title: Comparison of eye-tracking success in laser in situ keratomileusis after flap creation with 2 femtosecond laser models.
abstract: OBJECTIVE
  To determine the efficiency of an eye tracker after laser in situ keratomileusis (LASIK) flap creation with 1 of 2 femtosecond laser models.
  
  
  METHODS
  Tertiary referral center, Singapore National Eye Center, Singapore.
  
  
  METHODS
  Randomized clinical trial.
  
  
  METHODS
  The LASIK flap was created with an IntraLase (Group A) or a VisuMax (Group B) femtosecond laser. An Advanced Control Eye Tracker was initiated 3 times to obtain iris recognition. Eye tracking was considered successful if the eye movements could be followed despite the presence or absence of an opaque bubble layer (OBL). Univariate-multivariate logistic regression analysis was performed.
  
  
  RESULTS
  Preoperatively, the mean values (ranges) of the 87 eyes were sphere, -5.64 diopters (D) ± 2.17 (SD) (-9.75 to -0.25 D); cylinder 1.65 ± 1.63 D (-3.75 to 0.00 D); optical zone, 6.34 ± 0.20 mm (5.6 to 7.0 mm); keratometry, 43.48 ± 1.32 D (40.1 to 42.8 D); flap thickness, 109.30 + 5.21 μm (90 to 115 μm). Eye tracking was successful in 38 (90.5%) of 42 eyes in Group A and 43 (95.6%) of 45 eyes in Group B. No specific type of OBL was seen in either group. The LASIK was completed in all eyes. There was a statistically significant association between positive tracking and a smaller optical zone (P=.03). There were no statistically significant differences in eye tracking between the 2 femtosecond lasers.
  
  
  CONCLUSIONS
  Eye tracking was achieved in more than 90% of cases after LASIK flap creation with 1 of 2 femtosecond laser models, even in the presence of an OBL.
authors.affiliation: Singapore Eye Research Institute, National University of Singapore, Singapore.
authors.forename: Federico
authors.initials: F
authors.lastname: Luengo Gimeno
authors.forename: Cordelia M L
authors.initials: CM
authors.lastname: Chan
authors.forename: Lim
authors.initials: L
authors.lastname: Li
authors.forename: Donald T H
authors.initials: DT
authors.lastname: Tan
authors.forename: Jodhbir S
authors.initials: JS
authors.lastname: Mehta
mesh_terms: D000328:Adult; D000465:Algorithms; D003319:Corneal Stroma / Q000601:surgery; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005133:Eye Movements; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D013524:Surgical Flaps; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult