Comparison of the Retinal Microvascular Density Between Open Angle Glaucoma and Nonarteritic Anterior Ischemic Optic Neuropathy.

Purpose: To compare optical coherence tomography angiography (OCT-A) retinal vasculature measurements between nonarteritic anterior ischemic optic neuropathy (NAION) and open angle glaucoma (OAG) with altitudinal hemifield visual field defects.

Methods: This retrospective cross-sectional study included 10 NAION eyes and 16 OAG eyes, both demonstrating hemifield visual field defects, and 27 normal eyes serving as controls. The peripapillary and macular OCT-A scans were acquired. The retinal vessel density data were compared among NAION, glaucomatous, as well as control eyes.

Results: There was statistically significant difference in peripapillary whole image vessel density (wiVD), circumpapillary vessel density (cpVD), macular wiVD, and perifoveal vessel density (pfVD) between the three groups (P < 0.05 for all). In comparison between OAG and NAION groups, the NAION group demonstrated marked decrease in average cpVD (P = 0.008) and in most sectors of cpVD except the inferior one, while the OAG group demonstrated significant decreased macular wiVD and pfVD (P = 0.03 and 0.003, respectively). Multivariate analysis indicated that average thickness of retinal nerve fiber layer was the only predictor for peripapillary wiVD and cpVD (P = 0.005 for both). By contrast, thickness of ganglion cell complex was the only predictor for macular wiVD (P = 0.007).

Conclusions: OCT-A detected significant difference in peripapillary and macular retinal vessel densities between OAG and NAION eyes. These differences might provide comparative insight into the pathophysiology of these two diseases.