Agreement between IOL Master 700 and Pentacam in measuring total keratometry and posterior keratometry across different axial lengths in cataract patients.

PURPOSE: This study aims to systematically evaluate the consistency of total keratometry (TK) and posterior keratometry (PK) measurements obtained by the IOL Master 700 and Pentacam in cataract patients with varying axial lengths (AL).

METHODS

A total of 240 cataract patients (240 eyes) were recruited from Beijing Tongren Hospital between February and April 2025. Participants were categorized into six groups based on AL: < 22 mm, 22-24 mm, 24-26 mm, 26-28 mm, 28-30 mm, and ≥ 30 mm. All patients underwent preoperative examinations using the IOL Master 700 and Pentacam systems to obtain measurements of TK and PK. The paired t-test or Wilcoxon signed-rank test was employed to evaluate intergroup differences. The Bland-Altman analysis was conducted to assess the 95% limits of agreement (LoA), with calculation of the mean difference.

RESULTS

Except for the subgroup with AL < 22 mm, the TK measured by the IOL Master 700 was significantly higher than that obtained using the Pentacam across all AL subgroups. The mean difference ranged from 0.005D to 0.406 D, with the width of the 95% LoA varying between 1.071D and 2.382D. For PK, measurements obtained by the IOLMaster 700 were significantly flatter compared to those from the Pentacam across all subgroups. The mean differences ranged from 0.442 to 0.478 D, with the width of the 95% LoA ranging from 0.244 to 0.319 D.

CONCLUSION

Regardless of AL, the measurement discrepancies in TK and PK between the two devices exceed the clinically acceptable limits, suggesting that these devices are not interchangeable across patients with varying AL.