Insults to the cortex produced by a TBI cause stress in central and autonomic nervous systems. The effect on vision causes an interference with the ambient visual process which is part of the sensory-motor feedback loop. This disruption happens at the level of mid-brain where vision is matched with kinesthetic, proprioceptive, and vestibular processes. As a result, a head injured person may experience diplopia/double vision, binocular dysfunction, or concentration difficulties.
The eye alignment imbalances and other difficulties that result from a head injury often occur because of dysfunction of the ambient visual process, affecting sensory-motor spatial disorganization. This causes an eye to turn out (exotropia) or both eyes to diverge (exophoria).
The resulting binocular problems are part of what is known as Post Vision Trauma Syndrome (PVTS).
Characteristics of PVTS can include:
Extropia or high exophoria
Low blink rate
Poor fixations and pursuits
Unstable peripheral vision
Symptoms of PVTS can include:
Objects appear to move
Poor concentration and attention