title: Evaluating central corneal thickness measurements with noncontact optical low-coherence reflectometry and contact ultrasound pachymetry.
abstract: OBJECTIVE
  To compare the central corneal thickness (CCT) measurements obtained with noncontact optical low-coherence reflectometry (OLCR) and ultrasound (US) pachymetry.
  
  
  METHODS
  Prospective, comparative observational study.
  
  
  METHODS
  Three sequential ultrasonic measurements and a set of five OLCR scans of 52 eyes of 26 healthy subjects were recorded. Noncontact measurement was repeated five minutes after anesthetic drop instillation.
  
  
  RESULTS
  Mean CCT values for noncontact OLCR and US pachymetry were 544.03 microm and 548.66 microm, respectively, with mean SDs of 0.97 microm and 4.63 microm, respectively. Noncontact OLCR measured on average 4.64 microm less than US pachymetry (95% confidence interval -7.56 to -1.72; P = .003). The OLCR measured 1.68 microm less than US pachymetry in the thinner cornea group (< or =548.7 microm, n = 24) and 7.48 mum less in the thicker group (n = 25). This difference was statistically significant (P = .04).
  
  
  CONCLUSIONS
  There was agreement between the two pachymetric measurements. Noncontact OLCR appeared to measure slightly smaller than US pachymetry.
authors.affiliation: Department of Ophthalmology, College of Physicians and Surgeons of Columbia University, Columbia University, New York, New York 10032, USA.
authors.forename: Suzanna
authors.initials: S
authors.lastname: Airiani
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Trokel
authors.forename: Shing M
authors.initials: SM
authors.lastname: Lee
authors.forename: Richard E
authors.initials: RE
authors.lastname: Braunstein
mesh_terms: D000328:Adult; D001837:Body Weights and Measures; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D014463:Ultrasonography