Prediction of footplate position after implantable collamer lens implantation based on iris and ciliary body morphologies.

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

Setting: Hunan Provincial People's Hospital, Changsha, China.

Design: Retrospective case series.

Methods: This study included 124 patients (124 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: group 1 (<500 μm), group 2 (500 to 1000 μm), and group 3 (>1000 μm). The distribution of the vault range postoperatively was observed for the 3 groups.

Results: Ciliary sulcus angle and FD significantly affected the vault (adjusted R2 = 0.190, F = 6.763, P < .001), with FD being the most important factor influencing the vault (β = -0.383, 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 0.88 ± 0.24 mm. 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 = 0.373, F = 11.432, P < .001). The vault range differed significantly among the 3 groups (X 2 = 32.33, P < .001).

Conclusions: Different postoperative ICL footplate positions significantly affect the vault. CBT, IC, and IRCL can alter the position of the footplate from the expected position. This study provides reference for ICL size selection and vault prediction.