Ptosis

=Ptosis (Blepharoptosis)=

Introduction
Ptosis, also known as blepharoptosis, is defined as the drooping of the upper eyelid. A person may have both eyes effected or it could just be one. Ptosis can be caused by a variety of causes such as myogenic, aponeurotic, mechanical, neurogenic or traumatic causes. [1] These causes result in the dysfunction of the oculomotor nerve or the sympathetic nerves or result in the dysfunction of the muscles in which these nerves innervate which include the levator palpebral superioris or the superior tarsal muscle (Mueller muscle). [2]

Levator Palpebrae Superioris muscle
The levator palpebral superioris is a smooth muscle that has its origination on the wing of the sphenoid bone. The muscles aponeurosis inserts into the skin of the upper eyelid and to the superior tarsal plate. The action of the levator palpebral superioris is to elevate and retract the upper eyelid. The muscle is innervated by the ipsilateral superior division of the oculomotor nerve. [1]

Superior Tarsal Muscle
The second muscle that moves the eyelid is the Superior Tarsal muscle which is a smooth muscle that adjoins to the levator palpebrae superioris muscle. The superior tarsal inserts onto the superior tarsal plate of the eyelid. Since the superior tarsal muscle adjoins to the levator palpebrae superioris, you can assume that it is also innervated by the oculomotor nerve. The function of the superior tarsal muscle is to keep the upper eyelid raised when the levator palpebrae superioris has raised the eyelid.

Oculomotor Nerve Pathway
Innervation of the levator palpebrae superious and the superior tarsal muscle has its origination in the somatic portion of the oculomotor nucleus located in the midbrain near the dorsal midline. The fascicles of the somatic portion then combine with other somatomotor and parasympathetic portions to create the oculomotor nerve. The oculomotor nerve then leaves the brainstem between the superior cerebellar arteries and the posterior cerebral. After leaving the brainstem, the oculomotor nerve then enters the cavernous sinus where it then travels on the lateral wall. [3] As it is passing through here, it picks up sympathetic fibers from the internal carotid artery plexus and hen leaves the skull through the superior orbital fissure through the oculomotor foramen. From here the oculomotor nerve divides into two divisions, the superior and inferior. The superior portion will carry the somatomotor supply to the levator palpebral superiorus. To reach the levator palpebrae superiorus, the superior division goes into the orbit, medial to the optic nerve where it then divides into several fiber bundles. From here the bundles then reach the inferior surface of the levator palpebrae superiorus as well as the superior rectus muscles. [3]

Causes
Ptosis can result from a variety of ways. The best way to organize the causes is into congenital or acquired causes.

__Congenital ptosis__ means that ptosis is seen from birth. Most the of time, congenital ptosis happens from localized myogenic dysgenesis of the levator palpebrae superioris. In some cases it could be from chromosomal defects, or neurologic dysfunction. Below is a list of cases that would be considered congenital blepharoptosis: [2]


 * Congenital third cranial nerve palsy**- present at birth that happen due to developmental abnormality or birth trauma. Causes unilateral ptosis and ophthalmoplegia. Examples of birth trauma that would cause this is trauma by forceps delivery, fetal rotation, or vacuum extraction. [4]


 * Congenital Horner’s syndrome**- results from a defect from the sympathetic innervation to the eye. This causes ptosis, anhidrosis, miosis, and heterochromia.


 * Marcus Gunn Jaw-winking syndrome**- causes by misdirected innervations to the levator palpebrae superioris. This creates lid elevation with mastication, meaning that there is movement of the upper eyelid in a winking motion whenever the jaw is moved.


 * Congenital myogenic ptosis**- causes by dysgenesis of the levator muscle. So instead of having muscle fibers, there will be fibrous or adipose tissue that appears where the muscle fibers should be, enabling the levator muscle to contract or relax. [5]

__Acquired Ptosis__, which happens after birth, are caused by a variety of ways with the most common cause being aponeurotic ptosis. Other causes include myogenic, traumatic, neurogenic, and mechanical causes of acquired ptosis. Below we go into more detail about each cause: [1] [2]


 * Aponeurotic Ptosis**- results from stretching, dehiscence which is when there is a surgical complication that would cause a wound to rupture, or disinsertion of the aponeurosis of the levator palpebrae superioris or superior tarsal muscle. For patients who acquire aponeurotic ptosis from aging, it would be called involutional ptosis. Examples of other factors that would cause aponeurotic ptosis include continuous rubbing of the eye, long-term use of contact lenses, trauma or inflammatory diseases.


 * Myogenic ptosis**- results from diffuse or localized muscular diseases. Examples of this are muscular dystrophy, oculopharyngeal dystrophy, or chronic progressive external opthalmoplegia.


