Repeatability and Agreement of Four Biometers for Measuring Various Anterior Segment Parameters.

ABSTRACT

Purpose: To assess the repeatability and agreement of a new swept source optical coherence tomography (SS-OCT) biometer (IOL Master® 700, Carl Zeiss Meditec), an optical low coherence reflectometer (Lenstar LS 900®, Haag-Streit AG, Koeniz, Switzerland), a dual scheimpflug ray tracing biometer (Galilei G6®, Ziemer, Switzerland) and a partial coherence interferometer, AL scan® (Nidek Co. Ltd., Japan) to measure the keratometry (K), astigmatism (AST), axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT) and white-to-white (WTW) in cataractous eyes in a Cross-sectional study. Methods: 50 eyes of 50 consecutive patients scheduled for cataract surgery were included. Three consecutive scans were performed using the 4 biometers by a single operator. Within-subject standard deviation (Sw), test-retest repeatability and coefficient of variation for assessing repeatability were assessed. Bland-Altman plots for the agreement between the mean measurements of each machine were examined. Results: The mean age of patients was 60.2 ± 10.6 years. Dropouts for AL measurement were significantly higher in AL scan® and Galilei G6® compared to IOL Master® 700. There was good agreement between IOL Master® 700 and Lenstar LS 900® for AL and keratometry (P < 0.5). High variability was seen between the 4 machines for AST and WTW. Conclusion: The new SS-OCT biometer showed valid measurements, good repeatability and good agreement with the optical low coherence reflectometry biometer. The new long range SS-OCT biometer was better than the other three devices in acquiring AL measurements in denser cataracts due to better penetration.