To report a case of suprasellar arachnoid cyst with compressive optic neuropathy.

A 50-year-old man presented with decreased visual acuity in the right eye of 6 months duration. Best corrected visual acuity was 0.2 in the right eye, 1.0 in the left eye, and the intraocular pressure was 13 mm Hg in the right eye, and 18 mm Hg in the left eye. Fundus examination showed pale optic disc in the right eye and retinal nerve fiber layer defects in both eyes. Visual field examination revealed a central visual field of 10° in the right eye and an inferior visual field defect in the left eye. The brain magnetic resonance image (MRI) showed a suprasellar arachnoid cyst that compressing the optic nerve and chiasm.

The author experienced arachnoid cyst accompanied by optic disc atrophy and visual field defect in a patient diagnosed and treated for glaucoma. In cases of non-specific clinical features that differ from typical glaucomatous presentations, the utilization of brain MRI appears to be helpful in diagnosis and treatment.