Comparison of the Accuracy of Seven Vault Prediction Formulae for Implantable Collamer Lens Implantation

Abstract

Introduction This study aimed to compare the accuracy of seven implantable collamer lens (ICL) implantation vault prediction formulae. Methods We retrospectively analyzed 328 patients (328 eyes) who underwent ICL implantation and the prediction accuracy of seven formulae: NK, KS, WH, Luo, Zhu, Hun, and ZZ were compared. Moreover, the accuracy of the seven formulae for different ICL sizes was compared. The formulae were tested using mean absolute prediction error (MAE), median absolute prediction error (MedAE), prediction error (PE) percentages at ± 50 µm, ± 100 µm, ± 200 µm, and ± 300 µm, and Bland-Altman analysis. Results The PE of the seven formulae were statistically significant ( P < 0.001). The KS (101.00 µm) and WH formulae (116.65 µm) had the smallest MedAE, followed by the Luo (123.62 µm), NK (141.50 µm), Hun (152.68 µm), ZZ (196.00 µm) and Zhu formula (225.98 µm). The highest percentage of PE in the range of ± 300µm was 94.3% and 93% for the KS and WH formulae, respectively. Among the different ICL size groupings, the KS formula predicted the smallest MedAE for 12.1 mm and 12.6 mm, whereas the Luo and WH formulae predicted the smallest MedAE for 13.2 mm and 13.7 mm, respectively. Conclusions The KS and WH formulae provided better outcomes by predicting the vault with higher accuracy than of the NK, Hun, Luo, ZZ, and Zhu formulae. Trial Registration ChiCTR2200065501.