Comparative features of superior versus inferior hemisphere microvasculature dropout in open-angle glaucoma

Purpose This study aimed to investigate differences in microvasculature dropout (MvD) between the superior and inferior hemispheres in glaucoma patients.Study design Retrospective and cross-sectional.Methods Fifty-eight eyes of 58 open-angle glaucoma patients (age 61.12 +/- 10.19 years, mean deviation - 7.32 +/- 6.36 dB) were included. MvD was detected with en face images from swept-source optical coherence tomography angiography. Blood flow at the optic nerve head was measured with laser speckle flowgraphy, represented as the mean blur rate in tissue (MBRT). Logistic and linear regression models adjusted for age, intraocular pressure, axial length, and circumpapillary retinal nerve fiber layer thickness were used to investigate the relationship between various factors and MvD angle in each hemisphere.Results The presence of inferior MvD was related to peripapillary atrophy-beta area (odds ratio = 14.10 [2.49-234.00], P = 0.019). Superior MvD angle was significantly related to MBRT in the superior quadrant (beta = -0.31 [- 0.60 - -0.02], P = 0.037). Inferior MvD angle was significantly related to peripapillary atrophy-beta area (beta = 0.49 [0.21-0.77], P = 0.001).Conclusions Only superior MvD demonstrated a significant relationship with reduced ocular blood flow. In contrast, inferior MvD was associated with mechanical stress. These findings may suggest a potential difference in pathophysiology between superior and inferior MvD.