Nystagmus is a condition characterized by involuntary and uncontrolled movement of the eyes in all directions. It is often referred to as “dancing eyes”. Nystagmus indicates a problem with the pathways between the eyes and the brain and results in impaired vision. There are different types of nystagmus, and the most common type is known as congenital nystagmus. Congenital nystagmus, also known as infantile nystagmus syndrome, is first discovered in young infants and may develop from as early as six weeks after birth.
Certain cases of congenital nystagmus are associated with strabismus, wherein the eyes are unable to align or function properly at all. In other cases, the eyes move together and swing back and forth. Nystagmus may be very mild in some instances, but it is always advised to visit a doctor if symptoms of this condition are perceived. It does not always cause pain, but it may be indicative of the other underlying visual condition and always leads to some loss or damage to the visual senses. Experts have discovered key information on congenital nystagmus, most notably how it can be treated.
Causes of nystagmus
Congenital nystagmus is often attributed to genetics. Inherited ocular conditions from the parents may lead to nystagmus in their children. Eye conditions, such as glaucoma or cataract, can give rise to nystagmus. Bilateral congenital cataract is a form of infantile nystagmus caused by a cataract. Albinism is also usually associated with the condition, as are optic nerve hypoplasia, Leber’s congenital amaurosis, and retinal or optic nerve disorders.
Nystagmus is commonly identified as a neurological complication caused by damage or impairments in parts of the brain or nervous system. If caused by damage to the eyes or the neural pathways connecting to them, nystagmus is referred to as optokinetic. If related to the inner ear or closely situated parts of the brain that control eye movement, it is known as vestibular. A few conditions not directly related to the eyes, such as Down’s syndrome, have also been known to lead to congenital nystagmus.
Symptoms of nystagmus
The uncontrolled movement of the eyes is the first immediate symptom of congenital nystagmus. It first manifests itself conspicuously in young children and varies in how severely it affects the visual senses. The eyes involuntarily move in all directions, either in tandem or individually, from one side to the other, or around in circles. In some rare cases, nystagmus develops visible in only one eye, known as unilateral nystagmus. Instead of perceiving the world as shaking, people with the condition report blurry vision – a phenomenon known as oscillopsia.
All people with nystagmus are not able to see properly as their eyes are incapable of projecting a clear visual image into their brains because of the constant ocular movement. This causes many to also suffer from vertigo. Because nystagmus prevents patients from viewing things properly, they are forced to tilt their heads at a certain angle – known as the null point – so that they can see more clearly and where their eyes move the least. Both their appearances and social lives are affected, as they are unable to normally talk to or establish eye contact with others. Because of their various vision problems, people with congenital nystagmus are considered blind.
Diagnosis of nystagmus
Once one notices the symptoms of congenital nystagmus, they should notify a doctor as soon as possible. There are several non-invasive tests that can be used to diagnose the condition. In the caloric reflex test, the ear canal is filled with either cold or warm water, and the temperature difference stimulates the vestibuloocular reflex and tests for nystagmus.
Eye movement can be measured and recorded using electrodes through an electronystagmograph, a kind of electrooculography, or a videonystagmograph, which is an example of a video-oculography. There are other ocular conditions involving eye movement that is distinct from nystagmus, such as ocular flutter, wherein the movement is much faster. This is why it is important for doctors to precisely quantify and observe the manner of the movements, in order to properly diagnose it as nystagmus. Several other techniques have been developed in order to more accurately analyze and record eye movements.
Treating congenital nystagmus
There is no known treatment that can be used to definitively cure congenital nystagmus. However, there are several medications and forms of therapy that have shown promising results for many patients. Baclofen is a medication used for alcoholism and muscle spasticity and has been discovered to effectively inhibit periods of nystagmus. Gabapentin is an anticonvulsant and analgesic used to treat epilepsy that has successfully relieved symptoms in half the patients that chose to take it. Other effective nystagmus medications are levetiracetam, memantine, and acetazolamide.
Surgery does not completely cure nystagmus, however, it can decrease the intensity of its symptoms and improve vision. Strabismus surgery is used to treat conditions of eye muscles. Other types of surgery aim to lessen the angle the head has to tilt in order to reach the null point. Acupuncture therapy, especially of the sternocleidomastoid muscle in the neck, has produced some positive results. Neurological physical therapy is a specialized field targeted toward treating nystagmus and similar conditions. The most practical and common ways to counter nystagmus are the use of glasses or contact lenses.
Other kinds of nystagmus
Congenital nystagmus is only one of the several kinds of nystagmus that can inflict people. Acquired nystagmus is another common type that develops later on in life and is usually caused by previous diseases, like diabetic neuropathy, brain tumor, multiple sclerosis, or by accidents to the head or affecting the nervous system. Hyperventilation and direct exposure of light onto the eyes may both lead to acquired nystagmus. Manifest-latent nystagmus is a combination of both manifest and latent conditions, wherein the nystagmus is constantly present, but ends up worsening if one eye is covered. Positional nystagmus is a consequence of the position of one’s head, and spontaneous nystagmus is random and occurs regardless of one’s position. Pathologic nystagmus is characterized by slow eye movement in one direction and sudden rapid movement in the other. Nystagmus is also named after the direction of the eye movements, from the right – beat, left-beat, seesaw, downbeat, upbeat, and periodic alternating.
Further research and related issues
Experts are delving further into congenital nystagmus and trying to discover more about this condition to help those suffering from it. Some researchers have attempted to harness biofeedback to make patients conscious of their eye movements and learn to control them. The nature of nystagmus has prompted research into other similar eye conditions. A few examples of these include juvenile cataracts and cone dystrophies. Scientists have also attempted to study how other genetic or neurological conditions can give rise to acquired nystagmus.
An area that experts are focusing on is in helping patients cope with nystagmus. In children, it is often dismissed as a typical ocular disorder or even as a learning problem. Experts are encouraging patients to seek help immediately or get into contact with support groups and institutions targeted toward helping them cope. Spreading awareness of congenital nystagmus and discovering more about it are both instrumental in learning how to fight its effects.