[Agreement and repeatability of central corneal thickness measurement using the Pentacam and ultrasound pachymetry]

To compare the agreement and repeatability of the OCULUS Pentacam (a new Scheimpflug-based imaging system) with ultrasound pachymetry in the measurement of central corneal thickness (CCT).

Central corneal thickness was measured in 112 subjects (112 eyes) separately by two examiners, first using the Pentacam instrument, then using an ultrasonic pachymetry. Measurements were repeated 3 times for each pachymetry.

Mean values of CCT for each instrument were (538.63 ± 31.55) µm and (541.02 ± 30.45) µm using the Pentacam and the ultrasonic pachymeter, respectively. The difference is significant between the two instruments (t = -3.414, P = 0.001), the mean value of the difference is (-2.39 ± 7.42) µm. The Bland-Altman Plots displayed relatively good agreement (limits of agreement were -16.93 µm to 12.15 µm) between the two instruments. The intraclass correlation coefficient (ICC) of the two devices showed high repeatability (Separately 0.86 and 0.88).

The agreement between the Pentacam instrument and the ultrasonic pachymetry was good, and the repeatability was also good for both instruments independently, however it is needed to increase measure times to improve the repeatability of the Pentacam which is a promising new instrument for anterior eye evaluation.