Ophthalmoplegia is total or partial paralysis of some or all of the extraocular muscles that surround the eye. This condition may begin as weakness of the muscles that later progresses to paralysis of one or more of the six muscles that control eye movement and hold the eye in place. Depending on the cause of the eye disorder, the condition may be temporary or permanent, and if caused by certain types of underlying neurological disorders, it may be accompanied by debilitating symptoms such as muscle weakness or paralysis of the legs, arms, and neck.
Definition & Facts
Ophthalmoplegia is a condition in which one or more of the six muscles that hold the eye in place and control its movement become partially or completely paralyzed. This condition comes in two forms: internuclear ophthalmoplegia and chronic progressive external ophthalmoplegia. Both forms can cause blurred vision or double vision (diplopia) and an inability to hold the eyes in their normal position or move both eyes in each direction.
Ophthalmoplegia may occur in one or both eyes and it may have dozens of causes, including stroke, thyroid disease, and infection. Symptoms may appear in other areas of the body as a result of underlying disease.
Symptoms & Complaints
In some cases, ophthalmoplegia can take the form of internuclear ophthalmoplegia, which causes difficulty looking from side to side. For example, if the right eye is affected and the patient tries to look to the left, the right eye will barely move and the left eye will display uncontrolled movement that is usually associated with nystagmus.
In progressive external ophthalmoplegia (PEO), a serious genetic disorder, the symptoms will progress beyond the eyes and eventually cause weakness in the muscles of the legs, arms, and neck and make it difficult to swallow (dysphagia).
Children with congenital ophthalmoplegia usually learn to compensate for the problem and may not even be aware they have vision problems. When the condition is congenital, symptoms usually appear during childhood or even adolescence.
There are many possible causes of ophthalmoplegia, although many cases are caused by a neurological disorder that affects messages sent from the brain to the eyes. Common neurological problems that can cause ophthalmoplegia include brain tumor, stroke, multiple sclerosis, Parinaud's syndrome, myasthenia gravis, physical trauma to the eye, and venomous snake bites.
Ophthalmoplegia or the related condition, ophthalmoparesis, may also be caused by viral infections. Sometimes ophthalmoplegia progresses from ophthalmoparesis, or weakness of the eye muscles. Both of these related conditions can result from disorders of any part of the eye or central nervous system, including infection around the eye, disorder of the eye orbit that restricts mechanical movement (such as in Graves' disease), disorder in the muscle of the eye (often seen in progressive external ophthalmoplegia), disorder of the neuromuscular joint (seen in myasthenia gravis), problems with the cranial nerves, issues with the dorsal midbrain structures (found in Parinaud's syndrome), or parts of the cerebral cortex.
With internuclear ophthalmoplegia, horizontal eye movement is impaired by damage to the nerve fiber connections between the brain and the brainstem that coordinate movement. In younger people, multiple sclerosis is often the cause if both eyes are affected while a stroke may be the cause in older people when one eye is affected. Less common causes of internuclear ophthalmoplegia include Lyme disease, head injuries, and tumors.
Diagnosis & Tests
Ophthalmoplegia is usually diagnosed first with a physical examination of the eyes to check eye movement. After that, a computed tomography (CT) scan or magnetic resonance imaging (MRI) is conducted to look at the structures of the eye in greater detail.
Blood tests can be necessary to determine whether the ophthalmoplegia is caused by complications of an underlying disease like thyroid disease. Proper diagnosis will rule out other conditions and diseases that may mimic the symptoms of ophthalmoplegia such as proptosis, or bulging eyes, caused by Graves' disease.
Diagnosing ophthalmoparesis and ophthalmoplegia is fairly straightforward and may be done by an ophthalmologist who specializes in eye and vision health, but detecting and diagnosing the underlying cause of the eye disorder may require more testing and the work of several specialists.
Treatment & Therapy
There are dozens of potential treatments for ophthalmoplegia which depend on the symptoms, type, and underlying cause of the muscle paralysis. Adults who have sudden onset ophthalmoplegia may be fitted with specially designed glasses or wear an eyepatch over one eye to relieve double vision.
In rare cases, ophthalmoplegia is the result of vitamin B-1 or thiamine deficiency, in which case immediate vitamin B-1 supplements are given. When ophthalmoplegia is the result of multiple sclerosis or MS or an underlying disease, physical therapy may help prevent further loss of muscle control. Ophthalmoplegia that results from an idiopathic orbital inflammatory syndrome or Tolosa-Hunt syndrome typically responds well to corticosteroid therapy.
Little can be done through treatment aside from addressing the physical symptoms of the disorder. For example, drooping eyelids (ptosis) may be corrected surgically while eye patches can reduce double vision. Eyelid surgery does have risks, however, as it can make the cornea more exposed to drying out which can increase complications.
Prevention & Prophylaxis
As many cases of ophthalmoplegia are caused by damage to the cerebral cortex by stroke, stroke prevention is one way to prevent the eye disorder. Older adults can prevent their risk of stroke and eye disorder by controlling high cholesterol (hypercholesterolemia), diabetes mellitus, high blood pressure, and circulatory problems. Sufficient intake of thiamine, which is found in fortified cereals, nuts, and meat, can also reduce the risk of ophthalmoplegia.