Ptosis is an abnormally low position (drooping) of the upper eyelid. The drooping may be worse after being awake longer, when the individual's muscles are tired. This condition is sometimes called "lazy eye", but that term normally refers to amblyopia. If severe enough and left untreated, the drooping eyelid can cause other conditions, like amblyopia or astigmatism. This is why it is especially important for this disorder to be treated in children at a young age, before it can interfere with vision development.
Ptosis occurs when the muscles
that raise the eyelid (levator
muscles) are not strong enough to do so properly. It can affect one eye or both eyes and is more common in the elderly, as muscles in the eyelids may begin to deteriorate. One can, however, be born with ptosis. Congenital ptosis is not hereditary. Causes of congenital ptosis remain unknown. Ptosis may be caused by damage/trauma to the muscle which raises the eyelid, or damage to the nerve
(3rd cranial nerve (oculomotor nerve)) which controls this muscle. Such damage could be a sign or symptom of an underlying disease
such as diabetes mellitus
, a brain tumor
, and diseases which may cause weakness in muscles or nerve damage, such as myasthenia gravis
Depending upon the cause it can be classified into:
Aponeurotic and congenital ptosis may require surgical correction if severe enough to interfere with vision or if cosmesis is a concern.
Treatment depends on the type of ptosis and is usually performed by an ophthamolic plastic and reconstructive surgeon, specializing in diseases and problems of the eyelid.
Surgical procedures include:
- Levator resection
- Müller muscle resection
- Frontalis sling operation
Non-surgical modalities like the use of "crutch" glasses to support the eyelid may also be used.
Ptosis that is caused by a disease will improve if the disease is treated successfully.
- The AMA Medical Guide, Random House, Inc. New York, 1997 ed.
- The American Society of Ophthalmic Plastic and Reconstructive Surgery