Ptosis in Myasthenia Gravis

Myasthenia gravis ptosis is a condition in which the upper eyelid drops, causing the pupil to close and vision impairment.

Usually, the edge of the upper eyelid covers the iris of the eye by about 1.5 mm. If the eyelid drops below the upper edge of the iris by more than 2 mm, this indicates the presence of ptosis in myasthenia gravis. This pathology requires surgical intervention. Without surgery, the disease leads to decreased vision and the appearance of other ophthalmic diseases.

Ocular myasthenia may be present at birth (congenital ptosis) or develop as a result of aging, trauma, or the effects of cataract surgery or other corrective eye surgery.

This condition can also be caused by a problem with the levator muscles that lift the eyelid. Sometimes such difficulties are caused by individual anatomical features.

An eye tumor, a neurological disorder, or a systemic disorder such as diabetes can also cause drooping of the eyelids.

Symptoms can be mild or severe. The degree of weakness in the eye muscles may differ from day to day. The disease symptoms increase in the evening or after prolonged work that requires eye muscle tension. Many people with ocular myasthenia gravis find that their vision temporarily improves after minimal rest by closing their eyes for a few minutes. In the ocular form, there is usually no weakness in the muscles of the limb, and there are no problems with swallowing, speaking, and breathing.

Causes and Symptoms of Myasthenia Gravis 

The main causes of pathology:

• congenital disease, which is associated with insufficient development of the muscle designed to lift the upper eyelid;
• injury to the muscle that lifts the upper eyelid;
• damage to the oculomotor nerve;
• stretching of the tendon muscle that lifts the upper eyelid (typical for the elderly);
• the defeat of the cervical sympathetic plexus (the so-called Horner’s syndrome, expressed in ocular myasthenia, constriction of the pupil, and “retraction” of the eyeball);
• diabetes mellitus as a cause of metabolic muscle and nerve damage;
• acute violation of cerebral circulation (drooping of the eyelid is accompanied by several other symptoms);
• a tumor of the brain, spinal cord, or neck area;
• violation of neuromuscular transmission (myasthenia gravis or myasthenic syndrome);
• damage to the oculomotor nerve in the framework of polyneuropathy (in combination with damage to many other peripheral nerves);
• a complication of the introduction of botulinum toxin for cosmetic or medicinal purposes;
• botulism.

 Why are the muscles of the eyes most often affected in myasthenia gravis?

There are several opinions as to why the eye muscles are most often involved in the disease. However, there is still no exact proof and explanation. 

1. One hypothesis is that patients are more likely to notice weakness in the eye muscles than slight weakness in the muscles of the limbs.
   
2. Another suggests that the muscles of the eyes and eyelids differ in structure from the muscles of the trunk and limbs. 
3. The muscles of the eyes contain much fewer acetylcholine receptors. 
4. The eye muscles contract much faster and more frequently, which may be the reason for the quicker fatigue. 
5. The crucial difference between the muscles of the eyes and eyelids compared to other muscles in the body is the atypical response to an immune attack. 

For this reason, the eye muscles are most often affected by other autoimmune diseases, such as the thyroid gland.

The first symptoms of the disease are:

• Double vision and drooping of the eyelids are often the first symptoms of MG. 
• Despite most patients having vision problems at the onset of the disease, many develop muscle weakness, implying a generalized form of myasthenia gravis; this usually occurs within the first two years after diagnosis. Approximately one of 6-7 patients (15%) develops an ocular form of MG. 
• In half of the patients, generalized muscle weakness develops during the first year of the disease. With an ocular form that lasts more than 5 years, muscle weakness may be absent. It is impossible to predict the development of the form of MG.

Common symptoms of the disease are:

• partial or complete drooping of the edge of the upper eyelid, which leads to a deterioration in the quality of vision and headaches;
• throwing the head back to facilitate opening the eye;
• decreased visual acuity, the appearance of strabismus;
• constant eye fatigue;
• bifurcation of objects before the eyes.

Neurological Diseases Leading to Ptosis

Such diseases can lead to ptosis if they are not treated:

• Myasthenia gravis is a serious disease in which impulse transmission from the nerve to the muscle is impaired. This disease is characterized by increased muscle fatigue. The disease affects all muscles, but the most significant manifestations can only affect the eye muscles, causing ptosis, double vision, and decreased focus. For the primary myasthenia gravis diagnosis, a neurologist conducts a test with the introduction of proserin and examines the nerves and muscles using ENMG (electroneuromyography).

• In myopathy, double vision is also observed, omission of both eyelids, while the performance of the muscle that lifts the eyelid is weakened but present. The examination uses a needle EMG and some laboratory tests.

• Palpebromandibular synkinesis – involuntary friendly movements accompanying chewing, abduction, and opening of the lower jaw. For example, when the mouth is open, the prolapse can abruptly disappear, and after closing the mouth, it can recover. This condition can be both a common disease and the result of improper restoration of the motor fibers of the facial nerve after its defeat.

• Bernard-Horner syndrome (expressed by a combination of drooping of the upper eyelid, constriction of the pupil, and “retraction” of the eyeball). It is a manifestation of the pathology of the cervical sympathetic plexus. Sometimes pathology is found due to increased sweating on the face and incomplete paralysis of the brachial nerves on the diseased side.

Myasthenia Gravis Diagnosis and Treatment

Myasthenia gravis diagnosis

• Upper eyelid ptosis cannot be prevented, but you can get it diagnosed early. 
• You should start treatment before the field of vision is significantly limited and the cosmetic defect becomes noticeable.

