title: Conservative photorefractive keratectomy for residual myopia following radial keratotomy.
abstract: OBJECTIVE
  To evaluate the efficacy, predictability, stability and safety of a conservative approach to photorefractive keratectomy (PRK) (treating only 60% to 70% of the residual myopia) for residual myopia following radial keratotomy (RK).
  
  
  METHODS
  Case series.
  
  
  METHODS
  Laser eye surgery centre in Windsor, Ont.
  
  
  METHODS
  Thirty-three eyes of 27 patients with an average age of 40.1 years who underwent PRK between January 1993 and July 1995, 12 months or more after RK. All were followed for at least 12 months after PRK.
  
  
  METHODS
  Efficacy and safety were assessed by changes in the uncorrected and best corrected visual acuity. Predictability was determined by the proximity of the final result to emmetropia. The stability of the refractive outcome was assessed over the follow-up period.
  
  
  RESULTS
  At 12 months 12 eyes (36%) had 20/20 or better uncorrected visual acuity and 29 eyes (88%) had 20/40 or better uncorrected acuity. Twenty-seven eyes (82%) were within 0.50 D of emmetropia, and 30 eyes (91%) were within 1.00 D of emmetropia. There was a significant change in the mean postoperative spherical equivalent between 1 and 3 months (p < 0.001); however, there was no significant change after this time. Six eyes (18%) had a loss of 2 or more lines of best corrected visual acuity due to corneal haze; however, retreatment reduced this incidence to 9% at 12 months.
  
  
  CONCLUSIONS
  Our results show that conservative PRK for residual myopia following RK is efficacious and predictable and produces stable results. However, the risk of postoperative haze reduces the safety of this procedure.
authors.affiliation: Windsor Laser Center, Ont.
authors.forename: L E
authors.initials: LE
authors.lastname: Probst
authors.forename: J J
authors.initials: JJ
authors.lastname: Machat
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007646:Keratotomy, Radial / Q000009:adverse effects*; D054018:Lasers, Excimer; D008297:Male; D009216:Myopia / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods; D011183:Postoperative Complications; D012086:Reoperation; D012449:Safety; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology