title: Central corneal thickness measurements using Orbscan II, Visante, ultrasound, and Pentacam pachymetry after laser in situ keratomileusis for myopia.
abstract: OBJECTIVE
  To compare corneal pachymetry assessment using 4 measurement methods in eyes after laser in situ keratomileusis (LASIK) for myopia.
  
  
  METHODS
  Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Hong Kong SAR.
  
  
  METHODS
  Fifty-two consecutive patients (103 eyes) who had LASIK for the correction of myopia had Orbscan II (Bausch & Lomb), Visante (Carl Zeiss Meditec), Pentacam (Oculus, Inc.), and ultrasound (US) pachymetry (Sonomed, 200P) 6 months after surgery. Data were analyzed using the paired sample t test, Bland-Altman plots, and linear regression.
  
  
  RESULTS
  The mean postoperative pachymetry measured by US, Orbscan (0.89 acoustic factor), Pentacam, and Visante pachymetry were 438.2 microm+/-41.18 (SD), 435.17+/-49.63 microm, 430.66+/-40.23 microm, and 426.56+/-41.6 microm, respectively. Compared with the US measurement, Pentacam and Visante measurements significantly underestimated corneal thickness by a mean of 7.54+/-15.06 microm (P<.01) and 11.64+/-12.87 microm (P<.01), respectively. There was no statistically significant difference between US and Orbscan measurements.
  
  
  CONCLUSIONS
  Pentacam and Visante measurements of corneal thickness 6 months after LASIK were significantly less than those obtained using Orbscan and US pachymetry, although all 4 measurement methods showed a high correlation with each other.
authors.affiliation: Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, University Eye Center, Hong Kong Eye Hospital, Hong Kong, China.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ho
authors.forename: Arthur C K
authors.initials: AC
authors.lastname: Cheng
authors.forename: Srinivas K
authors.initials: SK
authors.lastname: Rao
authors.forename: Silvania
authors.initials: S
authors.lastname: Lau
authors.forename: Chris K S
authors.initials: CK
authors.lastname: Leung
authors.forename: Dennis S C
authors.initials: DS
authors.lastname: Lam
mesh_terms: D000886:Anthropometry / Q000379:methods*; D003315:Cornea / Q000000981:diagnostic imaging / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods; D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D009216:Myopia / Q000601:surgery*; D010781:Photography / Q000379:methods; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods; D014463:Ultrasonography