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Presentation type	Oral presentation
Title	Multicentric validation study of the LASSO-formulas for postoperative vault prediction in ICL surgery

Purpose	Recently Rocamorra et al. developed the LASSO formulas, three formulas that use AS-OCT and/or biometry parameters to predict the postoperative vaulting of the four different ICL-sizes available. In their study, the formulas were more precise than the golden standard formulas such as OCOS, Nakaumra 1 (NK1), and Nakamura 2 (NK2), however their algorithm was tested on 37 eyes. We took the next step by independently validating their results by using a larger sample size based on data from two different centres.
Methods	We retrospectively collected and analysed data from patients that underwent ICL surgery in UZ Leuven and the Goes Eye centre between 2018 and 2024. Different parameters retrieved from the IOLmaster 700 and the MS-39 were inputted in the LASSO formulas to make a prediction of the postoperative vaulting. We calculated the MAE (mean absolute error) for the different formulas by comparing the predicted postoperative vaulting to the real measured postoperative vaulting.
Results	We collected data of 386 eyes in total, of which 197 in UZ Leuven and 189 in the Goes Eye centre. The MAE of the LASSO-Full, Lasso-MS39 and LASSO-OCT formulas were 260 µm, 206µm and 155 µm respectively. The MAE of the NK1 and NK2 formulas were 284 µm and 237 µm respectively.
Conclusion	In our study we confirm that the Lasso-MS39 and LASSO-OCT formulas are superior to the NK1 and NK2 formulas (p<0,0001; except for LASSO-OCT vs. NK2 formula p=0.0614). These results support the study of Rocamora et al. The LASSO-full formula performed more poorly than the other LASSO-formulas, possibly by the low sample size (n=33) of patients examined by both the MS39 and IOLmaster preoperatively, emphasizing the importance of well-balanced sample sizes.
Conflict of interest	No

Authors 1

Last name	GOES
Initials	W
Department	UZ Leuven
City	Leuven

Authors 2

Last name	Delbeke Heleen
Initials	HD
Department	UZ Leuven
City	Leuven

Authors 3

Last name	Frank Goes Jr.
Initials	FG
Department	Goes Oogcentrum
City	Antwerpen