Retrospective multicenter validation study of tomography-based formulas for phakic intraocular lens sizing
William Goes1, Isabelle Saelens, Frank Goes
1From the Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium (W. Goes, Saelens, Delbeke); KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium (Saelens, Delbeke); Goes Oogcentrum, Antwerpen, Belgium (F. Goes, W. Goes); VITAZ, Beveren, Belgium (F. Goes); KU Leuven, Leuven, Belgium (Mulier).
Purpose:
To validate the least absolute shrinkage and selection operator (LASSO) formulas for phakic intraocular lens sizing, published by Rocamora et al. in 2023, in a larger and multicenter cohort.
Setting:
University hospital and private clinical practice.
Design:
Multicenter retrospective observational study in Belgium.
Methods:
Patients who underwent implantable collamer lens (ICL) surgery between September 2018 and June 2024 were included. The mean absolute error (MAE) was used as primary endpoint to compare LASSO-optical coherence tomography (OCT), LASSO-Biometry, LASSO-Full, Luo, Russo, Kim, Nakamura (NK) V1, NK V2, and NK V3 formulas. Secondary endpoints included the maximum absolute error and the percentage of eyes within error categories of <100 μm, <200 μm, <300 μm, <500 μm, and <750 μm.
Results:
437 eyes of 226 patients were included. The pooled MAE of the LASSO-OCT formula (155.6 ± 123.0 μm) was lower than that of the LASSO-Biometry (193.3 ± 140.3 μm) and LASSO-Full (247.2 ± 174.7 μm) formulas. The Russo formula showed the lowest MAE (142.3 ± 112.4 μm) followed by the NK V3 (149.3 ± 121.0 μm). The MAE was significantly higher for the LASSO-Full, Luo, NK V1, and NK V2 formulas when compared with the LASSO-OCT formula. At the center where postoperative vault was measured using Scheimpflug imaging, the LASSO-Full formula achieved a lower MAE than the LASSO-OCT formula, although this difference was not statistically significant.
Conclusions:
In this study, the accuracy of the LASSO formulas varies across the different models and according to the postoperative measurement method, with the LASSO-OCT formula outperforming the LASSO-Full when vault is measured with anterior segment OCT. Other OCT-based formulas, including NK V3 and Russo, demonstrated high accuracy and reliability, supporting the safety of OCT-based ICL sizing.
