Purpose: To evaluate the safety of photorefractive keratectomy (PRK) with mitomycin-C (MMC) in eyes with hyperopia after radial keratotomy.
Methods: Sixty eyes of 36 consecutive patients treated with corneal wavefront-guided PRK using an Esiris-Schwind excimer laser were prospectively evaluated. Corneal epithelium was mechanically removed, followed by photoablation and use of 0.02% MMC for 20 or 40 seconds. In 16 eyes (26.7%), MMC was applied for 40 seconds. These eyes underwent ablations deeper than 100 micron or had previous corneal sutures. Patients were followed up for 12 months.
Results: The mean spherical equivalent (SE) before PRK was +4.27 D +/- 2.18, and the mean best corrected visual acuity (BCVA) was 0.174 +/- 0.139 (logMAR). The planned laser SE correction was +4.74 D +/- 2.11, resulting in an ablation depth of 78 +/- 28 microm (from 33 to 148). No intraoperative complications were observed. At one year, mean SE was +0.04 D +/- 1.03 (p<0.001) and mean BCVA was 0.079 +/- 0.105 (p<0.001). There was a gain of 2 or more lines of BCVA in 20 eyes (33.3%) and only one eye (1.7%) lost 2 lines. Correlation analysis showed that the improvement in BCVA was inversely related to preoperative BCVA (r=-0.694; p<0.001). Five eyes developed peripheral haze grade 2 or 3 and one eye had central trace haze. No significant correlation was found between central or peripheral haze and the number of radial incisions, depth of the ablation or postoperative BCVA. Mean preoperative endothelial cell count was 2,681 +/- 455 cel/ mm(2) and after one year was 2,481 +/- 378 cel/mm(2) (p=0.124). One eye developed keratectasia due to the progressive widening of an inferior radial incision, which was later sutured.
Conclusion: PRK with MMC was safe after one year of follow-up for the reduction of hyperopia after radial keratotomy. A major improvement in BCVA was obtained with a small incidence of haze and other complications.
Trial registration: ClinicalTrials.gov NCT00917657.