Accuracy of new-generation intraocular lens calculation formulas in eyes with variations in predicted refraction

Purpose To investigate the characteristics of eyes with large variations in predicted refraction using four traditional intraocular lens (IOL) formulas and evaluate the accuracy of new-generation intraocular lens power calculation formulas. Methods Eyes that had variation in predicted refraction (≥ 0.75 D) using four traditional formulas (SRK/T, Holladay 1, Hoffer Q, and Haigis formulas) were included. Axial length (AL), anterior chamber depth (ACD), average keratometry (AK), and the ratio of axial length to corneal radius (AL/CR) were measured. New-generation formulas (Barrett Universal II, Emmetropia Verifying Optical 2.0, Kane, and Pearl-DGS formulas) and traditional formulas were compared. The median absolute error (MedAE) was the main parameter to evaluate the accuracy of formulas. Results A total of 79 participants (79 eyes) who had variation in predicted refraction of (≥ 0.75 D) using four traditional formulas out of 510 eyes (510 patients) underwent uncomplicated cataract surgeries. The Barrett Universal II (0.29 D), EVO 2.0 (0.31 D), Kane (0.30 D), and Pearl-DGS (0.33 D) formulas produced significantly lower median absolute errors (MedAEs) than the Hoffer Q (0.61 D) and Holladay 1 (0.59 D) formulas ( P < 0.01). The Wang-Koch (WK) adjustment significantly improved the accuracy of the Holladay 1 formula in long eyes ( P < 0.001). Conclusions Abnormal AL, ACD, and AK are more likely to lead to prediction errors using traditional formulas. New-generation formulas and traditional formulas with WK adjustment showed satisfactory prediction accuracy.