Impact of Ultrasound Biomicroscopy (UBM) versus White-to-White (WTW) measurement on sizing of Visian Implantable Collamer Lens (ICL) and Residual Postoperative Refraction

摘要

Purpose: The aim of this work is to compare residual postoperative refractive error after implantation of Visian Implantable Collamer Lens (ICL) in patients having the lenses sized with either Ultrasound Biomicroscopy (UBM) or white-to-white (WTW) measurements, and to determine if the residual refraction correlates with amount of postoperative lens vault. Methods: This cohort study included 33 eyes that underwent Visian ICL implantation. Sulcus-to-sulcus (STS) distances were determined using Ultrasound UBM in 23 eyes and with caliper assisted white-to-white (WTW) measurements in 10 eyes. Manifest refractions (spherical equivalents) and central lens vaults were compared between the two groups at the postoperative month 1 visit, using two-sample t-tests. Results: The pre-operative mean spherical equivalent (MSE) for all 33 patients was -10.97 diopters (D) (range: -5.37 D to -17.13 D). The pre-operative MSE was -10.18D for the UBM group, and -12.78D for the WTW group, respectively. The postoperative MSE was -0.43+/- 0.43D for the UBM group and -0.85 +/-0.53D for the WTW group (p=0.02). Postoperative mean central vault height was 495 +/- 167um in the UBM group and 710 +/- 250um in the WTW group (p0.05). Conclusions: This study suggests that UBM valuation of STS distance results in more precise sizing of the ICL implant and consequently in more accurate refractive outcomes. Effective lens position, reflected by postoperative lens vault may be a factor in postoperative refractive outcome. Residual refractive error was often the result of astigmatism in some patients.