What is nystagmus?
Nystagmus is the movement that the eyes perform to compensate for the movement of the head. It can be pathological, when it happens involuntarily, even without head movements, and is caused by several conditions, such as labyrinthitis .
When we move, especially in head movements, the eyes do not move in the same way. If they were perfectly still in their sockets while we turned our heads, our vision would be a blur since they would not be able to focus on anything. To avoid this there is nystagmus.
Nystagmus consists of two movements, one slow and one fast. The eyes are always fixed at some point when we move. If you turn your head to the right, your eyes use the slow movement to move to the left at the same rate to compensate and stay fixed at one point.
When the eyes reach the limit, the rapid movement causes them to return to the initial position, facing forward, and fix on this new point. The movements are repeated until the rotation stops.
Standing, lying down or even upside down, you always know which way it is up or down. This happens because of the vestibular system , a set of organs that, next to the cochlea, forms the labyrinth , also called the inner ear, which serves to detect body movements and control balance.
The vestibular system is composed of three channels in a semicircle that come together in the vestibule (where the name of the system comes from). These channels, called anterior , posterior and horizontal , are filled with a liquid.
The vestibular system (the three rings in the image) is not completely filled with this liquid and it is able to move there according to the movement of the head. In each position of the head, the liquid reaches different parts of the rings.
This fluid stimulates hair cells (which have sensitive cilia) present in the region and based on this stimulus, the brain knows in which position the head and body are and it is through this information that it is able to control its posture, eye position and balance.
With the use of the vestibular system the brain always knows the position of your head and, in order not to confuse your vision, the movements of the nystagmus come into action and move your eyes according to your movement.
To perform these movements, the ocular nerves are activated. They are part of the integrating nervous system , responsible for the analysis and storage of sensory information. Through it, orders from the brain are sent to the eye muscles, which perform the necessary movements.
Finally, the fixation reflex keeps the eyes in the correct position to capture the image of what you want to focus on and send this image to the brain to interpret.
Through these mechanisms the brain is able to capture images even when the head moves, preventing the vision from becoming a blur.
Pathological nystagmus happens when the movements of the nystagmus happen even without the movement of the head or in a way incompatible with the movement performed. In this text we will refer to pathological nystagmus only as nystagmus .
The condition can always be present or appear only when the head is in a certain position. This varies according to the severity and cause of the nystagmus.
If any of the mechanisms used in the eye control – fixation reflex, vestibular system or integrating nervous system – present disorders, the pathological nystagmus can be installed.
There are several types of nystagmus. They differ by the type of eye movement, which is varied, and by the causes.
Vestibular nystagmus is caused by injuries or disorders of the vestibular system, the part of the inner ear that regulates balance and eye movement. He can be:
Peripheral vestibular nystagmus has unidirectional and horizontal movements performed in the direction of the lesion. This means that if the vestibular system of the left ear is damaged, the eye will move slowly to the left and then correct with the fast movement to the right. If the injury is on the right side the opposite happens.
Peripheral vestibular nystagmus is often accompanied by tinnitus (ringing in the ear) or deafness in the affected ear.
Central vestibular nystagmus can be unidirectional or bidirectional. It is usually vertical and can be torsional . It is usually caused by lesions of the central vestibular system, inside the brain.
Nystagmus is called congenital when the pathological condition has been present since birth or develops in the baby. It occurs most frequently between 2 and 3 months of age and is usually of genetic origin. Usually the movement of this type of nystagmus is horizontal.
Evoked by the gaze
This type of nystagmus is quite common and occurs when there is an involuntary attempt to maintain an eccentric eye position. An eye position is eccentric when the eyes are not in the natural relaxing position. This is what happens when we look sideways without moving our heads or when we look at our nose with both eyes, voluntarily squinting.
The cause of this type of condition is a sign of defective eye position in the integrating nervous system. The brain receives the information that the eyes are in a different position than they actually are and tries to perform the correction by moving them to a non-centralized position.
Spasmus nutans is a condition that accompanies, in addition to nystagmus,torticollisand head swings. It usually affects children from 3 to 15 months of age, but it is common for it to disappear between 3 and 4 years of age. On rare occasions, you can accompany your child up to 5 or 6 years of age.
Nystagmus in this condition tends to have rapid and low amplitude oscillations, often affecting both eyes in the same way, but it can affect one eye, be asymmetrical and even vary from eye to eye in different positions.
Several conditions can cause nystagmus and there are several cases of the condition whose cause is unknown, but many can be found. Some of them are:
Labyrinthitis is an inflammation of the labyrinth, the name given to the inner ear which is composed of the cochlea and the vestibular system. It can be caused by infections and lead to loss of balance and dizziness. The condition can cause nystagmus.
