title: Excimer laser photorefractive keratectomy for residual myopia after radial keratotomy.
abstract: OBJECTIVE
  To evaluate the surgical outcome of excimer laser photorefractive keratectomy (PRK) for undercorrected myopia after radial keratotomy (RK).
  
  
  METHODS
  Case series.
  
  
  METHODS
  Gimbel Eye Centre, Calgary.
  
  
  METHODS
  Thirty-one patients (37 eyes) who underwent excimer laser PRK for residual myopia after RK and were followed for at least 12 months.
  
  
  METHODS
  Spherical equivalent refraction, uncorrected and best corrected Snellen visual acuity, attempted and achieved correction, and corneal haze.
  
  
  RESULTS
  The mean refraction before PRK was -3.11 (standard deviation [SD] 1.48) dioptres and 12 months after PRK, -1.18 D (SD 1.48 D) (p < 0.0001). Twelve months after PRK 24 eyes (64.9%) had an uncorrected visual acuity of 20/40 or better. Five eyes lost one line of best corrected acuity, and one eye lost more than two lines. At 12 months 28 eyes (75.7%) had no corneal haze or trace haze, 8 (21.6%) had mild haze, and 1 (2.7%) had marked haze.
  
  
  CONCLUSIONS
  Our results indicate that excimer laser PRK has the potential to manage undercorrection of myopia after RK. The issues of refractive predictability, loss of best corrected visual acuity and corneal haze require further study.
authors.affiliation: Gimbel Eye Center, Calgary, Alta.
authors.forename: H V
authors.initials: HV
authors.lastname: Gimbel
authors.forename: R
authors.initials: R
authors.lastname: Sun
authors.forename: P K
authors.initials: PK
authors.lastname: Chin
authors.forename: J
authors.initials: J
authors.lastname: van Westenbrugge
mesh_terms: D000328:Adult; D003315:Cornea / Q000503:physiopathology / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D007646:Keratotomy, Radial; D054018:Lasers, Excimer; D008875:Middle Aged; D009216:Myopia / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D012029:Refraction, Ocular / Q000502:physiology; D012086:Reoperation; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology