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Ptosis of the eyelids Classification and external resources
Ptosis of the left eyelid in a man with myasthenia gravis. The eyelid of the right eye shows compensatory retraction (Hering's law of equal innervation).
ICD-10	H02.4, Q10.0
ICD-9	374.3
DiseasesDB	25466
eMedicine	oph/201  oph/345
MeSH	D001763

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.

Causes

Ptosis occurs when the muscles that raise the eyelid (levator and Müller's 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 hereditary in three main forms.^[1] 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.

Classification

Depending upon the cause it can be classified into:

• Neurogenic ptosis which includes oculomotor nerve palsy, Horner's Syndrome, Marcus Gunn jaw winking syndrome, IIIrd cranial nerve misdirection.
• Myogenic ptosis which includes myasthenia gravis, myotonic dystrophy, ocular myopathy, simple congenital ptosis, blepharophimosis syndrome
• Aponeurotic ptosis which may be involutional or post-operative.
• Mechanical ptosis which occurs due to edema or tumors of the upper lid
• Neurotoxic ptosis which is a classic symptom of envenomation[1] by elapids such as cobras,^[2] or kraits.^[3] Bilateral ptosis is usually accompanied by diplopia, dysphagia and/or progressive muscular paralysis. Neurotoxic ptosis is a precursor to respiratory failure and eventual suffocation caused by complete paralysis of the thoracic diaphragm. It is therefore a medical emergency and immediate treatment is required.
• pseudo ptosis due to:1-Lack of lid support:Empty socket or atrophic globe. 2-Higher lid position on the other side: As in lid retraction

Treatment

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.

See also

• Dermatochalasis
• Iris sphincter muscle
• Cosmetic surgery
• Maxillofacial surgery
• Otolaryngology
• Plastic surgery

References

Further reading

• The AMA Medical Guide, Random House, Inc. New York, 1997 ed.

External links

• intelihealth
• Josef Finsterer, Ptosis: Causes, Presentation, and Management, Aesth. Plast. Surg. 27:193-204, 2003

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