RESUMO
This study aimed to compare two doses of Mitomycin C in reducing haze formation after photorefractive keratectomy. 170 eyes of 85 patients enrolled; in each patient one eye randomly assigned to be treated by low dose intraoperative MMC [LDMMC] and other eye by standard dose MMC [SDMMC]. Then the patients were followed up to 6 months and refraction, Uncorrected Distant Visual Acuity [UCDVA], Best Corrected Distant Visual Acuity [BCDVA] and haze formation submitted in each postoperative exam. The mean preoperative refraction in LDMMC eyes was -3.08 [SD 1.65] sphere and 0.92 [SD 0.88] cylinder. These values for SDMMC eyes were -3.25 [SD 1.80] sphere and 0.81 [SD 0.84] cylinder. Mean postoperative sphere in LDMMC group was -0.132 [SD 0.503] and -0.138 [SD 0.484] in 3 and 6 months after PRK. These results was -0.041 [SD 0.501] and -0.076 [SD 0.489] for SDMMC group. Mean postoperative cylinder 3 and 6 month after PRK was 0.435 [SD 0.218] and 0.423 [SD 0.255]. In LDMMC group and 0.435 [SD 0.247] and 0.426 [SD 0.261] in SDMMC group. In third month 14 eyes in LDMMC group presented with grade 1 score of clinical haze. From these eyes only 2 still had this haze after 6 month. 7 eyes in SDMMC group had grade 1 clinical haze at third month. but no clinical haze was seen at the end of 6[th] month. The results of the two doses of Mitomycin C were not significant. We suggest to use the lower dose to reduce its side effects