Optical Coherence Tomography Angiography in Detecting Subclinical Changes in Glaucoma Suspects: A Scoping Review

TL;DR

This review shows that OCTA can detect early blood vessel changes in people at risk for glaucoma before damage is visible, helping with early detection.

Contribution

The study provides a synthesis of OCTA's effectiveness in identifying early glaucomatous microvascular changes in glaucoma suspects.

Findings

OCTA shows reduced vessel density in glaucoma suspects compared to healthy controls.

Peripapillary and macular vessel density metrics have diagnostic accuracy comparable to structural OCT.

Microvascular asymmetry and capillary dropout are early markers of glaucoma progression.

Abstract

Optical coherence tomography angiography (OCTA) offers a promising approach for detecting subclinical microvascular changes in glaucoma suspects before structural or functional damage becomes apparent. This scoping review synthesizes evidence from 11 studies (2014-2025) to evaluate OCTA’s effectiveness in identifying early glaucomatous alterations. Findings consistently demonstrate reduced vessel density (VD) in glaucoma suspects compared to healthy controls, with whole-image VD averaging 51.3% versus 55.5% (P<0.001), respectively. OCTA-derived parameters, particularly peripapillary and macular VD, showed diagnostic accuracy (area under the receiver-operating characteristic curve (AUROC): 0.70-0.84) comparable to structural OCT metrics like retinal nerve fiber layer thickness. Notably, microvascular asymmetry and deep-layer capillary dropout emerged as early markers, often preceding visual field defects. Longitudinal data revealed faster VD decline in preperimetric glaucoma (−2.23%/year) than in healthy eyes (0.29%/year), highlighting OCTA's potential for monitoring progression. Despite methodological heterogeneity, OCTA complements structural assessments, providing actionable insights for early glaucoma detection. Standardization of protocols and longitudinal validation are needed to optimize clinical utility. These findings support OCTA's role in enhancing risk stratification for glaucoma suspects.

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