A Case of Myelin Oligodendrocyte Glycoprotein Antibody-Positive Optic Neuritis

Purpose: To report a case of optic neuritis associated with myelin oligodendrocyte glycoprotein (MOG) antibodies, treated with intravenous methylprednisolone pulse therapy.Case summary: A 40-year-old male patient with no underlying disease presented to clinic with sudden onset of bilateral blurry vision that began three days ago. He experienced severe headache and had history of bilateral refractive surgery. Best-corrected visual acuity measured right 0.06 and left 0.04. Relative afferent pupillary defect test was unremarkable, while Ishihara color vision test revealed inability to read any numbers in both eyes, except control plates. Although there were no limitations in extraocular movements, the patient reported pain in both eyes for all gaze movements. Widefield photograph and retinal nerve fiber layer image confirmed swelling of optic nerve head in both eyes. He was treated with high-dose intravenous methylprednisolone (1 g/day for 3 days). Magnetic resonance imaging demonstrated enhancement of the optic nerve sheaths in both eyes, and serum testing indicated positivity for MOG IgG antibodies. Three weeks later, visual acuity in both eyes improved to 1.0, and the color vision test showed correct identification of all 17 plates. Optic nerve head swelling in both eyes had resolved. However, optic neuritis recurred at 4, 6 weeks, and 3 months after the initial treatment, with each episode managed by high-dose intravenous methylprednisolone.Conclusions: This case shows early diagnosis and treatment of MOG antibody-associated optic neuritis can lead to improved visual outcomes. Appropriate serum testing for the diagnosis may be effective in patients with MOG antibody-associated optic neuritis.