Ptosis: Causes, Classification, Symptoms, Pathology and Treatment

It is a fall of the upper eyelid. It can be worse after being awake longer when the individual’s muscles are tired.

This condition is sometimes called “lazy eye,” but that term usually refers to the condition called  amblyopia .

If it is severe enough and not treated, the drooping eyelid may cause other conditions, such as amblyopia or astigmatism . This is why it is especially important that this disorder is treated in children at an early age, before it can interfere with the development of vision.

Etymology

Ptosis is derived from the Greek word πτῶσις (“fall”), and is defined as the “abnormal decrease or prolapse of an organ or part of the body.”

Causes

It occurs due to the dysfunction of the muscles that elevate the eyelid or the supply of their nerves (ocular motor nerve to elevate the upper eyelid and sympathetic nerves to the superior tarsal muscle).

It can affect one eye or both eyes and is more common in the elderly, since the muscles of the eyelids may begin to deteriorate. One can, however, be born with ptosis.

Congenital ptosis is hereditary in three main ways.

The causes of congenital ptosis remain unknown. Ptosis can be caused by damage to the muscle that lifts the eyelid, damage to the superior cervical sympathetic ganglion, or damage to the nerve (3rd cranial nerve, ocular motor nerve) that controls this muscle.

Such damage could be a sign or symptom of an underlying disease, such as diabetes mellitus, a brain tumor, a pancreatic tumor (apex of the lung) and diseases that can cause muscle weakness or damage to the nerves, such as myasthenia gravis or oculopharyngeal muscular dystrophy .

Exposure to toxins in some snake venoms, such as the black mamba, can also cause this effect.

Ptosis can be caused by the aponeurosis of the levator muscle, nerve abnormalities, trauma, inflammation or lesions of the eyelid or orbit. Elevator dysfunctions can occur as a result of autoimmune antibodies that attack and eliminate the neurotransmitter.

It can also be due to a myogenic, neurogenic, aponeurotic, mechanical or traumatic cause and, in general, it occurs in isolation, but it can be associated with other conditions, such as immunological, degenerative or hereditary disorders, tumors or infections.

Acquired ptosis is commonly caused by aponeurotic ptosis. This may occur as a result of senescence, dehiscence, or disinsertion of the levator aponeurosis.

In addition, chronic inflammation or intraocular surgery can lead to the same effect. It is considered that wearing contact lenses for long periods of time has a certain impact on the development of this condition.

Congenital neurogenic ptosis is thought to be caused by Horner’s syndrome. In this case, mild ptosis may be associated with ipsilateral ptosis, hypopigmentation of the iris and areola and anhidrosis due to Mueller muscle paresis.

The acquired Horner syndrome can appear after a trauma, a neoplastic lesion or even a vascular disease.

Ptosis due to trauma can occur after a laceration of the eyelid with the section of the elevators of the upper eyelids or the interruption of the entrance of the nerves.

Other causes of ptosis include eyelid neoplasms, neurofibromas, or scarring after inflammation or surgery. Mild ptosis can occur with aging.

A drooping eyelid may be one of the first signs of a third nerve palsy due to a brain aneurysm, which is otherwise asymptomatic and is known as ocular motor nerve palsy.

Drugs

The use of high doses of opioid drugs such as morphine, oxycodone, heroin or hydrocodone can cause ptosis. It is also known that pregabalin, an anticonvulsant drug, causes mild ptosis.

Classification and symptoms of ptosis

Depending on the cause, it can be classified as:

Neurogenic ptosis: which includes paralysis of the oculomotor nerve, Horner’s syndrome, winking syndrome of Marcus Gunn’s jaw, misdirection of the third cranial nerve.

The dysfunction or damage of the oculomotor motor or the sympathetic nerves or the central nervous system can cause ptosis. The third nerve passes from the midbrain through the interpeduncular cistern to the cavernous sinus before reaching the orbital apex.

The intracranial aneurysm (which generally arises from the posterior communicating artery) and the resulting subarachnoid hemorrhage, in addition to meningitis and other compressive and infiltrative lesions in the area, can cause ptosis by damaging the third nerve.

Because the levator is the primary muscle responsible for keeping the eyelid open, severe deficits in third nerve function usually cause deep or complete ptosis.

Depending on the cause, there must be a period of observation before the surgical intervention to allow recovery of nerve function and levator muscle. A front suspension with a silicone rod or fascia lata for the sling achieves the best results in these cases.

The Müller muscle provides only a small contribution to the height of the eyelid. Therefore, only mild ptosis is seen in Horner’s syndrome, in which there is an interruption of the sympathetic fibers that innervate the Müller muscle.

Horner syndrome can be caused by a variety of lesions, including carotid dissection, tumors of the cavernous sinus, or lesions of the pulmonary apex that alter the sympathetic chain.

Indirect causes of neurogenic ptosis include diabetes, tumors, carotid-cavernous aneurysms, and multiple sclerosis.

Due to the small contribution to ptosis of Müller muscle dysfunction, the procedures directed to the Müller muscle will correct only a small amount of ptosis. These would include the Fasanella-Servat procedure and similar measures.