Examination of the patient by an ophthalmologist for ocular myasthenia includes:

• Collecting anamnesis for a more accurate diagnosis of the cause of the disease;
• Measuring the width of the palpebral fissure (the distance between the edges of the upper and lower eyelids);
• Examination of the fundus to assess visual acuity;
• Biomicroscopy to determine the condition of the tear film, cornea, and conjunctiva.

To exclude cysts and tumors of the accessory apparatus of the eye and brain, the following instrumental studies can be carried out:

• Ultrasound of the accessory apparatus of the eye and orbit;
• MRI of the brain with the study of blood flow;
• CT scan of the brain;
• CT of orbits.

Treatment 

Treatment depends on the causes:

1. If the cause of the drooping of the eyelid is a neurological disease, such as myasthenia gravis or neuropathy, then, first of all, therapy of the underlying disease is carried out. Since ptosis is a symptom, it goes away after the underlying disease is cured.
2. In some cases, full recovery is impossible, so surgical treatment is carried out for cosmetic therapeutic purposes if ocular myasthenia leads to significant disruption of life due to deterioration of vision.
3. For children, such an operation is performed upon reaching the age of 3. But this should be done as soon as possible to prevent a decrease in vision and the development of strabismus.
4. The operation is recommended after puberty to eliminate a cosmetic defect (when vision is not impaired) when the facial bone skeleton is finally formed.
5. If the prolapse is caused by trauma, the operation can be performed directly during the initial treatment of the wound surface by the surgeon or after healing (6-12 months).

The doctor decides on the timing of the operation depending on the specific case.

Descent of the eyelid after the introduction of botulinum toxin

According to statistics, after injecting botulinum toxin (“Botox” and other preparations containing it) in the eye area, a drooping eyelid occurs in 20% of complicated cases, but this is almost always due to errors during the procedure or to an individual characteristic of a person.

The drooping of the eyelid after the introduction of Botox is unpleasant. But it cannot be considered a serious pathology since without additional therapy, the signs of drooping completely disappear within 3-4 weeks after the injection of the drug.

Prevention of the Development of Ocular Myasthenia  

Timely treatment of any diseases that can provoke this pathology is important in preventing prolapse of the eyelid. 

• For example, neuritis of the facial nerves must be treated immediately by a neurologist, and the possibility of drooping of the eyelids after Botox injections should be discussed with the specialist performing the manipulation.

• If you notice the weakness of the eyelids associated with age-related changes, then cosmetic and folk remedies can help you. Prevention methods include the use of tightening masks, oils, and massage treatments.

• You should massage the skin of the eyelids when drooping. Before the procedure, you can wipe the eyelids with lotion to remove the sebaceous scales and open the excretory ducts of the sebaceous glands. Massage with a cotton swab or disc soaked in an antiseptic solution or special ointment; use light pressure stroking in a circular and straight motion, moving from the inner corner of the eye to the outer corner. You can tap your eyelids lightly with your fingertips.

• There is a special gymnastics for the weakness of the eye muscles to prevent ocular myasthenia.

 Special Gymnastics to Prevent Ocular Myasthenia Gravis

Starting position: standing, sitting, or lying down.

1. Look up without raising your head, then sharply down. Repeat the movements 6-8 times.
2. Look up and to the right, then diagonally down and to the left. Repeat the movements 6-8 times.
3. Look up and to the left, then down and to the right. Repeat the movements 6-8 times.
4. Look as far as possible to the left, then to the right. Repeat the movements 6-8 times.
5. Stretch your hand forward- keep it straight. Look at the tip of your index finger and gradually bring it closer, without stopping to look until the picture begins to “double”. Repeat the movements 6-8 times.
6. Place your index finger on the bridge of your nose. Move your gaze to your finger alternately with your right and left eyes. Repeat 10-12 times.
7. Move your eyes in a circle to the right and left. Repeat the movements 6-8 times.
8. Blink quickly for 15 seconds. Repeat blinking up to 4 times.
9. Close your eyes tightly for 5 seconds, then sharply open your eyes also for 5 seconds. Repeat 10 times.
10. Close your eyes and massage your eyelids with your finger in a circle for 1 minute.
11. Move your gaze from the nearest point to the far one and vice versa.
12. The movement of the eyeball during exercise should be as wide as possible but so that it does not hurt you. The motor pace can be complicated over time. The duration of such prophylaxis is at least 3 months.

In the case of myasthenia gravis and myopathy, such exercises are contraindicated, as they contribute to the aggravation of the drooping of the eyelid due to “exhaustion” of the muscle. Therefore, before engaging in any method of treatment, it is necessary to consult a specialist.

FAQs

• What disease causes partial or complete drooping of the edge of the upper eyelid, constant eye fatigue and bifurcation of objects in front of the eyes?

Myasthenia gravis ptosis is a condition in which the upper eyelid drops, causing the pupil to close and vision impairment. 

• What is abduction nystagmus?

Abduction nystagmus is a dissociated, acquired form of jerky nystagmus with an abductive fast phase and a slow phase directed towards the midline. Usually occurs when the eye moves towards the temple, while the other eye remains motionless in the primary position. 

• Can Congenital Ptosis Be Cured?

Treatment of ptosis of the upper eyelid should be started immediately in order to avoid the development of complications (decreased visual acuity – amblyopia, strabismus, forced head position). It is important to note that ptosis usually does not go away without treatment; today, surgical treatment of this condition is accepted.

• How is the ptosis of the upper eyelid operated on?

If the functions of the muscle that lifts the upper eyelid are slightly impaired, an operation is performed to shorten it. In this case, the doctor makes an incision in the skin, selects the desired area of ​​muscle tissue, shortens it, and fixes it on the cartilage of the upper eyelid. Then a palpebral fold is formed.