Comparison of the Accuracy of Toric Intraocular Lens Formulas Used by the Online Calculator of the European Society of Cataract and Refractive Surgeons

Purpose To determine the precision of toric intraocular lens (IOL) formulas used by the online calculator of the European Society of Cataract and Refractive Surgeons (ESCRS). Methods This retrospective study included patients undergoing phacoemulsification with toric IOL implantation from July 2021 to June 2023 in Shanghai Sixth People's Hospital, Shanghai Jiao Tong University School of Medicine. The mean absolute prediction error (PE), standard deviation of the PE, and proportion of eyes with a PE within ±0.25, ±0.50, ±0.75, and ±1.00 diopters (D) were calculated by vector analysis. Results Among the 85 included patients, the mean and median absolute PE determined from the Barrett estimated posterior corneal astigmatism (EPCA), EVO 2.0, and Hoffer QST toric formulas varied considerably from those derived using the Kane toric formula ( P < .001, P = .045, P < .001, respectively). For all toric formulas, the centroid of the PE deviated considerably from zero ( P < .001). The EVO 2.0 toric formula yielded the best accuracy (61.2%) within ±0.50 D, followed by the Barrett EPCA (58.8%), Hoffer QST (58.8%), Barrett measured posterior corneal astigmatism (51.8%), and Kane toric (51.8%) formulas. However, the percentages of PEs 0.50 D or less and 0.75 D or less with all of the toric calculators did not differ significantly ( P > .05). The Hoffer QST displayed the least mean absolute PEs in the groups with different astigmatism types, as well as in the groups with medium and long axial length and medium keratometry. Conclusions The newly introduced ESCRS online toric calculator is a useful tool that yielded consistent results in this study. The EVO 2.0 and Hoffer QST toric formulas showed better performance, although the improved accuracy is likely to have minimal clinical importance. [ J Refract Surg . 2025;41(2):e120–e130.]