Eighteen-year follow-up of excimer laser photorefractive keratectomy

PurposeTo evaluate the long-term efficacy of photorefractive keratectomy (PRK).SettingUniversity Hospital, London, United Kingdom.DesignProspective case series.MethodsOne eye of patients who had PRK 18 years previously was examined. All had myopic corrections with a 6.0 mm optical zone.ResultsForty-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.ConclusionsA 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.Financial DisclosureDr. Marshall was a consultant to Summit Technology, Inc. No author has a financial or proprietary interest in any material or method mentioned.