Comparison of Standard and Low Dose Mitomycin C in the Prevention of Corneal Haze following Photorefractive Keratectomy

Purpose: Although applying mitomycin C (MMC) during photorefractive keratectomy (PRK) has shown to reduce postoperative corneal haze but there is considerable evidence of MMC toxicity in the literature and concerns exist regarding side effects and long-term complications. We conducted this study to compare the efficacy of MMC 0.02% and 0.01% in prevention of haze after PRK. Methods: 210 eyes were included in an interventional prospective comparative study. Both eyes of each patient were enrolled in this study. After laser ablation, MMC 0.02% (standard) were applied to right eyes of patients while the concentration was 0.01% (Low dose) for left eyes. Duration of MMC exposure was up to 40 seconds. Patients were followed on days 1 and 5 and 1, 3, 6 months after surgery and examined for refraction, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA) and corneal haze. Results: Ablation depth was 60-120 microns in all patients. One month after PRK, mean UCVAs were 0.06 and 0.04 and mean BCVAs were 0.02 and 0.01 in right and left eyes respectively. In the second follow-up visit performed 6 month after surgery mean UCVAs were 0.05 and 0.04 and mean BCVAs were 0.01 and 0.01 in right and left eye respectively. One month after PRK, 13 right eyes and 8 left eyes had grade 1+ and 2+ of haziness, while 6 months after surgery no haze were detected. Conclusion: Our data suggest that low dose (0.01%) MMC (LDMMC) can be as effective as standard dose (0.02%) MMC (SDMMC) in prevention of corneal haze after PRK, while reducing the side effects and future complications.