Usually, astigmatism will not cause droopy eyelid. Actually it is one of the causes of astigmatism. Droopy eyelid (it is also called ptosis or blepharoptosis) is a kind of condition in which the position of the upper lid is abnormally low. It can be divided into acquired ptosis and congenital ptosis while the former is more common. The Acquired ptosis is caused by the weakness or degeneration of the muscles that elevates the eyelids. The congenital ptosis is in-born due to the underdevelopment of levators. There are various causes of acquired ptosis, such as trauma in the muscles, aging. Some kinds of surgeries can result in ptosis. Besides, eye tumors, neurological disorders or some systematic diseases are the possible causes of droopy eyes. If the ptosis is mild, no treatment is needed. If it is severe, blepharoplasty surgery is necessary.