Mitomycin C reduces corneal light scattering after excimer keratectomy

Purpose, To evaluate the effect of intraoperative mitomycin C (MMC) on corn eal light scattering after excimer laser keratectomy. Methods, Phototherape utic keratectomy (PTK) was performed in 24 rabbit eyes. After 40-mum epithe lial ablation, animals were divided into three groups. In group 1, filter p aper discs soaked with MMC (group 1A, 0.5 mg/mL; group 1B, 0.25 mg/ml) were applied for 1 minute. In group 2, annular filter papers soaked with MMC (g roup 2A, 0.5 mg/mL; group 2B, 0.25 mg/mL) were applied for I minute. Contro ls received vehicle only (group 3). Six-millimeter diameter 100-mum deep PT K was performed. Corneal light scattering was measured weekly from 1 to 6 w eeks, at 10 weeks, and at 8 and 13 months using a scatterometer. A corneal light scattering index (SI) ranging from 0 to 10 was calculated; SI of 1 re presents normal scattering. Results. A statistically significant decrease i n mean SI was noted in group 2A (annular MMC 0.5 mg/mL; p < 0.05) as compar ed with the control group at 2 weeks. At 10 weeks, SI approached baseline l evels in group 2 and the control group but showed significant increase in g roup 1 (MMC disc; p < 0.05). At 8 and 13 months, SI showed no statistical d ifferences between groups. Conclusions. Controlled application of 0.5 mg/mL MMC in the corneal midperiphery transiently reduces corneal light scatteri ng after excimer keratectomy in this rabbit model.