Vitamin supplementation in the treatment of optic neuritis: A systematic review and meta-analysis.

OBJECTIVE: Previous research has demonstrated an association between vitamin D deficiency and the risk of developing optic neuritis (ON) and multiple sclerosis (MS). However, the role of vitamin supplementation as an intervention for ON has not been thoroughly investigated. This systematic review and meta-analysis assesses whether vitamin supplementation improves visual parameters and disease status among ON patients. RESULTS: A systematic literature search within PubMed, Embase, Web of Science, and the Cochrane Central Register of Clinical Trials yielded a total of 2465 peer-reviewed articles, from which 5 studies met inclusion criteria. The effect of MD1003 (high-dose biotin), vitamin A, and vitamin D on retinal nerve fiber layer (RNFL) thickness from pooled results showed a mean change of 0.15 (SMD 0.15, 95 % CI, -0.33 to 0.64, I2 = 61 %, τ² = 0.11, p = 0.08), which was not significant. Meta-analysis of visual acuity due to MD1003 and vitamin A from two studies showed a mean change of 0.01 (SMD 0.01, 95 % CI, -0.34 to 0.35, I2 = 0 %, τ² = 0, p = 0.36). Significant improvements in RNFL thickness due to vitamin A, visual acuity due to vitamins B1, B6, and B12, foveal sensitivity due to vitamins B1, B6, and B12, and the rate of conversion of ON to MS due to vitamin D were observed in individual studies. CONCLUSIONS: Although meta-analysis showed no significant effect of vitamins A, B1, B6, B7, B12, and D on several visual parameters, improvements observed in individual studies point to the essential role of vitamin sufficiency in ON. Due to the limited available evidence, additional high-quality studies are needed to determine the efficacy of vitamin supplementation as a potential therapeutic for ON. LEVEL OF EVIDENCE: N/A.