Purpose: To evaluate the effect of intraoperative use of mitomycin-C (MMC) on the corneal endothelium during excimer laser photorefractive keratectomy (PRK).
Setting: Vanak Eye Surgery Center, Tehran, Iran.
Methods: This nonrandomized trial comprised 81 patients (162 eyes) with bilateral low to moderate myopia and adequate corneal thickness to allow PRK (estimated postoperative residual stromal thickness >350 microm without considering epithelial thickness). The indication for intraoperative application of MMC 0.02% (0.2 mg/mL) was an ablation depth of 75 microm or more. Patients were divided into 3 groups: bilateral (both eyes treated with MMC), unilateral (only 1 eye treated with MMC), and untreated (no eye treated with MMC). Visual acuity, refraction, endothelial cell density (ECD), and corneal thickness were measured preoperatively as well as 1 week and 1, 3, and 6 months postoperatively.
Results: Overall, 76 eyes were treated with MMC. Eyes treated with MMC and untreated eyes were comparable in postoperative visual acuity and refraction. Preoperative to postoperative changes in ECD were statistically significantly greater in the treated eyes (-14.8%) than in untreated eyes (-5.1%) 6 months after PRK (P<.001). Longer MMC contact time (P<.001) and male sex (P= .04) were the only factors independently associated with greater endothelial cell loss.
Conclusions: The prophylactic use of diluted intraoperative MMC 0.02% solution caused corneal endothelial cell loss. The rate of cell loss was correlated with the duration of MMC exposure.