‘You cured my concussion’ he writes to me. This is exactly how he sees it. In reality what we did was diagnose and treat the vision conditions that were caused by his concussion. These vision conditions were responsible for many of the concussion symptoms that the he had been experiencing. Dizziness, fatigue, headaches, migraines, balance problems (watch the following video too), difficulty with computer screens and reading just to name a few. Post-concussion vision symptoms are incredibly common, yet commonly go undiagnosed and un-treated. Not all post concussion symptoms are vision related, and the right testing can easily rule vision problems in or out. The problem is that it’s not properly tested for at most exams.
At a time when ‘concussion clinics’ are popping up all over Vancouver Island, it’s really important that doctors, professionals, and people who have concussion symptoms think logically about care.
Let’s look at vision. The light that enters a person’s eyes is processed by the brain and used for balance (see video), motor coordination, eye tracking, and much more. If the visual perception of the world differs from the vestibular perception, it can cause dizziness, nausea and balance problems. Inefficiencies in how the eyes are working together can cause fatigue, headaches, migraines, problems reading, and difficulty tolerating computer screens. Eye tracking problems can also cause people to have to reduced reading comprehension, make mistakes in their work and trouble tracking moving objects. It can make the world appear to move (oscillopsia), or cause moving objects to appear like stop-motion.
70% of the incoming sensory information is visual, so it is no surprise that short term memory and following conversations can be a challenge. After all, what happens when one program on your computer is crashing? The computer grinds to a halt as all the resources are hogged by the one program that is not running properly.
One big problem for brain injury survivors is that these post-concussion vision conditions are often overlooked by most doctors and professionals. Even when the vision has been checked by an optometrist or ophthalmologist, most often the exam focuses on seeing clearly and the health of the eye, missing the critical visual functions that are responsible for so many post-concussion symptoms.
These patients often go on to vestibular rehabilitation, which includes some very basic vision rehabilitation, but largely assumes that vision is ok. Their vestibular rehabilitation often plateaus, because it requires properly functioning vision. They are often then put into a ‘habituation’ type program for a graduated return to work, where the premise is that ‘if this bothers you to do, more of doing it should help’. We wouldn’t say that to the patient with the broken leg would we? ‘More walking ought to help that!’ These things are done with the best of intentions but will ultimately fail if vision hasn’t been addressed.
Post-concussion vision problems are easy to detect using tests like VOMS (vestibulo-ocular-motor-screening), seeing if pattern glare causes symptoms, and an in-depth workup by an optometrist who has the necessary extra education in treating vision conditions associated with concussion and head injury.
Why isn’t it being detected? The unfortunate part is that most of medical school and optometry school is still teaching an outdated model of visual function, and it’s hard to change what people already think. It’s well known that once someone is taught a certain way of thinking, it’s much harder to change it. This is similar to how it took time for the medical system to recognize that certain bacteria in the gut is actually critical to our health, and the first doctors stating so were ridiculed by their peers. There is also a professional turf battle within vision that is stunting the advancement of patient care, but that’s a story for another day.