Clinical characteristics analysis of patients who underwent lens exchange or explantation after implantable collamer lens implantation

Background This study aims to analyze the clinical characteristics of patients receiving secondary lens exchange or explantation after implantable collamer lens (ICL) implantation. Methods This retrospective study included 2347 eyes of 1175 consecutive patients receiving ICL or toric ICL (TICL) implantation. Clinical characteristics and ocular biometric measurements of patients who underwent secondary lens exchange or explantation (Group Ex) were analyzed. Visual outcomes and safety indices of secondary surgery were compared with the control group (Group C). Results The overall exchange or explantation rate was 1.11%. Eight eyes (0.34%) exhibited an excessive vault height, which was corrected after exchange surgery. Seventeen eyes (0.72%) exhibited a low vault, of which one eye underwent explantation, 11 eyes achieved a vault > 250 µm after exchange surgery, and five eyes had a vault ≤ 250 µm. One eye (0.04%) experienced repeated vertical TICL rotation and was exchanged with a nontoric lens. The clinical characteristics associated with an insufficient vault included a higher crystal sagittal height, smaller ciliary processes, and a wide iris-ciliary angle (ICA). The efficacy index at one month postoperatively was significantly higher in Group C (1.20 ± 0.20) than in Group Ex (1.10 ± 0.19) ( P  < 0.05). The safety index was 1.16 ± 0.17 and 1.22 ± 0.18 in Group Ex and Group C ( P  > 0.05), respectively. Conclusions Abnormal vault height after ICL implantation is the main reason for secondary exchange or explantation surgery. Biometric characteristics, including higher crystal sagittal height, smaller ciliary processes, and wider ICA, were associated with low vault height. Trial Registration: Registration number: ChiCTR2100051739. Prospectively registered: 01 October 2021.