One: Convergence-the coordinated inclination of the two lines of sight towards their common point of fixation, or the point itself. (http://medical-dictionary.thefreedictionary.com/convergence) Some common disorders associated with convergence would include convergence insufficiency and conversion disorder. Convergence insufficiency can cause things like double vision particularly when reading or looking at something in close range. Convergence insufficiency is common in children and causes their eyes to drift outward. Children with convergence insufficiency have to use extra effort to direct their eyes back inward in order to avoid double vision. Conversion disorder is neurological and can cause numbness, blindness, and paralysis. Conversion