Injury to the vestibular system
Wounds and injuries to the vestibular system can lead to nystagmus. The injuries can be caused by the inappropriate use of flexible rods (cotton swabs) or other objects inserted in the ear.
Injuries to the midbrain, the vestibulocerebellum and other parts of the brain linked to the control of vision movement can cause nystagmus.
Tumors in regions that are related to eye movement control can lead to nystagmus.
Spinal cord injuries
Spinal cord injuries and changes can lead to nystagmus. This is the case with diseases such as Arnold-Chiari syndrome, multiple sclerosis and demyelination.
Other spinal cord injuries can occur due to trauma. This is the main reason why you should not move someone who has suffered a serious accident and the correct thing is to wait for specialized help, who knows how to move the patient with reduced risks to the spine and spinal cord.
Diseases that affect the cerebral vascular system can lead to nystagmus.
Brain infections can cause nystagmus. The types of infections that can lead to this condition are those that affect the brain, spinal cord, nervous system and inner ear.
Head trauma can cause problems with motor control of the eyes.
The use of drugs such as alcohol, lithium and anti-epileptics can cause nystagmus. Some sedatives like lidocaine and epinephrine can also lead to the condition.
Magnesium deficiency can lead to nystagmus, as well as a lack of vitamin B12.
Heat stroke is a malaise caused by prolonged exposure to the sun or heat. It is a serious condition, which can lead to confusion, dehydration and death. In addition, it can cause nystagmus due to the effects of excessive heat on the brain.
It is a sexually transmitted disease (STD) caused by a bacterium called Treponema palidum . When the disease is not treated properly, the bacteria can reach the brain, causing a condition known as neurosyphilis.
In neurosyphilis, the bacteria reaches the brain and spinal cord, causing a series of symptoms such as headache , mental confusion, paralysis and, of course, nystagmus.
A stroke occurs when there is an interruption in blood flow to some part of the brain. Depending on the affected part, they can cause serious problems as well as nystagmus.
Some people are more likely to suffer from nystagmus. Are they:
Vision problems are common in people with down syndrome, which can lead to nystagmus and place them at risk.
This condition is associated with nystagmus. Due to the lack of melanin, there may be impaired vision, which facilitates the appearance of nystagmus.
Multiple sclerosis is characterized by the destruction of the protection of the nerves (the so-called myelin sheath) by the person’s immune system. This can cause nystagmus in patients.
The main symptom of nystagmus is the involuntary movement of the eyes. However, this movement can be extremely varied.
Horizontal nystagmus is usually low in amplitude and causes horizontal eye movements.
Vertical nystagmus is presented by movements up and down, also of low amplitude.
This type of nystagmus is called a downbeat (from the English “beat down”) due to the fast downward movement performed by the eyes. It suggests a lesion at the cranial cervical junction such as Arnold-Chiari syndrome, a congenital disease caused by the invasion of brain tissue in the spinal canal.
Just as the downbeat , this type of nystagmus performs fast movements like a hit, but up (English, up ). It may suggest spinal cord injuries.
Torsional or rotational nystagmus appears as a rotational movement of the eye on its own axis. This movement, in most cases, cannot be carried out voluntarily.
In most cases of vestibular nystagmus, the horizontal or vertical movement is accompanied by a torsional movement. Torsional movement occurs when there are lesions in the anterior and posterior vestibular canals on the same side.
Pendular nystagmus is characterized by a sum of horizontal, vertical, elliptical and rotational eye movements. The result is a pendulum and circular movement in the eye socket with identical speeds for each direction. This may be a sign of brain stem or cerebellar dysfunction.
The seesaw movement in nystagmus happens when one eye moves up and out while the other eye moves down and out, often following the heart rate. It is a rare type of nystagmus that can be seen in patients with lesions in the ocular chiasm, the meeting point of the ocular nerves.
In addition to eye movements, other symptoms may accompany nystagmus. Some of them are:
Deafness and tinnitus
Peripheral vestibular nystagmus is often accompanied by deafness and tinnitus, a tinnitus that is not caused by an external stimulus.
Injuries that affect the vestibular system can also cause dizziness .
Vertigo, a feeling of spinning motion and dizziness can accompany nystagmus depending on the type of injury that causes the condition.
Sensitivity to light
The eyes may be more sensitive to light.
Problems with depth perception
The depth perception can be altered, especially when the images sent to the brain by the eyes are not interpreted with just one.
Difficulty in vision in the dark
Low-light vision can be hindered by nystagmus.
Feeling of “earthquake”
Due to repeated and involuntary eye movements, the person can see the world as if it were shaking, when in fact it is the eyes that are shaking.
One of the main functions of the vestibular system is to keep the body balanced. Injuries to it can cause nystagmus and a lack of balance.
