How Trauma can affect Vision
How Trauma Can Affect Vision
Trauma to the brain or Acquired Brain Injury (ABI) typically includes Traumatic Brain Injury (TBI), Mild Traumatic Brain Injury (mTBI), and Cerebrovascular Accident (CVA) – more commonly referred to as stroke.
Because of the global nature of a brain injury, many brain areas and their associated functions are adversely affected. Vision disturbances following Traumatic Brain Injury can include anomalies of accommodation, vergence difficulties (nonstrabismic, as well as strabismic), photosensitivity, visual field integrity, and ocular health (physical damage to the eyes).
In the TBI population, convergence insufficiency (not able to maintain binocular fixation at near) was found to be about 40%, some type of oculomotor dysfunction (eye movement or tracking) was 60% to 85%, cranial nerve (CN) palsy was 33%, and accommodative (focus) dysfunction was about 20%. (Reference: Ciuffreda et. al., State University of New York, SUNY, State College of Optometry; Optometry, 2007; Volume 78: 155-161)
A typical profile of an individual with Acquired Brain Injury can be: Loss of balance (vestibular system), Eyestrain and blur at near, Joint pain (TBI), and Numbness/Weakness of extremities (CVA).
Post TBI common vision complaints are: intermittent blur, loss of place while reading, skipping or re-reading words, reduced reading speed, double vision, eyestrain, motion sensitivity, spatial perceptual or awareness deficits, and extreme light sensitivity.
Midline shifts can occur when the resultant damage places the patient spatially off-centered.
Loss of critical brain function can also lead to Cerebral Visual Impairment which is also referred as Dorsal Stream Dysfunction. Normal Dorsal Stream of the brain gives a mental spatial mapping in order to guide physical movement. The inability to do this can be called optic ataxia.
The above are difficult problems that can be assisted through Vision Therapy.