title: Excimer laser photorefractive keratectomy. 18-month follow-up.
abstract: OBJECTIVE
  This study, comprising 120 patients (follow-up, 12 to 22 months; mean, 18 months), was designed to evaluate the efficacy and safety of excimer laser photo-refractive keratectomy.
  
  
  METHODS
  Ablation zone diameter (4 mm), ablation rate (0.22 microns/pulse), fluence (180 mJ/cm2), and frequency (10 Hz) were kept constant, and all patients used a standard topical corticosteroid regimen.
  
  
  RESULTS
  Overcorrection was followed by regression to a stable refraction by 4 months. At 1 year, 95% and 70%, respectively, of patients undergoing - 2.00 diopters (D) and -3.00 D corrections and 40% and 20% of those undergoing -6.00 D and -7.00 D corrections were within +/- 1.00 D of intended refraction. Anterior stromal "haze," maximal at 6 months and diminishing thereafter, was detected in 110 patients (92%). However, best-corrected Snellen visual acuity was reduced in only 22 (18%). Good correlation existed between haze and regression (r = 0.68). Night "halos," due to the relatively small 4-mm diameter ablation zone, were reported by 94 patients (78%) in the early postoperative period, and, at 1 year, 12 (10%) declined treatment of the other eye because of persistence of this problem.
  
  
  CONCLUSIONS
  Marked individual variation was found after photorefractive keratectomy. However, in low myopia, predictability is "fair," and the procedure is safe. The authors conclude that excimer laser photorefractive keratectomy holds considerable promise for refractive surgery in the future.
authors.affiliation: Department of Ophthalmology, St Thomas' Hospital, London, England.
authors.forename: D S
authors.initials: DS
authors.lastname: Gartry
authors.forename: M G
authors.initials: MG
authors.lastname: Kerr Muir
authors.forename: J
authors.initials: J
authors.lastname: Marshall
mesh_terms: D000328:Adult; D000368:Aged; D015858:Anisometropia / Q000601:surgery; D003315:Cornea / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects*; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D016896:Treatment Outcome; D014786:Vision Disorders / Q000209:etiology; D014792:Visual Acuity