What Causes Nystagmus?

During your eye examination, our optometrists are assessing a variety of components associated with the function and structure of your eyes. Eye movements are one of the main components and, in some cases, they may differ from the general population.

What is Nystagmus?

Nystagmus refers to an eye condition in which the eye moves in a repeating rhythmic fashion involuntarily. This could include movements side-to-side, up and down, or even in a circular pattern.

This can occur in one eye, both eyes, or alternate between the eyes. It may occur only in certain gaze directions or if one eye is covered, or it might happen all the time and increase or decrease in frequency and intensity under certain conditions.

One may experience dizziness, light sensitivity, or a sensation that the world is shaking. Associated visual problems are highly probable and a decrease in visual clarity is common.

Some may have already developed a head turn or tilted position to help compensate for the eye movements. The onset of nystagmus could be early in life or later in adulthood.

Causes of Nystagmus

Nystagmus could occur at birth and have no other associated conditions. If the nystagmus was present at birth, it may be associated with albinism (lack of pigment in the eyes, skin, and hair) or an eye turn.

It could also be associated with severe vision loss, either being the cause of vision loss or being due to severely decreased visual acuity. It can also be due to demyelination or degeneration of nerve connections between the eye and brain, which occurs in conditions like multiple sclerosis.

In some cases, nystagmus can occur as a result of a stroke episode or tumour within the brain. Neurological diseases may also cause nystagmus as the brain is unable to control the muscles well, such as in Parkinson’s disease.

Management of Nystagmus

There are a variety of ways to manage nystagmus. In some cases, treating the underlying cause for the condition can decrease or eliminate the eye movements.

This can include treating associated conditions such as myasthenia gravis or Parkinson’s. However, in nearly all cases, nystagmus is only managed and not cured.

Correcting the refractive error by providing a prescription for glasses or contact lenses may be helpful. In particular, using a contact lens that moves with the eye may help provide improved vision, although not perfect.

A lens that moves with the eye ensures that the center of the lens remains centered on the eye throughout frequent eye movements. Some patients may find that a rigid gas permeable contact lens (a small and hard lens) provides more stability for the eye movements and can decrease the amount of movement overall because of the sensation it provides.

The eye movements associated with nystagmus may also be reduced in certain gazes, such as if the head is turned to a certain position. If this is the case, glasses can be prescribed with prisms such that the visual world is shifted to this position, which is referred to as the null point.

Other management options include surgery, special image stabilizing devices, and pharmaceuticals.