title: Assessment of central corneal thickness using OCT, ultrasound, optical low coherence reflectometry and Scheimpflug pachymetry.
abstract: OBJECTIVE
  Accurate measurement of central corneal thickness (CCT) is essential in refractive surgery and advanced glaucoma diagnostics. The gold standard for pachymetry is full-contact ultrasound-based pachymetry. As this method is associated with potential sources of error, noncontact methods have been introduced. The aim of this study was to compare CCT results measured using 4 different techniques.
  
  
  METHODS
  In this analysis of 20 patients (40 eyes) at the University Eye Hospital Heidelberg, Germany, we compared a slit-lamp-mounted optical coherence tomography (OCT) system (SL-OCT, Heidelberg Engineering, Heidelberg, Germany), conventional ultrasound pachymetry (IOPac, Heidelberg Engineering), optical low coherence reflectometry (OLCR, Haag-Streit, Germany), and scanning-slit pachymetry (Orbscan).
  
  
  RESULTS
  Comparison among the 4 groups did not show significant differences, except the comparison of OLCR to Orbscan; the mean was significantly different (p=0.0247) and the Orbscan detected slightly thicker values than the other methods.
  
  
  CONCLUSIONS
  Orbscan, SL-OCT, and OLCR provide non-touch technology, without the need for local anesthesia, and limiting the risk of infection or artifacts. Extreme care must be used interpreting the results obtained from Orbscan, as this technique may overestimate the CCT significantly.
authors.affiliation: University Eye Hospital Mannheim, Medical Faculty Mannheim of the University of Heidelberg, Mannheim, Germany.
authors.forename: Sven C
authors.initials: SC
authors.lastname: Beutelspacher
authors.forename: Nermin
authors.initials: N
authors.lastname: Serbecic
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Scheuerle
mesh_terms: D000328:Adult; D000886:Anthropometry; D003315:Cornea / Q000033:anatomy & histology*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007368:Interferometry; D008297:Male; D010781:Photography; D015203:Reproducibility of Results; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D014463:Ultrasonography; D055815:Young Adult