title: Central corneal pachymetry in patients undergoing laser in situ keratomileusis.
abstract: OBJECTIVE
  To report the preoperative ultrasonic central pachymetric measurements on a large group of eyes undergoing laser-assisted in situ keratomileusis (LASIK) surgery for myopia and myopic astigmatism, to determine whether central corneal thickness is correlated with other geometric features of the eye or is correlated with age or gender, and to discuss the resulting limitations on possible ablation depths.
  
  
  METHODS
  Prospective, multisite, cross-sectional study.
  
  
  METHODS
  Eight hundred ninety-six eyes in 450 patients from 21 to 66 years of age.
  
  
  METHODS
  Central corneal thickness and its correlation to intraocular pressure, corneal curvature, axial length, horizontal corneal diameter, refraction, age, and gender.
  
  
  RESULTS
  The mean central corneal thickness was 550 microm with a standard deviation of 33 and a range of 472 to 651 microm. The lower 25th quantile was 528 microm. The central corneal pachymetry correlated with the mean manual keratometric measurement (P = 0.0001), simulated keratometry (Sim K) (P = 0.0001), and intraocular pressure (P = 0.0001). Central corneal thickness did not correlate with axial length, age, gender, horizontal corneal diameter, and refraction.
  
  
  CONCLUSIONS
  This clinical study shows there is a substantial range of central corneal thickness in normal myopic eyes. With LASIK, there is a general concern that one should not thin the cornea further than a given amount. Because this study shows wide variability in central corneal thickness, it is prudent to measure pachymetry before surgery and gear treatment plans accordingly. Possible treatment limits relative to corneal thickness are discussed.
authors.affiliation: Price-Whitson Center for Refractive Surgery, Indianapolis, Indiana, USA.
authors.forename: F W
authors.initials: FW
authors.lastname: Price
authors.forename: D L
authors.initials: DL
authors.lastname: Koller
authors.forename: M O
authors.initials: MO
authors.lastname: Price
mesh_terms: D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D003315:Cornea / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D011446:Prospective Studies; D014463:Ultrasonography