AIM:To evaluate the mitomycin-C(MMC)0.02% efficacy in preventing haze after trans-epithelial photorefractive keratectomy(Trans-PRK)in the treatment of the high myopia.

METHODS: Retrospective case series. Trans-PRK were performed on 142 eyes with a preoperative spherical equivalent. They were divided into with 0.02% MMC(MMC group)and without MMC(control)groups. In MMC group there were 94 eyes with MMC 0.02%; in control group there were 48 eyes. Patients were treated with an intraoperative application of MMC 0.02% for 30-45s depending on refractive error in MMC group. After surgery, fluorometholone 0.1% eye drops were used for 4mo in all groups. The mean follow-up time was 6mo. The regression trees were used to analyse the relationship between different related factors and haze.

RESULTS:Haze was quantified with Fantes. Incidence of haze was 8.5% eyes in MMC group and 33.3% in without MMC group(P=0.001). In the regression trees, optical zone and ablation depth MAX were related to haze(P<0.01). It was possibility induce haze when optical zone is ≤5.6mm. When optical zone is >5.6mm, ablation depth MAX becomes the main factor for haze.

CONCLUSION: The design of optical zone and ablation depth MAX in Trans-PRK should be considered for the treatment of the high myopia with thin cornea and abnormal corneal morphology. MMC 0.02% was effective in preventing haze after Trans-PRK in the treatment of the high myopia.