title: Central corneal thickness measurements with Fourier-domain optical coherence tomography versus ultrasonic pachymetry and rotating Scheimpflug camera.
abstract: OBJECTIVE
  To compare the accuracy and repeatability of Fourier-domain optical coherence tomography (FD-OCT) with ultrasonic pachymetry (USP) and a rotating Scheimpflug camera for measuring the central corneal thickness (CCT).
  
  
  METHODS
  The CCT was measured in 30 subjects (30 normal corneas) by the same examiner using RTVue-100 FD-OCT with an anterior segment adaptor, Pentacam rotating Scheimpflug camera, and SP-2000 USP. Two examiners obtained one FD-OCT measurement from 10 eyes of 5 subjects to assess interexaminer reproducibility.
  
  
  RESULTS
  The mean CCT (±SD) measured by FD-OCT, USP, and the Pentacam were 530 ± 33, 544 ± 34, and 552 ± 35 μm, respectively. Significant correlations were found between FD-OCT and USP (r = 0.97; P < 0.0001), FD-OCT and Pentacam (r = 0.97; P < 0.0001), and USP and Pentacam (r = 0.96; P < 0.0001). Pairwise comparisons showed that the FD-OCT CCT measurement was significantly thinner than those of the other 2 methods (P < 0.001 for all comparisons). Regarding intraexaminer repeatability, the intraclass correlation coefficients ranged between 0.97 and 0.98. There was high repeatability of the CCT measurements with all methods. FD-OCT also had high interexaminer reproducibility (intraclass correlation coefficient = 0.98).
  
  
  CONCLUSIONS
  RTVue-100 FD-OCT may be a useful alternative for measuring the CCT; however, it significantly underestimates the CCT compared with the USP and the Pentacam with slight differences. Although highly correlated, the measurements are not directly interchangeable in clinical practice.
authors.affiliation: Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Hokkaido, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ishibazawa
authors.forename: Sho
authors.initials: S
authors.lastname: Igarashi
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Hanada
authors.forename: Taiji
authors.initials: T
authors.lastname: Nagaoka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishiko
authors.forename: Haruna
authors.initials: H
authors.lastname: Ito
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Yoshida
mesh_terms: D000328:Adult; D000886:Anthropometry; D003315:Cornea / Q000033:anatomy & histology*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D010781:Photography / Q000295:instrumentation; D012016:Reference Values; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000295:instrumentation; D014463:Ultrasonography / Q000295:instrumentation