Nystagmus is an eye condition, more specifically, a periodic rhythmic ocular oscillation. It can be unilateral or bilateral and when it appears unilaterally, it is usually asymmetric more than it is really unilateral. It can also move in different directions including horizontal, vertical and torsional, with a combination of movement being superimposed on each other at times.
In the condition, a person will have rhythmic shaking and wobbling eyes, which are very noticeable.
It has also been described in more layman’s terms as "dancing eyes." Sometimes in order to describe the condition, think of the condition as the eye movements having a kind of pendulum-like movement.
There are usually two groups of nystagmus, sensory and motor.
In sensory nystagmus, there is a loss of vision, while in the motor variety there is a loss of control in the muscle function of the eyes.
However, doctors have named over 45 different types because there are many different kinds of eye movements that can result from the condition.Symptoms
The different forms of nystagmus have different symptom. The type of nystagmus that occurs usually depends on the age at which the condition begins.
There are three categories, congenital, childhood and acquired adult nystagmus.
The symptoms of congenital nystagmus can be seen when the eyes are unaware of the eye movements, as the objects that are been looked at do not seem to move at all.
If it is developed during childhood, the child usually nods its head a lot in the direction of the nystagmus.
When it is acquired as an adult the environment of the affected person looks as if it oscillates horizontally, vertically or torsionally.
Usually when it appears in adults some symptoms include blurred and unstable vision.
Some kinds of nystagmus can be association with minor eye problems such as diminished vision which usually occurs in the case of farsighted people or people who have scars of the retina or optic nerve.
Though it is not common in the least bit nystagmus can occur as a result of brain tumors or other critical problems with the brain and various serious neurological disorders.
In order to understand what happens in the case of nystagmus, one must know how the nervous system works in keeping the position of eyes. In order to obtain the highest level of visual acuity foveal centration of an object is essential.
There are three mechanisms that are vital for this – fixation, the vestibulo-ocular reflex, and the neural integrator.
Fixation is the primary position of the visual system’s ability to be able to detect when the foveating image drifts. The vestibular system is involved with the oculomotor system very closely and complexly.
The system is very complex and involves neural interconnections that maintain foveation when a person’s head position chances. The proprioceptors in the system are canals in the inner ear that respond to the changes in head rotation.
The neural integrator is also another important aspect of such a condition. When the eye is turned in an extreme position, the movement of the fascia and ligaments that suspends the eye exerts elastic forces that will enable the eye to return to a normal position later. This system does not work well when the condition is present which leads to the occurrences of problems with the position of a person’s eye.
The most important elements of the integrator include the vestibular pathways, the cerebellum, and the occulomotor nuclei. They make up the core of the system that is needed for these movements of the eyes to function properly.