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Intraobserver and interobserver reproducibility in the evaluation of ultrasonic pachymetry measurements of central corneal thickness
  1. S Miglior1,
  2. E Albe2,
  3. M Guareschi2,
  4. G Mandelli2,
  5. S Gomarasca1,
  6. N Orzalesi2
  1. 1Department of Ophthalmology, University of Milan Bicocca, Department of Neurosciences and Biomedical Technologies, Monza, Italy
  2. 2Department of Ophthalmology, University of Milan, Department of Medicine, Surgery and Dentistry, Monza, Italy
  1. Correspondence to: Stefano Miglior MD, Dipartimento di Neuroscienze e Tecnologie Biomediche, Universita’ degli Studi di Milano Bicocca, Via Cadore 48, 20052 Monza (MI), Italy;


Purpose: 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 ⩽±1% and ⩽± 2% respectively (95% confidence interval).

Conclusions: The measurement of CCT by means of ultrasonic pachymetry is highly reproducible.

  • CCT, central corneal thickness
  • ICC, intraclass correlation coefficient
  • IOP, intraocular pressure
  • OHT, ocular hypertension

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  • Funded by a grant from the Ministero dell’Universita’ e della Ricerca Scientifica, Italy

  • None of the authors has any proprietary or commercial interest in the manuscript.