title: Q-factor customized ablation profile for the correction of myopic astigmatism.
abstract: OBJECTIVE
  To compare the results of the Q-factor customized aspheric ablation profile with the wavefront-guided customized ablation pattern for the correction of myopic astigmatism.
  
  
  METHODS
  Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland.
  
  
  METHODS
  Thirty-five patients were enrolled in a controlled study in which the nondominant eye was treated with the Q-factor customized profile (custom-Q study group) and the dominant eye was treated with wavefront-guided customized ablation (control group). Preoperative and 1-month postoperative high-contrast visual acuity, low-contrast visual acuity, and glare visual acuity, as well as aberrometry and asphericity of the cornea, were compared between the 2 groups. All eyes received laser in situ keratomileusis surgery, and the laser treatment was accomplished with the Wavelight Eye-Q 400 Hz excimer laser.
  
  
  RESULTS
  For corrections up to -9 diopters (D) of myopia, there were no statistically significant differences between the 2 groups regarding any visual or optical parameter except coma-like aberrations (3rd Zernike order), where the wavefront-guided group was significantly better 1 month after surgery (P = .002). For corrections up to -5 D (spherical equivalent), the Q-factor optimized treated eyes had a significantly smaller shift toward oblate cornea: DeltaQ15 = 0.25 in Q-factor customized versus DeltaQ15 = 0.38 in wavefront-guided treatment (P = .04).
  
  
  CONCLUSIONS
  Regarding safety and refractive efficacy, custom-Q ablation profiles were clinically equivalent to wavefront-guided profiles in corrections of myopia up to -9 D and astigmatism up to 2.5 D. Corneal asphericity was less impaired by the custom-Q treatment up to -5 D of myopia.
authors.affiliation: Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland.
authors.forename: Tobias
authors.initials: T
authors.lastname: Koller
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Iseli
authors.forename: Farhad
authors.initials: F
authors.lastname: Hafezi
authors.forename: Michael
authors.initials: M
authors.lastname: Mrochen
authors.forename: Theo
authors.initials: T
authors.lastname: Seiler
mesh_terms: D000328:Adult; D000465:Algorithms; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D019781:Corneal Topography; D019466:Glare; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology