title: Effects of reference axes used during measurements of ocular and corneal higher-order aberrations in patients following LASIK.
abstract: OBJECTIVE
  To determine the effects of the reference axes used during the measurements of ocular and corneal higher-order aberrations (HOAs) in patients before and after laser in situ keratomileusis (LASIK).
  
  
  METHODS
  Wavefront sensing and corneal topography were determined for 29 eyes of 15 patients before and after LASIK. Ocular and corneal HOAs were calculated for 4-mm- and 6-mm-diameter pupils with the instrument aligned with the line of sight (LOS) or with the vertex normal (VN).
  
  
  RESULTS
  For ocular HOAs after surgery, the spherical-like aberration was significantly larger when the VN axis rather than the LOS axis was used for pupils of both diameters. For corneal HOAs before surgery, in addition to the larger spherical-like aberration for VN, coma-like aberrations were significantly larger with LOS than with VN for both pupil diameters. For corneal HOAs after surgery, the spherical-like aberrations and total HOAs for 4-mm-diameter pupils with VN were significantly larger than those with LOS.
  
  
  CONCLUSIONS
  The HOAs were significantly different depending on the axes used and should be described on the basis of a common axis. These results suggest that the anterior surface of the normal or post-LASIK cornea is more rotationally symmetrical along the VN than along the LOS.
authors.affiliation: Department of Ophthalmology, Osaka University Medical School, Suita, Osaka, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Takehara
authors.affiliation: Department of Ophthalmology, Osaka University Medical School, Suita, Osaka, Japan. nmaeda@ophthal.med.osaka-u.ac.jp.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Maeda
authors.affiliation: Department of Applied Visual Science, Osaka University Medical School, Suita, Osaka, Japan.
authors.forename: Sayuri
authors.initials: S
authors.lastname: Ninomiya
authors.affiliation: Department of Applied Visual Science, Osaka University Medical School, Suita, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujikado
authors.affiliation: Topcon Corporation, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hiroha
authors.affiliation: Topcon Corporation, Tokyo, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Mihashi
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000209:etiology / Q000473:pathology*; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery