What Causes Strabismus?
Many things and/or events can cause a strabismus. They include genetics, inappropriate development of the “fusion center” of the brain, problems with the controlled center of the brain, injuries to muscles or nerves or other problems involving the muscles or nerves. Surprisingly, most cases of strabismus are not a result of a muscle problem, but are due to the control system — the brain.
Treatment should be directed at the source of the problem. The eye doctor must determine if the strabismus is due to an eyeglass problem or brain problem. Sometimes, bifocals are needed to eliminate the eye turn.
Different Types Have Different Causes
Strabismus is classified into many different types. Each type has its own causes, characteristics, and appropriate treatment plan. See Types and Treatment of Strabismus. You will also find pull-down lists at the bottom of each page.
- the patient will see double because the two eyes are not aimed at the same point;
- one of the eyes can suppress or turn off (in the brain) to avoid double vision (technically called diplopia). This condition is called suppression.;
- the brain can develop a new match with each eye so that fusion occurs even though the eyes are not aimed at the same spot. This last phenomenon is known as anomalous retinal correspondence. It occurs early in life and will almost never occur if the strabismus develops after four years of age.
If the eye turn develops after the age of 6 then suppression, confusion, and/or anomalous retinal correspondence will not occur.
If any of these three sensory conditions occur, then the eyes are not working together and can not have normal stereopsis. The only way to eliminate these obstacles to fusion and stereopsis is with Vision Therapy (orthoptics).
The longer suppression has been in effect, the more difficult it will be for the patient to eliminate and re-establish normal binocular vision. Early detection and treatment is very important in all cases of strabismus!