Effect of mitomycin-C on the corneal endothelium during excimer laser surface ablation

PURPOSE: To study the effects of mitomycin-C (MMC) on the corneal endothelium after surface ablation. METHODS: This prospective observer-masked study comprised 40 consecutive patients (80 eyes) scheduled to have laser-assisted subepithelial keratectomy (LASEK) to correct myopia. The patients were divided into 2 groups. Group 1 included 32 eyes in which the ablation depth was 50 mu m or less and that received no MMC. Group 2 included 48 eyes in which the ablation depth exceeded 50 Pm and were treated with intraoperative MMC 0.02% for 30 seconds over the ablated zone. Preoperatively and 3 months postoperatively, 3 photographs of the central cornea of each eye were obtained using specular microscopy. A masked observer evaluated the endothelial cell density and compared the results between groups and the preoperative versus the postoperative results within the same group. RESULTS: The mean patient age was 31.5 years +/- 4.6 (SD) in Group 1 and 33.2 +/- 7.9 years in Group 2 (P = .3). Within-group comparison between the preoperative and postoperative endothelial cell density values showed a statistically significant increase in both groups. The mean values in Group 1 were 2462.5 +/- 226.8 cells/mm(2) preoperatively and 2562.5 +/- 258.7 cells/mm(2) postoperatively (P = .0001). The means in Group 2 were 2466.6 +/- 294.1 cells/mm(2) and 2525 +/- 312.5 cells/mm(2), respectively (P=.0008). The differences in endothelial cell counts between Group 1 and Group 2 preoperatively and postoperatively were not statistically significant (P=.9 and P=.5, respectively). CONCLUSION: A single intraoperative application of MMC 0.02% for 30 seconds after laser surface ablation did not seem to cause a substantial change in corneal endothelial cell density.