Association of relapses with visual outcomes in optic neuritis: a post hoc analysis of the optic neuritis treatment trial

Objective: To examine whether the number of relapses is associated with visual outcomes in patients with optic neuritis.

Design: A post hoc analysis using data from the Optic Neuritis Treatment Trial, a multicenter randomized controlled trial conducted to explore the efficacy of corticosteroids on optic neuritis.

Methods: Multivariate linear mixed effect models were used to estimate the associations of the number of ipsilateral relapses in the baseline affected eye with visual outcomes. The modeling accounted for the number of ipsilateral relapses and adjusted for time to follow-up visit, baseline visual function, treatment groups, the number of contralateral relapses, the interaction between the number of relapses and time to follow-up, as well as demographic covariates of age, sex, race/ethnicity.

Results: Among the 449 included patients, 71 (15.8%) had one ipsilateral relapse, and 24 (5.3%) had ≥2 ipsilateral relapses. The mean age of the patients was 31.9 years, with 345 (76.8%) females and 384 (85.5%) Whites. The median follow-up time was 15.9 years. In the adjusted mixed model, higher number of ipsilateral relapses was associated with poorer visual outcomes, including visual acuity (mean difference [MD], 0.20 logarithm of the minimal angle of resolution unit; 95% confidence interval [CI], 0.15 to 0.25 for ≥2 vs no ipsilateral relapse), contrast sensitivity (MD, -1.14 lines; 95% CI, -1.54 to -0.73 for ≥2 vs no ipsilateral relapse), visual field mean deviation (MD, -3.57 decibels; 95% CI, -4.38 to -2.76 for ≥2 vs no ipsilateral relapse), and color vision (MD, 1.94 error scores; 95% CI, 0.74 to 3.14 for ≥2 vs no ipsilateral relapse).

Conclusions: Increasing number of relapses was associated with worse visual outcomes. More aggressive management following an initial episode is imperative to prevent relapse.