Nystagmus is an oculomotor disorder characterized by involuntary, repetitive eye movements, often from left to right (horizontal), up and down (vertical), or in a circular motion. These movements can be rapid or slow and affect vision by making it difficult to focus on an object.
Nystagmus: a complex neurological response
Nystagmus is usually caused by a problem affecting the areas of the brain responsible for controlling eye movements, including the cerebellum, brain stem, and vestibular system (which controls balance). It can also result from abnormalities in the inner ear, optic nerves, or eye muscles.
However, the main cause of nystagmus depends on its type, and there are two main categories: congenital nystagmus and acquired nystagmus.
The main cause of congenital nystagmus
Congenital nystagmus usually appears at birth or in the first few months of life. It is often linked to an abnormality in visual development. In other words, when the eyes or brain do not receive or process visual information properly in the first few months of life, this disrupts the eye stabilization system.
The main cause of congenital nystagmus is poor visual acuity from an early age, often linked to conditions such as:
- Ocular albinism (lack of pigmentation in the eyes)
- Optic nerve abnormalities
- Congenital cataracts
- Retinal dystrophies
In these cases, the brain tries to compensate for the poor quality of the image received by making rapid eye movements, which leads to nystagmus.
The main cause of acquired nystagmus
Acquired nystagmus can occur at any age and is usually the result of a neurological or vestibular disorder. It can be caused by:
- Brain diseases (multiple sclerosis, tumors, stroke)
- Infections or inflammation affecting the central nervous system
- Head trauma
- The use of certain medications or drugs (e.g., anticonvulsants, alcohol)
- Inner ear disorders (such as Ménière's disease or vestibular disorders)
The main cause of acquired nystagmus is damage to the vestibular or neurological system, which disrupts the coordination of eye movements and causes involuntary oscillations.
Can nystagmus be treated?
Treatment depends on the underlying cause. For congenital forms, although it is not always possible to eliminate it, certain visual aids and surgeries can improve vision and head position. For acquired forms, treatment targets the cause (e.g., stopping a medication, treating an infection or tumor).
Therapies such as orthoptics, the use of special glasses (with prisms or filters), or adapting visual environments can also greatly help to live better with this condition.
Nystagmus is an eye movement disorder that can have several causes. In children, the main cause is poor early vision due to congenital eye abnormalities. In adults, it is most often caused by a neurological or vestibular problem.
If you or a loved one has unusual eye movements or associated visual disturbances, it is important to consult an optometrist. A comprehensive evaluation will determine the cause of the nystagmus and guide the best treatment options.
