Preoperative Biometric Parameters Predict The Vault After ICL Implantation

Purpose:To investigate the correlation between the preoperative biometric parameters of the anterior segment and the vault after Implantable Collamer Lens (ICL) implantation via this retrospective study.Methods:A total of 78 eyes from 41 patients who underwent ICL implantation surgery were included in this study. Preoperative biometric parameters including white-to-white (WTW) diameter, central corneal thickness (CCT), keratometer (K), pupil diameter (PD), anterior chamber depth (ACD), sulcus-to-sulcus (STS) diameter, anterior chamber area (ACA) and central curvature radius of anterior surface of lens (Lenscur) and were measured. Lenscur and ACA were measured with rhinoceros 5.0 software on the image scanned with ultrasound biomicroscopy (UBM). The vault was assessed by UBM at 3 months after surgery. Multiple stepwise regression analysis was employed to identify the explanatory variables that were correlated with vault.Results:Before ICL implantation surgery, the preoperative mean value of Sphere diopter, Cylindrical diopter, ACD, ACA, WTW, Lenscur, STSL, central corneal thickness, horizontal keratometer, vertical keratometer, pupil diameter, ICL diameter, ICL diopter, were-14.78±3.47D,-1.43±1.10D,3.22±0.33mm,22.43±4.25mm2, 11.36±0.29mm,9.15±1.21mm50.47±0.16mm,0.52±0.04mm,43.78±1.36D, 45.05±1.42D,4.47±0.68mm,11.8±0.30mm,-19.33±3.58D. The postoperative mean value of vault was 0.33±0.19mm. According to curve estimation, the P value of ICLdiopter, horizontal STS, vertical STS, PD, spherical equivalent, horizontal corneal keratometer, vertical corneal keratometer, CCT and ICL diameter were 0.079,0.151, 0.236,0.182,0.273,0.519,0.655,0.544,0.602. There was no statistically significant difference between above preoperative biometric parameters and postoperative vault. However, the P value of preoperative ACD, ACA, Lenscur, STSL, WTW were< 0.001, < 0.001,< 0.001,0.001,0.029. The determination coefficient R2 of ACD, ACA, Lenscur, STSL, WTW were 0.163,0.196,0.159,0.137,0.061. After Multiple stepwise regression analysis, the results showed that the vault was correlated with 3 explanatory variables:ACA, WTW and Lenscur. The non-standardized partial regression coefficient of ACA was 0.017 and the standardized partial regression coefficient was 0.390. The non-standardized partial regression coefficient of WTW was-0.203 and the standardized partial regression coefficient was-0.313. The non-standardized partial regression coefficient of Lenscur was 0.051 and the standardized partial regression coefficient was 0.335. The regressive equation was: vault (mm)= 1.785+0.017 x (ACA)+0.051 x (Lenscur)-0.203 x (WTW).Conclusions:Biometric parameters of the anterior segment (ACA, WTW and Lenscur) can predict the vault after ICL implantation using a new regression equation.