Eyelids, congenital ptosis of the: Drooping of the upper eyelids at birth. The lids may droop only slightly or they may cover the pupils and restrict or even block vision. Moderate or severe pstosis calls for treatment to permit normal vision development. If not corrected, amblyopia ("lazy eye") may develop which can lead to permanently poor vision. Ptosis at birth is often caused by poor development of the levator muscle which lifts the eyelid. Children with ptosis may tip their heads back into a chin-up position to see underneath the eyelids or raise their eyebrows in an attempt to lift up the lids. Congenital ptosis rarely improves with time. Mild or moderate ptosis usually does not require surgery early in life. Treatment is usually surgery to tighten the eyelid-lifting muscles, the levators. If the levator is very weak, the lid can be attached or suspended from under the eyebrow so that the forehead muscles can do the lifting. Even after surgery, focusing problems can develop as the eyes grow and change shape. All children with ptosis, whether they have had surgery or not, should therefore be followed by an ophthalmologist.