Role of cysteine in corneal wound healing after photorefractive keratectomy

AIMS: To evaluate the efficacy of cysteine oral supplements in corneal wound healing after photorefractive keratectomy (PRK). METHODS: A total of 200 eyes (100 patients) underwent PRK. We divided patients into 2 groups; each group was composed of 50 patients (100 eyes). Group 1 patients were assigned to use oral L-cysteine, with a daily dose of 200 mg (100-mg pills to be taken twice a day) for a duration of 14 days, starting from the week preceding the operation; the patients in group 2 were used as a control, and received the oral supplementation of 40-mg placebo pills to be taken twice a day for a duration of 14 days, starting from the week preceding the operation. RESULTS: All the eyes of patients treated with cysteine oral supplements showed shorter times to re-epithelization than the eyes of the control group. The mean time of corneal wound healing observed in group 1 was 102 +/- 15 h, compared to an average of 159 +/- 9 h in group 2. CONCLUSION: Our research showed that oral cysteine supplementation, in a daily dose of 200 mg, reduces mean corneal wound healing time in patients after PRK.