Strabismus is the medical term used to define crossed eyes. People having such eyes will have one of their eyes looking in or out. They cannot focus in the same object like the other eye. One eye may turn up/down and this process is increased when the person gets stressed or with heightened emotion. The intensity of turning up/down of one of the eyes may be all the time or only during certain occasions.
Types :
Strabismus can be defined as some kind of misalignment of the eyes. Strabismus can be classified according to the direction of misalignment of eye. Some of the common kinds are exotropia (when eyes are turned in outward direction), esotropia (eyes are turned inward), hypertropia and hypotropia (both are types of vertical misalignment).
Strabismus Causes :
Often, strabismus or crossed eyes are inherited and the child is born with this defect. In some children, there is no specific cause for strabismus. It can be caused by nervous problem caused in the cranial nerves that are responsible for the movement of eyes. Any weakness in these cranial nerves can cause strabismus.
Crossed eye can be caused due to paralytic nerve and some kinds of such paralysis are oblique palsy and third nerve palsy. Strabismus can be caused due to poorly controlled neuromuscular movement. Often, strabismus can be repaired or corrected in childhood. In case necessary correction is not done, the same eye pattern will continue when the person grows into an adult. In some people, strabismus can cause double vision. If there is sudden problem in the eyes or misalignment (not from childhood) in otherwise healthy person, it can be due to serious nervous problem. In such case, you need to consult your doctor immediately.
Complications :
Misalignment in the eyes can cause double vision or amblyopia. Normally when you see any object, the image of the object is perceived by the brain in the form of visual image. But in children with strabismus the brain receives two different images. Under such circumstances, the brain would ignore one image received from abnormal eye. Subsequently this can cause poor vision.