Association of Individual-Level Factors With Visual Outcomes in Optic Neuritis: Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE: Using corticosteroids to treat acute demyelinating optic neuritis has been identified as an area for shared decision-making. However, no analysis exists to support personalized shared decision-making that considers long- and short-term treatment benefits. OBJECTIVE: To develop models of individual-level visual outcomes for patients with optic neuritis. DESIGN, SETTING, AND PARTICIPANTS: This secondary analysis of the Optic Neuritis Treatment Trial (ONTT), a randomized clinical trial, was performed at 14 academic eye centers and 1 large community eye center. Adults aged 18 to 46 years with incident acute unilateral optic neuritis within 8 days of vision loss onset were included. Data were collected from July 1988 to June 1991, downloaded on October 15, 2018, and analyzed from January 24, 2019, to February 20, 2020, using multivariable linear regression modeling. EXPOSURES: Intravenous corticosteroids vs placebo. MAIN OUTCOMES AND MEASURES: Visual acuity (VA) at 1 year. Secondary outcomes were 1-year contrast sensitivity (CS) and VA and CS at 15 and 30 days. Independent variables included age, sex, race, multiple sclerosis status, optic neuritis episodes in the fellow eye, vision symptoms (days), pain, optic disc swelling, viral illness, treatment group, and baseline VA or CS. RESULTS: Of the 455 participants, median age was 31.8 (interquartile range [IQR], 26.3-37.0) years; 350 (76.9%) were women; and 388 (85.3%) were white. For 410 participants (90.1%) with 1-year outcomes, median VA improved from 20/66 (IQR, 20/28-20/630) at enrollment to 20/17 (IQR, 20/14-20/21) at 1 year. Baseline VA was the primary variable associated with 1-year VA (regression coefficient, 0.056 [95% CI, 0.008-0.103]; P = .02) if baseline VA was better than count fingers (CF). At 15 days, baseline VA and treatment status were associated with VA in those participants with baseline VA better than CF (regression coefficient, 0.305 [95% CI, 0.231-0.380]; F = 9.42; P < .001). However, the difference of medians (20/18 [95% CI, 20/17-20/19] with intravenous corticosteroids vs 20/23 [95% CI, 20/21-20/26] with placebo) was small for the median VA (20/66) in the trial. Treatment was not associated with 15-day or 1-year VA in participants with baseline VA of CF or worse. CONCLUSIONS AND RELEVANCE: In this study, long-term VA was associated with severity of baseline vision loss. Early benefits with intravenous corticosteroid treatment were limited to participants with baseline VA better than CF. However, the early, temporary benefit of intravenous corticosteroids is of questionable clinical significance and should be weighed against potential harms.