title: Central corneal thickness measured with three optical devices and ultrasound pachometry.
abstract: OBJECTIVE
  To evaluate the reliability of three noninvasive pachometry methods against the ultrasound pachometer considered the gold standard.
  
  
  METHODS
  Central corneal thickness (CCT) was measured using a Paxis ultrasound (US) pachometer, Orbscan II, Pentacam, and Topcon SP-3000 specular microscope in 22 right eyes of 22 healthy adults (7 men, 15 women). Three repeated measures were obtained and then compared to obtain the repeatability of each instrument and the agreement between pachometers.
  
  
  RESULTS
  Pentacam is the optical system that renders values of CCT closer to those obtained with US pachometry. Conversely, a specular microscope shows a poorer agreement with US measures, and differences depend on the thickness being measured. The Orbscan system shows a consistent trend toward underestimation of CCT compared with US and Pentacam irrespective of the value measured.
  
  
  CONCLUSIONS
  Different optical methods used to measure CCT showed significantly different results compared with US pachometry except for the Pentacam system. Clinicians should take into account the fact that specular microscopy might either underestimate or overestimate values of CCT, whereas Orbscan systematically overestimates CCT compared with US and Pentacam.
authors.affiliation: Optometry Research Group, Universidade de Santiago de Compostela, A Coruña, Spain. javier.gonzalez@usc.es
authors.forename: Javier
authors.initials: J
authors.lastname: González-Pérez
authors.forename: José Manuel
authors.initials: JM
authors.lastname: González-Méijome
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Rodríguez Ares
authors.forename: Manuel Angel
authors.initials: MA
authors.lastname: Parafita
mesh_terms: D000328:Adult; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D019781:Corneal Topography / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D015203:Reproducibility of Results; D014463:Ultrasonography; D055815:Young Adult