Accuracy of Modern IOL Power Calculation Formulas in Eyes After Myopic Laser Vision Correction: A Stratified Axial Length Analysis

Purpose To evaluate the accuracy of modern intraocular lens (IOL) power calculation formulas in eyes with previous myopic laser vision correction (LVC), and to assess the impact of axial length (AL) on the formula performance. Methods A total of 108 eyes were included, with 52 eyes in the AL less than 28 mm group and 56 eyes in the AL 28 mm or greater group. Refractive prediction errors (RPEs) were compared among nine post-LVC formulas: Haigis-TK, Haigis-TK CMAL (incorporating Cooke-modified axial length [CMAL]), PEARL-DGS, Hoffer-QST TK, LISA TK, Barrett True-K TK, EVO TK, Haigis-L, and Shammas. Pearson correlation analysis was employed to evaluate the influence of AL and other biometric parameters on RPEs. Results In the AL less than 28 mm group, no significant differences were observed between all formulas (all adjusted P > .05). However, in the AL 28 mm or greater group, Haigis-TK CMAL demonstrated significantly lower root mean square absolute error (RMSAE) and mean absolute error (MAE) compared to the Hoffer-QST, Barrett True-K TK, Shammas, and Haigis-L (all adjusted P < .001). Similarly, the PEARL-DGS showed significantly lower RMSAE than the Barrett True-K TK, Shammas, and Haigis-L (both adjusted P < .001), and significantly lower MAE compared to the Barrett True-K TK and Haigis-L (both adjusted P < .001). The Haigis-TK CMAL had the highest percentage of eyes with RPEs within ±0.50 diopters (D) (73.21%), whereas the PEARL-DGS had the highest percentage of eyes with RPEs within ±1.00 D (94.64%). A significant negative correlation between AL and RPE was found in most formulas, leading to a myopic shift in eyes with extremely long AL. Conclusions The performance of current post-LVC formulas was comparable in eyes with AL less than 28 mm, whereas the Haigis-TK CMAL and PEARL-DGS demonstrated superior accuracy in eyes with AL 28 mm or greater. A notable myopic shift occurred in post-LVC eyes with extremely long AL, highlighting the need for careful formula selection in such cases. [ J Refract Surg . 2025;41(5):e435–e443.]