Concussion and vision problems typically go hand in hand.
There are many vision issues that can arise from the result of concussion or traumatic brain injury. Concussions are a very tricky subject. It is difficult to fully diagnose a concussion, difficult to combat the old norms of grading mild or severe concussions and sometimes, even though all physical testing with MRI and CT scans come back normal, people suffering from concussions still have symptoms years later.
Due to the close relationship between concussion and vision problems, we are on the forefront to initially diagnose, manage and treat patients who have suffered these types of traumas or events. At the same time, you should NEVER attempt to manage concussion patients alone.
Here are some main concussion and vision related problems that will tip you off that further testing might be necessary.
Light sensitivity (CFF)
Many of your concussion patients will complain of being sensitive to light. Some may notice that fluorescent lights at work or school and electronic screens are usually the most painful. This photosensitivity is without an anterior chamber reaction and in absence of inflammation. Research has shown that this light sensitivity could come from changes in a patient’s critical flicker frequency, CFF.
For those of you that do not remember, CFF is the frequency at which a flickering stimulus of light is perceived as constant.
Chang, Ciuffreda and Kapoor (2007) found that mild traumatic brain injury, TBI, patients with more light and motion sensitivity had a higher CFF than those mild TBI patients who did not complain of light and motion-sensitivity. Therefore, the light needs to be at a much higher frequency to be perceived as constant. If you can imagine almost every light you encounter throughout the day acting like a strobe light, you would not be very happy functioning in everyday life.
One way to help with this light sensitivity is the use of sunglasses or tints. Every patient is different in their preference so testing out different tints is important instead of using one ubiquitous tint for everyone.
Blurry Vision, Headaches, Eyestrain (Accommodative Abilities)
If you have ever had a concussion, there are a wide variation of side effects. Fatigue is a common one that can range from slight drowsiness to needing sleep continuously throughout the day. This is the body’s way of telling you that there is only so much the brain can handle after being injured before it runs out of energy.
The brain needs to handle many essential functions in order to keep the body alive. Facilitating skeletal muscle-function is not at the top of its priority list.
The extra-ocular muscles and ciliary body are no exception. Therefore, you may have people coming in complaining of blurry vision, headaches or eyestrain while reading. After assessing these people you may notice a recent onset of convergence insufficiency, accommodative infacility or accommodative insufficiency. They have either lost it, or it has become difficult to have the fine motor control to perform the everyday functions they were able to do unconsciously before they suffered the trauma.
If you think about an injured or tired muscle elsewhere in your body, you know that it will also have limited range of motion and limited function. As Optometrists, we know that we can fix all of these issues with prescription glasses for sustained near work and vision therapy to help learn how to use those muscles again.
Nausea, Dizziness, Loss of Balance (Shrunken fields)
Many of your concussion patients will also tell you that they get symptoms of dizziness and nausea, especially in crowded spaces or when riding in the back seat of a car. If you have ever tried testing the visual fields of your mild TBI patients, you will see that the fields are constricted. However, there is no pathology that would give a reason for these shrunken visual fields like sudden onset of retinitis pigmentosa or glaucoma.
The shrunken visual fields are not because their peripheral retina is incapable of seeing anymore, but that the patient is choosing to pay attention to a smaller central area.
It is less energy consuming and easier on an injured brain to pay attention to a smaller area. Since that smaller area is central, any movement happening outside that attended area triggers peripheral retina and the patient will move their eyes to look at the peripheral target. With that central field being shrunken, many more targets now become peripheral and a lot more re-fixations are needed.
As non-TBI patients with a wide field of view, you could use peripheral viewing to determine whether you want to move your whole visual system to another target or choose to ignore that peripheral object.
After a concussion, you do not have that luxury.
Mild TBI patients are so focused on what they are paying attention to that if anything moves in the periphery, they need to find the object and fixate on it before they can figure out whether they want to pay attention to it or not.
Next time you are in the mall, try looking around at every person walking past you and you will get nauseous and dizzy very quick. Using small amounts of prism for these patients to help with expanding that visual field makes a huge difference in their comfort and quality of life.
Oculomotor Dysfunction/Carsick (Loss of fine motor control, CI and Shrunken fields)
Has it ever happened where you wake up from a nap or a good night sleep and you try to reach for your phone? Instead of grabbing it properly you might grab the corner of it, start to lift it off the night table and then proceed to drop it because you never had a good grip in the first place?
While your brain is still drowsy and waking up, it is not able to get the muscles in your fingers to perform the necessary fine motor skills to securely grab your phone. TBI patients have that similarly tired brain and the extra-ocular muscles are unable to make those acute, fine-motor adjustments to properly hold a target.
Saccades and pursuits will be greatly affected with over-shoots, under-shoots and overall jerky movements.
Before a concussion, one saccadic movement allowed you to quickly and efficiently switch between targets. Now it takes two or three back and forth movements. This, coupled with the shrunken visual fields I discussed earlier, can really make public spaces or riding in a car a very uncomfortable experience. Take a close look at your TBI patients’ saccades and pursuits and you will notice the many corrections that need to take place.
Some of these patients will compensate for loss of that fine-motor control by recruiting bigger muscles to help with making those movements. Head, neck and body movements during saccades and pursuits are another giveaway that this patient does not have full, accurate and efficient control of their eye muscles.
Although the glasses will help with any accommodative and visual field issues I mentioned earlier, in order to help with this oculomotor dysfunction your patient needs an individualized vision therapy plan that will help them develop the necessary skills to use their eyes accurately and efficiently.
A lot of the symptoms TBI patients experience are vision-related.
Who is better at making visual tasks easier than an optometrist? That is why you as an optometrist can help make a massive difference in your TBI patients’ lives where no one else can.
Be careful though!
TBI is a very serious condition that has other issues we cannot solve in our scope of practice. Make sure to work in conjunction with their family doctor, chiropractor and occupational/physiotherapists to get the appropriate imaging done as well as work on healing the entire body.
Chang T, Ciuffreda K, Kapoor N. Critical flicker frequency and related symptoms in mild traumatic brain injury. Brain Injury. 2007;21:1055-62