To evaluate the safety and efficacy of photorefractive keratectomy (PRK) with intraoperative mitomycin C (MMC) after deep anterior lamellar keratoplasty (DALK) for keratoconus.
This was a prospective, noncomparative single-surgeon study. Eyes with compound myopic astigmatism after DALK with a spherical equivalent (SE) between −3 and −10 D were treated by PRK. After ablation, MMC 0.2 mg/mL was placed on the stromal bed for 45 seconds. A 6% undercorrection was planned.
The study was completed on 10 eyes of 10 patients. The preoperative mean SE was −4.98 ± 1.75 (SD) D. At 10 months after surgery, the mean SE was 0.28 ± 0.61 D, and the mean defocus equivalent was 1.08 ± 0.58 D. Postoperatively, 9 eyes were within 2 D, 6 were within 1 D, and 1 eye was within 0.5 D of defocus equivalent. The preoperative mean best spectacle-corrected visual acuity (BSCVA) was 0.68 ± 0.15 D, and at 10 months it was 0.78 ± 0.13 D. The 95% confidence interval for the mean difference of pre- and postoperative BSCVA was 0.02-0.17 (P < 0.05). No lines of BSCVA were lost. The mean postoperative uncorrected visual acuity was 0.55 ± 0.1. The safety index was 1.15, and the efficacy index was 0.81. Corneal haze was grade 0 in 8 eyes and grade 0.5 in 2 eyes. Mean epithelialization time was 4.1 ± 0.99 days. Preoperative mean endothelial cell density was 2320 ± 184 cells/mm2, and at 10 months it was 2284 ± 175 cells/mm2.
PRK with MMC can safely and effectively correct myopia and regular myopic astigmatism after DALK. Undercorrection should be planned to compensate for the overcorrecting effect of MMC.