title: Effect of scanning patterns on the results of femtosecond laser lenticule extraction refractive surgery.
abstract: OBJECTIVE
  To report the clinical results of refractive lenticule extraction using a femtosecond laser and describe the effect of scanning patterns on the results.
  
  
  METHODS
  Private laser center, Vadodara, India.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  The Visumax femtosecond laser system was used to perform lenticule extraction to treat refractive errors using 2 scanning trajectories. The laser was used to cut a refractive lenticule intrastromally to correct myopia or myopic astigmatism. The lenticule was then physically extracted from the stroma. In scanning pattern A, the laser scanned from the center out and the periphery in while the 2 surfaces of the lenticule were cut. In scan pattern B, the laser scanned from the periphery in and the center out. Outcome measures were corrected and uncorrected distance visual acuities and manifest refraction during a 6-month follow-up. Differences between the 2 scanning patterns were also analyzed.
  
  
  RESULTS
  The study comprised 329 eyes of 173 patients. One week postoperatively, there were statistically significant differences in refractive outcomes (P=.03), safety (P<.01), and efficacy (P<.01), between the 2 scanning-pattern groups. At 6 months, there were no significant differences.
  
  
  CONCLUSIONS
  Early visual recovery and refractive outcomes after femtosecond lenticule extraction were affected by the scanning trajectory of the laser. A trajectory that scanned from the periphery to the center and the center to the periphery to cut the 2 lenticule surfaces had a positive effect on visual recovery.
authors.affiliation: New Vision Laser Centers, Vadodara, India. rupal@newvisionindia.com
authors.forename: Rupal
authors.initials: R
authors.lastname: Shah
authors.forename: Samir
authors.initials: S
authors.lastname: Shah
mesh_terms: D000293:Adolescent; D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D003319:Corneal Stroma / Q000601:surgery*; D048988:Corneal Surgery, Laser; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology; D012029:Refraction, Ocular / Q000502:physiology; D013524:Surgical Flaps; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult