Nystagmus is a condition of involuntary (or voluntary, in rare cases) eye movement, acquired in infancy or later in life, that may result in reduced vision. Due to the involuntary movement of the eye, it is often called “dancing eyes”
In a normal condition, while the head rotates about any axis, distant visual images are sustained by rotating eyes in the opposite direction on the respective axis. The semicircular canals in the vestibule sense angular acceleration. These send signals to the nuclei for eye movement in the brain. From here, a signal is relayed to the extra ocular muscles to allow one’s gaze to fixate on one object as the head moves. It also occurs when the semicircular canals are being stimulated (e.g. by means of the caloric test, or by disease) while the head is not in motion. The direction of ocular movement is related to the semicircular canal that is being stimulated.
It is is usually infantile, meaning people have it from a very early age. Experts say that about one child out of every several thousand has nystagmus.
Types of Nystagmus
The different kinds include:
- Manifest nystagmus
- Congenital nystagmus
- Manifest-latent nystagmus
- Acquired nystagmus
- Latent nystagmus
Congenital nystagmus is present at birth. With this condition, your eyes move together as they oscillate (swing like a pendulum). Most other types of infantile nystagmus are also classified as forms of strabismus, which means the eyes don’t necessarily work together at all times.
Children with it may need extra help in learning to adapt to schoolwork and social situations.
Manifest nystagmus is present at all times, but worsens when one eye is covered.
Latent nystagmus occurs when one eye is covered.
Acquired nystagmus can be caused by a disease (multiple sclerosis, brain tumor, diabetic neuropathy), an accident (head injury), or a neurological problem (side effect of a medication). Hyperventilation, a flashing light in front of one eye, nicotine and even vibrations have been known to cause nystagmus in rare cases.
Some acquired nystagmuses can be treated with medications or surgeries.
The brain controls eye movement. Your eyes move automatically to adjust when you move your head slightly. This stabilizes the image that you are looking at so you see a sharper image. In people with this condition, the areas of the brain that control eye movements do not work properly.
In some cases, it is not clear why someone has it. In other cases, it may be related to other eye problems.
Nystagmus can be related to the following:
- Having a family history of nystagmus
- Albinism (lack of color, or pigmentation, in the skin)
- A wide range of eye problems, including cataracts, strabismus and focusing problems
- Inner ear problems, such as Meniere’s disease
- Multiple sclerosis
- Stroke (a common cause of acquired nystagmus in older people)
- Head injury (a common cause of acquired nystagmus in younger people)
- Use of certain medications
- Alcohol or drug use
What Are the Symptoms of Nystagmus?
Your eyes move without your control. It might be fast, then slow, then fast again. The movement might be in one eye, but it’s usually in both eyes. You may notice that you nod your head or keep it in strange positions. You do that because it helps you focus when you can’t hold your gaze steady. Things look clearer when you tilt or turn your head.
Objects may seem a little blurry to children with the ondition. But the world doesn’t look shaky to them. It’s different if you develop the condition as an adult. Then the world appears to move a little when you look around.
It may also affect your vision. You might have a hard time seeing in the dark, or you may be sensitive to bright light. You may have problems with balance and dizziness. These can be worse if you’re tired or stressed.
This condition is diagnosed by an ophthalmologist. They will examine the inside of your eyes and test your vision. Your ophthalmologist will also look for other eye problems that may be related to nystagmus. These problems could include strabismus (misaligned eyes), cataract (clouding of the eye’s lens), or a problem with the eyes’ retina or optic nerve.
One way to see nystagmus is to spin a person around for about 30 seconds, stop and then have them try to stare at an object. If they have nystagmus, their eyes will first move slowly in one direction, then move rapidly in the opposite direction.
Other tests that may be used to diagnose nystagmus are:
- eye-movement recordings (to confirm the type of nystagmus and see details of the eye movements)
- an ear exam
- a neurological exam
- tests to get images of the brain, including computerized tomography (CT) and magnetic resonance imaging (MRI)
If you developed nystagmus as an adult, there may be simple things you can do to lessen its effects. Sometimes you may just have to stop a medicine or quit drinking alcohol or taking drugs.
Wear the right contacts or glasses to improve vision. It won’t cure nystagmus, but it can help with other eye problems that can make it worse.
Eye muscle surgery may be an option. The goal is to help with the head tilt that often comes with nystagmus. Sometimes surgery improves vision, too.
Some drugs may ease symptoms in adults but not children. These include the anti-seizure medicine gabapentin
Tips for Living With Nystagmus
There are things you can do at home to make it easier to deal with your “dancing eyes.” Use large-print books and turn up the print size on your computer, tablet, and phone. More lighting may help with vision, too.
If your child has nystagmus, encourage her to use her eyes. Big and brightly colored toys are easiest to use. Choose toys that make noise and have unique textures.
Let your child hold books close to her eyes with her head tilted. Let her wear tinted glasses to reduce glare.
Talk to your child’s teacher to make things easier at school. It would be hard for her to share books or papers. Let her choose where to sit so she can see the board and the teacher.
Not only do nystagmus patients have vision loss, but they also are faced with cosmetic problems from the constant eye movements and often an unusual head/eye position. Patients may be teased about their appearance or chastised and told to hold their head correctly.
The teacher of a child with nystagmus needs to understand how to aid a child with nystagmus and associated vision loss. Timed tests may create emotional stress that can cause the nystagmus to increase and the child’s vision to temporarily decrease. The teacher must understand the need for the child to turn his eyes or head in a specific manner. Allowing the child to sit at the front of the classroom is also needed. Depending on the level of vision, low vision adaptation may be required including large print books, closed circuit television, optical low vision aids, etc. Low vision children should always have their own books and worksheets. Sharing materials is difficult for low vision patients. Materials should be enlarged and of high contrast. A simple clear yellow acetate sheet with a black line across it may be helpful in keeping one’s place especially when looking away to the chalkboard or to a computer screen.