Metabolic Alterations Within the Primary Visual Cortex in Early Open-angle Glaucoma Patients: A Proton Magnetic Resonance Spectroscopy Study

Purpose: To detect changes in metabolites and explore cortical plasticity at the metabolic level within the primary visual cortex through proton magnetic resonance spectroscopy in early open-angle glaucoma (OAG) patients. Methods: A total of 23 symmetrically bilateral early OAG patients and 21 normal controls (NC) were recruited as the early OAG group and NC group, respectively. All subjects underwent a proton magnetic resonance examination, and then, the N-acetylaspartate (NAA), glutamine-glutamate (Glx), myo-inositol (Ins), choline (Cho), and creatine (Cr) concentrations within the bilateral primary visual cortex were determined. The mean NAA/Cr ratio, mean Cho/Cr ratio, mean Glx/Cr ratio, and mean Ins/Cr ratio of the bilateral sides were compared between early OAG patients and NC using the independent samples t test. Results: Compared with NC, the mean Glx/Cr ratio (corrected P=0.003) in primary visual cortex was significantly higher, whereas the mean Ins/Cr ratio (corrected P=0.001) was statistically lower in early OAG patients. However, no apparent difference was found in the mean Cho/Cr ratio or mean NAA/Cr ratio between the OAG group and NC group. Conclusions: Abnormal metabolites were found in our study through proton magnetic resonance spectroscopy and could contribute to cortical plasticity of the primary visual cortex in early OAG patients.