Myogenic ptosis: including oculopharyngeal muscular dystrophy, myasthenia gravis, myotonic dystrophy, ocular myopathy, simple congenital ptosis, blepharophimosis syndrome.

Congenital myogenic ptosis is the result of the dysgenesis of the levator muscle. Instead of normal muscle fibers, adipose or fibrous tissue is present in the muscular belly, which decreases the capacity of the levator muscle to contract and relax.

Therefore, most congenital ptosis caused by poorly developed levator muscle is characterized by decreased elevator function, eyelid delay and, sometimes, lagophthalmos .

The amount of function of the elevator is an indication of the amount of normal muscle. The crease of the upper eyelid is often absent or poorly formed, especially in cases of more severe ptosis.

Congenital myogenic ptosis associated with a deficient Bell phenomenon or with vertical strabismus may indicate concomitant malformation of the superior rectus muscle (double levator paralysis or monocular elevation deficiency).

Acquired myogenic ptosis is rare and is due to localized or diffuse muscular disease, such as muscular dystrophy, chronic progressive external ophthalmoplegia, MG or oculopharyngeal dystrophy.

Due to underlying muscle dysfunction, surgical correction can be difficult, requiring procedures and / or front sling procedures to repair lower eyelid retraction and improve corneal protection.

Aponeurotic ptosis that can be involutive or postoperative.

Aponeurotic ptosis is the most common type of acquired ptosis, it is also called senile or involutional ptosis because it occurs more frequently in the elderly as an involutional disorder.

This entity was first described by Jones Quickert and Wobig in 1975, who demonstrated that the aponeurosis of the elevator appeared dehiscent or disinsected from the tarsus. This disinsertion can be congenital or acquired.

Congenital aponeurotic ptosis is uncommon, but could be secondary to trauma with the use of forceps, vacuum extraction, fetal rotation and shoulder dystocia.

There are multiple factors that can cause the dislocation of the levator aponeurosis, such as continuous rubbing of the eye, chronic use of contact lenses, inflammatory diseases, trauma or after eyelid or intraocular surgery.

Approximately 6% of patients who undergo cataract surgery develop ptosis.

In some patients a normal levator aponeurosis has been revealed, but a myogenic degeneration of the muscle itself, which is characterized by a fatty degeneration in the area of ​​Whitnall’s ligament.

This fatty alteration has been confirmed by optical microscopy and appears to be a degenerative change found in adults with acquired ptosis.

The Müller muscle appeared to be macroscopically intact, but microscopic fibrosis with abundant collagen fibers was observed in the Müller muscles of patients with acquired blepharoptosis induced by the prolonged use of hard contact lenses.

Patients with aponeurotic ptosis can present a spectrum of symptoms ranging from a visually significant obstruction to cosmetic asymmetry of the lower eyelid, visually asymptomatic.

Obstruction of the visual field results in a functional blockage of the upper visual field. Symptoms often get worse when reading or looking down. Patients tend to compensate with frontal muscle hyperactivity. The persistent elevation of the eyebrow can cause frontal fatigue or even headache.

It is also important to look for fluctuations in fatigue symptoms throughout the day that may indicate myasthenia gravis.

In these cases, patients should also be asked about the use of drugs with statins, since recent reports have been received of myasthenic syndromes that gave rise to ptosis.

Once the diagnosis of aponeurotic ptosis is made, there are different surgical options available.

The goal of the surgery is to replace a dislocated or dehiscent aponeurosis on the superior anterior surface of the tarsus, or shorten and tighten a weak levator muscle, usually performed under local anesthesia, with or without intravenous sedation.

The reapplication or resection of the anterior aponeurotic muscle of the levator is effective. Some surgeons perform a posterior resection of the Müller muscle in patients who demonstrate adequate elevation of the eyelid after the instillation of topical phenylephrine.

We also compared a small previous procedure of minimal dissection with a traditional anterior aponeurotic approach, and the results of the less invasive surgery were as effective as the traditional approach.

The small incision procedure uses a surgical opening of approximately 4 mm, in contrast to the traditional 10 mm. In the study, those in the small incision group also experienced a better outcome in the eyelid contour.

In addition, with the minimal dissection technique, the operation time was significantly less overcorrection or undercorrection.

Mechanical ptosis: that occurs due to edema or tumors of the upper eyelid. This occurs when the eyelid is too heavy for the muscles to elevate it, as in blepharocalasia, the prolapse of orbital fat and eyelid tumors.

The continuous increase in weight in the eyelid will cause the skin to stretch from the thin eyelid. Removal of the ptosis-inducing mass (if present) and excessive eyelid skin, with or without a possible attached resection of the levator, alleviates the problem.

Neurotoxic ptosis: which is a classic symptom of elapid snake poisoning such as cobras, kraits, mambas and taipans. Bilateral ptosis is usually accompanied by diplopia, dysphagia and / or progressive muscle paralysis.

