Evaluation of Reliability of Formulas for Intraocular Lens Power Calculation After Hyperopic Refractive Surgery

Background: We evaluate the accuracy of intraocular lens (IOL) power calculation in the following formulas-Barrett True-K No History (BTKNH), EVO 2.0 Post-Hyperopic LASIK/PRK (EVO 2.0), Haigis-L, Pearl-DGS, and Shammas (SF)-with patients who have undergone cataract surgery at the Eye Unit of University of Campania Luigi Vanvitelli, Naples, Italy, and had prior hyperopic laser refractive surgery. Methods: A monocentric, retrospective, comparative study, including the charts of patients who had undergone cataract surgery and previous hyperopic laser refractive surgery, was retrospectively reviewed. Patients with no other ocular or systemic disease which might interfere with visual acuity results and no operative complications or combined surgery were enrolled. The mean absolute prediction error (MAE) was calculated for each formula and compared. Subgroup analysis based on the axial length and mean keratometry was performed. Results: A total of 107 patients (107 eyes) were included. The MAE calculated with SF provided less accurate (p < 0.05) results when compared to both BTKNH and EVO 2.0 formulas. The MAE obtained using Haigis-L, EVO 2.0, Pearl-DGS, and BTKNH showed no significant differences. Conclusions: The analysis of the accuracy of the selected formulas shows no clear advantage in using one specific formula in standard cases, but in eyes where it is mandatory to reach the target refraction, SF should be avoided.