Paired-eye comparison of endothelial cell density and vault height after implantable collamer lens implantation.

In clinical practice, the effect of a high vault on corneal endothelial cells after implantable collamer lens (ICL) implantation remains unclear. Many clinicians theoretically assume that a high postoperative vault leads to rapid endothelial damage, but no study has yet proven this hypothesis. We conducted a paired-eye study to compare changes in corneal endothelial cell density (ECD) between high and low postoperative vault groups. This retrospective study included 150 eyes of 75 patients with bilateral postoperative vault levels differing by more than 200 μm after ICL implantation. Patients were followed up for 7 years with ECD measurements, and changes in ECD were assessed between 6 months and 7 years post-surgery. Over the 7-year follow-up period, the percentage of ECD loss was 15.04% and 14.45% in the high- and low-vault groups, respectively. The bilateral paired-eye comparison revealed a significant reduction in ECD in the high-vault group at 3, 5, and 7 years postoperatively (P-value < 0.001). In this paired-eye comparison of long-term observations, a higher vault was associated with greater ECD loss. Our study confirms that a high vault level may be an important risk factor for ECD loss following ICL implantation.