Postoperative vault prediction for phakic implantable collamer lens surgery: LASSO formulas

Purpose: To develop and evaluate reliable formulas for predicting postoperative vaultmore accurately after implantable collamer lens (ICL) surgery in aWhite patient population with varying degrees of ametropia. Setting: Private clinical practice. Design: Retrospective analysis on dataset split into a separate training and test set. Methods: 115 eyes of 59 patients were used to train regression models predicting postoperative vault based on anterior segment optical coherence tomography (OCT) parameters (Least Absolute Shrinkage and Selection Operator [LASSO]-OCT formula), ocular biometry data (LASSO-Biometry formula), or data from both devices (LASSO-Full formula). The performance of these models was evaluated against the manufacturer's nomogram (Online Calculation and Ordering System [OCOS]) and Nakamura 1 (NK1) and 2 (NK2) formulas on a matched separate test set of 37 eyes of 19 patients. Results: Themean preoperative spherical equivalent was similar to 5.32 +/- 3.37 (range: +3.75 to similar to 17.375 diopters). The mean absolute errors of the estimated vs achieved postoperative vault for the LASSO-Biometry, LASSO-OCT, and LASSO-Full formulas were 144.1 +/- 107.9 mm, 145.6 +/- 100.6mm, and 132.0 +/- 86.6mm, respectively. These resultswere significantly lower compared with the OCOS, NK1, and NK2 formulas (P <.006). Postoperative vault could be estimated within 500 mm in 97.3% (LASSO-Biometry) to 100% of cases (LASSO-OCT and LASSO-Full). Conclusions: The LASSO suite provided a set of powerful, reproducible yet convenient ICL sizing formulas with state-of-the-art performance in White patients, including those with low to moderate degrees of myopia. The calculator can be accessed at http://icl.emmetropia.be.