Ptosis

A drooping of the upper eyelid. This condition is causedby paralysis of that branch of the third or motoroculi nerve which supplies the levator palpebramuscle. It may also be caused by the thickening of the upper

Source: Ophthalmic Dictionary including pronunciation, derivation and definition of the words used in Optometry and Ophthalmology by James J. Lewis, Oph. D. Professor of Optometry in the Northern Illinois College of Ophthalmology and Otology, Chicago.