The purpose of this study was to investigate the error tendency between preoperative expected refraction and postoperative manifest refraction based on axial length, anterior chamber depth, and keratometric data obtained by an automated keratometer and Pentacam® in cataract surgery cases and to report how their differences affect determination of intraocular lens (IOL) power.

The authors retrospectively reviewed the medical records of 110 eyes of 84 patients who underwent cataract surgery. Axial length and anterior chamber depth were measured by A scan ultrasound biometry, while keratometric values were obtained by an automated keratometer and Pentacam®. IOL power was calculated using the SRK/T formula. Patients were divided into 3 groups based on the axial length, anterior chamber depth, and the difference of keratometric values between the 2 devices. Refractive error was analyzed 2 months after surgery.

There were no statistically significant differences between axial length and anterior chamber depth among the groups; however, the K reading differences were statistically significant. Although the mean absolute error (MAE) of each group showed no statistical significance among the groups, the MAE was more pronounced in the group in which the keratometeric value measured by Pentacam® differed more than 1.00 diopter from the automated keratometer measurements.

There was no statistically significant difference between axial length and anterior chamber depth among the groups. A difference of 1.00 diopter or more between the keratometric values obtained by an automated keratometer and Pentacam® significantly affects the postoperative refractive error; therefore, these factors should be considered when determining IOL power.