Foveal Avascular Zone Morphology in Glaucoma: A Systematic Review of Oct Angiography Findings

Abstract

Introduction: Globally, glaucoma ranks as the foremost contributor to permanent blindness. Optical coherence tomography angiography (OCT-A) enables direct assessment of the foveal avascular zone (FAZ). Measurements of FAZ morphology provide reproducible and objective metrics, functioning similarly to laboratory-based biomarkers.   OCT-A offers measurable and consistent evaluations of FAZ morphology specifically area, perimeter, and circularity that can serve as imaging biomarkers, akin to laboratory test results. Standardization of these parameters may enable integration into laboratory information systems and AI-driven diagnostic tools.

Objective: This review was conducted to systematically examine evidence on FAZ alterations in glaucoma as detected by OCT-A.

Evidence Review: A systematic search of PubMed, ScienceDirect, and Google Scholar identified studies from January 2015 to July 2025. Eligible articles included original research on FAZ in glaucoma assessed by OCT-A. Reviews, case reports, editorials, and non-English papers were excluded. Study selection and reporting followed PRISMA guidelines.

Results: Eighteen studies were included. The majority demonstrated that glaucoma patients, especially those with moderate-to-severe disease or central field impairment, had larger FAZ areas, increased perimeters, and reduced circularity compared with controls. These vascular changes were significantly correlated with thinning of the retinal nerve fiber layer and ganglion cell–inner plexiform layer, alongside decreased central field sensitivity. Some variability was noted across glaucoma subtypes and disease stages. Surgical interventions such as trabeculectomy were reported to partially reverse FAZ enlargement.

Conclusions: FAZ enlargement and loss of circularity represent consistent vascular biomarkers of glaucomatous damage. The OCT-A assessment of FAZ may enhance the monitoring of disease progression and treatment efficacy, requiring validation in larger longitudinal studies.