Implantable Collamer Lens Sizing Optimization Based On The Anterion As-Oct Biometric Parameters
Published 2024 - 42nd Congress of the ESCRS
Reference: PO1221 | Type: Free paper | DOI: 10.82333/0tb0-r151
Authors: Ramin Salouti* 1 , Mostafa Nazarpour-Servak 1 , Mohamad Mehdi Dehghani 1 , Mohammad Zamani 2 , Kia Salouti 3 , Maryam Ghoreyshi 2 , M. Hossein Nowroozzadeh 1
1Department of Ophthalmology,Shiraz University of Medical Sciences,Shiraz,Iran, Islamic Republic Of, 2Salouti Cornea Research Center, Salouti Eye Clinic,Shiraz,Iran, Islamic Republic Of, 3Science Department,The University of British Columbia,Vancouver,Canada
Purpose
To develop regression formulas for determining optimal Implantable Collamer Lens (ICL) size using biometric data.
Setting
Salouti Eye Clinic, Shiraz, Iran.
Methods
89 patients in the development phase and 57 patients in the validation phase were included. The study developed the SN formula, a multiple step-wise linear regression model, incorporating ACW, LTh, and ACV as predictors, to determine optimal ICL size (R-square=0.602). Another formula predicted ICL vault using a cubic non-linear model and the difference (Delta) between implanted and predicted ICL size as an explanatory variable (R-square=0.599). Logistic regression determined the probability of achieving optimal vault or acceptable vault post-surgery.
Results
Delta was the sole independent factor predicting postoperative ICL vault. A ∆ value of 0.3 mm corresponded to a 65% probability of achieving optimal vault, while a ∆ value of 0.15 resulted in an 80% probability. The SN formula matched with the STAAR nomogram in 69.9% of cases (79/113). Compared to the STAAR formula, the SN formula recommended a larger size in 10 eyes (8.8%) and a smaller size in 24 (21.2%). The 95% LoA for SN-predicted and actual ICL vault were (-339 to 518) µm. The mean absolute error was 191 µm (SD,139), and 72 eyes (63.7%) had a difference of ≤200 µm.
Conclusions
The developed regression formula provided acceptable predictions for proper ICL sizing in our patients. However, its performance may vary across different populations or measurement devices, signifying the need for smaller increments of ICL sizes to improve postoperative outcomes.