Intraobserver and interobserver reproducibility in the evaluation of ultrasonic pachymetry measurements of central corneal thickness
- 1Department of Ophthalmology, University of Milan Bicocca, Department of Neurosciences and Biomedical Technologies, Monza, Italy
- 2Department of Ophthalmology, University of Milan, Department of Medicine, Surgery and Dentistry, Monza, Italy
- Correspondence to: Stefano Miglior MD, Dipartimento di Neuroscienze e Tecnologie Biomediche, Universita’ degli Studi di Milano Bicocca, Via Cadore 48, 20052 Monza (MI), Italy; stefano.migliorunimib.it
- Accepted 15 June 2003
Abstract
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
Footnotes
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Funded by a grant from the Ministero dell’Universita’ e della Ricerca Scientifica, Italy
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None of the authors has any proprietary or commercial interest in the manuscript.







