title: Five and three year follow-up of photorefractive keratectomy for myopia of -1 to -6 diopters.
abstract: BACKGROUND
  To report the 5 and 3 year results of photorefractive keratectomy for -1 to -6 D of myopia and less than 1.50 D astigmatism.
  
  
  METHODS
  All eyes were treated with a VISX 20/20 excimer laser with an ablation diameter of 5 mm. Our initial series of 133 eyes were treated in four groups: IIA, IIB, III and III No Nitrogen and reported on previously with follow-up from 6 to 36 months. The present report extends the observation period to 3 and 5 years for 114 eyes.
  
  
  RESULTS
  Groups IIA and IIB were followed for 5 years and Groups III and III No Nitrogen for 3 years. Group IIA achieved 77% (10 of 13 eyes) +/-1.00 D (54% within +/-0.50 D) of emmetropia with stability from 6 months and 54% (seven of 13 eyes) had visual acuity of 20/20 or better. In Group IIB, 35% (six of 17 eyes) were +/-1.00 D (18% within +/-0.50 D) of emmetropia and stable from 18 months. Two of 17 eyes (12%) had 20/20 or better visual acuity. Group III had 76% (42 of 55 eyes) within +/-1.00 D (51% within +/-0.50 D) of emmetropia with stability after 12 months; 60% (33 of 55 eyes) had 20/20 or better visual acuity. Group III No Nitrogen had 73% (11 of 15 eyes) within +/-1.00 D (60% within +/-0.50 D) of emmetropia and were stable after 6 months; 47% (seven of 15 eyes) had 20/20 or better visual acuity. There was no hyperopic refractive shift. No correlation was found between the percent of correction achieved and preoperative amount of myopia, age, or sex.
  
  
  CONCLUSIONS
  Refractive stability was achieved from 6 to 12 months in most eyes; a few required 18 months to stabilize. Groups IIA and III continued to be stable; Groups HB and III No Nitrogen showed mild regression that was not statistically significant.
authors.affiliation: University of Missouri-Kansas City Eye Foundation, 64108, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Matta
authors.forename: L W
authors.initials: LW
authors.lastname: Piebenga
authors.forename: M R
authors.initials: MR
authors.lastname: Deitz
authors.forename: J
authors.initials: J
authors.lastname: Tauber
authors.forename: L P
authors.initials: LP
authors.lastname: Garner
mesh_terms: D000328:Adult; D003315:Cornea / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D009584:Nitrogen / Q000008:administration & dosage; D018903:Photorefractive Keratectomy; D012029:Refraction, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity
chemical_list: D009584:Nitrogen