 * Traumatic ptosis**- results from any type of eyelid laceration of upper eyelid elevators, or could result from disruption of the neural pathway of the oculomotor nerve. Examples of traumatic ptosis include injuries in which third nerve palsy or Horner’s syndrome arise due to disruption of the oculomotor nerve pathway.


 * Mechanic ptosis**- results from the eyelid mass, for example neurofibroma where a noncancerous tumor grows on the eyelid so that the eyelid cannot be raised.

Signs & Symptoms of Ptosis
Patients who have ptosis will often complain that their eye (involved) being small, having a tired appearance, headaches, and a limited field of vision. [2] In terms of acquired ptosis, it can happen at any age, but it is often seen in older adults. As for congenital ptosis, you will see it at birth. There is no gender or racial in predilection of ptosis. [6] In order to have a proper diagnosis, the history of the patient will proved a very good indication of the etiology of the ptosis - for example, the onset of ptosis, aggravating factors, family history in regards to ptosis, and history of trauma or surgery. [2]

When looking at signs of ptosis, visual acuity as well as refractive error should be tested. Another sign would be the position of the eye brow and any extra skin of the eyelid in either or both eyes. Ocular mobility should be checked as well. Along with careful examination, palpation of the eyelid should be performed. [1] When examining the eye, measurements of key areas should be taken. These measurements include:


 * The length of the palpebral fissure, the distance between the upper and lower eyelid when it is in vertical alignment with the center of the pupil. [2]
 * The levator function, which is the distance that the eyelid travels from downgaze to upgaze when the frontalis muscle is held inactive at the brow. When there is a measurement that is greater than 10mm, then that is what is considered normal, while a measurement that is 5mm or less is considered poor.

Patients who have unilateral ptosis should have their involved eyelid lifted manually in order to test for any masked ptosis in the contralateral eye. [3] In order to test the Mueller muscle, sympathomimetic eyedrops can be used which stimulate the Mueller muscle. If a good response is seen, then it is likely that the ptosis is repairable by a conjunctival resection.

In terms of diagnostic procedures, clinical examination is good enough for most patients. After preforming all of these tests, visual field limitability will often be requested to see the affect that ptosis has on the peripheral field of vision. When a patient has neurologic deficits that accompany ptosis, imaging of the brain, orbits, and cerebrovascular system is generally recommended. For patients who have inflammatory or infiltrative orbital process as the cause, then a orbital CT or MRI scan is then recommended.

Treatment
Treatment of ptosis is primarily surgical. In mild congenital ptosis, if there are no signs of strabismus, abnormal head posture, or amblyopia then observation is the only thing needed. On the other hand if there is a risk for any of these, then surgery must be done as soon as possible. Surgical correction of ptosis can be done at any time for the improvement of the field of vision, or even just for aesthetic appearance. [3]

If the patient has myasthenia gravis, which is weakness of voluntary muscles which causes ptosis, then their condition may be improved with medical treatment. Sympathomimetic tropical eye drops can be used to stimulate the muscles of the upper eyelid so that it lifts. Sympathomimetic tropical eye drops include apraclonidine and phenylephrine. [3] [6]

Regarding congenital ptosis, if there is no risk of the development of amblyopia or significant abnormal head position, then surgical correction of the ptosis can be done at any age, but still depends on the severity of the disease. Depending on treatment goals, the diagnosis, and degree of levator function, the appropriate surgery technique will be used for surgical treatment. [3] [6]

Surgical Techniques

 * Muller Muscle-conjunctival resection**- Patients who have mild or moderate aponeurotic ptosis will have the option of this surgical technique. If there is a good response to the sympathomimetic tropical eye drop test, then it is a good indication that this type of surgery will have a high success rate for the patient. [6] If the patient has congenital ptosis, then this surgery will not work most likely. The procedure of the surgery is to mark the conjunctiva and the muller muscle. These two structures are then clamped followed by the suture passing under the clamp. Once passed through in a continuous manner, then the tissues that are above the clamp are resected. [3]

When a patient has poor levator function, less than 4 mm of movement then there are a variety of autogenetic and allogeneic materials can be used to create a type of sling for the eyelid. The sling, made out of for example fascia lata, will connect the eye lid with the eye brow so that when there is any elevation of the eyebrow, the eye will open. A downside to post-surgery is that the patient will not be able to close their eyelids for the first few months during sleep. [6] If ptosis goes untreated, and can affect a patient’s life drastically. For one, ptosis can lead to amblyopia, which is diminished vision, and can also lead to astigmatism, which is a condition which causes blurred vision. Not only this, but ptosis can cause frontal headaches and psychosocial effects which could lead to a poor performance in work or school. [6] Many medical and surgical approaches are available which provide good results for managing ptosis. Having to have more than one surgery to fix ptosis is not uncommon, especially for congenital ptosis. [2]
 * Levator advancement or resection**- This surgery involves the shortening of the aponeurosis of the levator muscle in relative accordance to the severity of the ptosis. This type of surgery only works effectively for patients which good levator function.

