title: Photorefractive keratectomy for myopia and photoastigmatic keratectomy for astigmatism.
abstract: BACKGROUND
  We conducted a clinical trial to evaluate the efficacy and safety of excimer laser photorefractive keratectomy (PRK) and photoastigmatic refractive keratectomy (PARK) using the Nidek EC-5000 excimer laser.
  
  
  METHODS
  A total of 67 eyes from 47 patients whose average age was 35 years were enrolled in the study. The mean spherical equivalent of the manifest refraction before surgery was -7.50 diopters (D). Patients were followed for at least 6 months. One year after surgery, uncorrected visual acuity improved in 98% of the eyes, while spectacle-corrected visual acuity had not deteriorated in any patient. The achieved corrections were within +/-1.00 D of attempted correction in 72.5% of eyes. Predictability was poor in eyes in which the correction was more than 10.00 D. Subepithelial haze occurred in all eyes to minimal extent, and disappeared gradually.
  
  
  CONCLUSIONS
  Photorefractive keratectomy and photoastigmatic refractive keratectomy, performed with the Nidek EC-5000 excimer laser, is a reliable and adequately safe procedure to correct myopia of a limited range.
authors.affiliation: Department of Ophthalmology, Rhime University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ohashi
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Yorii
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy; D012449:Safety; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology