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

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 .