To define the time course of visual recovery after optic neuritis and factors predictive of this course in the patients enrolled in the Optic Neuritis Treatment Trial.The cohort for this study consisted of the 438 patients who completed the 6-month follow-up visit. Visual acuity was measured at baseline and at seven follow-up visits during the first 6 months. Factors predictive of recovery were evaluated with univariate and multivariate statistical tests.Visual recovery was rapid in all three treatment groups. In almost all patients, regardless of treatment group and initial severity of visual loss, improvement began within the first month. Among the 278 patients with baseline visual acuity of 20/50 or worse, all patients improved at least one line of visual acuity, and all except six improved at least three lines, during the 6-month follow-up period. Baseline visual acuity was the best predictor of the 6-month visual acuity outcome (P = 0.0001). Older age was statistically associated with a slightly worse outcome (P = 0.02), but this appeared to be of no clinical importance.In most patients with optic neuritis, visual recovery is rapid. The only factor of value in predicting the visual outcome is initial severity of visual loss. However, even when initial loss is severe, visual recovery is still good in most patients. Patients not following the usual course of visual recovery should be considered atypical. For such patients, further investigation in regard to etiology of the visual loss may be appropriate.