Strabismus is a condition in which the eyes point in different directions. Usually one eye is pointed straight ahead and the other is pointed in, out, up, or down.
With normal vision, both eyes are aimed at the same target and the brain blends the 2 similar pictures into one clear, three-dimensional picture (called binocular vision). With strabismus, 2 different pictures are sent to the brain. In a young child, the brain starts to ignore the picture from one of the eyes, and the child loses vision in this eye. This loss of vision is called amblyopia, or lazy eye.
People who develop strabismus as adults often have double vision because the brain is used to processing 2 pictures and cannot easily ignore the picture from the turned eye.
Some types of strabismus are:
Strabismus happens when the eye muscles are not balanced. The movements of the muscles of one eye do not match those of the other eye. Sometimes the cause of eye muscle imbalance is not known. Children may be born without the ability to move the eyes together. Children with cerebral palsy or Down syndrome often develop strabismus.
Strabismus in adults may be caused by:
The eyes appear to be looking in different directions all or part of the time. In some cases, it may happen only if you are tired or sick. Other symptoms include turning or tilting the head or squinting one or both eyes.
The eyes of babies younger than 3 months old may appear to look in different directions for a few moments, often just before going to sleep. This does not always mean they have strabismus. If a baby's eyes look misaligned constantly by the time they are 2 months old or misaligned part of the time by the age of 3 months, take your baby to an ophthalmologist (medical eye doctor).
The healthcare provider will do several tests. He may hold a small light in front of the baby's eyes to check if the reflection of this light is properly centered in each eye. In another test, the provider covers one of the child's eyes and then the other to see if the eyes shift abnormally when focusing on a near or distant object.
The provider will test the vision and ability to follow objects with each eye. In older children or adults, the provider will test if the eyes can work well together by checking for three-dimensional vision. He or she will also examine the eyes for any signs of disease.
The goals of treatment for strabismus are to:
Children who have strabismus need to be treated as soon as possible by an eye care provider so they can develop normal vision. Treatment that begins after the age of 6 years may improve a child's appearance but does not always help vision problems.
Treatment of strabismus includes:
More than one surgery may be needed. The success of surgery depends partly on the coordination between the eyes and brain. It needs to be good enough to keep the eyes locked on target and in alignment.
Prism glasses may be prescribed for adults. Wearing these glasses can sometimes help double vision.
All adults and children should have eye exams regularly. Tell your provider about any eye misalignment you notice in yourself or in family members. If your eye care provider recommends patching or any other treatment, follow your provider's instructions exactly.