title: Laser in situ keratomileusis versus photorefractive keratectomy in the correction of myopic astigmatism.
abstract: OBJECTIVE
  To evaluate retrospectively the effectiveness of astigmatism correction in eyes treated with laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).
  
  
  METHODS
  Patients with low to moderate myopia with astigmatism ranging from +0.25 to +4.50 diopters were included in the study. PRK was performed on 62 eyes and LASIK on 70 eyes. Six-month data were analyzed with regard to astigmatism power, astigmatism axis, spherical equivalent, uncorrected visual acuity, vector astigmatism change, and topographic corneal regularity.
  
  
  RESULTS
  Mean astigmatism magnitude change was 0.54 +/- 0.76 in PRK-treated eyes and 0.60 +/- 0.67 in LASIK-treated eyes (61% versus 64% change, respectively, p = 0.61) at 6 months after surgery. Mean spherical correction change was -2.79 +/- 1.51 for PRK and -2.90 +/- 1.03 for LASIK (p = 0.63). Mean spherical equivalent change was -2.5 +/- 1.57 for PRK and -2.6 +/- 1.23 for LASIK (p = 0.73). Mean change in astigmatism axis was 20.8 +/- 73.1 for PRK and 33.8 +/- 81.7 for LASIK (p = 0.34). Mean change in uncorrected visual acuity (LogMar) was 0.84 +/- 0.26 for PRK and 0.89 +/- 0.23 for LASIK (p = 0.21). Mean vector-corrected astigmatism change was 0.88 +/- 0.66 for PRK and 0.95 +/- 0.59 for LASIK (p = 0.51). Mean vector-corrected astigmatism axis for PRK was 86.9 +/- 59 degrees and for LASIK 83.8 +/- -47.6 degrees (p = 0.75).
  
  
  CONCLUSIONS
  There was no significant difference in astigmatism correction between PRK and LASIK at 6 months after surgery.
authors.affiliation: Department of Ophthalmology, University of Washington School of Medicine, Seattle, Washington 98195-6485, U.S.A.
authors.forename: F W
authors.initials: FW
authors.lastname: Fraunfelder
authors.forename: S E
authors.initials: SE
authors.lastname: Wilson
mesh_terms: D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000601:surgery*; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy; D012029:Refraction, Ocular; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity