A vault-prediction formula for implantable collamer lens based on preoperative parameters: A retrospective clinical study

Objectives: The aim of the present study was to predict the vault of implantable collamer lens (ICL) using a formula established based on the preoperative parameters. Methods: : This retrospective study included data on 226 eyes from 114 patients(the median age and range was 27.5±5.7; 18-46 years) who underwent EVO-ICL surgery between May 2021 and April 2022. Preoperative parameters, such as anterior chamber depth (ACD) horizontal angle-to-angle diameter (ATA), Crystalline lens rise (CLR), and vault (1 week after surgery) were measured by anterior segment optical coherence tomography. The axial length of eyes (AL) and white-to-white (WTW) values were measured using an IOLmaster and calipers under a slit lamp separately. Result: The mean WTW, ACD, horizontal ATA diameter, CLR, AL, and vault 1 week after surgery were 11.42±0.37 mm, 3.25±0.25 mm, 11.72±0.44 mm, 45.78±175.42 μm, 27.61±1.93 mm, and 586.51±254.54 μm respectively. Multivariate regression analysis showed that the ICL-width, ACD (β=0.293), ATA (β =-0.657), CLR (β =-0.157), and the anterior chamber angle in temporal side (T:ACA) (β=-0.277) were predictors of the vault size (adjusted-R 2 =0.39, P<0.001). Conclusion: The formula built based on these preoperative parameters could be used to predict the vault before surgery. The present study showed that several preoperative parameters that may seem to be of less importance, such as CLR and T:ACA, should be taken into account when choosing the optimal ICL.