Aim The aim of this study was to show if primary open-angle glaucoma (POAG) is associated with structural neurodegenerative changes along the visual pathway.Patients and methods The patients included in the study were divided into two groups: group 1 (200 patients having POAG) and group 2 (200 patients having no POAG as a control group). Brain MRI was done to evaluate the structural changes in the visual pathway.Results MRI brain showed that patients in group 1 have significantly lower optic nerve cross-sectional area (14±2.3 mm2) compared with group 2 (35±3.1 mm2) (P=0.012), and significantly lower lateral geniculate nucleus volume (58.4±4.7 mm3 in group 1 compared with 89.2±5.9 mm3 in group 2, P=0.009).Conclusion The pathology in POAG extended beyond the globe to involve the optic nerve cross-sectional area, and the lateral geniculate nucleus volume was significantly lower in patients with POAG. Such changes can be precisely detected with MRI. So, MRI can be considered as a tool for diagnosis and follow-up of patients with POAG.