Eighteen-year follow-up of excimer laser photorefractive keratectomy

Abstract

To evaluate the long-term efficacy of photorefractive keratectomy (PRK). University Hospital, London, United Kingdom. Prospective case series. One eye of patients who had PRK 18 years previously was examined. All had myopic corrections with a 6.0 mm optical zone. Forty-six patients were examined. The mean preoperative spherical equivalent (SE) refractive error was -4.86 diopters (D) (range -2.75 to -7.375 D). The mean programmed correction was -4.43 D (range -2.50 to -7.00 D). Between 1 year and 18 years, the mean change in SE was -0.31 D (P = .06) and a significant increase in variance occurred (P < .002). The mean change in SE was -0.54 D in patients younger than 40 years at the time of correction (P < .02) and -0.05 D in patients older than 40 years (P = .9). The mean SE change was -0.40 D in women (P < .04) and -0.08 D in men (P = .8). The efficacy index was 0.58. The safety index was 0.998. The corrected distance visual acuity (CDVA) improved significantly from 1 to 18 years (P < .01). Ninety-six percent of corneas were clear at 18 years, with a reduction in haze scores (P < .001). There was no evidence of ectasia. A significant increase in myopic SE occurred between 1 year and 18 years after PRK in patients younger than 40 years and in women. Predictability decreased between 1 year and 18 years. The procedure was safe with no long-term complications. The CDVA and corneal transparency improved with time. Dr. Marshall was a consultant to Summit Technology, Inc. No author has a financial or proprietary interest in any material or method mentioned.