Nystagmus

 

What is nystagmus?

Nystagmus refers to the abrupt, involuntary and rhythmic movements of the eyes, encompassing a forth and a back phase. These movements can be horizontal, vertical or rotary. Nystagmus normally involves both eyes, and it exacerbates by looking at a specific side.The ophthalmologists of Tehran-Iran Noor Eye Hospital can decrease the amplitude of nystagmus with advanced ophthalmic procedures and equipment.

 

Common types of nystagmus

Nystagmus can be divided into sensory and motor types. Motor nystagmus appears to begin between six weeks and three months of age. Other members of the family may also suffer from similar abnormal eye movements, which are usually horizontal.

Closely looking at objects or looking in odd directions often reduces the nystagmus intensity and improves the vision. Fortunately, patients do not see the world moving as their eyes move. Vision may be reduced with a distance, although it is almost normal up close. Patients with motor nystagmus normally do not suffer any types of potential learning limitations.

The other type of this eye disorder, " sensory nystagmus", is associated with reduced vision of any cause. Sensory nystagmus usually begins at 6-8 weeks of age. The eyes appear to move, sometimes quickly and sometimes slowly. The eyes often rotate upward, followed with the potential eyelid movements. The cause of the reduced vision may be treated, as in babies born with cataracts. Other conditions causing sensory nystagmus may not be treatable, including eye diseases that affect the optic nerve or the retina. Nevertheless, identifying the underlying cause is crucial for predicting the baby's future visual status.

The question is what the benefits of these eye movements are. To put it simply, one can retain the picture of what they want to see on the macula using a complex mechanism involving a tight relationship of the equilibrium system with the brain and the visual system, which helps maximize the vision and prevent the movements of the object, the body or the head from changing the picture. If compensatory mechanisms cannot retain the picture on the retina by causing corrective eye movements in response to the head movements, one cannot obtain a clear vision of the object.

To simplify the matter, the following examples can be discussed:

  1. One cannot continuously have a completely clear picture of a mobile object in the absence of smooth pursuit eye movements.
  2. In the absence of nystagmus movements, we would not be able to watch the outside of a moving train from the inside in real time and the images would pass from our view like a blurry and vague movie. In the present example, we trace the images of the outside objects using a smooth movement in the opposite direction of the train, and the eyes return to their initial point using a saccadic movement when the object disappears from our field of vision.

 

Causes of nystagmus

Nystagmus is mostly congenital and can be sensory or motor in type. Sensory nystagmus is associated with an underlying eye disease causing a severe visual impairment since birth, such as cataracts, congenital glaucoma, albinism and congenital disorders of the retina and the optic nerve. Other ocular disorders are absent in motor nystagmus and the patients have good vision.

Nystagmus is rarely caused by brain tumors or severe neurological disorders. Nystagmus may be congenital and is not associated with other diseases.

Nystagmus can also be caused by medications. This type of nystagmus is rarely associated with double vision and often causes problems with peripheral vision. Other causes include heavy drinking or use of medicines for controlling the disease. This type of nystagmus is often relieved by stopping the medication.

Some people can create voluntary nystagmus, as they can move their ears. In other words, they can create horizontal, fast and fine movements and continue them for a short time. This type of nystagmus is often used for drawing attention.

Disease-associated nystagmus is rare and often associated with neurological symptoms showing the disease severity.

 

Nystagmus symptoms

The main symptom of nystagmus is the rhythmic movements, which are often detectable by the naked eye. The abnormal compensatory head position in some of the patients is used for minimizing nystagmus. Strabismus may also be present in some patients with nystagmus.

In addition to the above symptoms, other visual symptoms of underlying diseases can be diagnosed in sensory cases, including drooping eyelid, cataracts and the disease of the retina or the optic nerve. If it is diagnosed that nystagmus is likely to be caused by a neurological disorder, the necessary comprehensive examinations should be done in this regard and the child should be immediately referred to a neurologist.

To diagnose the main cause or causes of nystagmus comprehensive examinations are crucial, which are performed by ophthalmologists or even the  cooperation of the specialists of other fields. The cause can be usually diagnosed. The diagnosis mainly depends on factors such as the age of the patient, family history, the patient's general health and the use of special routine medications. Ophthalmologists may evaluate the type, speed and direction of nystagmus and look for other visual disorders such as drooping eyelid, cataracts and diseases that affect the retina and the optic nerve. Taking blood tests and special images can help to diagnose the cause.

Nystagmus treatment

Diagnosing and eliminating the causes of nystagmus can sometimes help to treat the patient's nystagmus. Although nystagmus is often persistent, reduced vision can be alleviated by using glasses and low-vision aids. When the eyes are more stable in certain directions, using prismatic glasses or eye muscle surgery may improve the head position and improve the vision.

The patients can be provided with the state-of-the-art and most advanced treatment techniques of nystagmus in Tehran-Iran Noor Eye Hospital.

Nystagmus surgery is conducted to achieve multiple objectives:

1. Modifying the abnormal head position

2. Modifying the associated potential strabismus

3. Reducing the intensity and amplitude of nystagmus

Different types of surgical procedures are used for this purpose. It should be noted that none of the above methods are capable of completely treating nystagmus.

- What is nystagmus?

- How many types of nystagmus are there? Do all of them cause visual impairment?

- At what age does motor nystagmus emerge?

- At what age does sensory nystagmus emerge?

- Is nystagmus a visual disorder?

- What are the common causes of nystagmus?

- Do congenital eye diseases affect nystagmus?

- Can nystagmus be treated completely?

- In what instances are nystagmus surgical procedures used?

 

 

 

- What is nystagmus?

Nystagmus refers to the abrupt, involuntary and rhythmic movements of the eyes, encompassing a forth and a back phase.

- How many types of nystagmus are there? Do all of them cause visual impairment?

1. Motor nystagmus does not often cause visual problems.

2. Sensory nystagmus is often associated with visual problems.

3. Voluntary nystagmus (conscious tiny movements of the eyes) does not cause visual problems and is often used for drawing attention.

- At what age does motor nystagmus emerge?

It can usually be diagnosed between six weeks and three months of age.

- At what age does sensory nystagmus emerge?

It begins at the age of 6-8 weeks. The eyes appear to be moving and their movements are sometimes slow and sometimes fast.

- Is nystagmus a visual disorder?

It is naturally not a visual disease, since in the absence of back and forth movements, one was not able to clearly watch the scenery in motion. Certain disorders affect normal eye movements, which should be taken care of.

- What are the common causes of nystagmus?

In most of the patients, nystagmus is a congenital problem emerging as a sensory or motor disorder. Sensory nystagmus often follows an underlying eye disease and is associated with severe visual impairments, usually present from birth. Other visual disorders are not in motor nystagmus and the patients usually have good vision.

- Do congenital eye diseases affect nystagmus?

Yes, including cataracts, congenital glaucoma, albinism and congenital disorders of the retina and the optic nerve.

- Can nystagmus be treated completely?

 When these underlying causes are treated, nystagmus may be cured. Although nystagmus is not completely curable, reduced vision can be alleviated by using glasses and low-vision aids.

- In what instances are nystagmus surgical procedures used?

1. To modify the abnormal head position

2. To modify the associated potential strabismus

3. To reduce the intensity and amplitude of nystagmus