Comparison of anterior segment measurements obtained using a swept-source optical coherence tomography biometer and a Scheimpflug-Placido tomographer

Abstract

Purpose: To assess the repeatability and agreement of anterior segment measurements between an optical biometer (IOLMaster 700) using swept-source optical coherence tomography and a Scheimpflug-Placido tomographer (Sirius) in patients scheduled for corneal refractive surgery.

Setting: Eye Hospital of Wenzhou Medical University, Zhejiang, China.

Design: Prospective case series.

Methods: The parameters, including the central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth, keratometry (K) values, astigmatism, J0 (Jackson cross-cylinder with axes at 180 degree and 90 degrees) and J45 vectors (Jackson cross-cylinder with axes at 45 degrees and 135 degrees), and horizontal corneal diameter, were measured 3 times per instrument. The intraobserver repeatability was assessed using test-retest repeatability, the coefficient of variation (CoV), and the intraclass correlation coefficient (ICC). Paired t tests were used to compare the difference between the 2 methods. Agreement was evaluated using Bland-Altman analyses.

Results: The study enrolled 100 right eyes. All measurements of the 2 devices showed high repeatability. The CoV of all measured parameters was less than 0.93 and the ICC value was more than 0.85. The paired t test did not show a significant difference in CCT, astigmatism, J0 or J45 vector. The mean ACD and aqueous depth were statistically lower with the optical biometer; however, the 95% limits of agreement (LoA) were low (from -0.20 to -0.03 mm). The K and corneal diameter values obtained using the optical biometer were higher by 0.1 diopter and 0.1 mm, respectively, but with narrow 95% LoA.

Conclusions: The optical biometer and the Scheimpflug-Placido tomographer showed high repeatability for all anterior segment measurements. The measured parameters showed good agreement and could be used interchangeably.