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

Abstract

The LASSO sizing formulas are easy to implement into clinical practice and can significantly improve the predictability of postoperative vault after ICL implantation.

Purpose:

To develop and evaluate reliable formulas for predicting postoperative vault more accurately after implantable collamer lens (ICL) surgery in a White 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:

The mean preoperative spherical equivalent was −5.32 ± 3.37 (range: +3.75 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 μm, 145.6 ± 100.6 μm, and 132.0 ± 86.6 μm, respectively. These results were significantly lower compared with the OCOS, NK1, and NK2 formulas ( P < .006). Postoperative vault could be estimated within 500 μm 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.