Diplopia is the double vision. It can appear in cases of nystagmus, especially in specific positions. This can happen when there is a lesion in the optic chiasm , the meeting point of the ocular nerves.
The chiasm is what helps the brain to interpret the two images sent by the eyes as one. In case of injury, they can be interpreted as two images.
Nystagmus is easily observed with the naked eye and easily diagnosed. It can be diagnosed by the neurologist , general practitioner and ophthalmologist .
Despite the ease of diagnosis of nystagmus itself, its cause must be investigated. For this, the doctor may need specific information about the condition such as the patient’s history, when the condition arose, whether it is constant or intermittent, whether there are positions in which the condition worsens or alleviates, whether dizziness, imbalance or deafness accompany the nystagmus between other symptoms.
For specific measurements of nystagmus, some methods can be used. Are they:
This exam can evaluate eye movements through recordings, in addition to tests of the vestibular system. It serves to diagnose, in addition to nystagmus, problems with dizziness, vertigo and imbalance.
With the same function as electronystagmography, this test uses small video cameras to analyze nystagmus.
Computed tomography (CT)
This test can be used to identify other causes of nystagmus in the brain, such as tumors and brain damage when previous tests are not enough to identify the causes of the condition.
Magnetic resonance imaging (MRI)
Like CT, magnetic resonance imaging is used to look for causes of nystagmus when other tests are not enough to find them.
Nystagmus can be cured if its cause is curable. In cases where nystagmus is acquired its cure is more likely, since it is enough to treat the cause and some of them are easily resolved.
When nystagmus is congenital , that is, it is born with the person, the chances of a complete improvement are reduced, although not impossible. Only the doctor can tell whether a specific nystagmus can be cured or not.
There are several treatments for nystagmus. The condition is not always completely cured, but in some cases it can be eliminated.
Removal of medicines
When nystagmus is caused by a medication, such as anticonvulsants, removing the medication resolves the situation. The same applies to drugs and alcohol.
When nystagmus is caused by an inner ear infection, antibiotics can be used to deal with this cause, which eliminates the condition.
Use of contact lenses
In some cases of nystagmus the use of contact lenses can help. This type of treatment is especially useful for congenital nystagmus.
On rare occasions, surgery may be performed to modify the position of the muscles that move the eyes, reducing the effects of nystagmus. Surgery cannot cure the condition, but it does improve the patient’s visual quality.
Nystagmus does not allow precise vision, as the involuntary movement of the eyes impairs the focus. However, following the treatments, it is possible to reduce the effects of the condition and improve visual acuity.
In the mildest cases of nystagmus, living with the condition is not difficult. However, due to other symptoms that usually appear with eye movements, special care may be necessary.
Frequent neurologist and ophthalmologist
Tracking the condition is important. Preventing it from getting worse and treating it when possible can make all the difference.
Follow the treatment
Paying attention to the treatment and following it to the letter guarantees better chances of cure or improvement of visual accuracy.
Children with nystagmus must be accompanied by professionals to improve the focusing of images and make the damage caused by the condition as small as possible in their education.
Treatment can lead to a complete cure of nystagmus. There is no guarantee, but certain causes are curable and the condition can be eliminated.
Untreated nystagmus can make it difficult for the patient to see, preventing him from focusing on the images properly. This can impair reading, driving and other activities.
In most cases, there is no way to prevent nystagmus. The situations that cause the condition, in most cases, cannot be prevented. The best you can do is to take care of your ear hygiene to avoid infections in the inner ear. However, care must be taken not to cause injury.
Avoid using cotton swabs inside the ear
The flexible cotton swabs, or cotton buds, are made for cleaning the ear , not the inner part of the ear. They should not be placed in the ear canal as they can hurt the eardrum by pushing wax. They can also cause direct damage to the vestibular system, which can cause nystagmus.
Heat stroke can cause nystagmus. It is important to hydrate yourself, especially when you spend a lot of time in the sun. It is also important to use sunscreen in these cases.
The syphilis is a sexually transmitted disease that can cause nystagmus. It is possible to avoid it with the use of condoms during sexual intercourse.
Strokes are not completely preventable, but it is possible to reduce the chances of one happening.
- Do not smoke
- Eat properly
- Consume little alcohol
- Consume little salt
- Control your weight
- Evite o stress
Eat foods rich in magnesium and vitamin B12
Especially fish are recommended, such as herring, salmon and trout, for vitamin B12. In the case of magnesium, bananas are an excellent source of the material.
You have learned that nystagmus is a natural movement of the eyes to accompany the rotation of the head, but that in certain situations it can be pathological and problematic. Share this text with your friends so they can learn about nystagmus!