PREDICTION OF FOOT PLATE POSITION AFTER IMPLANTABLE COLLAMER LENS IMPLANTATION BASED ON IRIS AND CILIARY BODY MORPHOLOGY ASSESSED BY UBM

To investigate the factors affecting footplate position and its influence on vault characteristics after implantable collamer lens (ICL) implantation.

Prospective case series 

Prospective case series of 248 patients (248 eyes). Ultrasound biomicroscopy (UBM) was performed to assess the iris and ciliary body morphologies and observe the footplate position .Using multiple linear regression, the relationship between various ocular and ICL parameters and the vault as well as the factors affecting the footplate distance (FD) were analyzed. Based on the FD, 3 groups were formed: group1 (<500µm), group 2 (500to1000µm), and group3 (>1000µm). The distribution of the vault range post operatively was observed for the 3 groups.

Ciliary sulcus angle and footplate distance (FD) significantly affected the vault (adjusted R²=0.190, F=6.761, P<.001), with FD being the most important factor influencing the vault (β= - 0.381,P<.001). Postoperative UBM revealed that the footplate was located at different positions in the posterior chamber, with the majority (52%) being located on the ciliary body. The mean size of the 4 footplate orientations was 0.86±0.24mm. Multiple linear regression analysis revealed that ciliary body thickness (CBT), iris curvature (IC), and ICL iris contact length (IRCL) significantly influenced the FD (adjusted R²=0.371, F=11.432, P<.001). The vault range differed significantly among the 3 groups(X²= 32.31, P<.001).

Different postoperative ICL footplate positions significantly affect the vault. ciliary body thickness (CBT), iris curvature (IC), and ICL iris contact length (IRCL) can alter the position of the footplate from the expected position. These parameters help in ICL size selection and vault prediction.