Short-term Change in Haptic position of Implantable Collamer Lenses and its correlation with the variation of vault

Purpose: To examine changes in the haptic position of the implantable collamer lens (ICL) within the postoperative3 months and its correlation with vault variation. Setting: Eye and ENT Hospital, Fudan University, Shanghai, China. Design: Prospective non-randomized study. Methods: This study included 58 right eyes of 58 patients who underwent ICL implantation for the correction of myopia or myopic astigmatism. The position of the ICL haptic was measured using ultrasound biomicroscopy (UBM) at postoperative 1 month (P1M) and 3 months (P3M) and was classified into three types: haptic in the ciliary sulcus (ICS), haptic in the ciliary body (ICB), and haptic under the ciliary body (UCB). Results: Among haptics classified as ICS at P1M (n=131), 120 remained ICS (91.60%), 9 became ICB (6.87%), and 2 became UCB (1.53%) at P3M. Among haptics classified as ICB at P1M (n=66), 44 remained ICB (66.67%), 17 became ICS (25.76%), and 5 became UCB (7.58%). Among haptics classified as UCB at P1M (n=35), 26 remained UCB (74.29%) and 9 became ICB (25.71%). The maximum ciliary body thickness (CBTmax, P=0.010), iris thickness at 500 μm (IT500, P=0.029), and trabecular-ciliary angle (TCA, P=0.045) were associated with ΔIRH P3M-P1M (distance between the iris root and the tip of haptic, P3M-P1M). Anterior chamber depth (ACD, P=0.031) and Δvault P1M-P1D (P=0.005) correlated significantly with Δvault P3M-P1M . Conclusions: Haptics inserted in the ciliary body are more susceptible to positional shifts. Increased IRH is more likely to occur in eyes with a thinner ciliary body, thinner iris, and wider TCA.