title: Multizone photorefractive keratectomy for high and very high myopia: long-term results.
abstract: OBJECTIVE
  To compare 2 year results of multizone excimer laser photorefractive keratectomy (PRK) in eyes with myopia (spherical equivalent [SE]) from 6.00 to 10.00 diopters (D) with those in eyes with myopia from 10.25 to 25.75 D.
  
  
  METHODS
  Wellington Hospital and Laser Vision Harley Street, London, England.
  
  
  METHODS
  Of the 281 PRK cases with an SE of at least -6.00 D, 59 eyes had a minimum follow-up of 2 years. Twenty-six of these had an SE from -6.00 to -10.00 D and 33, from -10.25 to -25.75 D. The single-pass, multizone technique was used to create ablation zones at 5.0, 5.5, and 6.0 mm. Postoperatively, patients received a minimum of 4 weeks of fluorometholone 0.1%; those exhibiting regression after corticosteroids were discontinued were restarted on a tapering regimen.
  
  
  RESULTS
  The refraction stabilized 3 months postoperatively in the -6.00 to -10.00 D group, and the final mean SE refraction was a small undercorrection. Two years postoperatively, 88.5% of eyes had a visual acuity of 20/40 or better, and 77.0% were within +/- 1.00 D of the intended correction. In eyes with myopia greater than 10.00 D, regression continued during the 2 years and refraction did not stabilize. Forty-two percent had an uncorrected acuity of 20/40 or better, and 48.0% were within +/- 1.00 D of the intended correction. The incidence and severity of haze were higher in the group with myopia greater than 10.00 D. The overall incidence of complications was low.
  
  
  CONCLUSIONS
  Two years after multizone PRK, refractive and visual acuity results in eyes with myopia from 6.00 to 10.00 D were good. Results in eyes with myopia of more than 10.00 D were not satisfactory, and refraction had not stabilized.
authors.affiliation: Laser Vision Harley Street, London, England.
authors.forename: D K
authors.initials: DK
authors.lastname: Williams
mesh_terms: D000328:Adult; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D003318:Corneal Opacity / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D054018:Lasers, Excimer; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications; D012029:Refraction, Ocular; D012449:Safety; D016896:Treatment Outcome; D014792:Visual Acuity