Retinotopic Changes in the Gray Matter Volume and Cerebral Blood Flow in the Primary Visual Cortex of Patients With Primary Open-Angle Glaucoma

To assess the cortical structure and cerebral blood flow changes in the brain of patients with primary open-angle glaucoma (POAG). High-resolution anatomical magnetic resonance imaging (MRI) and arterial spin labeling (ASL)-MRI were performed in 23 POAG patients and 29 controls. Patients were further divided into early-moderate and advanced groups based on mean deviation (MD) cutoff of 12 dB. A baseline scan was obtained and repeated during visual stimulation to the central preserved visual field in the more affected eye of POAG patients and a randomly selected eye of controls. Gray matter volume (GMV) and cerebral blood flow (CBF) throughout the whole brain were compared between patients and controls. Compared to controls, a region with significant reduction of GMV was detected in the anterior calcarine fissure of advanced POAG patients (P < 0.001, voxels = 503, 1698 mm3). Patients with early-moderate POAG had resting CBF similar to that of controls. However, a region with marked CBF decrease was detected in the anterior calcarine fissure of advanced POAG patients (P < 0.001, voxels = 1687, 13,496 mm3). The region with CBF reduction in advanced POAG showed good colocalization with the region with GMV decrease in this group. Following visual stimulation, patients with advanced POAG showed significantly lower increase in CBF in the occipital lobes (P < 0.001, voxels = 112, 896 mm3) as compared to controls (P < 0.001, voxels = 1880, 15,040 mm3) and early-moderate POAG (P < 0.001, voxels = 2233, 17,864 mm3). Primary open-angle glaucoma patients demonstrate a disease severity-dependent retinotopic pattern of cortical atrophy and CBF abnormalities in the visual cortex. Cerebral blood flow may be a potential biomarker for the brain involvement in glaucoma.