Independently, neurotoxic ptosis is a precursor to respiratory failure and eventual asphyxia caused by complete paralysis of the thoracic diaphragm. Therefore, it is a medical emergency and immediate treatment is required.

Similarly, ptosis can occur in victims of botulism (caused by botulinum toxin) and this is also considered a potentially fatal symptom.

Traumatic ptosis: in some cases, the elevator can be disinserted. In more extensive trauma, the levator tendon may have been sectioned with scar formation and secondary mechanical ptosis.

There may also be a third nerve damage. An individualized evaluation is needed to establish the appropriate surgical approach. Traumatic ptosis can also worsen later in life as a slip of the aponeurosis occurs.

Pathology of ptosis

Myasthenia gravis is a common neurogenic ptosis that could also be classified as neuromuscular ptosis because the site of the pathology is in the neuromuscular junction.

Studies have shown that up to 70% of patients with myasthenia gravis present with ptosis, and 90% of these patients will eventually develop ptosis.

In this case, the ptosis can be unilateral or bilateral and its severity tends to oscillate during the day, due to factors such as fatigue or the effect of the drug.

This particular type of ptosis is distinguished from the others with the help of a Tensilon challenge test and blood test.

In addition, specifically for myasthenia gravis is the fact that coldness inhibits the activity of cholinesterase, which makes it possible to differentiate this type of ptosis by applying ice on the eyelids.

It is very likely that patients with myasthenic ptosis experience a variation of the drooping of the eyelid at different times of the day.

The ptosis caused by oculomotor paralysis can be unilateral or bilateral, since the subnucleus of the levator muscle is a shared structure of the midline in the brainstem.

In cases where paralysis is caused by compression of the nerve by a tumor or an aneurysm, it is very likely that it results in an abnormal ipsilateral papillary response and a larger pupil.

Paralysis of the third surgical nerve is characterized by a sudden onset of unilateral ptosis and an enlarged or inactive pupil to light. In this case, imaging tests such as computed tomography or magnetic resonance imaging should be considered.

Medical paralysis of the third nerve, unlike paralysis of the third surgical nerve, usually does not affect the pupil and tends to improve slowly over several weeks.

Surgery to correct ptosis due to medical paralysis of the third nerve is usually considered only if the improvement of ptosis and ocular motility are not satisfactory after half a year.

Patients with third nerve palsy tend to have a decreased or absent levator function.

When caused by Horner’s syndrome , ptosis is usually accompanied by miosis and anhidrosis. In this case, the ptosis is due to the result of the innervation of the interruption of Muller’s sympathetic and autonomic muscle instead of to the somatic muscle of the levator palpebrae superioris.

The position of the eyelid and the size of the pupil are usually affected by this condition and ptosis is usually mild, no more than 2 mm. The pupil may be smaller on the affected side.

While 4% of cocaine instilled into the eyes can confirm the diagnosis of Horner’s syndrome, hydroxyamphetamine drops can differentiate the location of the lesion.

Chronic progressive external ophthalmoplegia is a systemic condition that occurs and usually affects only the position of the eyelid and the external movement of the eye, without involving the movement of the pupil.

This condition represents almost 45% of the cases of myogenic ptosis. Most patients develop ptosis due to this disease in adulthood. The characteristic of the ptosis caused by this condition is the fact that the protective rolling of the eyeball when the eyelids are closed is very poor.

Treatment

The severity of ptosis is usually divided as follows: mild (1-2 mm), moderate (3-4 mm) or severe (> 4 mm). In addition, the function of the elevator is commonly classified as good (> 8 mm), regular (5-7 mm) or deficient (0-4 mm).

To determine the optimal surgical approach, the function of the remaining levator must be considered with the amount of ptosis that must be corrected, along with the etiology of the ptosis.

Aponeurotic and congenital ptosis may require surgical correction if it is severe enough to interfere with vision or if cosmetics are a concern.

The treatment depends on the type of ptosis and is usually performed by an ophthalmic plastic and reconstructive surgeon, specialized in diseases and eyelid problems. Surgical procedures include:

  • Resection of the levator muscle.
  • Resection of Müller’s muscle.
  • Frontal sling operation (preferred option for Oculopharyngeal muscular dystrophy).

The advancement of the levator aponeurosis, which tenses or reattaches the aponeurosis to the tarsal plate, should address the needs of patients with good elevator function.

The surgical technique of Fasanella Servat is an alternative option for those with good lifting function.

People with poor elevator function will probably get the most benefit from the frontal sling procedure, which suspends the upper eyelid of the frontalis muscle.

This procedure, which is effective in cases such as myogenic ptosis, allows a certain degree of voluntary control of the eyelid. Elevator resection is another option in patients with moderate to low elevating function.

The partial resection of the upper eyelid elevator achieves a better height of the upper eyelid by strengthening the muscle.

Non-surgical modalities can also be used, such as the use of “crutches” or Ptosis crutches or special scleral contact lenses to support the eyelid.

Ptosis caused by a disease can improve if the disease is treated successfully, although some related diseases, such as oculopharyngeal muscular dystrophy, currently have no treatments or cures.