Strabismus is caused by a lack of coordination between the eyes. As a result, the eyes look in different directions and do not focus simultaneously on a single point.
In most cases of strabismus in children, the cause is unknown. In more than half of these cases, the problem is present at or shortly after birth (congenital strabismus).
In children, when the two eyes fail to focus on the same image, the brain may learn to ignore the input from one eye. If this is allowed to continue, the eye that the brain ignores will never see well. This loss of vision is called amblyopia, and it is frequently associated with strabismus.
Some other disorders associated with strabismus in children include:
Acquired strabismus in adults can be caused by injuries to the orbit of the eye or brain, including closed head injuries and strokes. People with diabetes often have loss of circulation causing an acquired paralytic strabismus. Loss of vision in one eye from any cause will usually cause the eye to gradually turn outward (exotropia). Because the brains of adults are already developed for vision, the problems associated with amblyopia, in which the brain ignores input from one eye, do not occur with adult strabismus.
Some disorders associated with strabismus in adults include:
A family history of strabismus is a risk factor. Farsightedness may be a contributing factor. In addition, any other disease causing visual loss may produce strabismus as a complication.
|