Refining Intraocular Lens Power Calculations With Prediction Modifications: A Multiformula Analysis in High-Power Lenses.

PURPOSE: To evaluate the effectiveness of prediction modifications (PMOD) in improving refractive accuracy of modern intraocular lens (IOL) formulas in high-power TECNIS IOLs.

DESIGN

Retrospective accuracy and validity analysis.

SUBJECTS: Eyes with high-power and central power diopter IOL undergoing cataract surgery.

METHODS

This retrospective study included 645 eyes (497 patients) implanted with TECNIS ZCB00 or ICB00 IOLs. Eyes were stratified into central power (17.5-23.5 D) and high-power (>23.5 D) groups. Formula constants were optimized using the central power group and applied to both groups. PMOD, based on prior large-scale regression data, were applied to the high-power group. Twelve IOL power formulas were evaluated before and after PMOD application. Prediction errors were analyzed using mean refractive error (MRE), mean absolute error (MAE), and root mean square absolute error (RMSAE) with the Wilcox-Holladay-Wang-Koch method.

MAIN OUTCOME MEASURES: MRE, MAE, and RMSAE.

RESULTS

In the high-power group, eyes exhibited significantly shorter axial length, shallower anterior chamber depth, and greater lens thickness (all P < .001). All formulas, including Barrett Universal II, Cooke K6, EVO 2.0, Haigis, Hoffer QST, Holladay 1, Holladay 2 with nonlinear regression (H2 NLR), Kane, Olsen, PEARL-DGS, SRK/T, and T2, achieved -0.01 to 0.01 D MRE after optimization in the central power (17.5-23.5 D) group. In the high-power (>23.5 D) group, PMOD effectively corrected the myopic shift, significantly reducing MRE, MAE, and RMSAE across all formulas (all P < .05), except for MAE in PEARL-DGS (P = .050).

CONCLUSIONS

PMOD is a simple diopter-specific adjustment applied to the formula-predicted spherical equivalent. It effectively improved refractive prediction accuracy and reduced residual systematic errors that persisted in high-power IOLs across formulas, even after applying constants optimized in the central power group.