Accuracy of Reported Sizes of the EVO/EVO+ Visian Implantable Collamer® Lenses

Purpose The purpose of this study is to assess the variability between published manufacturer sizes and actual sizes measured in the operating room (OR) for Implantable Collamer® Lenses (ICLs) (STAAR Surgical, Monrovia, CA). Methods A prospective observational study was performed where the diagonal length of 50 ICLs from 50 consecutive cases was measured between June 26, 2023, and November 1, 2023. ICLs were positioned "face down" next to an OR ruler and photographed using the NGENUITY® 3D Visualization System (Alcon, Geneva, Switzerland). These images were processed in Adobe Photoshop 24.6 (Adobe Inc., San Jose, CA) to eliminate perspective distortions, and the images were scaled using known dimensions of the OR ruler. Accurate diagonal measurements were taken using the caliper tool. Measurements were repeated across ICLs in the other direction to ensure consistency. Average size discrepancy, defined as measured ICL size minus published ICL size, was reported along with standard deviation (SD) and confidence interval (CI). A two one-sided t-test (TOST) was used to compare statistical equivalence between spherical and toric ICLs within a 0.017 mm margin. Results TOST analysis revealed that the mean measured size of all lens sizes (12.1 mm, 12.6 mm, and 13.2 mm) and types (spherical and toric) is statistically equivalent (α = 0.05) to their labeled size, indicating a high level of manufacturing precision. No ICLs deviated from published measurements by more than 0.05 mm. Conclusion The actual sizes of ICLs closely match the published manufacturer sizes, suggesting high manufacturing precision. There is no significant variability between spherical and toric ICLs, supporting the reliability of published sizing for clinical decisions.