Repeatability and agreement of two swept-source optical coherence tomographers and Scheimpflug imaging for measurements of corneal curvature

Abstract

Abstract Purpose: To evaluate the repeatability and agreement of two swept-source optical coherence tomographers and Scheimpflug imaging for corneal curvature in healthy subjects. Methods: Simulated keratometry (SimK), posterior keratometry (Kp), total corneal power (TCP), and total corneal astigmatism(TCA) were measured with CASIA2, Anterion, and Pentacam. Within-subject standard deviation (Sw), repeatability coefficient (RC), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were used to assess inter-device repeatability. Bland-Altman analysis was performed to determine inter-device agreement. Results: Three devices showed good repeatability for SimK, Kp, and TCP with all the ICC > 0.980. Pentacam showed the highest repeatability while the CASIA2 revealed the lowest repeatability for SimK and TCP. Anterion and CASIA2 revealed better repeatability for Kp than Pentacam. Pentacam and Anterion showed good repeatability for TCA, whereas the CASIA2 showed moderate repeatability. Three instruments demonstrated good agreement with the maximum absolute 95% Limits of agreement (LoA) of 1.00 D for SimK, Kp, and TCP. Wide LoA were found between for TCA with the maximum absolute 95% LoA ≥0.66 D between the three devices. Conclusions: Three devices illustrated good repeatability for SimK, Kp, and TCP. Both Anterion and Pentacam showed good repeatability for TCA while CASIA2 displayed moderate repeatability. Good agreement was found for SimK, Kp, and TCP but not for TCA.