Optic perineuritis with anti-myelin oligodendrocyte glycoprotein antibody.

A 25-year-old male presented with blurred peripheral vision and movement pain in his right eye. Fundus examination revealed unilateral disc swelling in his right eye with normal intracranial pressure. MRI showed remarkably high intensity in the optic nerve sheath and slightly high intensity in the optic nerve, indicating optic perineuritis (OPN). Anti-myelin oligodendrocyte glycoprotein (MOG) antibody was positive in both serum and cerebrospinal fluid. The patient responded promptly to corticosteroid treatment. OPN can be associated with the presence of anti-MOG antibody.