Comparison of Biometric Measurements Between Anterior Segment Hyperparallel and Swept-Source Optical Coherence Tomography

Purpose: To evaluate the inter-device agreement between hyperparallel optical coherence tomography (HP-OCT) and swept-source OCT (SS-OCT) in quantitative anterior segment parameters. Methods: Phakic subjects aged ≥40 years were consecutively recruited at a tertiary eye hospital. Horizontal B-scans (0°-180°) were analyzed. On SS-OCT, parameters were measured automatically; on HP-OCT, they were extracted manually using 3D Slicer. Agreement was evaluated using intraclass correlation coefficients (ICCs), Bland-Altman plots, and orthogonal regression. Results: A total of 118 sectors from 59 subjects were analyzed. ICCs were ≥0.88 for all parameters except iris thickness (IT) at 750 µm (IT750, ICC = 0.66). HP-OCT consistently measured lower values than SS-OCT for angle opening distance (AOD) at 500 µm (AOD500: -0.024 [-0.036 to -0.013]) and 750 µm (AOD750: -0.032 [-0.050 to -0.015]), trabecular-iris space area (TISA) at 500 µm (TISA500: -0.008 [-0.013 to -0.003]) and 750 µm (TISA750: -0.012 [-0.020 to -0.004]), iris curvature (IC: -0.015 [-0.021 to -0.009]), IT750 (-0.031 [-0.041 to -0.022]), and anterior chamber depth (-0.118 [-0.138 to -0.098]). For the following parameters, differences between devices increased with larger measurements, with HP-OCT yielding proportionally lower values (proportional bias): AOD500, AOD750, TISA500, TISA750, IC, and lens vault. Conclusions: For anterior segment biometry, HP-OCT and SS-OCT showed high ICCs but limited interchangeability because of systematic and proportional bias. Translational Relevance: Understanding how HP-OCT measurements compare with those from SS-OCT is essential for clinical integration, because inter-device agreement and interchangeability guide how HP-OCT can be applied and interpreted in practice.