title: [Mutiple factors analysis of the effects of excimer laser photorefractive keratectomy].
abstract: OBJECTIVE
  To observe the effect of excimer laser photorefractive keratectomy (PRK) correcting myopia and astigmatism, and to study the related factors.
  
  
  METHODS
  PRK was performed with the aim to correct myopia errors from 1.00 to 16.00 diopters on 529 myopia eyes (306 patients). All eyes were divided into two groups: Group I: -1.00-6.00 D(294 eyes); group II: -6.25-16.00 D(235 eyes). All the patients were followed up for 3 to 12 months.
  
  
  RESULTS
  At postoperative 12 months the rates of uncorrected visual acuity more than or equal to 10/20 or 20/20 were 97.5%, 77.5% in group I, and 80.3%, 32.8% in group II respectively; 92.5% of eyes were within +/- 1.00 diopter of the desired emmetropia in group I, but 42.6% in group II; The influential factors of changes of postoperative diopters was the severity of corneal haze, methods of removing corneal epithelium, intraocular pressure, the central corneal thickness.
  
  
  CONCLUSIONS
  The excimer laser PRK is regarded to be a very predictable, safe, stable, and effective method to correct myopia up to -6.00 D. Prior to operation, the plan would be disigned according to diopters, ages, corneal thickness intraocular pressure. During operation, the corneal epithelium bad better to be removed by laser.
authors.affiliation: Ophthalmic Laser Center, Xiangya Hospital, Hunan Medical University, Changsha 410008, China.
authors.forename: X
authors.initials: X
authors.lastname: Xia
authors.forename: S
authors.initials: S
authors.lastname: Liu
authors.forename: P
authors.initials: P
authors.lastname: Huang
authors.forename: Z
authors.initials: Z
authors.lastname: Wu
authors.forename: X
authors.initials: X
authors.lastname: Tan
authors.forename: E
authors.initials: E
authors.lastname: Mei
authors.forename: S
authors.initials: S
authors.lastname: Hu
mesh_terms: D001251:Astigmatism / Q000601:surgery; D003316:Corneal Diseases / Q000209:etiology; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D015999:Multivariate Analysis; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000009:adverse effects; D014792:Visual Acuity