Refractive examination before ICL crystal surgery is very important, surgical safety, through the examination, is not adapted to the operation, is a very critical step, the examination is divided into: 1, routine eye examination, including naked eye vision, corrected vision, refractive status, eye has no active eye disease, including inflammation or retina and some other serious diseases, the first thing that must be ruled out; 2, for the ICL special surgical methods of Some special examinations, including: corneal horizontal diameter, i.e. corneal size; anterior chamber depth, the anterior chamber depth is very important for the surgery, because the ICL crystal is placed in the posterior chamber, which is closely related to the depth of the anterior chamber; highly nearsighted eyes, because most of the ICL eyes are highly nearsighted eyes, so the fundus examination, including OCT, UBM and so on, is very critical, and it plays a vital role in the safety of the surgery; special auxiliary examinations, such as binocular visual function examination and so on. Special auxiliary examinations, such as binocular visual function examination, are also helpful for the recovery of visual function after surgery.