Purpose: To evaluate the performance of Holladay 1 and SRK/T formulas with the axial length (AL) adjustment methods including the linear and nonlinear versions of Wang-Koch AL adjustment methods and Cooke-modified AL (CMAL); and to determine whether the CMAL should be extended to the latest Barrett Universal II, Ladas Super formula (LSF), and Emmetropia Verifying Optical formulas in highly myopic eyes.
Design: Retrospective, consecutive case-series study.
Methods: A total of 164 eyes of 164 patients with AL ≥26.0 mm were included and divided into 2 groups: AL <28.0 mm (Group 1) and AL ≥28.0 mm (Group 2). The average arithmetic spherical equivalent prediction error (PE), mean absolute PE, median absolute error (MedAE), and the percentage of eyes within ±0.25 diopter (D), ±0.50 D, and ±1.0 D of PE were determined.
Results: The Holladay 1 formulas showed the smallest MedAE when combined with the first linear or nonlinear version of Wang-Koch AL adjustment methods, both in total and in subgroups. The SRK/T formula displayed the highest prediction accuracy in combination with the first linear version of Wang-Koch adjustment method in total and subgroups. The CMAL reduced the absolute PE of LSF in total (P = .003) and in Group 1 (P = .017).
Conclusions: The Holladay 1 and SRK/T formulas combined with specific AL adjustment methods had accuracy similar to the fourth-generation formulas for highly myopic eyes. Moreover, the CMAL can improve the accuracy of the LSF for highly myopic eyes.
Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.