Agreement between a new SS-OCT biometer and a SD-OCT/Placido topographer for anterior segment measurements

PURPOSE: To evaluate the agreement of anterior segment biometric measurements between a new swept-source optical coherence tomography (SS-OCT) biometer (ZW-30) and a spectral-domain optical coherence tomography combined with Placido-disk topography (SD-OCT/Placido topographer, MS-39). SETTING: Eye and ENT Hospital of Fudan University, Shanghai, China. DESIGN: Prospective cross-sectional study. METHODS: This prospective, cross-sectional study recruited 70 healthy eyes from 70 participants. Each eye underwent 3 consecutive scans with both ZW-30 and MS-39. Parameters analyzed included central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), mean keratometry (Km), J 0 and J 45 astigmatism vector components, and corneal diameter (CD). Interdevice differences were evaluated using paired t tests, and Bland-Altman analysis with 95% limits of agreement (LoA) assessed the agreement. RESULTS: Significant differences were observed in all parameters measured, except for J 0 . Bland-Altman analysis indicated high agreement for CCT (mean difference: 5.38 ± 3.67 μm; 95% LoA: -2.73 to 13.48 μm), ACD (-0.11 ± 0.03 mm; -0.18 to -0.03 mm), LT (-0.06 ± 0.05 mm; -0.17 to 0.05 mm), Km (0.07 ± 0.16 diopter [D]; -0.33 to 0.47 D), J 0 (0.02 ± 0.12 D; -0.31 to 0.27 D), and J 45 (-0.08 ± 0.09 D; -0.32 to 0.16 D). A larger discrepancy was observed for CD (0.48 ± 0.13 mm; 0.17 to 0.79 mm). CONCLUSIONS: The ZW-30 SS-OCT biometer and the MS-39 SD-OCT/Placido topographer demonstrated high agreement for most anterior segment parameters, indicating their interchangeability in clinical practice. However, caution is advised when using CD measurements interchangeably because of the observed systematic differences between devices.