Double eyelid is the common name of double eyelid, which is called upper eyelid fold in ophthalmology. From an aesthetic point of view, the shape of the upper eyelid of the double eyelids makes people's eyes more expressive of emotions and reveal bright eyes. Single eyelids often give people a monotonous, bloated and lifeless feeling. In order to change this deficiency, the method of forming double eyelids by surgery was born.