Accuracy of Modern Intraocular Lens Formulas in Highly Myopic Eyes Implanted with Plate-Haptic Intraocular Lenses

Purpose To evaluate the predictive accuracy of modern intraocular lens (IOL) formulas and axial length (AL) adjusted traditional IOL formulas, including Wang-Koch and Cooke-modified AL (CMAL) method, in long eyes with plate-haptic IOLs, and to compare refractive prediction error variances with C-loop IOLs. Design Retrospective consecutive case series study. Methods Data from 391 eyes with Zeiss 509M and 302 eyes with Alcon SN6CWS implants in highly myopic patients, following cataract surgery from January 2019 to November 2023, were collected. One eye per patient was selected. Predictive outcomes of 15 modern formulas (Barrett Universal II (BU II), Cooke K6 (K6), Emmetropia Verifying Optical (EVO) 2.0, Hoffer-QST, Kane, Karmona, Ladas AI, Naeser 2, Olsen, Pearl-DGS, Radial Basis Function (RBF) 3.0, T2, VRF-G, Zhu-Lu, and Z-Calc) and 4 traditional IOL formulas (Haigis, Hoffer Q, Holladay 1, and SRK/T) with AL adjusted methods, were evaluated. The mean prediction error, mean absolute prediction error (MAE), root-mean-square absolute prediction error (RMSAE) and the proportions of eyes with PEs within ±0.25 Diopter (D), ±0.50 D, ±0.75 D and ±1.00 D were analyzed. Top 10 RMSAE-ranked formulas underwent further subgroup analysis based on AL, anterior chamber depth (ACD), and keratometry (K). Results For the 509M group, RMSAE ranking for the top 10 IOL formulas were the RBF 3.0 (0.432), Zhu-Lu (0.436), Olsen (0.436), EVO 2.0 (0.437), Pearl-DGS (0.447), K6 (0.452), VRF-G (0.454), Naeser 2 (0.464), Haigis-CMAL (0.465) and Karmona (0.477). Karmona and Naeser 2 showed poorer performance in the extremely long AL and steep K subgroups, respectively (p≤0.042). Haigis-CMAL accuracy was significantly lower in shallow ACD and flat K subgroups (p≤0.045). The SN6CWS group showed significantly lower MAE and RMSAE compared to the 509M group for the BU II, EVO 2.0, Hoffer-QST, Kane, Pearl-DGS, and Zhu-Lu formulas (p≤0.024). Conclusions In long eyes with plate-haptic IOLs, RBF 3.0 performed best, closely followed by Zhu-Lu, Olsen, and EVO 2.0; Karmona and Naeser 2 are discouraged for extreme AL and steep K conditions, respectively; Haigis-CMAL is not suggested for shallow ACD and flat K cases. Refractive outcomes in eyes implanted with a C-loop design IOL were more accurate than for those implanted with a plate-haptic design, for most tested formulas.