Photorefractive keratectomy after radial keratotomy.

We report the results of a prospective study that evaluated the efficacy, predictability, and safety of excimer laser photorefractive keratectomy (PRK) to correct residual myopia after radial keratotomy (RK). Using a 193 nm excimer laser, we performed PRK on ten undercorrected myopic eyes that had previous RK surgery. The mean interval between the RK and PRK was 1.5 years. Mean follow-up was seven months. Mean preoperative refraction was -4.08 +/- 1.35 diopters (D) and after PRK was +1.61 +/- 1.18 D at three months, +1.05 +/- 0.75 D at six months, and +0.79 +/- 0.83 D at 12 months. An uncorrected visual acuity of 20/40 or better was achieved in eight eyes at three months, seven eyes at six months, and three eyes at 12 months. One eye had a transient loss of two Snellen lines of best spectacle corrected visual acuity because of increased haze. No other significant complication was noted. Our study shows that PRK is a predictable, effective, stable, and safe technique to correct residual myopia after RK. The results were similar to those of PRK without prior surgery, although we noted a slightly greater hyperopic deviation. We believe that eyes undercorrected by RK may benefit from subsequent PRK.