Peripapillary Microvascular Parameters in Unilateral Open-Angle Glaucoma Using the Optical Coherence Tomography-Angiography

Abstract

Objective: This study compared the peripapillary retinal nerve fiber layer (pRNFL) microangiographic properties [vessel area density (VAD) and blood flux index (BFI)] of unilateral open-angle glaucomatous eyes to contralateral eyes-at-risk, and to eyes of healthy age- and sex-matched subjects. Methods: This was a single-center, case-control study of Filipinos diagnosed with unilateral primary openangle glaucoma (POAG) or normal-tension glaucoma (NTG). Mean overall and quadrantal VAD and BFI of the three groups were measured with optical coherence tomography- angiography (OCT-A). Area under the receiver operating characteristic (AROC) was used to measure diagnostic ability. Results: Twenty-two (22) glaucomatous subjects (15 POAG and 7 NTG eyes), 22 contralateral eyes-at-risk, and 22 normal eyes from age- and sex-matched control subjects completed the study. Eyes with glaucoma showed lower mean overall VAD (40%) and BFI (0.37) compared to eyes-at-risk (44.4% and 0.42, respectively; p <0.001) and control eyes (45.6% and 0.44, respectively; p <0.001). Mean VAD and BFI values of eyes-at-risk and control groups did not significantly differ from each other. Overall pRNFL thickness showed highest diagnostic accuracy for glaucoma (AROC = 0.97), followed by VAD (0.94), and BFI (0.88) (p=0.46). Conclusion: VAD and BFI were significantly diminished in unilateral open-angle glaucoma, suggesting that the utility of OCT-A in the detection of glaucoma is comparable to pRNFL thickness.

Keywords

• oct-angiography
• peripapillary microcirculation
• blood flux index
• vessel area density
• unilateral glaucoma