post-trauma vision syndrome
post-trauma vision syndromeA defect in visual perception that follows a neurological event (e.g., traumatic brain injury, cerebrovascular accident, multiple sclerosis, cerebral palsy), which is characterised by the perception of movement by objects that are known to be stationary, the running together of printed text, attempting to walk on a seemingly tilted floor, significant imbalance and spatial disorientation when in crowded, moving environments.
Evaluation of PTVS using visually evoked potentials suggests that the ambient visual process frequently becomes dysfunctional after a neurologic event, and that the visual symptoms relate to dysfunction of two visual processes:
• The ambient process, which organises one’s self in space for balance and movement; and
• The focal process, which provides details, such as looking at a traffic light.
The syndrome occurs when there is a disconnect between the ambient and focal process, causing the person to overemphasise detail; for instance, the brain looks at blocks of text as isolated letters on a page and has difficulty organising them. Prisms and binasal occlusion can effect functional improvement.