Balance depends on signals the brain receives from the muscles and joints, the inner ear, and the eyes, says the Vestibular Disorders Association (VEDA). If one or more of these are compromised, dizziness may result.
Eyes help maintain balance by providing visual cues to the brain regarding surroundings and head position. If the wrong signals reach the brain, whether from the inner ear or muscles and nerves, the eyes may move irregularly, resulting in dizziness.
Nystagmus is a rapid and involuntary eye movement, according to the National Institutes of Health (NIH), that can either be horizontal, side to side, vertical, up and down, or rotary. Nystagmus may occur in one or both eyes, depending on the cause.
Types of Nystagmus
There are two types of nystagmus, congenital and acquired. Congenital nystagmus appears at birth or soon after, says NIH, and is usually so mild as to not be noticeable. More rarely, it occurs due to a congenital disease that results in poor vision or vision loss. Congenital nystagmus is not usually associated with dizziness.
Acquired nystagmus happens later in life and usually causes a dizziness classified as vertigo, says the Merck Manual. Vertigo is the feeling that you, your surroundings, or both are spinning, while you remain still, and is often accompanied by nausea and loss of balance.
Acquired Nystagmus: BPPV
Nystagmus is a characterisation of benign paroxysmal positional vertigo, or BPPV. With BPPV, you may experience intense episodes of vertigo lasting no longer than fifteen seconds, says the National Institute on Deafness and Other Communication Disorders (NIDCD), occurring when your head is in specific positions.
BPPV happens when otoconia, small crystals of calcium carbonate in the ear, tumble into the wrong ear canal, resulting in conflicting signals to the brain about head position. BPPV may be caused by head injury, ageing or a virus, and can be treated with non-invasive techniques in your doctor's office.
Aquired Nystagmus: Multiple Sclerosis
Multiple Sclerosis, or MS, is an inflammatory disease in which the immune system erodes the protective sheath covering the nerves, says the Mayo Clinic. As a result, communication between the brain and the body is compromised, and the nerves deteriorate. People may lose the ability to walk or talk.
Another symptom is nystagmus, says Health Central. If nerves involving eye muscles are inflamed, eye movement may become limited or irregular. This, in combination with inflamed nerves to the inner ear, may result in dizziness, vertigo, double vision, imbalance or nausea.
Diplopia, or double vision, is seeing two images of one object, says the Merck Manual. It can occur when only one eye is open, monocular, or disappear when one is closed, binocular.
Diplopia is a serious symptom, says WebMD, that should be discussed immediately with your doctor. Possible causes include infection or damage to the cornea, cataracts, muscle problems, nerve problems caused by MS or other nerve conditions, stroke, aneurysms, head trauma, tumours or migraines.
Symptoms include crossed eyes, pain with eye movement or around the eye, headache, weakness in the eyes, droopy eyelids, dizziness and nausea.