title: Laser in situ keratomileusis versus long-term contact lens wear: decision analysis.
abstract: OBJECTIVE
  To compare the risk for vision loss from laser in situ keratomileusis (LASIK) versus long-term contact lens wear using decision analysis.
  
  
  METHODS
  Oregon Health & Science University, Portland, Oregon, USA.
  
  
  METHODS
  Based on previously published data, a decision tree was constructed using Markov modeling to calculate the probability of vision loss from LASIK versus contact lenses over time. An outcome variable, visual acuity-adjusted life-year (VALY), was defined to account for timing and severity of vision loss. The VALYs were tallied over a 30-year simulation to determine whether the risk for vision loss with contacts exceeded that with LASIK. Sensitivity analyses were performed to test the effect of changes in key variables including probability of contact lens-related keratitis, probability of ectasia after LASIK, and probability of early post-LASIK vision loss.
  
  
  RESULTS
  The model's conclusions were highly sensitive to changes in several variables tested, especially risk for post-LASIK ectasia, risk for early vision loss after LASIK, and risk for contact lens-related keratitis (which correlated with type of lenses worn). Rigid gas-permeable lenses were safer than LASIK in every analysis. The safety of LASIK exceeded that for daily-wear soft lenses only when assumptions were most favorable to LASIK, whereas the safety of LASIK always exceeded that for extended-wear lenses except when assumptions were least favorable to LASIK.
  
  
  CONCLUSIONS
  This decision analysis found that the risk for vision loss associated with LASIK and with long-term contact lens wear might be closer than generally assumed.
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239-4197, USA.
authors.forename: Hall T
authors.initials: HT
authors.lastname: McGee
authors.forename: William D
authors.initials: WD
authors.lastname: Mathers
mesh_terms: D003261:Contact Lenses / Q000009:adverse effects*; D003661:Decision Support Techniques; D003663:Decision Trees; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D054018:Lasers, Excimer; D008390:Markov Chains; D009216:Myopia / Q000628:therapy*; D011336:Probability; D019057:Quality-Adjusted Life Years; D018570:Risk Assessment; D013997:Time Factors; D014786:Vision Disorders / Q000209:etiology*; D014792:Visual Acuity / Q000502:physiology