The current consensus on the range of degrees that can be corrected by excimer laser surgery is that myopia should not exceed 1200 degrees, hyperopia should not exceed 600 degrees, and astigmatism should not exceed 600 degrees. If the preoperative corneal thickness, corneal refractive power and pupil factors are integrated, some myopia can occasionally achieve 1200 degrees, and some myopia can only achieve 800 degrees or even less. So what is the solution for those with more than 1000 degrees of myopia, especially those with 1400 degrees of myopia or higher, where corneal surgery is not suitable? Laser corneal surgery is to cut the cornea to make it flatter and thinner, which is “subtractive” in a way, but if a lens is implanted in the eye, which is very fine and thin, it can be seen as “additive”. For ultra-high myopia of over 1200 degrees, high myopia with relatively thin corneas, or moderate myopia with too thin corneas, in principle, as long as there is no restriction of intraocular space, especially anterior chamber depth, or abnormalities of corneal endothelium, all are suitable for “additive” lens implantation. Additive surgery, refractive lens implantation to correct high myopia, has been widely used in the United States and Europe. It does not require the removal or destruction of corneal tissue, does not require sutures after surgery, and is highly effective and safe. ICL, for example, is a purified collagen polymer (Collamer) that is biocompatible and has no adverse effects in the eye. From the early anterior chamber type lens to the current posterior chamber type lens, there is a growing trend in China to expand this “additive” lens surgery. In just a few years, the number of refractive lens implantations has increased significantly. Our hospital started to perform posterior chamber ICL implantation in 2007, mainly for those who are in need of help with ultra-high myopia of over 1000 degrees or even 2200 degrees with thin corneas. What are the other clinical advantages of the “addition” procedure? The entire surgery takes only about 15 minutes and does not require hospitalization. The incision is small and the lens can be folded without altering the structure and shape of the eye tissue, so the post-operative recovery is quick and you can work the next day. Under the slit lamp microscope, the ICL fixed in the ciliary sulcus is the closest to the natural human lens and has a better appearance. Since it is an “addition”, it is possible to remove the lens if there is a problem, which means that the procedure is highly reversible. For people with 1000 to 2200 degrees of myopia or more, it can be assumed that ICL and other crystal surgery has features that cannot be matched by conventional LASIK and other laser surgery, and will definitely be carried out more vigorously.