Ptosis - Overview Ptosis is an abnormally low position (drooping) of the upper eyelid 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.

Defintion

• 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, such as 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.

 

NOTE

There are two 'main' surgeries that may be performed on the upper eyelid.
This section addresses Ptosis  which is the medical term for drooping of the
upper eyelid; it may affect one or both eyes.

The other surgery of the upper eyelid addresses excess skin  is repaired by blepharoplasty.

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.

• Ptosis can be caused by the apneurosis of the levator muscle, nerve abnormalities, trauma, inflammation or lesions of the lid or orbit. 
• Dysfunctions of the levators may occur as a result of a lack of nerve communication being sent to the receptors due to antibodies needlessly attacking and eliminating the neurotransmitter.
• Ptosis may be due to a myogenic, neurogenic, aponeurotic, mechanical or traumatic cause and it usually occurs isolated, but may be associated with various other conditions, like immunological, degenerative, or hereditary disorders, tumors, or infections

• Acquired ptosis is most commonly caused by aponeurotic ptosis. This can occur as a result of senescence, dehiscence or disinsertion of the levator aponeurosis. Moreover, chronic inflammation or intraocular surgery can lead to the same effect. Also, wearing contact lenses for long periods of time is thought to have a certain impact on the development of this condition.
• Congenital neurogenic ptosis is believed to be caused by the Horner syndrome.
  
• In this case, a mild ptosis may be associated with psilateral ptosis, iris and areola hypopigmentation and anhidrosis due to the paresis of the Mueller muscle. Acquired Horner syndrome may result after trauma, neoplastic insult, or even vascular disease.
• Ptosis due to trauma can ensue after an eyelid laceration with transection of the upper eyelid elevators or disruption of the neural input.
• Other causes of ptosis include eyelid neoplasms, neurofibromas or the cicatrization after inflammation or surgery. Mild ptosis may occur with aging.

Droopy eyelid; (πτωσις "falling, a fall") refers to droopiness of any body part

Graves' disease is an autoimmune disease. It most commonly affects the thyroid, causing it to grow to twice its size or more (goiter), be overactive, with related hyperthyroid symptoms such as increased heartbeat, muscle weakness, disturbed sleep, and irritability. It can also affect the eyes, causing bulging eyes (exophthalmos). It affects other systems of the body, including the skin and reproductive organs. It affects up to 2% of the female population, often appears after childbirth, and has a female:male incidence of 5:1 to 10:1. It has a strong hereditary component; when one identical twin has Graves' disease, the other twin will have it 25% of the time. Smoking and exposure to second-hand smoke is associated with the eye manifestations but not the thyroid manifestations. Diagnosis is usually made on the basis of symptoms, although thyroid hormone tests may be useful, particularly to monitor treatment.

Blepharoplasty can be both a functional and cosmetic surgical procedure intended to reshape the upper eyelid or lower eyelid by the removal or repositioning of excess tissue as well as by reinforcement of surrounding muscles and tendons

Heredity is the passing of traits to offspring (from its parent or ancestors). This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause a species to evolve. The study of heredity in biology is called genetics, which includes the field of epigenetics.

Levator palpebrae superioris muscle: The levator palpebrae superioris (latin for: elevating muscle of upper eyelid) is the muscle in the orbit that elevates the superior (upper) eyelid.