Comparison of the accuracy of six intraocular lens power calculation formulas for eyes of axial length exceeding 25.0mm

Abstract

Purpose: To compare intraocular lens power calculation formulas for eyes longer than 25.0mm in terms of absolute error and the percentages of postoperative emmetropia and hyperopia.

Methods: The data for myopic patients who underwent uneventful phacoemulsification between October 2015 and June 2019 were reviewed. Intraocular lens power was calculated using Holladay 1, SRK/T, Hoffer Q, Holladay 2, Haigis, and Barrett Universal II formulas. The power of the lens implanted was based on Holladay 2. Three months after phacoemulsification, the refraction was measured, and the mean absolute error was calculated. The percentage of patients with good uncorrected visual acuity and percentage of hyperopic patients for each formula was established. ROC curves with a cut-off point of axial length were drawn for each formula and the area under the curve was evaluated.

Results: Seventy patients (81 eyes) whose ocular axial length ranged between 25.01mm and 28.57mm were included. The Barrett Universal II formula achieved the lowest mean absolute error of 0.08±0.08D. Additionally, with the Barrett Universal II, the percentage of patients with good uncorrected visual acuity (81.5%) was the highest, and the percentage of hyperopic patients (4.9%) was the lowest. The Barrett Universal II and Holladay 1 formulas had the largest area under curve (0.764 and 0.718, respectively).

Conclusion: 1. The Barrett Universal II formula is recommended for intraocular lens power calculation for eyes with axial length greater than 25.0mm. 2. Considering the ROC curve method, the Barrett Universal II and Holladay 1 formulas appear to be the most appropriate.

Keywords: Courbe ROC; Intraocular lenses; Lentilles intraoculaires; Myopia; Myopie; Phacoemulsification; Phacoémulsification; ROC curve.