Glossary of terms

 * Ptosis-the drooping or falling of the upper eyelid.
 * Congenital- something that is present at birth.
 * Myogenic- origination of the muscle tissue
 * Dysgenesis- abnormal organ development.
 * Palpebral fissures- a space that is between the medial and lateral canthi of the two open lids of the eye.
 * Aponeurotic-tendon-like material that connects a muscle with the part that it moves.
 * Neurogenic-caused, controlled, or arising from nervous system.
 * Dystrophy-disorder where a organ or tissue that is of the body wastes away.
 * Ophthalmoplegia-weakness or paralysis of the muscles of the eye.
 * Neurofibroma- a benign nerve sheath tumor.

Listing of relevant links or suggesting readings
This article as the name suggests seeks to address the question of whether your droopy eyelid is of anything to be concerned about.
 * [|Do I need to seek medical attention for my droopy eyelid?]**

[|Eyelid Droop After Fungal Keratitis] This is an article that discusses the effect of eyelid droop after being treated for Fungal Keratitis.

Youtube videos of someone with Ptosis
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Multiple Choice/T-F
Congenital ptosis is where ptosis is seen from birth? Which cranial nerve innervates the muscles of the upper eyelid? Ptosis is a temporary disorder which will go away on its own so there is no need to be treated? What is the most common cause of acquired ptosis? In congenital myogenic ptosis, what will the muscle body consist of since there will not be muscle fibers? Ptosis is only seen in older, aging adults? Do males or females have a higher chance of getting ptosis?
 * True
 * False
 * Abducens nerve
 * Oculomotor nerve
 * Accessory nerve
 * Trigeminal nerve
 * True
 * False
 * Aponeurotic
 * Myogenic
 * Traumatic
 * Mechanical
 * Nothing, the whole muscle disappears
 * Dense connective tissue
 * Epithelium tissue
 * Fibrous or adipose tissue
 * True
 * False
 * Males
 * Females
 * Neither, they have the same chance

Short Answers
What would be some key indications that someone has ptosis?

Define aponeurotic ptosis and give some examples of how it could be caused.

What is the muscle that adjoins to the levator palpebrae superioris muscle and what is its action?

Essay
What is the pathway of the oculomotor nerve from the brain to the muscles of the upper eyelid?

Answers
Congenital ptosis is where ptosis is seen from birth? Which cranial nerve innervates the muscles of the upper eyelid? Ptosis is a temporary disorder which will go away on its own so there is no need to be treated? What is the most common cause of acquired ptosis? In congenital myogenic ptosis, what will the muscle body consist of since there will not be muscle fibers? Ptosis is only seen in older, aging adults? Do males or females have a higher chance of getting ptosis?
 * True
 * Oculomotor nerve
 * False
 * Aponeurotic
 * Fibrous or adipose tissue
 * False
 * Neither, they have the same chance

What would be some key indications that someone has ptosis?
 * Patients who have ptosis will often complain that their eye (involved) being small, having a tired appearance, headaches, and a limited field of vision.

Define aponeurotic ptosis and give some examples of how it could be caused.
 * Aponeurotic Ptosis- results from stretching, dehiscence which is when there is a surgical complication that would cause a wound to rupture, or disinsertion of the aponeurosis of the levator palpebrae superioris or superior tarsal muscle. An example of a cause that could lead to aponeurotic ptosis is continuous rubbing of the eye.

What is the muscle that adjoins to the levator palpebrae superioris muscle and what is its action?
 * The second muscle that moves the eyelid is the Superior Tarsal muscle which is a smooth muscle that adjoins to the levator palpebrae superioris muscle. The function of the superior tarsal muscle is to keep the upper eyelid raised when the levator palpebrae superioris has raised the eyelid.

What is the pathway of the oculomotor nerve from the brain to the muscles of the upper eyelid?
 * Innervation of the levator palpebrae superious and the superior tarsal muscle has its origination in the somatic portion of the oculomotor nucleus located in the midbrain near the dorsal midline. The fascicles of the somatic portion then combine with other somatomotor and parasympathetic portions to create the oculomotor nerve. The oculomotor nerve then leaves the brainstem between the superior cerebellar arteries and the posterior cerebral. After leaving the brainstem, the oculomotor nerve then enters the cavernous sinus where it then travels on the lateral wall. As it is passing through here, it picks up sympathetic fibers from the internal carotid artery plexus and hen leaves the skull through the superior orbital fissure through the oculomotor foramen. From here the oculomotor nerve divides into two divisions, the superior and inferior. The superior portion will carry the somatomotor supply to the levator palpebral superiorus. To reach the levator palpebrae superiorus, the superior division goes into the orbit, medial to the optic nerve where it then divides into several fiber bundles. From here the bundles then reach the inferior surface of the levator palpebrae superiorus as well as the superior rectus muscles.