Keratometry evaluations with the Pentacam high resolution in comparison with the automated keratometry and conventional corneal topography

Abstract

Purpose: To determine the reliability and repeatability of keratometry (K) measurements obtained with the Pentacam high resolution (HR), automated keratometry, and corneal topography systems.

Methods: The right eyes of 46 healthy subjects were examined prospectively. Keratometry measurements in the flat (Kf) and steep (Ks) meridians were taken by 2 independent investigators with the Pentacam HR (Oculus, Wetzlar, Germany) followed by automated keratorefractometry (KR-8100; Topcon, Tokyo, Japan), and corneal topography (TMS-4; Tomey, Erlangen, Germany).

Results: The mean K readings of the Pentacam HR, automated keratometry, and corneal topography were 43.40/43.34 diopter (D), 43.99/43.98 D, and 43.80/43.83 D, respectively. The difference between the values was statistically significant (P < 0.0001, repeated measures analysis of variance). Strong significant correlation was observed between the Pentacam HR and keratometry (Kf: r = 0.952/0.954; Ks: r = 0.845, Spearman rank test), and Pentacam HR and corneal topography (Kf: r = 0.933/0.930; Ks: r = 0.838/0.829) (P < 0.0001). No significant difference was presented between the 2 investigators for any of the instruments (P = 0.215-0.983). Moreover, high correlation was found between the K readings of the observers (interoperator intraclass correlation coefficients ranged from 0.95 to 0.99).

Conclusions: The Pentacam HR provided reliable K measurements in clinical practice in comparison with an automated keratometer and a corneal topographer. Based on the results, for patient follow-up, one keratometry device is recommended.