​Short-term changes in and preoperative factors affecting vaulting after posterior chamber phakic Implantable Collamer Lens implantation

Abstract Background: To describe the very early changes in vault in the first month after Implantable Collamer Lens (ICL) implantation and to evaluate the effect of preoperative biometric factors on vault.Methods: A total of 83 eyes from 83 subjects with complete data who met follow-up requirements were recruited in this retrospective study between May 2019 and March 2020. We quantitatively assessed postoperative vault at 2 hours, 1 day, 1 week, and 1 month following implantation. Associations between postoperative vault and age, ICL size, spherical equivalent (SE), axial length (AL), central corneal thickness (CCT), flat K, steep K, mean K, anterior chamber depth (ACD), crystalline lens thickness (LT), white-to-white (WTW) diameter obtained by three devices, horizontal and vertical sulcus-to-sulcus (STS) diameter, bright and dark pupil sizes (BPS and DPS) and DPS-BPS were investigated using Spearman’s correlation analysis and stepwise multiple regression analysis.Results: The mean vault values at 2 hours, 1 day, 1 week, and 1 month after ICL implantation were 672.05 ± 30.72, 389.15 ± 28.33, 517.23 ± 30.76 and 530.12 ± 30.22 μm, respectively. There were significant differences in vault values between 2 hours, 1 day and 1 week after the operation. ICL size (β = 0.942; p < 0.001), followed by horizontal STS (β = -0.517; p < 0.001), crystalline LT (β = -0.376; p < 0.001) and vertical STS (β = -0.257; p = 0.017), significantly influenced vault at 1 month after the operation. The multiple regression equation was expressed as follows: central vault (μm) = -1369.05+ 657.121 × ICL size- 287.408 × horizontal STS - 432.497 × crystalline LT - 137.33 × vertical STS (adjusted R2 = 0.643).Conclusions: After ICL implantation, vault decreased and then increased, but it did not return to the vault value at 2 hours after surgery. ICL size, horizontal and vertical STS and crystalline LT were key factors for predicting postoperative vaulting.