title: Measuring central corneal thickness with ultrasound pachymetry.
abstract: OBJECTIVE
  To determine how many ultrasound pachymetry measurements are required to obtain a reasonable estimate of central corneal thickness.
  
  
  METHODS
  Five central corneal thickness measurements were obtained from each eye of 101 patients with normal corneas. The means of fewer than five readings were compared with the mean of five values for each eye to determine the incremental clinical value of additional measurements.
  
  
  RESULTS
  Compared with the mean of five values, fewer than three measurements per eye provided a mean central corneal thickness value with inadequate confidence. Conversely, means of more than three readings provided little additional confidence over means of three values.
  
  
  CONCLUSIONS
  Central corneal thickness by ultrasound pachymetry can be adequately assessed in the majority of eyes by taking three measurements per eye.
authors.affiliation: Department of Ophthalmology, Jones Eye Institute, University of Arkansas for Medical Sciences, 4301 West Markham Street, Mail Slot 523, Little Rock, AR 72205, USA. hypotony@yahoo.com
authors.forename: Tony
authors.initials: T
authors.lastname: Realini
authors.forename: Kim
authors.initials: K
authors.lastname: Lovelace
mesh_terms: D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D019781:Corneal Topography / Q000592:standards*; D006801:Humans; D009907:Optometry / Q000295:instrumentation; D015203:Reproducibility of Results; D014463:Ultrasonography; D014894:Weights and Measures