METHODS: Using “vitamin C” and “corneal ulcer” as keywords, the randomized controlled trials(RCT)of subconjunctival injection of vitamin C in Embase, Cochrane library, Pubmed, CNKI and Wanfang database in the treatment of corneal ulcer was searched. Relevant reference published before February 2021. The risk bias tool provided by the Cochrane cooperation scale was used to assess the risk bias of included studies of RCTs. The publication bias of the included studies were assessed by the Egger's test with Stata software. Meta-analysis was performed with RevMan 5.3.

RESULTS: A total of 32 eligible articles were included, all of which were Chinese literatures, with a total of 4 514 patients. The control group was treated with routine treatment, and the experimental group was treated with subconjunctival injection of vitamin C combined with routine treatment. The Meta-analysis showed that the experimental group was better than control group(OR=4.61, 95%CI:3.70, 5.74). The recurrence rate was lower than control group(OR=0.24, 95%CI: 0.18, 0.31). The cure time in experimental group was shorter than control group(MD= -6.29, 95%CI: -7.08, -5.51), 32 studies do not adequately report adverse drug reactions(ADR). Egger's test was performed on the total effective rate, recurrence rate and cure time. The results showed that there was publication bias in the total effective rate and cure time. Trim and fill method showed that the publication bias did not affect the results.

CONCLUSION: Subconjunctival injection of vitamin C is feasible in the treatment of corneal ulcer. The clinical effect, cure time and recurrence rate were better than routine treatment. However, due to the low intensity of the included research evidence, more multicenter, randomized double-blind clinical trials are needed to improve the evidence intensity of vitamin C in the treatment of corneal ulcer.