Incidence and timing of recurrence of optic neuritis.

To describe the incidence and timing of recurrence in patients with optic neuritis (ON). Medical documents of adult patients with ON were retrospectively reviewed. The incidence and timing of recurrence of an ON episode were analyzed. 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. 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.