Comparison of 9 modern intraocular lens power calculation formulas for a quadrifocal intraocular lens

PURPOSE: To evaluate the accuracy of 9 formulas (Barrett Universal II, Haigis, Hill-Radial Basis Function [RBF], Hoffer Q, Holladay 1, Holladay 2, Olsen, Sanders-Retzlaff-Kraff/theoretical [SRK/T], and T2) calculating the power of the quadrifocal Acrysof IQ Panoptix TFNT00 intraocular lens (IOL). SETTING: Department of Ophthalmology, Goethe University, Frankfurt, Germany. DESIGN: Retrospective case series. METHODS: The study included patients having cataract surgery with insertion of a quadrifocal IOL over 15 months. Preoperative biometry measurements were obtained from an IOLMaster 500. Optimized IOL constants were calculated to reduce the mean refractive prediction error. The primary outcomes were differences in mean absolute prediction error between the formulas. Median and maximum absolute prediction errors were evaluated as well as percentages of eyes within prediction errors of ±0.25 diopters (D), ±0.50 D, ±1.00 D, and ±2.00 D. RESULTS: The study comprised 75 eyes of 38 patients. The formulas were ranked by the mean absolute refractive prediction error as follows: Barrett Universal II (0.294 D), Hill-RBF (0.332 D), Olsen (0.339 D), T2 (0.351 D), Holladay 1 (0.381 D), Haigis (0.382 D), SRK/T (0.393 D), Holladay 2 (0.399 D), and Hoffer Q (0.410 D). The differences in absolute errors between the formulas were significant (P < .001). The lowest maximum absolute prediction error was obtained with the Barrett Universal II. CONCLUSION: The most accurate predictions of actual postoperative refraction were achieved using the Barrett Universal II, Hill-RBF, Olsen, or T2 formula. Thus, one of these formulas should be used for IOL power calculation of the quadrifocal IOL.