Most often strabismus is the result of an interference in learning how to use the two eyes. Binocular vision is a learned skill. There appears to be an inborn program and schedule for its development. Sometimes factors such as head injury, a cataract, a droopy eye lid can disrupt the development of binocular vision, usually it comes from an interference in the neural control centers or the ability to attend to and absorb information from both eyes.
Disturbances in the neural control centers occur with high fevers and childhood illnesses. Sometimes the neural interference occurs for other reasons. This is probably the reason that studies show a relationship between the development of strabismus and the delay in a child's learning to sit, walk, talk, and control elimination functions.
It seems that the mind pays attention more fully to the workings of the visual system between the ages of four months and six years (or most critically between four months and three and a half years). After that period the mind is more critically involved in other learning skills. A delay in neural growth or the protective covering of nerves may put binocular development out of phase with the concentrated attention necessary to convert the eye coordination skills into conditioned habit patterns. If visual habits are not firmly fixed they are then more vulnerable to loss.
