title: Variables affecting refractive outcome following LASIK for myopia.
abstract: OBJECTIVE
  To investigate factors affecting refractive outcome following LASIK for myopia.
  
  
  METHODS
  Six hundred and seventy-four consecutive uncomplicated myopic LASIK surgeries, performed by a single surgeon, either using the Technolas 217 planoscan (n=372) or the NIDEK EC 5000 (n=302), were evaluated. Stratified random sampling was used to match the groups for refractive error, patient age, and gender. The final analysis included 302 patients from each treatment group. Conditions were identical for both surgeries, and pre-operative refractive errors were between -1.00 and -14.00 DS and <-1.50 DC. Refractive success was defined as -0.50 to +0.50 DS of the targeted refraction measured 3 months after surgery. A stepwise logistical regression analysis was used to determine variables associated with refractive failure.
  
  
  RESULTS
  A successful refractive outcome was achieved in 78% (235/302) of surgeries using the Technolas laser and in 88% (266/302) using the NIDEK laser. Predictor variables for not achieving refractive success were pre-operative refractive error of above -5.00 DS, age more than 40 years, and surgery performed with the Technolas laser.
  
  
  CONCLUSIONS
  Both the Technolas 217 and the NIDEK EC-5000 excimer lasers achieve a successful refractive outcome in the majority of cases. However, patient and surgical factors can influence refractive outcome.
authors.affiliation: Mark Feltham Optometrists, London Circuit, Canberra, Australian Capital Territory, Australia.
authors.forename: M H
authors.initials: MH
authors.lastname: Feltham
authors.forename: R
authors.initials: R
authors.lastname: Wong
authors.forename: R
authors.initials: R
authors.lastname: Wolfe
authors.forename: F
authors.initials: F
authors.lastname: Stapleton
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000601:surgery; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000209:etiology / Q000601:surgery*; D018579:Patient Selection; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000150:complications*; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology