title: Intraobserver and interobserver reproducibility in the evaluation of ultrasonic pachymetry measurements of central corneal thickness.
abstract: OBJECTIVE
  To assess reproducibility of central corneal thickness (CCT) measurement by means of ultrasonic pachymetry.
  
  
  METHODS
  Fifty one volunteers underwent three sessions of CCT measurements, each consisting of three CCT measurements, performed by each of three different observers. Intra- and interobserver reproducibility was calculated by means of intraclass correlation coefficient (ICC). The expected range of variability between two independent evaluations was calculated using scatter plots of each test-retest difference against their mean. The standard deviation of the mean differences in the test-retest scores was used to describe the differences in the score spread.
  
  
  RESULTS
  The ICC ranges of the intra- and interobserver evaluations were 0.95-0.97 and 0.89-0.95 respectively; the expected variability was < or = +/-1% and < or = +/- 2% respectively (95% confidence interval).
  
  
  CONCLUSIONS
  The measurement of CCT by means of ultrasonic pachymetry is highly reproducible.
authors.affiliation: Department of Ophthalmology, University of Milan Bicocca, Department of Neurosciences and Biomedical Technologies, Via Cadore 48, 20052 Monza, Milan, Italy. stefano.miglior@unimib.it
authors.forename: S
authors.initials: S
authors.lastname: Miglior
authors.forename: E
authors.initials: E
authors.lastname: Albe
authors.forename: M
authors.initials: M
authors.lastname: Guareschi
authors.forename: G
authors.initials: G
authors.lastname: Mandelli
authors.forename: S
authors.initials: S
authors.lastname: Gomarasca
authors.forename: N
authors.initials: N
authors.lastname: Orzalesi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000473:pathology; D003941:Diagnostic Techniques, Ophthalmological; D005902:Glaucoma, Open-Angle / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D015588:Observer Variation; D009798:Ocular Hypertension / Q000000981:diagnostic imaging / Q000473:pathology; D012016:Reference Values; D015203:Reproducibility of Results; D014463:Ultrasonography