Vertical And Horizontal Icl Rotation: An Effective Methods To Adjust Postoperative Suboptimal Vault With A Minimally Invasive Technique

The implantable collamer lens(ICL) is one of the most widely used posterior chamber phakic IOL for refractive surgery and is available in 4 sizes. Postoperative vault is one of the key factors in determining surgical success. Surgeons select an appropriate ICL size based on patient's preoperative measurements to achieve an optimal vault. However, when vault is excessively high or low, conventional approach has been exchanging ICL for a different size. Since sulcus-to-sulcus length is different from horizontal to vertical direction, vertically or horizontally rotating ICL could offer an alternative method for adjusting vault without ICL size exchange. This study aims to evaluate the effect of ICL rotation in suboptimal postoperative vault.

This study included patients who underwent posterior chamber phakic intraocular lens implantation to treat myopia or myopic astigmatism at B&VIIT Eye Center (Seoul, South Korea) between January 1, 2024, and December 31, 2024. Among them, eyes which required postoperative vault adjustment and underwent either horizontal or vertical ICL rotation were analyzed. Anterior segment optical coherence tomography (CASIA 2) was used to measure and compare vault values before and after rotation.

A total of 3232 eyes underwent ICL implantation. Among them, 1216 eyes received non-toric ICLs, while 2016 eyes received toric ICLs. ICL rotation for postoperative vault adjustment was performed in 14 eyes with non-toric ICLs. Since toric ICLs require speific toric axis to be placed to correct astigmatism, only eyes implanted with non-toric ICLs which resulted in suboptimal vault were treated with this methods. Initial ICL placement either horizontal or vertical were decided based on surgeons' experience. For eyes with excessive vault after horizontal ICL placement, vertical rotation was performed to reduce vault. Also, for eyes with low vault after vertical placement, horizontal rotation was performed to increase vault.

Initally horizontal placed ICL with high vault were vertically rotated in 8 eyes. The pre-rotation (horizontal) vault was 910.87 ± 65.52 µm, and the post-rotation (vertical) vault decreased to 530.62 ± 43.08 µm, showing a statistically significant vault reduction (p < 0.05). Also, 6 eyes with vertically placed ICL that resulted in low vault were treated with horizontal rotation. The pre-rotation (vertical) vault was 101.00 ± 58.96 µm, and the post-rotation (horizontal) vault increased to 277.75 ± 54.96 µm, showing vault increase (p = 0.06).

ICL rotation can be considered as a minimally invasive method for postoperative vault adjustment in non-toric ICLs. When an ICL is initially implanted horizontally and results in high vault, rotating it to a vertical position can effectively and safely reduce the vault. Also, when an ICL is initially implanted vertically and results in low vault, rotating ICL to a horizontal position can help achieve a more optimal vault. This offers a simple yet effective technique for adjusting postoperative vault without ICL size exchange.