Definition
Ptosis (TOE-sis) is the medical term for drooping of the upper
eyelid, a condition which may affect one or both eyes. It can be
congenital (present at birth) or acquired later in life.
People usually want to correct ptosis because they don't like the effect it has on their appearance, but it can also reduce the field of vision if
the lid droops far enough to cover the pupil. Someone with severe
ptosis may need to tilt his or her head back, lift the eyelid with a
finger, or raise their eyebrows in an effort to see
from under the drooping eyelid(s). In cases of congenital ptosis,
correction is important because vision can be permanently damaged if
the condition is left untreated.
Causes
Congenital ptosis is usually a result of failure of the levator
muscle to develop properly.
The most common cause of aquired ptosis is the stretching and thinning
of muscles with age, causing a loss of muscle tone and the inability
to hold one's eyelid completely open. The tendon of the levator
muscle may also loosen with age, with similar results.
Ptosis may also be caused by the weight of the eyelid simply becoming
too much for the muscles to lift, usually because of excess fat. This
condition is sometimes called brow ptosis, and is most common in men.
Less innocuous causes of ptosis involve damage to the muscle or to
the nerves that control it. The damage may be caused by diabetes,
tumors, aneurysms, strokes, trauma, Horner's Syndrome,
myasthenia gravis, or Graves' disease. This is by no means an
exhaustive list.
Complications
Children with congenital ptosis may also have amblyopia (lazy eye),
strabismus (eyes that are not properly aligned), refractive errors,
astigmatism, or blurred vision. In addition, drooping of the eyelid
may make them look odd (if the ptosis is confined to one eye) or
stoned (if the patient is doubly afflicted).
Symptoms and Diagnosis
A drooping eyelid is the principal sign of ptosis. Children with
congenital ptosis often tilt their heads back or raise their eyebrows
to lift the eyelid. Adults have the same symptoms, but they may also
notice a loss of vision, especially in the upper field.
In the case of acquired ptosis, it is especially important to
determine the cause of the problem. If the ptosis is caused by a
neurological or muscular problem, it's important to treat the
disease first. If the ptosis is caused by a tumor, it may disappear
if the tumor is removed. Blood tests, X-rays, and neurological tests are used to determine the cause of the ptosis and plan a course of treatment.
Treatment
Ptosis can usually be corrected. Some forms of ptosis respond to
medication, but most of them require surgery. Congenital ptosis is
always treated surgically. If the ptosis is not severe,
surgery is usually delayed until the child is three to five years
old. If the ptosis interferes with the child's vision, surgery is
performed much earlier to allow normal visual development.
Surgery for the correction of ptosis is usually performed by
plastic or reconstructive surgeons who specialize in eyelids and
adjacent facial structures. The surgery usually involves either
shortening the affected muscle or tendon (if the ptosis is caused by
aging), suspending the lid from the eyebrow muscle (if the levator
muscle doesn't work), or re-attaching the muscle and/or tendon to the
eyelid (in the case of injury). In adults, the surgery is usually
performed under a local anaesthetic and light sedation.
Surgery is sometimes performed on both eyes, even if only one is
affected, in order to achieve a more symmetrical
result.
Prognosis
It is difficult to guarantee a successful surgery. Approximately 85
percent of patients are satisfied with the results of their first
operation. The remaining 15% require a second procedure to correct
such problems as the eyelid being too low, the eyelid being too high,
the curve being irregular or the skin crease being defective. There
is also a danger of the muscles being over tightened, which results in
the inability to close the eye completely after
surgery. This situation creates a dry eye condition that may lead to
infections.
Thanks to Chark for suggesting I node this.
Sources:
www.nlm.nih.gov
www.asoprs.org
www.oculo-doc.com
www.steen-hall.com
www.moorfields.co.uk
| 
