Nystagmus is a condition defined by involuntary, repetitive eye movements that can occur side-to-side, up and down, or in circular patterns. This condition stems from the brain’s inability to properly control the eyes, which can disrupt vision. The movements can vary in speed and affect both eyes.
Characteristics and Symptoms of Nystagmus
The eye movements are categorized into two types. Pendular nystagmus is characterized by smooth, back-and-forth motions, similar to a pendulum. Jerk nystagmus involves a slow drift of the eyes in one direction followed by a quick, corrective jerk back.
Common symptoms include shaky or blurred vision, which can make tasks like reading difficult. Many people also experience dizziness, problems with balance, and poor depth perception. Sensitivity to light and trouble seeing in the dark are also frequently reported.
To cope with these visual disturbances, individuals may adopt a specific head tilt or turn. This is an attempt to find the “null point,” a particular gaze angle where the eye movements are minimized and vision becomes clearer and more stable. While adults with the condition often perceive their surroundings as shaky, children who have had it from a young age may not experience this sensation, though they may have blurry vision.
Causes of Nystagmus
The causes of nystagmus fall into two categories: congenital and acquired. Congenital nystagmus is present at birth or develops within the first few months of life. The specific cause is often unknown, though it can be inherited and is sometimes associated with other conditions like albinism, cataracts, or strabismus.
Acquired nystagmus develops later in life and can be a symptom of an underlying medical issue. Common causes include:
- Problems within the inner ear, such as Meniere’s disease or labyrinthitis
- Neurological issues, where a stroke is a frequent cause in older adults and a head injury is common in younger people
- Diseases that affect the central nervous system, such as multiple sclerosis
- The use of certain medications, including anti-seizure drugs or lithium
- Excessive alcohol or drug use
How Nystagmus is Diagnosed
Diagnosing nystagmus begins with a thorough eye examination by an ophthalmologist. The doctor will assess the patient’s vision and examine the internal structures of the eyes. This includes tests to observe the eye movements directly, such as asking the patient to track a moving object.
A detailed review of the patient’s medical history is also an important part of the diagnosis. This helps the doctor identify potential underlying conditions by inquiring about family history, existing medical issues, and current medications.
If an underlying cause is suspected, further tests may be ordered. A magnetic resonance imaging (MRI) or computed tomography (CT) scan of the brain can identify neurological abnormalities. Vestibular function tests can also be used to assess the inner ear’s role in the condition.
Managing and Treating Nystagmus
The management approach for nystagmus depends on its cause. If it is a symptom of an underlying medical issue, treating that root cause can alleviate the eye movements. For congenital nystagmus or when a cause is unknown, the focus is on managing symptoms and improving vision.
Corrective lenses, such as glasses or contacts, are a primary management tool. While they do not stop the movements, they can improve visual acuity. Prisms can be incorporated into glasses to shift images to the eye’s null point, reducing the need for a head tilt.
Other treatments and adjustments can also help manage the condition:
- Medications to reduce the severity of the eye movements
- Surgical procedures to reposition eye muscles
- Lifestyle adjustments to accommodate vision challenges
- Alternative therapies that may offer relief