A concussion can be caused by direct blows to the head, gunshot wounds, violent shaking of the head, or force from a whiplash-type injury. Both closed and open head injuries can produce a concussion. A concussion is the most common type of traumatic brain injury.
A concussion is caused when the brain receives trauma from an impact or a sudden momentum or movement change. The blood vessels in the brain may stretch and cranial nerves may be damaged.
A person may or may not experience a brief loss of consciousness (not exceeding 20 minutes). A person may remain conscious, but feel “dazed".
A concussion may or may not show up on a diagnostic imaging test, such as a CAT scan.
Skull fracture, brain bleeding, or swelling may or may not be present.
A concussion can cause injury resulting in permanent or temporary damage.
Following a concussion, there is often an interruption in communication between the eyes and the brain. Studies show that at least 50% of Traumatic Brain Injury patients suffer from visual dysfunctions, with one such study finding a 90% incidence of post-trauma visual complications (1).
Some symptoms may only last a few seconds while others can linger for months or years. The Concussion Legacy Foundation and the Neuro Optometric Rehabilitation Association (NORA) put together this list of vision problems and symptoms following a concussion (2):
Symptoms can include discomfort and even dizziness when scrolling on a computer screen or phone, or when in busy environments such as grocery stores, social settings, or sporting events.
Eye movements are important in the reading process, as well as tracking moving objects with the eyes, like a ball being thrown.
Recent studies have suggested that LCD screens (such as from computers or smartphone devices) can be particularly bothersome after a concussion.
This can be extremely disorienting and can cause dizziness, difficulty balancing, walking, and reading.
The inability to properly point the eyes at a page or screen, often causing reading-based difficulty.
Judgement of where objects are in space; difficulty with eye-hand coordination.
Reduced awareness of objects or people in one’s peripheral vision, being easily startled by things appearing from the side, or a tendency to bump into things that were not seen.
Visual deficits related to a traumatic brain injury should be evaluated by an optometrist who is trained in the evaluation and management of eye and vision complications of concussion. Treatment requires a multi-disciplinary effort, including vision rehabilitation as an important part of post-concussion care. To locate an appropriately trained provider in your area, visit http://www.noravisionrehab.org. For more concussion information and resources, visit http://www.concussionfoundation.org.
Concussions remain one of the most difficult neurological issues to detect and accurately diagnose. Evidence of a concussion may not always be visible on MRI or CT scans, and there is no blood test or saliva test to indicate a concussion.
A doctor may perform neuropsychological tests to determine if you are having difficulty with cognition and memory after a concussion. These tests may also detect any emotional changes. A neuropsychological test may involve answering questions or performing tasks. For example, to test for attention span and memory, the doctor might ask you to repeat a series of numbers, letters, or words. To test for language and speech skills, you might be asked to name the objects in pictures or as many words as you can think of that begin with a certain letter.
New research and new technologies are showing exciting promise in the area of concussion and traumatic brain injury screening and diagnosis. There are eye tracking technologies emerging that are showing early positive results in detection of concussion.
Visual problems are often overlooked during the initial treatment of a brain injury and a regular eye exam often does not reveal the extent that the visual process has been affected. Individuals who have experienced some sort of neurological insult or injury, and who are experiencing visual symptoms, can benefit from a vision assessment from a Neuro-Optometric Rehabilitation Optometrist, an eye care professional who specializes in the diagnosis, treatment, and rehabilitation of neurological conditions adversely affecting the visual system.
With mild traumatic brain injuries, individuals should be monitored closely at home for any persistent, worsening, or new symptoms. Indications for returning to work, school, or physical activities are based upon the physician’s recommendations.
Anyone with signs or symptoms of moderate to severe traumatic brain injury should receive medical attention as soon as possible.
Moderate to severe traumatic brain injuries may require emergent medical care to ensure that the individual has proper oxygen supply to the brain and the rest of the body, adequate blood flow and normal blood pressure. Further medical management may be required based on the patient’s symptoms.
Most people with a significant brain injury will require some form of rehabilitation to relearn basic skills and perform their daily activities. The type and duration of rehab depend on the severity of the injury and what part of the brain was injured.
A neuro-Optometric Rehabilitation is a specialized, individualized treatment regimen for those who have visual deficits as a direct result of physical disabilities, traumatic brain injuries, and other neurological insults. Neuro-Optometric Rehabilitation therapy utilizes therapeutic prisms, lenses, filters and occlusion to help stimulate parts of the brain which are not functioning to their highest potential, due to interruptions caused by the brain injury.
Neuro-Optometric Rehabilitation is not to be confused with vision therapy, which is an additional therapy needed by some brain injury survivors. Vision therapy is a highly effective non-surgical treatment for many common visual problems such as lazy eye, crossed eyes, double vision, convergence insufficiency and some reading and learning disabilities. In the case of learning disabilities, vision therapy is specifically directed toward resolving visual problems which interfere with reading, learning and educational instruction.
(1) Ciuffreda KJ, Kapoor N, Rutner D, Suchoff IB, Han ME, Craig S. Occurrence of oculomotor dysfunctions in acquired brain injury: a retrospective analysis. Optometry 2007;78(4):155-61.
(2) "Common Vision Problems and Symptoms Following a Concussion" Concussion Legacy Foundation and Neuro Optometric Rehabilitation Association. https://noravisionrehab.org/uploads/media/NORA_CLF_CommonVisionProblems_FINAL_11-18.pdf
(3) “Sports-Related Head Injury” American Association of Neurological Surgeons. www.aans.org/Patients/Neurosurgical-Conditions-and-Treatments/Sports-related-Head-Injury
(4) Master CL, Scheiman M, Gallaway M, Goodman A, Robinson RL, Master SR, Grady MF. Vision Diagnoses are Common After Concussions in Adolescents Clin Pediatr (Phila). 2016 Mar;55(3):260-7. doi: 10.1177/0009922815594367. Epub 2015 Jul 7
(5) Phil Veliz, PhD et al. Prevalence of Concussion Among US Adolescents and Correlated Factors. JAMA, September 2017 DOI: 10.1001/jama.2017.9087
(6) The Concussion Legacy Foundation website