Predictive Accuracy of Intraocular Lens Formulas Calculated by Biometers with Multiple Refractive Indices According to Axial Length

<b>Background/Objectives:</b> This study aimed to analyze the accuracy of the SRK/T, Haigis, Barrett Universal II (BUII), Kane, and EVO intraocular lens (IOL) formulas for normal and long axial length (AL) groups using an ARGOS (Alcon, Fort Worth, TX, USA), which uses the specific refractive indices. <b>Methods:</b> We performed a review of patients who underwent uneventful cataract surgery with the implantation of an Acrysof IQ SN60WF IOL (Alcon, Inc.) between January 2020 and December 2021. Biometry was obtained with the ARGOS; patients were separated into subgroups based on AL as follows: normal (22.0 ≤ AL < 26.0 mm) and long (AL ≥ 26.0 mm). Outcomes included the mean error (ME), the mean absolute error (MAE), the median absolute error (MedAE), and the proportion of eyes within ±0.25, ±0.50, ±0.75, and ±1.00 diopters (D) of the prediction error. <b>Results:</b> A total of 191 eyes of 191 patients were included: 162 eyes of 162 patients in the normal AL group and 29 eyes of 29 patients in the long AL group. The EVO formula was the most accurate for the normal AL group, which had the lowest MAE and MedAE. The MAE and MedAE of EVO were the lowest in the long AL group; EVO showed the highest percentage of eyes within ±0.25, ±0.75, and 1.00 D compared with other formulas. <b>Conclusions:</b> When using an ARGOS, the EVO formula had the lowest MAE and the highest proportion of eyes within ±1.00 D of the predicted target in both the normal and high myopia groups.