Ptosis

–Ptosis is drooping of the upper eyelid of one eye or both.

–There are many kinds of ptosis according to its cause :

–It could be congenital , which is the most common type , due to weakness of the levator muscle that lifts up the upper eyelid. This congenital causes could be genetic or due to some infections or drugs that had been used by mother during pregnancy period.

–Another kind of ptosis  is the paralytic one, which occurs due to paralysis of the third cranial nerve which is responsible for the movement of the eye and eyelid muscles , or could be due to paralysis of the sympathetic nerves that share in lifting up the upper eyelid. This paralysis of the nerves may occur due to traumatic damage , infections , vascular obstruction or tumors.

–Thirdly,ptosis  could be of mechanical cause , where there is some load over the upper eyelid that makes it heavy and droop down, as some tumors or oily cysts or due to recurrent inflammations that make the upper lid heavier.

–Lastly , ptosis  could be of traumatic etiology, as due to sharp trauma or burns, which cause damage to the levator muscle and lead to eyelid drooping.