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 acquired 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:
http://www.nlm.nih.gov/
http://www.asoprs.org/
http://www.oculo-doc.com
http://www.steen-hall.com/
http://www.moorfields.co.uk/

Pto"sis (?), n. [NL., fr. Gr. a falling.] Med.

Drooping of the upper eyelid, produced by paralysis of its levator muscle.

 

© Webster 1913.

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