ObjectiveTo compare the repeatability and consistency among three instruments, namely, manual keratometer, optical coherence biometer (IOLMaster) and VERION digital navigation system, for measuring corneal curvature. MethodsThe three instrument mentioned above were separately applied to 39 patients (78 eyes) with cataract for corneal biometry, and their steep keratometry (Ks), flat keratometry (Kf) and astigmatic axis were recorded. The three different instruments were compared in terms of repeatability and consistency of their detection results. ResultsThe 2.77 within-subject standard deviation (Sw) and within-subject coefficient of variation (CVw) for Kf were all less than or equal to 0.19 D and 0.16%, respectively, among the three different instruments, and intraclass correlation coefficient (ICC) greater than or equal to 0.91; the 2.77 Sw and CVw for Ks were all less than or equal to 0.25 D and 0.21%, respectively, and ICC greater than or equal to 0.90. The pairwise comparison between different instruments revealed that the maximum average values of Kf difference in the right eye, Kf difference in the left eye, Ks difference in the right eye, and Ks difference in the left eye were 0.27 D, 0.24 D, 0.14 D and 0.16 D, respectively. After a pairwise comparison, the Kf values of left and right eyes measured by the three different instruments, except for manual corneal curvatures measured by VERION system (right eye P=0.26, left eye P=0.44), showed statistically significant differences. After a pairwise comparison, the Ks values of left and right eyes measured by the three different instruments, except for manual corneal curvatures measured by VERION system (right eye P=0.84, left eye P=0.89), showed statistically significant differences. 95% limits of agreement (LoA) for each instrument was less than 0.5 D, with a narrow consistency range. ConclusionThe three instruments have a good repeatability and a high accuracy in measuring corneal curvature, achieving a favorable consistency.

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