Comparison of Corneal Curvature and Astigmatism Measurements Among Three Optical Biometers in Age-Related Cataract...

Precise preoperative corneal measurements are crucial for optimizing intraocular lens power calculation in cataract surgery. Nevertheless, the agreement among different biometers remains ambiguous. This study was designed to compare the agreement of corneal curvature and astigmatism measurements obtained with CASIA2 (device 1), IOLMaster 700 (device 2), and Pentacam HR (device 3) in patients with age-related cataract. In this cross-sectional study, 800 eyes of 593 patients with age-related cataract were examined prior to phacoemulsification. The steep keratometry (Ks), flat keratometry (Kf), mean keratometry (Km), and astigmatism (J0, J45) of the anterior, posterior, and total cornea were documented. Repeated-measures analysis of variance (rANOVA) or Friedman tests were employed to assess inter-device differences. Agreement was evaluated using Intraclass correlation coefficients (ICCs) and Bland-Altman analysis with 95% limits of agreement (LoA). Statistically significant differences were detected in most parameters across devices. Simulated keratometry (SimK) exhibited excellent inter-device reliability, with over 95% of differences within ± 1.0 D. Total keratometry (TK) showed good agreement, whereas posterior keratometry (PK) demonstrated poor agreement. Regarding astigmatism, the J0 components displayed higher consistency than the J45 components. Bland-Altman analysis revealed clinically acceptable LoA for SimK but greater variability for TK and PK parameters. SimK measurements showed high agreement across the three devices in this cataract cohort, supporting their clinical utility. However, due to significant discrepancies in TK and PK parameters, device-specific protocols are recommended for posterior and total corneal assessments. These findings may provide guidance for device selection in preoperative cataract evaluation.