title: Thirty-six month follow-up of excimer laser photorefractive keratectomy for myopia.
abstract: OBJECTIVE
  The aim of the study was to evaluate the refractive outcome 36 months following excimer laser photorefractive keratectomy (PRK) performed on myopic eyes. We analyzed the refractive stability between 24 and 36 months.
  
  
  METHODS
  PRK was performed on 457 eyes with a pre-operative refraction ranging from -1.25 to -7.50 diopters (D). Ablation zone diameters of 4.3 to 4.5 mm were used. The follow up time was 36 months.
  
  
  RESULTS
  The mean refraction 36 months following surgery was -0.22 to 0.75 D for the whole group, which was not significantly different from the mean at 24 months (-0.27 +0.74D). If we analyze the subgroups at 36 months, we find a significantly better refractive outcome in the low myopia group (up to -2.90D) compared with those with higher myopia. At 36 months, 91% of the 456 eyes had an uncorrected visual acuity of at least 20/40, and 88% of the eyes were within 1.00 D of emmetropia.
  
  
  CONCLUSIONS
  These results show stability between 24 and 36 months.
authors.affiliation: S:t Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Hamberg-Nyström
authors.forename: P
authors.initials: P
authors.lastname: Fagerholm
authors.forename: B
authors.initials: B
authors.lastname: Tengroth
authors.forename: C
authors.initials: C
authors.lastname: Sjöholm
mesh_terms: D000328:Adult; D001128:Argon; D005459:Fluorides; D005500:Follow-Up Studies; D006801:Humans; D007834:Lasers; D054018:Lasers, Excimer; D008875:Middle Aged; D009216:Myopia / Q000145:classification / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000295:instrumentation / Q000379:methods; D012029:Refraction, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity
chemical_list: C047730:argon fluoride; D001128:Argon; D005459:Fluorides