Vision and Concussion
What is a Concussion?
A concussion is a mild traumatic brain injury (TBI) that results from impact to the head causing a disruption in normal brain function. As the head is moving back and forth (coup contrecoup injury), your brain is twisting and turning in the skull which can lead to chemical changes and damage of brain cells. Concussions are not usually life threatening but can lead to side effects that can last days, weeks, or sometimes much longer.
In Ontario, the annual average concussion rate is about 1.2% of the population - that is over 150,000 cases of concussions each year!
How is Vision related to Concussion?
More than 50% of the brain is either directly or indirectly involved in the visual process. Shearing forces during the incident can disrupt the coordination of various aspects of the visual system that are required to work together to ensure clear, comfortable, and single vision. A concussion often disrupts the communication between the eyes and the brain, and consequently, it is not uncommon to experience a number of different visual symptoms.
According to a retrospective study “Vision Therapy for Post Concussion Vision Disorders” (Gallaway et al, 2017), out of 218 concussion patients, 82% of them experienced a vision disorder. Of those who experienced a vision disorder, 62% had an eye teaming problem, 54% had an eye focusing problem, and 21% had an eye tracking problem. There was often an overlap of different vision difficulties in the concussion population.
Vision Disorder Post-Concussion
of those with concussion had a vision disorder
had eye teaming difficulties
had eye focusing difficulties
had eye movement difficulties
Possible Visual Symptoms after a Concussion:
Blurred Vision
Headaches
Slow to shift focus, near to far
Difficulty taking notes
Loss of place while reading
Double vision
Wandering eye
Pain with eye movement
Pulling or tugging sensation around eyes
Eyes get tired while reading
Unable to sustain near work for adequate periods
Difficulty remembering what has been read
Difficulty recalling things seen in the past
Dizziness
Poor eye-hand coordination
Loss of balance
Poor handwriting
Head tilt or face turn
Covering or closing one eye
Bothered by crowded places such as a busy grocery store or shopping mall
Reduced depth perception
Light sensitivity
Feeling you have ‘tunnel vision’
Post-Concussion Visual Skills Assessment
If you experience any of the above visual symptoms after a concussion, it is recommended that you undergo a Visual Skills Assessment, which will be tailored specifically to the brain injury patient. The second step would be to undergo a Visual Information Processing exam to detect for visual perceptual concerns related to your concussion.
After testing, Dr. Yew may recommend a pair of spectacles, neuro-rehabilitation (vision therapy for those brain injury), or a combination of both. Dr. Yew has had additional training with the traumatic brain injury population and is experienced in prescribing different coloured tints, mild prisms, and selective occlusion to aid in your visual symptoms. It is important to note that a collaborative care effort with other health professionals (ex. physiotherapists, occupational therapists, chiropractors, physicians, etc.) are essential in the recovery of a patient with concussion.