Repeatability and agreement of three biometers measuring corneal keratometry and astigmatism in eyes with cataract and high myopia

Background

Accurate ocular biometric measurements are essential for intraocular lens (IOL) power calculation and postoperative refractive assessment. Various diagnostic devices, including the IOL Master 700, OPD-SCAN III, and Pentacam Scheimpflug system, are commonly used to measure corneal curvature and astigmatism. However, discrepancies between these devices may exist, particularly in patients with high myopia. This study aimed to evaluate the agreement and interchangeability of keratometric (K1, K2) and astigmatism (AST) measurements obtained from these three devices in patients with cataracts and high myopia.

Methods

This cross-sectional study included 30 eyes from 30 patients with mild-to-moderate cataracts and high myopia. Each participant underwent keratometric measurements using the IOL Master 700, OPD-SCAN III, and Pentacam Scheimpflug system. Differences between devices were assessed using one-way ANOVA with Bonferroni’s post hoc test. Pearson’s correlation coefficients were calculated to assess inter-device correlations, and Bland-Altman plots were used to evaluate agreement and interchangeability.

Results

Strong correlations were observed among the three devices for K1 (r > 0.96, p < 0.001) and K2 (r > 0.95, p < 0.001) measurements, while AST showed slightly lower correlations (r > 0.77, p < 0.001). Significant differences were noted in K1 between Pentacam and the other two devices (p < 0.01), while K2 and AST exhibited varying degrees of disagreement. Bland-Altman analysis demonstrated narrow 95 % limits of agreement, but systematic differences were identified, particularly in AST measurements.

Conclusion

Despite strong correlations, significant inter-device differences suggest that keratometric and astigmatism measurements from these three devices are not fully interchangeable. Clinicians should be cautious when using different devices for preoperative assessments and IOL power calculations in patients with high myopia. Further research is needed to refine measurement algorithms and optimize clinical accuracy.