title: Corneal irregular astigmatism after hyperopic laser in situ keratomileusis.
abstract: OBJECTIVE
  To evaluate the changes in irregular astigmatism after hyperopic laser in situ keratomileusis (LASIK).
  
  
  METHODS
  In a prospective case series, 15 eyes of 12 patients who had hyperopic LASIK were evaluated. Corneal topography was obtained before and after hyperopic LASIK. Corneal irregular astigmatism (asymmetry and higher-order irregularity) was calculated using Fourier harmonic analysis of the topography data.
  
  
  RESULTS
  Hyperopic LASIK significantly increased the asymmetry component at 3 (P = 0.0085) and 6 months (P = 0.0307) postoperatively. The mean higher-order irregularity was not significantly changed at any postoperative time-point (P = 0.222). The achieved change in the spherical equivalent was significantly correlated with the post/preoperative ratio of asymmetry (R = 0.695, P = 0.0030).
  
  
  CONCLUSIONS
  Hyperopic LASIK significantly increases the asymmetry component of the cornea, which is correlated with the achieved change in the spherical equivalent.
authors.affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan. amanos-tky@umin.ac.jp
authors.forename: Shiro
authors.initials: S
authors.lastname: Amano
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nanba
authors.forename: Naoki
authors.initials: N
authors.lastname: Hamada
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Oshika
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Uno
authors.forename: Atsuko
authors.initials: A
authors.lastname: Toshino
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ohashi
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000175:diagnosis / Q000209:etiology*; D003315:Cornea / Q000473:pathology / Q000601:surgery; D003316:Corneal Diseases / Q000175:diagnosis / Q000209:etiology*; D019781:Corneal Topography; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D006956:Hyperopia / Q000601:surgery*; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies