Retrobulbar Optic Neuritis after COVID-19 Infection

Purpose: To report a case of retrobulbar optic neuritis after COVID-19 infection.Case summary: A 20-year-old Korean man, without any previous relevant medical history, presented with sudden blurred vision in the left eye that began 6 days after a COVID-19 infection. At his initial visit, the best-corrected visual acuity in the left eye was counting fingers at 30 cm. The pupil showed a grade 2 relative afferent pupillary defect. The fundus exam was normal in both eyes. In the visual evoked potential (VEP) exam, the P100 amplitude of the left eye was decreased and delayed. Orbit magnetic resonance imaging showed asymmetric enlargement and mild enhancement in the left optic nerve. No other lesions were observed around the optic nerve. Steroid pulse therapy was started after a diagnosis of retrobulbar optic neuritis. After 1 month, the patient’s visual acuity had improved to 1.0 in the left eye. The relative afferent pupillary defect and visual field defect disappeared. On VEP, the P100 amplitude recovered, and the delay disappeared.Conclusions: Retrobulbar optic neuritis is a possible neuro-ophthalmological complication of COVID-19 infection. In such cases, high-dose steroid pulse therapy may be helpful, as in the treatment of other forms of optic neuritis.