Concussion

Concussion, is a complex pathophysiological neurological process, that impacts a large number of people. Data from the United States suggests that as many as  3.8 million people in that country alonehave had a concussion. Concussion is a form of brain injury. Health authorities classify it as a "mild traumatic brain injury" (mTBI). It is caused by a bump, blow, or jolt to the head or by a hit to the body that causes a rapid to and fro movement of the head and brain altering brain function.

Concussions can impact a person's activities of daily living and quality of life. Some activities that can suffer because of concussion are school or work performance and recreational activities. Concussions can also impact cognition, mood or sleep. Significantly, for developmental optometrists, concussions can impact vision. At our clinic we treat the visual symptoms caused by concussions. 

Thirty percent of concussion or mTBI patients have vision problems. Examples of vision problems caused by concussion include:

>constant or intermittent blur,
>double vision,
>slowed or inaccurate reading ability,
>eyestrain,
>sensitivity to light,
>dry eye, 

>increased sensitivity to visual motion, and

>increased vestibular symptoms in visually stimulating environments and with eye/ head/body movements. 

Convergence insufficiency is a common binocular vision disorder experienced by concussion patients. But it is often present with other, related vision disorders. In one study, titled "Concurrent Vision Dysfunctions in Convergence Insufficiency With Traumatic Brain Injury", published in 2012 the journal Optometry and Vision Science, researchers looked at the medical records of 557 brain injury patients and assessed the visual acuity, oculomotor function, binocular vision function, accommodation, visual fields, ocular health, and vestibular function for each patient. 

Only 9% of the TBI brain injury patients had convergence insufficiency without the following simultaneous diagnoses: saccade or pursuit dysfunction; third, fourth, or sixth cranial nerve palsy; visual field deficit; visual spatial inattention/neglect; vestibular dysfunction; or nystagmus.

It was far more common for the brain injury patients to have convergence insufficiency with other vision problems. Here are some examples:

>Photophobia (light sensitivity) together with convergence insufficiency was observed in 16.3% (21 of 130), 

>vestibular dysfunction together with convergence insufficiency was observed in 18.5% (24 of 130) 

>Convergence insufficiency and cranial nerve palsies were present in 23.3% (130 of 557) and 26.9% (150 of 557), respectively

Other vision disorders were also present. Accommodative dysfunction was common, as were visual field deficits or unilateral visual spatial inattention/neglect. 

The study findings support the idea that patients who have suffered a concussion or other traumatic brain injury need to be tested for a wide variety of vision problems. Where visual problems are found to result from a brain injury, vision rehabilitation/ vision therapy is an effective treatment.