Stability of laser epithelial keratomileusis with and without mitomycin C performed to correct myopia in thin corneas:: A 15-month follow-up

PURPOSE: To study the stability of the refraction 15 months after myopic laser epithelial keratomileusis (LASEK) performed in thin corneas with and without adjuvant mitomycin C (MMC). DESIGN: Retrospective review. METHODS: One hundred and thirty-six consecutive eyes that had undergone LASEK to correct their myopia and that had a preoperative central corneal thickness (CCT) of <500 mu m at Vissum Madrid, Spain, were included. Intraoperative MMC was applied when the ablation depth exceeded 50 mu m (49 eyes). We compared the residual refraction between the three- and 15-month examinations to detect a possible myopic change that would suggest secondary corneal ectasia. RESULTS: Mean preoperative CCT +/- standard deviation (SD) was 484.4 +/- 11.8 mu m (range, 440 to 499 mu m). Mean CCT +/- SD three months after surgery was 417.9 +/- 32.1 lim (range, 339 to 473 mu m). Mean preoperative spherical refraction +/- SD was -3.49 +/- 2. 10 diopters (D). Mean preoperative cylinder +/- SD was -0.87 +/- 1.20 D. The mean residual sphere +/- SD was 0.15 +/- 0.40 D three months after surgery and 0.11 +/- 0.60 D 15 months after surgery (P = .45). The mean cylinder +/- SD was -0.13 +/- 0.30 D and -0.25 +/- 0.50 D, respectively (P = .06). Both the uncorrected visual acuity (UCVA) and the best-spectacle corrected visual acuity (BSCVA) showed statistically significant improvement on the 15-month examination (P = .01 and P = .0001, respectively). When analyzed separately, the subgroup treated with intraoperative MMC also showed stability of the refraction and a statistically significant improvement both in UCVA and in BSCVA. Topography showed no signs of ectasia in any case. CONCLUSIONS: Myopic LASEK performed on thin corneas, regardless of the use of intraoperative MMC, seems to obtain stable refractive results, with no sign of ectasia during a 15,month follow,up.