Double eyelid surgery (double eyelid surgery) can increase the height of eye fissure, which makes people feel that their eyes are bright and their appearance is more beautiful and charming after operation. Therefore, cutting double eyelids has become the most common operation for cosmetic surgery in the East. According to the elasticity and relaxation degree of the upper eyelid skin, it can be divided into three types. 1. Positive force type: upper eyelid skin has no relaxation, good elasticity and moderate subcutaneous fat filling, which is more common in young people; 2. Weak type: the upper eyelid skin is slack, with poor elasticity and scarce subcutaneous fat, which is more common in middle-aged and elderly people; 3. Super-force type: the eyelid skin is tense and bright, and the fat at this moment is over-filled and swollen, commonly known as "puffy eyes" and "puffy eyes".