What are crossed eyes?
Normally, both eyes look at the same object at the same time. In crossed eyes, however, one eye is directed at the object and the other looks upward, downward, or to the side. The medical name for this is strabismus.
There are various types of crossed eyes. As with poorly aligned front wheels of a car that remain out of alignment no matter which way the steering wheel is turned, the relationship between the eyes remains abnormal no matter where they look. Most commonly, one eye is directed too far inward. Alternatively, one eye may be directed outward, a condition referred to as walleyed. Sometimes one eye looks upward or downward in relation to the other; this is called vertical strabismus.
In order to focus, the person often squints. Unless it is corrected, strabismus usually leads to double vision. Crossed eyes generally develop in early childhood, but the condition also occurs in adults. The movements of one or both eyes may be restricted.
- Eyes that look in different directions.
- Double vision.
- Restricted eye movements.
What causes crossed eyes?
Eye movement is controlled by six muscles. When the functioning of these muscles is disrupted, crossed eyes result. In adults, crossed eyes are usually caused by a disease of the eye muscles or the nerves that control them.
When the disorder is caused by loss of tone in the eye muscle, it is referred to as nonparalytic strabismus. When it is due to nerve damage that results in paralysis of the eye muscle, it is called paralytic strabismus.
Diseases that can lead to crossed eyes in adults include stroke, diabetes, multiple sclerosis, temporal arteritis (an inflammation of the arteries), and muscular dystrophy. Since most of these diseases affect the entire body, there are usually numerous symptoms.
How are crossed eyes diagnosed and treated?
When crossed eyes develop in adults, the doctor conducts a complete physical examination aimed at establishing the underlying cause. The examination should include blood and urine tests and other laboratory studies. Depending upon the suspected cause, x-rays and other imaging studies may be needed.
Treatment is directed at eliminating the underlying disease. The doctor may also prescribe eye exercises, patching of the normal eye to strengthen the muscles of the one that is affected, and wearing special glasses.
If crossed eyes persist after the underlying cause is alleviated, continued use of special glasses may be needed. In some cases, surgery is undertaken. During the operation, muscles that control the eye may be tightened or loosened, or the position of the eye with respect to the muscle may be changed. Sometimes, several operations on one or both eyes are needed to bring them into normal alignment.
What can I do myself?
To correct double vision, you may be advised to cover one eye temporarily with a patch that can be purchased in a pharmacy. Sometimes, wearing such a patch is part of the treatment.
You may also be taught exercises to strengthen specific eye muscles. However, any exercise regimen should be designed by an ophthalmologist to ensure that the proper muscles are strengthened.
When should I see my doctor?
See a doctor as soon as possible if you suddenly
can be a symptom of a serious muscle or neurological disease. You should also see a doctor, preferably an ophthalmologist, if you develop crossed eyes, especially if the condition comes on abruptly.
What will the doctor do?
The doctor can determine the severity of the crossed eyes by holding a pencil or a flashlight in front of your eyes and asking you to focus on this object. He or she then alternately covers and uncovers your eyes, one at a time, and observes their movements as they fixate on specific objects. Special optical instruments may be used to determine the angle of the crossed eyes. After this evaluation, tests are done to determine what is causing the crossed eyes and treatment is initiated.
The course of crossed eyes
Depending on the course of the underlying disorder, crossed eyes may develop gradually over several months or even years, or it may come on suddenly. Unless there is irreversible damage to the eye muscles or nerves that control them, crossed eyes can usually be cured.
If crossed eyes are left untreated, vision loss due to a disorder called amblyopia may occur. In this condition, popularly referred to as lazy eye syndrome, the brain attempts to overcome double vision by suppressing the weak, distorted, or inappropriate nerve signals from the deviating eye. If this suppression continues, the brain loses its ability to interpret signals from the weaker eye and vision is decreased. Children are especially vulnerable to amblyopia. If the problem is not detected by the age of 6 or 7, vision in the weaker eye may be lost completely.
Are crossed eyes dangerous?
Crossed eyes can prevent the person from seeing clearly. More importantly, however, the condition may be a sign of a serious disorder.
What can I do to avoid crossed eyes?
There are no specific preventive measures for this condition.