New polynomial regression formula to improve second-eye refractive outcomes in sequential bilateral cataract surgery

Purpose: To assess a new polynomial regression formula integrating the refractive prediction error of the first-operated eye to improve the intraocular lens power calculation of the second eye in cataract surgery. Setting: Centre Hospitalier Universitaire, Toulouse, France. Design: Retrospective multicentric dataset study. Methods: A polynomial regression formula, WeOptimeye2nd (WO2nd), was developed using a machine-learning algorithm trained on a dataset of 534 patients who underwent sequential bilateral cataract surgery. A separate multicentric dataset was used to retrospectively calculate predicted refraction with WO2nd, SRK/T and Barrett Universal II formulas, and 3 other methods of constant factors (CFs) second-eye refinement (CF0.38, CF0.35, and CF0.5). Mean absolute errors (MAEs) and percentage of eyes within +/- 0.25, +/- 0.5, and +/- 1.0 diopter (D) from predicted spherical equivalent were compared between formulas. Results: The study comprised data on 722 patients. In the overall population, WO2nd had the lowest MAE: 0.339 vs 0.347 (P = .137), 0.340 (P = .956), 0.350 (P = .066), 0.399 (P < .001), and 0.410 (P < .001), with CF0.38, CF0.5, and CF0.35, Barrett II, and SRK/T, respectively. WO2nd had the highest percentage of eyes within +/- 0.5 D of the predicted refraction, and the difference was statistically significant vs SRK/T and Barrett II formulas but not vs CF0.38, CF0.5, and CF0.35. WO2nd performed the best in axial length (AL) < 22 mm with the lowest MAE and a statistically significant difference vs any other formula. Conclusions: WO2nd improved the refractive outcome of the second-operated eye and performed well in extreme AL and mean keratometry subgroups. Copyright (C) 2021 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.

Automated summary

This study aimed to improve the calculation of intraocular lens power for the second eye in cataract surgery. A new polynomial regression formula (WO2nd) was developed and compared with other formulas. The results showed that WO2nd performed well in predicting refractive errors and was particularly effective for eyes with shorter axial length.