Arch height is a term used in the context of IOL implantation in the toric eye; the height from the anterior surface of the lens to the posterior surface of the implanted ICL IOL after ICL implantation is called the arch height. Having the proper arch height is a very important factor in ensuring the success of the ICL implantation procedure. It is important to routinely check the anterior chamber depth before surgery to ensure that there is a proper postoperative arch height. If the postoperative arch height is too low, it can easily cause the ICL IOL to shift in position, resulting in glare and poor postoperative vision. If the postoperative arch height is too high after ICL surgery, the iris will bulge forward, the anterior chamber will be crowded, the atrial angle will be narrowed or closed, and the atrial water will flow out poorly, leading to secondary glaucoma, which is a very serious complication.