Agreement Between Two Optical Biometers Based on Large Coherence Length SS-OCT and Scheimpflug Imaging/Partial Coherence Interferometry.

Abstract

To evaluate the agreement between measurements obtained with a new optical biometer (Argos; Movu Inc) using large coherence length swept-source optical coherence tomography (SS-OCT) and those obtained with an optical biometer with a rotating Scheimpflug camera, combined with partial coherence interferometry (PCI) (Pentacam AXL; Oculus Optikgeräte GmbH) in adults. The following measurements were examined and evaluated: axial length, central corneal thickness (CCT), anterior chamber depth (ACD), mean keratometry, J0 and J45 vectors, and corneal diameter. Measurements with the two biometers were conducted in triplicate per instrument in a random order by the same examiner. Paired t tests were employed to compare the difference between the two devices. The Bland-Altman method was implemented to assess their agreement. A total of 145 patients were enrolled in the study. The differences between the Scheimpflug/PCI-based biometer and the SS-OCT biometer were as follows: -0.02 ± 0.05 mm for axial length, 1.15 ± 5.79 µm for CCT, -0.04 ± 0.04 mm for ACD, -0.28 ± 0.16 diopters (D) for mean keratometry, 0.01 ± 0.11 D for J0, -0.02 ± 0.10 D for J45, and -1.03 ± 0.62 mm for corneal diameter. Bland-Altman plots showed narrow ranges in axial length, CCT, ACD, mean keratometry, and J0 and J45, which implied excellent agreement between the two biometers. Corneal diameter displayed poor agreement, with a 95% limits of agreement ranging from -2.25 to 0.19 mm. Excellent agreement was established between the measurements provided by the new optical biometer based on SS-OCT and the optical biometer using Scheimpflug imaging and PCI, except for corneal diameter. [J Refract Surg. 2020;36(7):459-465.].