Congenital ptosis is caused by congenital dysplasia of the levator muscle or of the nerve that governs the levator muscle, resulting in inability to open the eyes fully. The common manifestation of ptosis is that one or both eyes do not open fully, and children often have to tilt their heads back when looking at something. When the degree of ptosis is not the same on both sides, it often manifests as a difference in the size of the two eyes. The degree of ptosis can be divided into mild: slight ptosis, slightly different from normal; moderate ptosis: the difference can be seen more clearly, with the upper lid margin approaching the pupil or slightly covering the pupil; and severe ptosis: significantly different from the normal or healthy side of the eye, with the upper lid margin covering a small or even half of the pupil, and the child often tilting his or her head to look at things. The time and method of treatment for congenital ptosis can be performed after the age of 2 years. Mild ptosis can be treated at a slightly older age, while moderate to severe ptosis, which already covers part or all of the pupil, can usually be corrected after the age of 2 years. Treatment of ptosis requires surgery to correct the ptosis while forming a double eyelid, and the healthy side of the eye can be made double eyelid at the same time if it is monolid. In moderate to severe ptosis, the pupil will be covered to varying degrees, affecting the child’s vision, which can affect the normal development of vision and lead to amblyopia. On the other hand, children with ptosis often raise their eyebrows or adopt an upturned posture to see in order to free their visual axis from the interference of the ptosis, resulting in deeper forehead wrinkles, upturned eyebrows, and poor head tilting habits, which can lead to deformities of the neck muscles or cervical vertebrae, and even a slanted neck and distorted face. Therefore, severe ptosis should be corrected early.