Effects of differenta mitomycin C concentrations on laser-assisted subepithelial keratectomy.

The aim of the present study was to determine the effect of different concentrations of mitomycin C (MMC) administered intraoperatively during laser-assisted subepithelial keratectomy (LASEK) surgery. A total of 261 patients (496 eyes) were randomly divided into two groups: 0.04% MMC treatment group consisting of 133 patients (245 eyes) and the 0.02% MMC treatment group consisting of 128 patients (251 eyes). The MMC solutions were dropped intraoperatively onto the ablation region and the duration was dependent on the preoperative refractive power of the patient's cornea: ≤-3.00 diopters (D), 30 sec; between -3.25 D and -6.00 D, 60 sec; between -6.25 D and -9.00 D, 90 sec and ≥-9.25 D, 110 sec. Postoperative observations included haze formation, visual acuity, changes in refractive power, corneal endothelial cell density and incidence of complications. The one year postoperative incidence of haze differed significantly between the groups (P<0.05). The one week and one year comparisons of postoperative visual acuity also differed significantly between the groups (P<0.05). Postoperative changes in corneal refractive power at one, six and 12 months following surgery significantly differed between the groups (P<0.05). No statistically significant difference was identified between the density of corneal endothelial cells prior to surgery and the density at one, six and 12 months following surgery (P>0.05). Thus, the intraoperative application of 0.04% MMC solution effectively inhibited haze formation and markedly improved the efficacy of LASEK surgery, when compared with that of 0.02% MMC.