Effect of mitomycin-C on the variance in refractive outcomes after photorefractive keratectomy.

Purpose: To compare the variance in manifest refraction spherical equivalent (MRSE) after photorefractive keratectomy (PRK) with mitomycin-C (MMC), PRK without MMC, and laser in situ keratomileusis (LASIK) for the treatment of myopic astigmatism.

Setting: Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, California, USA.

Design: Retrospective case series.

Methods: Patients were classified into 3 groups of preoperative refraction-matched eyes as follows: PRK with MMC 0.02%, PRK without MMC, and LASIK. The preoperative and postoperative MRSE, preoperative corrected distance visual acuity, and postoperative uncorrected distance visual acuity (UDVA) were analyzed.

Results: Each group comprised 30 eyes. Follow-up was at least 6 months in the LASIK group and 12 months in the 2 PRK groups. There were no statistically significant differences in the mean preoperative MRSE (P=.95) or postoperative MRSE (P=.06) between the 3 groups. The mean postoperative MRSE was -0.07 diopter (D) ± 0.47 (SD), -0.14 ± 0.26 D, and 0.02 ± 0.25 D in the PRK with MMC 0.02% group, PRK without MMC group, and LASIK group, respectively. The variance in the postoperative MRSE in the PRK with MMC 0.02% group was significantly higher than that in the PRK without MMC group (P=.002) and in the LASIK group (P=.001). There was no statistically significant difference in the mean postoperative UDVA between the 3 groups (P=.47).

Conclusions: Refractive outcomes after PRK for myopia were more variable when MMC 0.02% was used. This should be weighed against the advantage of intraoperative MMC use in reducing haze after PRK.