
Ptosis
Ptosis occurs when the
upper eyelid droops to an abnormal level and covers part of the
eye. It can have many causes including age, injury or nerve malfunction.
It can also occur at birth.
Age is the most common cause of ptosis. The muscles that elevate
the eyelid stretch and become thinned, resulting in a loss of
muscle tone and the inability to hold the upper lid in the proper
position above the eye.
Injury is another common cause of ptosis. Trauma to the eye,
such as during an automobile accident, can damage the delicate
structures around and in the eye.
Sometimes ptosis can be noticed at birth. In these cases it is
due to an abnormality in the development of the muscles that
elevate the upper lid. Three-quarters of the time it affects
only one eye.
Ptosis can also be caused by a malfunction of the nerves which
control and activate the eyelid muscles. These cases are rare
and proper diagnosis is important in order to avoid unnecessary
surgery. When a neurological disorder is present, symptoms typically
include visual complaints independent of the droopy eyelid. Difficulty
reading and driving are common complaints. Raising the entire
brow with the muscles of the forehead and scalp may cause headaches
and eyestrain as well. In newborns, this problem must be addressed
and treated properly to insure normal maturation of the visual
system and the avoidance of amblyopia (lazy eye).
The most common treatment for ptosis is surgical, and there are
a number of possible approaches. The goal is to tighten the muscles
so that the lid is elevated to match the lid on the other side,
but with a minimum of scars and side effects. One possible complication
is that the muscles can be over tightened. This results in the
inability to close the eye completely after surgery. Such a situation
creates a dry eye condition that may be difficult to manage.
In the age-related form, both eyelids may be drooping, but only
one is low enough to require surgery. Almost invariably in these
cases, the unoperated eyelid will appear lower after a successful
repair of the first eye. The second eye also may eventually require
surgery. |