Performance of formulas included in the ESCRS intraocular lens power calculator.

Purpose: We wanted to compare the refractive prediction errors (PEs) of formulas included in the ESCRS IOL power calculator to aid in informed decisions on IOL power selection based on the output of this tool.

Setting: Cullen Eye Institute, Baylor College of Medicine, Houston.

Design: Retrospective case-series.

Methods: We have included 748 eyes of 748 patients following implantation of one of 3 lenses, single-piece: the SN60WF (Alcon, USA), PCB00/ZCB00 (Tecnis, USA) and 3-piece: MA60MA (Alcon, USA). IOL constants recommended by the calculator were utilized for the study. We performed analysis for the whole dataset, short (<22mm) and long eyes (>25mm) as well as in subgroups based on the type of the implanted IOL. SD and RMSAE were selected as the primary endpoints.

Results: Cooke K6 had the lowest SD of PEs in the whole dataset (p<0.05) when compared with Barrett, EVO, and Hoffer-QST. In the subgroup of long eyes, the Kane formula had the lowest RMSAE (p<0.05) when compared with Barrett and EVO. We did not find any significant differences in primary endpoints for implantation of the 3 types of IOL. However, the median absolute error following implantation of the MA60MA was significantly higher than for all other formulas except for Pearl-DGS.

Conclusions: We found significant differences in the performance of formulas included in the calculator. In the whole dataset, Cooke K6 had the lowest SD of PEs among the analyzed formulas.