Nearly 70% of the neural connections within the brain are involved with some aspect of vision (visual input, perception or integration), so visual dysfunction is very common following a brain injury. A 2016 study
found that 80% of post-concussion patients suffered from an oculomotor problem, the most common being convergence insufficiency (reduced eye teaming ability) and accommodative insufficiency (reduced eye focusing ability). Some other common effects on the visual system following a brain injury include:
-blurry vision at distance and/or near
-visual field loss
-oculomotor dysfunction (eye movement deficiency)
-reduced visual perception
-reduced visual processing speed
Although all of these vision problems can have detrimental effects to the patient, two of the above are exceptionally devastating and impairing: visual field loss and double vision.
Visual Field Loss
- Following a brain injury, visual field loss can range from complete loss of peripheral vision, to small areas of partial loss. Hemianopsia (loss of half of the field) and quadranopsia (loss of quarter of the field) are common. Theses individuals are at an increased risk of further injury from bumping into objects, being struck by approaching objects, and falls. Optometrists specializing in neuro-optometric rehabilitation are able to employ techniques to teach these individuals how to scan into their area of field loss. Scanning therapy, optical field awareness, field enhancing prisms and other adaptive strategies are employed to aid in the functional rehabilitation of the visual field loss.
Double Vision (diplopia)
- This is another common visual finding after an acquired brain injury and can be very debilitating. The patient's ability to read, walk, and perform other activities of daily living suddenly become disrupted or nearly impossible when living with sudden onset diplopia. A combination of therapies including prisms, fusion training and selective occlusion can be employed by a trained optometrist and/or vision therapist with the goal of re-establishing single, clear, binocular vision. Selective occlusion ("spot patching") is preferred over full occlusion when treating diplopia in brain injury patients. The spot patch eliminates diplopia by blurring central vision but without compromising peripheral vision. This ensures the patient does not lose peripheral fusion, visual field or the visual components contributing to orientation, balance, and mobility.
As mentioned above, neuro-optometric rehabilitation is a specialized area of optometry that addresses the specific ocular and neurological symptoms associated with acquired brain injuries. Patients of all ages who have experienced neurological deficits may benefit from a neuro-optometric assessment and treatment. Modalities such as corrective lenses, prisms, tints, selective occlusion and vision therapy may be used in the treatment of brain injury patients. However, a comprehensive, multi-disciplinary rehabilitation regimen involving occupational therapy, physiotherapy etc, is advised in conjunction with neuro-optometric rehabilitation to help elicit a full recovery.
Two of our own vision therapy optometrists, Dr. Patricia Fink and Dr. Shirley Ha, both have extensive training in neuro-optometric rehabilitation and are members of the Neuro-Optometric Rehabilitation Association (NORA). They are both able to assess and treat individuals with acquired brain injuries (including both traumatic and non-traumatic causes).
For more information, be sure to check out:
Neuro-Optometric Rehabilitation Association