Parafoveal vessel changes in primary open-angle glaucoma and normal-tension glaucoma using optical coherence tomography angiography

PURPOSE: To evaluate parafoveal and peripapillary perfusion in healthy, glaucoma suspect, normal-tension glaucoma, and primary open-angle glaucoma subjects. PATIENTS AND METHODS: This was a retrospective cross-sectional study with optical coherence tomography angiography imaging with RTVue XR Avanti (Optovue, Inc., Fremont, CA) of 56 eyes (14 healthy, 14 glaucoma suspect, 16 normal-tension glaucoma, and 12 primary open-angle glaucoma) at a tertiary academic referral center. Parafoveal and peripapillary superficial vessel density and parafoveal superficial retinal thickness were the main parameters of interest. Area under receiver operating characteristic curves were calculated. RESULTS: There were significant decreases in parafoveal superficial vessel density in primary open-angle (40.06±4.54%, P<0.001) and normal-tension glaucoma (42.82±5.16%, P=0.010) but not suspect eyes (45.72±4.37%, P=0.916) compared to healthy eyes (48.10±2.82%). Similarly, decreases were observed in parafoveal inner retinal thickness in primary open-angle (83.19±14.29 μm, P<0.001) and normal-tension glaucoma eyes (94.97±12.44 μm, P=0.035), but not suspect eyes (99.93±9.00 μm, P=0.648), compared to healthy controls (107.00±9.55 μm). Only primary open-angle glaucoma eyes displayed significant changes in peripapillary vessel density (37.63±7.19%) compared to healthy controls (49.12±2.80%, P<0.001). Further statistical adjustment for sex and age revealed a significant decrease in parafoveal vessel density in suspects relative to controls (P=0.039). Diagnostic accuracy of parafoveal vessel density was high with an area under the curve of 0.833±0.073 for normal-tension glaucoma and 0.946±0.049 for primary open-angle glaucoma. CONCLUSION: Parafoveal vessel density was significantly reduced in glaucomatous eyes, with good diagnostic accuracy. These findings provide further evidence that these changes may be useful in the diagnosis and monitoring of disease in glaucoma patients.