Abstract:AIM: To observe clinical effects and complications analysis of adjunctive mitomycin C(MMC)on photorefractive keratectomy(PRK)for myopia.
METHODS: In this retrospective study, 80 eyes of 40 patients were treated by PRK in 2009 as control group with the LaserSight SLX excimer laser. Eighty eyes of 40 patients were treated with 0.2g/L MMC 20s during PRK in 2010 as MMC group. Uncorrected visual acuity(UCVA), refraction, corneal epithelial healing, erosions, dry eyes, and haze were examined at 1 month, 3, 6 and 12 months postoperatively, and the 2 groups were compared and analyzed.
RESULTS: The differences between control and MMC group were not statistically significant in preoperative mean ages, UCVAs, best spectacle-corrected visual acuities, corneal depths, spherical equivalents(SEs), and laser ablation zones, depths, and times. During one year follow-up, the differences were also not in UCVAs, SEs, corneal epithelial healing, and dry eyes. But corneal erosions with filament keratitis were observed in 9 eyes in MMC group and 2 in control group, the difference was statistically significant(Pearson χ2=4.783, P=0.029). All the eyes were cured, and no recurrence occurred. The haze frequencies were 26%, 6%, 2%, 0 in MMC group at the 1 month, 3, 6, 12 months, and 44%, 25%, 10%, 2% in control group, respectively. The frequency differences were statistically significant at the 1 month(Pearson χ2=5.385, P=0.02)and 3(Pearson χ2=10.667, P= 0.001)months after surgery between the 2 groups.
CONCLUSION:Intraoperative MMC can reduce the haze frequency and grade after PRK for myopia. The effect of MMC on preserved corneal epithelium may be one of the reasons to happen corneal erosions after PRK. It is important to avoid 0.2g/L MMC exposure to corneal epithelium outside treatment zone.
