A congenital eyelid defect is a rare congenital malformation of the eyelid. It is a defect of the entire structure of the eyelid, including the skin, orbicularis oculi, lid plate, conjunctiva and its accessory glands. It is most commonly seen in the upper lid, and in some cases is combined with absence of the eyebrow, lid bulb adhesions, corneal dermatomalacia, and corneal clouding. Congenital eyelid defects not only seriously affect the appearance but can also cause corneal damage. Surgical correction is both cosmetic and protective of the eye. The exact cause of congenital eyelid defects is not known. In the third month of life, the upper and lower lid margins are in contact with each other and the inner and outer ends begin to adhere. They are completely separated by the 6th or 7th month of life. Any factor affecting this process will result in abnormal development of the eyelid defects, eyelashes and other connected structures. Professor Tessier, a French craniomaxillofacial specialist, considers congenital eyelid defects to be a type of craniofacial cleft, type 11, while the amniotic stripe theory states that the force applied to the face by the amniotic stripe during development will result in a shallow or absent superior vault, adhesions between the cleft and the eye, and absence of the eyebrows. In addition, intrauterine infection, poor placental circulation, and abnormalities of the vascular system have been suggested as possible causes. The main treatment for this disease is surgical plastic surgery. The timing of surgical treatment depends on the size of the defect and the degree of corneal exposure. For smaller defects with no corneal exposure, surgical correction is recommended at 3-4 years of age because more eyelid tissue is available for reconstruction; for defects larger than 1/3 of the lid margin length, early surgical correction is necessary given its impact on visual development and later life and cosmetic appearance. The first step in surgery is to measure the area of the defect, including the vertical and horizontal lengths, and then to select the appropriate surgical approach.