title: Noncontact corneal pachymetry with slit lamp-adapted optical coherence tomography.
abstract: OBJECTIVE
  The purpose of this study was to determine the accuracy, the reproducibility, and the limits of agreement of noncontact central corneal thickness measurement with slit lamp-adapted optical coherence tomography (OCT).
  
  
  METHODS
  Nonrandomized comparative clinical trial.
  
  
  METHODS
  In a prospective comparative observational study, a total of 108 consecutive patients (108 eyes) with normal corneas (92 eyes) and different corneal alterations (16 eyes) participated. Six sequential measurements of the central corneal thickness with slit lamp-adapted OCT and with ultrasound (US) pachymetry at 1640 ms(-1) were performed. The main outcome measures were accuracy, reproducibility assessed with precision and coefficient of variation (CV), and limits of agreement of central corneal thickness measurement.
  
  
  RESULTS
  The mean central corneal thickness values were 541 +/- 43 microm (OCT) and 549 +/- 44 microm (US) with a mean precision of +/- 5.8 microm (CV 1.08%) and of +/- 4.0 microm (CV 0.73%), respectively. The method comparison revealed equivalence (+/- 2SD) in the 5% range with a mean difference between both methods of 7.9 microm (1.45%). The relative error was 8.7 microm (1.6%), which corresponded to limits of agreement (+/- 2SD) ranging from -9.5 microm to 25.3 microm.
  
  
  CONCLUSIONS
  Central corneal pachymetry with slit lamp-adapted OCT revealed, for clinical purposes, an excellent accuracy and reproducibility with a high degree of agreement compared with US pachymetry. Thus, the presented OCT system seems to be a promising diagnostic modality to objectively measure corneal thickness in a convenient noncontact mode.
authors.affiliation: Klinik für Augenheilkunde, Vivantes-Klinikum Neukölln, Berlin, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Wirbelauer
authors.forename: Christian
authors.initials: C
authors.lastname: Scholz
authors.forename: Hans
authors.initials: H
authors.lastname: Hoerauf
authors.forename: Duy Thoai
authors.initials: DT
authors.lastname: Pham
authors.forename: Horst
authors.initials: H
authors.lastname: Laqua
authors.forename: Reginald
authors.initials: R
authors.lastname: Birngruber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D003316:Corneal Diseases / Q000473:pathology; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007368:Interferometry; D008027:Light; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D014054:Tomography / Q000379:methods; D014463:Ultrasonography