness and visual field mean deviation were also lower in POAG eyes. FAZ area showed no significant difference, although qualitative irregularities were noted in POAG patients. Conclusion: OCTA effectively detects early microvascular changes in POAG, even before structural or functional deterioration becomes evident. Its integration into routine glaucoma assessment may enhance early diagnosis and intervention, improving long-term visual outcomes.