title: Pachymetry assessment with Orbscan II in postoperative patients with myopic LASIK.
abstract: OBJECTIVE
  To compare central corneal thickness after LASIK for myopia, using ultrasonic pachymetry and Orbscan II measurements, and to evaluate changes in these measurements over time.
  
  
  METHODS
  Central corneal thickness measurements obtained by ultrasonic pachymetry and Orbscan II (Bausch and Lomb, Rochester, NY) in patients who underwent myopic LASIK between July 2002 and May 2003 were analyzed. The two measurements were assessed preoperatively and postoperatively at 1 day and 1, 3, 6, and 12 months.
  
  
  RESULTS
  In 237 eyes, using the correction factor 0.93, no significant difference was noted in the preoperative central corneal thickness measured by ultrasonic pachymetry (561.89 +/- 28.66 microm) and Orbscan pachymetry (562.28 +/- 28.18 microm) (P =.713). Postoperatively, the difference was statistically significant at day 1 and 1, 3, and 6 months (P < .001), but was not significant at 12 months (P = .130).
  
  
  CONCLUSIONS
  Orbscan II measurements of central corneal thickness after myopic LASIK are less than those measured by ultrasonic pachymetry; however, this difference decreases with time and may not be significant after 1 year.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, University Eye Center, Hong Kong Eye Hospital, Kowloon, Hong Kong, People's Republic of China. arthurcheng@cuhk.edu.hk
authors.forename: Arthur C K
authors.initials: AC
authors.lastname: Cheng
authors.forename: Srinivas K
authors.initials: SK
authors.lastname: Rao
authors.forename: Emily
authors.initials: E
authors.lastname: Tang
authors.forename: Dennis S C
authors.initials: DS
authors.lastname: Lam
mesh_terms: D000328:Adult; D003315:Cornea / Q000000981:diagnostic imaging* / Q000601:surgery; D003941:Diagnostic Techniques, Ophthalmological; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008875:Middle Aged; D009216:Myopia / Q000000981:diagnostic imaging / Q000601:surgery*; D011184:Postoperative Period; D012189:Retrospective Studies; D016896:Treatment Outcome; D014463:Ultrasonography