The majority of ptosis cases are due to hypoplasia of the levator muscle or abnormalities in the motor nerve that innervates it, the oculomotor nerve, which is not fully functional. In a small number of cases, this is due to tightness of the external and internal corners of the levator muscle and the superior transverse ligament or excessive adhesion of the fibers to the posterior wall of the orbital septum, which restricts the movement of the levator muscle. Ptosis can be divided into congenital ptosis and acquired ptosis. Congenital ptosis is the most common type of ptosis, with a population prevalence of 0.12%, and is an autosomal dominant or recessive disorder that is mostly bilateral and hereditary. Symptoms: 1. The upper lid cannot be lifted sufficiently; 2. The frontal brow or tilt of the head to raise the upper lid to see; 3. It can affect vision. The levator aponeurosis begins at the orbital apex and travels forward above the superior rectus muscle along the superior orbital wall and gradually spreads out in a fan-like pattern to form the levator aponeurosis. When it reaches the superior margin of the upper lid (often in front of the lid in the East), it fuses with the fibers of the orbital septum. The levator muscle is 50-55 mm in length, and near the superior orbital rim, its sheath thickens to form the superior transverse ligament, also known as the ligament of restraint, which is usually located in front of the levator muscle and may also surround the muscle, serving to limit the excessive lifting of the upper lid to some extent. The upper lid margin is located at the midpoint between the superior pupillary margin and the superior corneal margin when the eye is naturally open in situ, i.e., the upper lid margin covers the cornea above by 1.5-2.0 m. For unilateral patients, the amount of ptosis is easily determined by measuring the height of the lid fissure on both sides in situ, and the difference between the two is the amount of ptosis. The grading of the levator muscle strength plays a very important role in the choice of surgical approach. Traditionally, the strength of the levator muscle is measured by pressing the thumb back against the entire brow of the affected side, completely blocking the frontalis muscle from lifting the upper lid as much as possible, asking the patient to look down as far as possible, aligning the upper lid margin with the zero point of the meterstick, and then asking the patient to look up as far as possible, with the lid margin being raised from the bottom to the top (expressed in mm). The strength of the levator muscle in a normal person is 13-l6mm without the frontalis muscle, increasing to 16-19mm with the frontalis muscle, and is divided into three levels: good: greater than 10mm moderate: 4-9mm weak: less than 4mm. generally speaking, the worse the strength, the more pronounced the ptosis. Surgical treatment of ptosis: 1. surgery to shorten or enhance the strength of the levator muscle; 2. surgery with the help of frontalis muscle power 3. surgery to reduce the load on the levator muscle 4. shortening of the M ulle r muscle 5. fixed suspension: orbital periosteal suspension.