A Comparison of Predicted and Achieved Postoperative Vaults in Implantable Collamer Lenses in White and Asian Eyes.

Abstract

Purpose: To compare clinically achieved vaults with the predicted NK-formula V2 (NK-V2) and NK-formula V3 (NK-V3) vaults in a White and Asian population in patients undergoing Implantable Collamer Lens (ICL) surgery.

Methods: Data were collected retrospectively from three surgeons for all patients who had ICL surgery for myopia between September 2020 and August 2022 at Moorfields Eye Hospital. ICL sizing was performed using the optimal NK-V2 sizing formula. The postoperative vault was measured using anterior segment optical coherence tomography. Back calculation was used to evaluate predicted versus achieved vaults for the newer NK-V3 formula.

Results: A total of 136 eyes from 72 patients were eligible. Seventy-two eyes of 72 patients were included in the analysis, 50 White (69%) and 22 Asian (31%). The mean residual vault for NK-V2 was -0.08 and -0.11 (P = .76) and NK-V3 was 0.04 and 0.02 (P = .78) for White and Asian, respectively. Mean absolute errors of the White sample were 0.2 and 0.16 for NKV2 and NK-V3, respectively (P = .23). Mean absolute errors of the Asian sample were 0.31 and 0.22 for NK-V2 and NK-V3, respectively (P = .16). There was no statistical significance when comparing mean absolute errors from White and Asian samples for NK-V2 or NK-V3.

Conclusions: NK-V2 formula for ICL sizing, originally derived from an Asian population sample, appeared to perform at least as well in Whites with no adverse outcomes or safety issues. NK-V3 was superior in predicting postoperative vault compared to NK-V2 in Asian eyes and comparable for White eyes. [J Refract Surg. 2025;41(7):e702-e708.].