What question did this study set out to answer?

The research aims to evaluate the consistency of measurements from a new biometer, ZW-30, against established devices IOLMaster 700 and Sirius in cataract patients.

March 12, 2026Open Access

Ocular biometry agreement among ZW-30, IOLMaster 700, and sirius in cataract patients

Key Points

The research aims to evaluate the consistency of measurements from a new biometer, ZW-30, against established devices IOLMaster 700 and Sirius in cataract patients.
Included 307 cataract patients and measured various biometric parameters among three devices.
Conducted Bland-Altman analysis and Spearman correlation analysis to assess consistency and correlation of measurements.
Established inter-device agreement equations based on measured parameters.
Strong correlations found for ACD, CCT, AL, LT, and anterior corneal curvature with no significant mean differences between devices.
Total corneal parameters and kappa angle showed significant differences, exceeding clinical thresholds.
Pupil diameter measurements showed systematic bias, indicating they are not interchangeable between devices.

Abstract

Accurate ocular biometry is crucial for the success of refractive cataract surgery. This study aims to assess the consistency and differences of a new biometer, the ZW-30, compared with the mainstream devices IOLMaster 700 and Sirius in patients with cataracts. A total of 307 patients with cataracts (603 eyes) were included. The anterior chamber depth (ACD), central corneal thickness (CCT), white-to-white (WTW) distance, pupil diameter (PD), flat K (K1), steep K (K2), corneal astigmatism (ΔK), total keratometry (TK), total corneal astigmatism (TCA), astigmatism axis, kappa angle (κ), axial length (AL), and lens thickness (LT) were measured using the ZW-30, IOLMaster 700, and Sirius. The consistency between devices was evaluated using Bland-Altman analysis, the correlation of parameters was assessed using Spearman correlation analysis, and inter-device agreement equations were established. Strong correlations (r ≥ 0.7) and no statistically significant differences in mean values (p > 0.05) were found for ACD, CCT, AL, LT, and anterior corneal curvature (K1/K2) among the three devices, but the 95% limits of agreement (LoA) exceeded the clinical threshold. Total corneal parameters (TK/TCA) and κ angle showed strong correlations (r ≥ 0.5) among the three devices, with significant inter-device differences in mean values (p < 0.05) and 95%LoA exceeding the clinical threshold. Corneal diameter (WTW) had a weak correlation (r = 0.48) between the ZW-30 and Sirius, and differences in PD measurement methods led to systematic bias. The ZW-30 is consistent with the IOLMaster 700 and Sirius in terms of group trends for basic biometric parameters (ACD/CCT/anterior corneal curvature), but significant individual differences exist (95%LoA exceeding the threshold). Total corneal parameters (TK/TCA) and κ angle require cross-validation with Sirius. WTW and PD are not interchangeable between devices due to differences in measurement principles. Cross-device parameter conversion should be avoided in clinical practice to ensure the accuracy of refractive surgery.

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Ocular biometry agreement among ZW-30, IOLMaster 700, and sirius in cataract patients

Key Points

Abstract

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