title: Vector analysis of myopic astigmatism corrected by femtosecond refractive lenticule extraction.
abstract: OBJECTIVE
  To evaluate the visual outcome of refractive lenticule extraction in eyes with myopic astigmatism using the Visumax femtosecond laser.
  
  
  METHODS
  Department of Ophthalmology, HELIOS Klinikum Erfurt, Erfurt, Germany.
  
  
  METHODS
  Nonrandomized clinical trials.
  
  
  METHODS
  The data set encompassed treatments of sphere and astigmatism. Vector analysis was performed to study the astigmatic results at each follow-up visit at 1 week and 1, 3, and 6 months. Visual outcomes were analyzed for the 6-month follow-up period.
  
  
  RESULTS
  The data evaluated was a complete set of refractive data of 182 treatments (87 left eyes, 95 right eyes). Efficacy, predictability, and safety with regard to astigmatic correction were comparable to the results with U.S. Food and Drug Administration-approved excimer lasers. At 6 months, the mean error ratio was 0.68 ± 0.75 (SD) and the mean correction ratio was 1.11 ± 0.69. There was slight astigmatic undercorrection (approximately 10%) over time. The residuum of the linear regression analysis of the predictability plot was approximately 0.4 diopter. Ninety-six percent of the eyes had a corrected distance visual acuity (CDVA) of 20/20 or better; no eye had a CDVA worse than 20/32.
  
  
  CONCLUSIONS
  Femtosecond refractive lenticule extraction is an effective procedure for correcting myopic astigmatism.
authors.affiliation: Department of Ophthalmology, HELIOS Klinikum Erfurt, Erfurt, Germany.
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Kunert
authors.forename: Christoph
authors.initials: C
authors.lastname: Russmann
authors.forename: Marcus
authors.initials: M
authors.lastname: Blum
authors.forename: Georg
authors.initials: G
authors.lastname: Sluyterman V L
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D003319:Corneal Stroma / Q000601:surgery*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult