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.
Eye Hospital of Wenzhou Medical University, Zhejiang, China.
Prospective case series.
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.
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.
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.