The influence of keratometry on the accuracy of intraocular lens formulas in highly myopic eyes

To investigate the influence of keratometry on the predictive accuracy of modern IOL formulas in determining optimal IOL power for cataract patients with high myopia. A total of 302 eyes from highly myopic patients who had undergone cataract surgery were divided into subgroups based on axial length AL and K. The predictive outcomes were to compare the accuracy of the following formulas: BU II, EVO 2.0, Haigis, Hoffer Q, Hoffer-QST, Holladay 2, K6, Kane, Pearl-DGS, SRK/T. For each formula, the ME, MAE, MedAE and the percentage of eyes with PEs within ± 0.25 D, ± 0.50 D, ± 0.75 D, and ± 1.00 D were analyzed. Among all patients, the Hoffer QST formula achieved the lowest MAE (0.41 D), closely followed by EVO 2.0 (0.42 D). In the axial length subgroups, the Hoffer QST, BU II, and Haigis formulas achieved the lowest MAE (0.35 D) in the long AL group, while K6 achieved the lowest MAE (0.46 D) in the super-long AL group. For the extreme-long AL group, Hoffer QST demonstrated the lowest MAE at 0.41 D, closely followed by EVO 2.0 (0.44 D). In the keratometry subgroups, Hoffer QST consistently showed superior accuracy: in the flat-K group, it attained the lowest MAE (0.35 D) with BU II closely trailing (0.36 D); in the average-K group, it maintained the lowest MAE (0.41 D) followed by EVO 2.0 (0.43 D); and in the steep-K group, it achieved the lowest MAE (0.43 D), closely followed by EVO 2.0 (0.44 D). In highly myopic eyes, modern IOL formulas demonstrate significantly superior predictive accuracy compared to traditional formulas for the different keratometry, with Hoffer QST and EVO 2.0 exhibiting the best performance in this study.