Comparison of toric intraocular lens calculation with the integrated K method and three single biometric devices.

Purpose: To compare astigmatic outcomes using the Integrated K method and anterior surface keratometry from 3 different biometric devices.

Setting: Lions Eye Institute, Perth, Australia.

Design: Retrospective case series.

Methods: Eyes of patients who underwent uneventful cataract surgery were analyzed. Predicted postoperative astigmatism was calculated for Integrated K method, IOLMaster 700, Lenstar and Pentacam. The mean centroid error in predicted postoperative refractive astigmatism (PE), mean absolute PE and percentage of eyes within 0.5 diopter (D), 0.75 D and 1 D of absolute magnitude of PE were compared. A subset analysis was done where the difference in cylinder magnitude between the 2 methods was more than 0.25 D. Spherical prediction outcomes were also analyzed.

Results: 241 eyes of 139 patients were included in the study. The mean centroid PE of Integrated K method (-0.07 @ 69) was significantly different from IOLMaster and Pentacam. The mean absolute PE with Integrated K method (0.33 ± 0.17) was significantly lower than all 3 devices. The percentage of eyes within 0.5 D and 0.75 D of absolute magnitude of PE was 82% and 99% for Integrated K method, 76% and 95% for IOLMaster and Lenstar, and 60% and 86% for Pentacam. In the subset analysis, the improvement in accuracy of the Integrated K method compared with a single device was greater in terms of the percentage of eyes predicted within 0.5 D. The Integrated K method did not impact the spherical prediction outcomes.

Conclusions: The integrated K method is more accurate and precise than anterior surface keratometry from a single biometric device.