Mitomycin C Application After Corneal Cross-Linking For Keratoconus Increases Stromal Haze

PURPOSE: To evaluate and compare corneal haze as determined by optical coherence tomography (OCT) after corneal cross-linking (CXL) for the treatment of mild to moderate keratoconus with or without mitomycin C (MMC) application.METHODS: This was a retrospective analysis of 87 eyes of 72 patients with mild to moderate keratoconus. The first group (n = 44 eyes) underwent CXL between June 2013 and January 2015 and the second group (n = 43 eyes) underwent CXL with MMC (CXL+MMC) between February and December 2015, both following the Dresden protocol. Patients were evaluated preoperatively and at 1, 3, 6, and 12 months postoperatively. Main outcome measures were corneal reflectivity and haze reflectivity measured by a specially developed OCT image analysis software.RESULTS: Anterior corneal reflectivity at 1 month and 1 year postoperatively was 14.79 +/- 4.68 and 25.97 +/- 15.01 (P < .001), and 13.88 +/- 4.39 and 18.41 +/- 9.25 (P = .025) for the CXL and CXL+M MC groups, respectively. The reflectivity of the anterior stromat haze region at 1 month and 1 year postoperatively was 23.15 +/- 5.91 and 33.14 +/- 16.58 (P = .005), and 20.58 +/- 7.88 and 27.14 +/- 12.80 (P = .049) for both groups, respectively. The changes in simulated keratometry from preoperatively to postoperatively were similar in both groups. The CXL+MMC group showed larger maximum keratometry flattening: 53.41 +/- 6.88 diopters (D) preoperatively and 49.44 +/- 5.66 D 1 year postoperatively versus 52.27 +/- 5.78 and 50.91 +/- 4.25 D for CXL alone (P = .008).CONCLUSIONS: MMC application following CXL significantly increases corneal haze. Similar studies need to be performed on simultaneous CXL and photorefractive keratectomy to evaluate the role of MMC in haze formation in such procedures.