Nystagmus (Involuntary Eye Movements)

Nystagmus refers to involuntary, rhythmic eye movements that can impair vision. The eyes move back and forth, up and down or in a circular pattern, without the person affected being able to control this. Nystagmus can be congenital or can appear later in life.

Forms of nystagmus

Congenital (infantile) nystagmus

This form typically appears in the first months of life. A distinction is made between:

• Sensory nystagmus: arises from a congenital visual disorder that prevents the brain from receiving a clear image. Possible causes are albinism, optic nerve hypoplasia, aniridia (absence of the iris), congenital cataract, or retinal conditions such as Leber congenital amaurosis.
• Idiopathic infantile nystagmus: occurs without any identifiable eye condition. The cause is a fault in the control of eye movements in the brain. Vision is generally only mildly reduced.

Acquired nystagmus

Appears for the first time in childhood or adulthood and can point to neurological conditions, for example multiple sclerosis, brain tumours, strokes or disorders of the balance organ. Newly appearing nystagmus should always be investigated by a doctor promptly.

Symptoms and effects

With congenital nystagmus, those affected do not perceive any "wobbling" of their surroundings: the brain largely compensates for the eye movements. Reduced visual acuity is, however, frequently present. Many children develop a noticeable abnormal head posture: they turn or tilt the head so that the eyes reach a position in which the nystagmus is least pronounced. This position is called the null point (or "quiet zone").

With acquired nystagmus, by contrast, a distinct sensation of oscillopsia can occur: the surroundings appear to sway. This can be accompanied by dizziness and nausea.

Diagnosis

The assessment includes:

• Ophthalmological examination with assessment of eye movements, visual acuity and the structures of the eye
• Determination of the type of nystagmus (pendular, jerk, direction)
• Identification of a possible null point
• Where a neurological cause is suspected: imaging of the brain (MRI) and, if needed, further neurological investigation

Treatment

A cure for nystagmus is not possible in most cases, but various measures can improve vision and quality of life:

• Glasses and contact lenses: correct accompanying refractive errors and can stabilise vision. Contact lenses offer the advantage that they move with the eye.
• Prisms: can be incorporated into glasses in order to bring the head into a more neutral position.
• Medicines: in certain cases active substances such as gabapentin, memantine or baclofen can dampen the eye movements.
• Botulinum toxin (Botox): can temporarily reduce the eye movements in certain forms of nystagmus.
• Surgery: a surgical procedure on the eye muscles (Kestenbaum-Anderson operation) can shift the null point into the straight-ahead position and so reduce an abnormal head posture. The nystagmus itself is not eliminated by this, but vision in the primary position can improve.

Living with nystagmus

Children with congenital nystagmus can generally lead a largely normal life. It is helpful to inform the school environment about the visual impairment, so that appropriate support (e.g. an adapted seating position, enlarged materials) can be provided. Magnifying visual aids and digital aids can offer additional support in everyday life.

Dr. Stefan Langenegger

Treating Ophthalmologist

044 442 04 05