Ultrasound Biomicroscopy for Determining Visian Implantable Contact Lens Length in Phakic IOL Implantation

Purpose: To assess the efficacy of the ultrasound biomicroscopic (UBM) method in estimating the sulcus-tosulcus horizontal diameter for Visian Implantable Contact Lens (ICL, model V4) length determination to obtain optimal ICL vault. Methods: The results of postoperative ICL vaults in 30 eyes of 18 patients were retrospectively analyzed. In 17 eyes, ICL length was determined using the conventional method, and in 13 eyes, ICL length was determined using the UBM method. The UBM method was carried out by measuring the sulcus to limbus distance on each side by 50 MHz UBM and adding the white-to-white diameter by caliper or Orbscan. The ICL vaults were measured using the UBM method at 1 and 6 months postoperatively and the results were compared between the two groups. Ideal ICL vault was defined as vault between 250 and 750 µ m. The relation between the ICL vault, footplate location, and ICL power was also investigated. Results: In the UBM method group, ICL vault was within the ideal range in all 13 (100%) eyes at 1 and 6 months postoperatively, whereas in the conventional method group, 10 (58.8%) eyes showed ideal vault at 1 month postoperatively ( P =.01) and 9 (52.9%) eyes showed ideal vault at 6 months postoperatively ( P <.01). The ideal ICL footplate location was achieved in the ciliary sulcus in 11 (84.6%) eyes of the UBM method group and 10 (64.7%) eyes of the conventional method group. However, the differences between the two groups were not statistically significant. The ICL vault was not significantly affected by the ICL power. Conclusions: Implantable Contact Lens length determined by the UBM method achieved significantly more ideal ICL vault than that of the conventional white-to-white method. The UBM method is superior to the conventional method in terms of predicting the sulcusto-sulcus horizontal diameter for ICL length determination. [ J Refract Surg . 2007;23:362–367.]