Incidence and timing of recurrence of optic neuritis.

PURPOSE: To describe the incidence and timing of recurrence in patients with optic neuritis (ON). METHODS: Medical documents of adult patients with ON were retrospectively reviewed. The incidence and timing of recurrence of an ON episode were analyzed. RESULTS: One hundred eleven patients with ON were included in this study. Their mean follow-up duration was 4.1 ± 3.1 years. Seven relapses occurred after intravenous methylprednisolone treatment. The estimated cumulative incidence of recurrence in either eye was 26% at 1 year, 33% at 3 years, 37% at 5 years, and 50% at 10 years after the first episode of ON. If there was no recurrence until 6 months after the first episode of ON, the next 5-year recurrence-free survival probability was 67%. If there was no recurrence until 1 year, the next 5-year survival probability was 72%. If there was no recurrence until 2 years, the next 5-year survival probability was 81%. Relapse within 1 month and the presence of neuromyelitis optica-immunoglobulin G were factors that increased the recurrence rate over time. CONCLUSIONS: We evaluated the incidence and timing of the recurrence in patients with ON after the first episode. Lower probability of recurrence was observed in patients with longer recurrence-free follow-up period. However, monitoring for recurrence is needed even in patients with a single episode of ON due to the increasing tendency of the estimated cumulative incidence of recurrence over many years.