Total keratometry is not better than standard keratometry: An IOL refractive prediction outcome evaluation for cataract surgery

Abstract

Abstract Purpose To evaluate if total keratometry (TK) is better than standard keratometry (K) for predicting an accurate intraocular lens (IOL) refractive outcome for cataract surgery in four IOL power calculation formulas. Methods 449 eyes that underwent monofocal intraocular lens implantation were enrolled in this study. IOLMaster 700 was used for optical biometry. Median absolute prediction error (MedAE), mean absolute error (MAE), median absolute prediction error (MedAE), proportions of eyes within ± 0.25 diopters (D), ± 0.50 D, ± 0.75 D, ± 1.00 D, ± 2.00 D adjusted prediction error, and formula performance index (FPI) were calculated for each K- and TK-based formula. Results Overall, the accuracy of each TK and K formula was comparable. The MAEs and MedAEs showed no difference between the K-based and the TK-based formula. The percent of eyes within ± 0.25 D for TK was not significantly different from that for K. The analysis of PE across various optical dimensions revealed that TK had no effect on the refractive results in eyes with different preoperative axial length, anterior chamber depth, keratometry, and lens thickness. K-based Barrett Universal II formula performed showed the leading FPI score and had the best refractive prediction outcomes among the four formulas. Conclusion In all investigated formulas, the predictive accuracy of TK-based formulas is not superior than that of standard K-based formulas. TK cannot substitute K for IOL power calculation in monofocal IOL implantation cataract surgery.