Evaluation of 7 modern IOL power calculation formulas in two PARTIAL-Range of Field IOL designs and a new constant optimization method

To evaluate the performance of seven modern intraocular lens (IOL) power calculation formulas in two different PARTIAL-Range of Field (RoF) extend IOL designs, and a novel IOL constant optimization method. 200 eyes implanted with Acrysof IQ Vivity or Tecnis Symfony IOL were included. Postoperative refractive outcomes of the Barrett Universal II (BUII), Cooke K6, EVO 2.0, Hill-RBF 3.0, Hoffer QST, Kane, and Pearl DGS formulas were compared. IOL constant is optimized by using ‘three variable optimization’ (TVO) ( https://ioloptimization.com/calculator ). Formula Performance Index (FPI), root-mean-square absolute prediction error (RMSAE), and SD of prediction errors were selected as the primary endpoints. In the Vivity group, the FPI in descending order was Cooke K6 (0.613), Kane (0.496), Hill-RBF 3.0 (0.478), Pearl DGS (0.474), BUII (0.430), EVO 2.0 (0.405), and Hoffer QST (0.341). No significant inter-formula differences were found in RMSAE and SD. In the Symfony group, the FPI in descending order was Cooke K6 (0.495), Pearl DGS (0.473), Hill-RBF 3.0 (0.428), BUII (0.403), Kane (0.385), EVO 2.0 (0.352), and Hoffer QST (0.310). Cooke K6 outperformed Hoffer QST (P = 0.032) and Pearl DGS (P = 0.027) in SD. The optimized A-constants vary among formulas derived from the same IOL model (Vivity: range 118.97 to 119.14; Symfony: range 119.17 to 119.36). All formulas achieved a mean prediction error of less than 0.012 D after constant optimization. Modern IOL power calculation formulas exhibit high accuracy for PARTIAL-RoF extend IOLs, with performance varying by IOL model. The TVO proved to be an effective and convenient tool.