Association between time from symptom onset to initial treatment on visual acuity outcomes among immune-mediated optic neuritis patients: a retrospective cohort study

This study aimed to evaluate the association between time from symptom onset to initial intravenous methylprednisolone (IVMP) treatment and 3-month best-corrected visual acuity (BCVA) and to explore a clinically relevant treatment window associated with visual recovery. This retrospective single-center cohort study included patients with immune-mediated optic neuritis of various etiologies. Outcomes were 3-month BCVA (continuous) and a binary visual recovery outcome defined as failure to regain a VA of 20/32 (0.204 logMAR). Both were analyzed for time from symptom onset to initial IVMP treatment, categorized as ≤ 7 days, 8–10 days, or > 10 days. A total of 66 patients with definite and possible optic neuritis confirmed by neuro-ophthalmologists were included. The most common etiologies were idiopathic (54%), followed by NMOSD (24%), MOGAD (11%) and MS (6%). At 3 months post-treatment, median BCVA was 0.14, 0.12, and 0.71 logMAR in the ≤ 7-day, 8–10-day, and > 10-day groups, respectively ( P = 0.03). Compared to patients treated within 7 days, the mean difference in BCVA (logMAR) was 0.15 (95% confidence interval [CI]: -0.27 to 0.58, P = 0.5) for the 8–10-day group and 0.52 (95% CI: 0.16–0.87, P = 0.005) for the > 10-day group. The odds of failing to regain a logMAR of 0.204 were 1.92 (95% CI: 0.45–8.52, P = 0.4) and 4.35 (95% CI: 1.28 − 16.7, P = 0.023) for the 8–10-day and > 10-day groups, respectively. Initial treatment > 10 days post-symptom onset was associated with significantly worse visual outcomes than that via earlier treatment. Mean VA change or likelihood of failing to regain BCVA ≤ 20/32 did not differ significantly between treatment within 7 days and that 8–10 days post-symptom onset. Prompt initiation of treatment remains critical, and this finding should not be interpreted as evidence that treatment can safely be delayed to day 10.