Reduced brain subcortical volumes in patients with glaucoma: a pilot neuroimaging study using the region-of-interest-based approach.

BACKGROUND: While numerous neuroimaging studies have demonstrated that glaucoma is associated with smaller volumes of the visual cortices in the brain, only a few studies have linked glaucoma with brain structures beyond the visual cortices. Therefore, the objective of this study was to compare brain imaging markers and neuropsychological performance between individuals with and without glaucoma. METHODS: We identified 64 individuals with glaucoma and randomly selected 128 age-, sex-, and education level-matched individuals without glaucoma from a community-based cohort. The study participants underwent 3 T brain magnetic resonance imaging and neuropsychological assessment battery. Regional cortical thickness and subcortical volume were estimated from the brain images of the participants. We used a linear mixed model after adjusting for potential confounding variables. RESULTS: Cortical thickness in the occipital lobe was significantly smaller in individuals with glaucoma than in the matched individuals (ß = - 0.04 mm, P = 0.014). This did not remain significant after adjusting for cardiovascular risk factors (ß = - 0.02 mm, P = 0.67). Individuals with glaucoma had smaller volumes of the thalamus (ß = - 212.8 mm3, P = 0.028), caudate (ß = - 170.0 mm3, P = 0.029), putamen (ß = - 151.4 mm3, P = 0.051), pallidum (ß = - 103.6 mm3, P = 0.007), hippocampus (ß = - 141.4 mm3, P = 0.026), and amygdala (ß = - 87.9 mm3, P = 0.018) compared with those without glaucoma. Among neuropsychological battery tests, only the Stroop color reading test  score was significantly lower in individuals with glaucoma compared with those without glaucoma (ß = - 0.44, P = 0.038). CONCLUSIONS: We found that glaucoma was associated with smaller volumes of the thalamus, caudate, putamen, pallidum, amygdala, and hippocampus.