title: Active eye-tracking improves LASIK results.
abstract: OBJECTIVE
  To study the advantage of active eye-tracking for photorefractive surgery.
  
  
  METHODS
  In a prospective, double-masked study, LASIK for myopia and myopic astigmatism was performed in 50 patients using the ALLEGRETTO WAVE version 1007. All patients received LASIK with full comprehension of the importance of fixation during the procedure. All surgical procedures were performed by a single surgeon. The eye-tracker was turned off in one group (n = 25) and kept on in another group (n = 25). Preoperatively and 3 months postoperatively, patients underwent a standard ophthalmic examination, which included comeal topography.
  
  
  RESULTS
  In the patients treated with the eye-tracker off, all had uncorrected visual acuity (UCVA) of > or = 20/40 and 64% had > or = 20/20. Compared with the patients treated with the eye-tracker on, they had higher residual cylindrical astigmatism (P < .05). Those treated with the eye-tracker on achieved better UCVA and best spectacle-corrected visual acuity (P < .05). Spherical error and potential visual acuity (TMS-II) were not significantly different between the groups.
  
  
  CONCLUSIONS
  The flying-spot system can achieve a fair result without active eye-tracking, but active eye-tracking helps improve the visual outcome and reduces postoperative cylindrical astigmatism.
authors.affiliation: Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan. derrick@url.com.tw
authors.forename: Yuan-Chieh
authors.initials: YC
authors.lastname: Lee
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000517:prevention & control; D003315:Cornea / Q000601:surgery*; D019781:Corneal Topography; D004311:Double-Blind Method; D005133:Eye Movements; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011446:Prospective Studies; D011680:Pupil / Q000502:physiology; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*