Canthus is a common condition among Oriental peoples, which is characterized by a top-down or bottom-up reversed webbed skin fold in the inner canthus, often accompanied by a single eyelid. The presence of canthal folds obscures the inner canthus and makes the eye fissure look thinner and shorter, which affects the aesthetics and therefore makes friends with canthal folds think about opening the inner corner of the eye. It is true that even a successful double eyelid surgery will be inferior to the presence of canthus in patients with single eyelids with obvious canthus. Therefore, it is necessary to surgically correct severe canthus. There are many surgical methods to correct canthus, but the most common method used in cosmetic outpatient surgery is to perform a “Z” reshaping of the inner canthus, which is a relatively simple procedure with few incisions and is suitable for all degrees of canthus. The Mustard method (Four Flap method), also known as the four flap method, was once popular for the correction of medial canthus, but because of the excessive incisions and obvious scarring, it is less commonly used for simple medial canthus correction. Nevertheless, all types of canthus correction will leave a relatively obvious recent scar in the inner canthus that is difficult to cover, so the patient should be carefully asked if he or she is a keloid before surgery, and if it does exist, it is recommended not to do the surgery, and even if he or she is not a keloid, the patient should be fully prepared before surgery. For mild canthus, it is generally not necessary to treat it. Years of clinical experience have confirmed that the design of a narrow inner and wide outer eyelid line can effectively conceal the defect of inner canthus.