The purpose of this work is to evaluate the repeatability and concordance of the Oculus Pentacam system when using it for measuring several parameters of the anterior segment of the eye and to check whether this device can substitute a standard corneal topographer in the measurement of the corneal first surface. Reliability has been assessed using 10 successive measurements in two eyes taken by a single examiner. Within-observer and between-observer concordance measurements have been performed on 21 emmetropic and ametropic eyes without ocular pathology. Intraclass correlation coefficients (ICC) have also been calculated. To evaluate the interchangeability between the Oculus Pentacam and the Humphrey Atlas reflection corneal topographer, 22 eyes have been measured with two different systems, and differences between devices have been represented by the Bland-Altman method. The reliability study shows values lower than 5% for the coefficient of variation. Within-observer concordance for all variables measured was higher than 95%. Between-observer concordance is also generally good. The performed comparative study shows that Oculus Pentacam and Humphrey Atlas systems do not provide completely equivalent measures of the first corneal surface. The Oculus Pentacam system shows a good within-observer and between-observer concordance for the measurements provided by the system. Pentacam and Atlas systems are not completely interchangeable. Depending on the specific measured variable, differences between systems are statistically and could be clinically relevant.

This work has been supported by the Ministerio de Educación y Ciencia through the project nr. FIS2005-05053.