The turn may also be precipitated by illness or fatigue again due to the fact that there is an increased effort involved in keeping the world clear under these situations. Again, there can also be a genetic predisposition for this to occur. This type of eye turn is treated with spectacles. Some individuals seem to have an excessive stimulation of the inner muscles that pull the eyes inwards when the eyes try to focus. Eventually the brain learns to leave one eye in and turn it off to alleviate the effort of pulling both eyes out.
Some children have a combination of both b. and c. conditions.
Either way it is important that you understand that rarely is an eye turn due primarily to muscle problem. Unfortunately, very rarely will a child grow out of an eye turn. Usually exactly the opposite occurs in that the turn will get worse if left untreated. Having said that, even if the eye is turned a little the child will still be making the same adaptations to the problem. That is, the eye will still be turned off and becoming lazy.