Congenital ptosis is a condition in which the upper eyelid does not lift properly due to hypoplasia of the levator muscle or due to a developmental disorder of the central or peripheral nerves that innervate the levator muscle. There is no universal standard for whether, when, or how congenital ptosis should be treated. Choosing the best timing for treatment is critical to the physical and mental development and visual function of the child. The timing of surgery is as follows: 1. For bilateral severe congenital ptosis to prevent spinal deformity, or monocular severe ptosis to prevent amblyopia, surgery can be performed at about one and a half years of age. 2. For monocular congenital ptosis with ipsilateral astigmatism, surgery can be performed at the age of 3-5 years to prevent the development of amblyopia. 3. To prevent the effects on the child’s psychological development, surgery can be performed before school age. 4.If it does not affect physical, mental and visual development surgery should be done when local anesthesia can be tolerated. This is because surgery at a younger age can affect the surgical results due to poor development of the levator and frontalis muscles.