Vision is the process of deriving meaning from what is seen all around us. This complex process starts with light particles passing through the pupils, projected on the retina, where millions of receptors (called rods & cones) turn the light particles into electric signals. Approximately 10 million of those electric signals travel the optic nerve to the brain at the speed of 275 MPH. This is followed by a learned and developed set of functions that involves the occipital lobe for vision and visual processing, the parietal lobe for sensory processing, and the temporal lobe for language memory. Research estimates that over 85% of our perception, learning, cognition and activities are mediated through vision. The amount of information that is passed from the eyes to the brain is enormous, and requires the most data compression known in the human body.
Given this complex process, it is not hard to understand that after even a mild brain injury, and the slightest brain function disruption, there will be an impact on this dynamic, and may lead to varied vision issues. It is estimated that about 80% of brain injury survivors will experience one or more visual symptoms, which can impair and negatively affect the quality of life. The five most common resulting conditions are blurred vision (what you see isn’t sharp and crisp), visual field loss (have trouble seeing objects out of one or more corners of both eyes), diplopia or double vision (seeing two images of a single object), aniseikonia or vision balance disorder (difference in image size perceived between the eyes from unequal magnification), and depth perception (the ability to see objects in three dimensions, including length, width, depth, and to judge how far away an object is).
After a brain injury, any one or combination of these conditions is usually present, whether it be the ability to correctly focus and capture what you see, pass meaningful data to the brain, or all the subsequent brain processing that follows. This is caused by disruption to those sets of complex functions that usually take place in fractions of a second. Those disruptions may lead to symptoms such as eyestrain, dizziness, headaches, disorientation, balance issues, etc. While some of these vision issues and symptoms may resolve on their own over time, others may require follow-up with a neurologist and neuro-ophthalmologist for evaluation, testing, and treatment. For best outcome, it highly recommended that CFBI seek evaluation, treatment, and therapy as soon as vision symptoms appear, as this will prevent additional issues and minimize confounded symptoms.
Our experience
Our experiences have been limited to blurry vision, double vision, and visual field loss. Visual field defects are the result of either brain, retina, or optic nerve damage, all of which are considered irreversible after 3-6 months, especially since the retina and optic nerve do not regenerate. Nevertheless, there is a potential for recovery of the visual field loss in cases of brain damage, where brain regeneration is possible. In Sarah’s case, 23 years later, her loss in the field of vision has been permanent. On the other hand, blurred vision and double vision are usually temporary, resolving over time, as they did in our case. In all cases, dealing with vision related issues is one thing, but the resulting symptoms are a whole different story. This includes not only the frequent eyestrain, but also dizziness, headaches, disorientation, balance issues, etc. As long as you are awake, your eyes are open and working, and you can not stow away your vision issues or symptoms, like resting a broken arm, for example. However, there are things that you can do to help minimize those symptoms and improve the quality of daily living.
Immediately after my accident, I had a double vision condition. While I thought it was a considerable issue, the doctors in the hospital had other important medical issues to deal with, such as the multiple amputations, and the many wounds and stitches in my head, back and leg. I remember being dismissed frequently when I talked about it, and the consequential headaches and dizziness. I was on enough morphine at the time, which helped me not care as much, and incidentally I was addicted for a while. I remembered the first time I was in a movie theatre after my accident. I was watching two overlapping screens or two separate screens side by side, depending on the distance from the screen. But, about 6-8 months later, the double vision started to adjust back toward normal, as in two objects started to come closer, until matched or seeing just one object. I was thankful.
As for Sarah, she reported blurred vision shortly after her hemorrhagic stroke, for which there were no remedies. With blurry vision, there is bad vision input to the brain, and the picture is not complete, so the brain works harder and overcompensates in order to fill in missing details. This has led to several associated symptoms including dizziness, disorientation, and balance issues. But the worst part was the overcompensation, which led to serious migraines. This was all made worse as she was a student who was almost always looking at a book or a computer for school, and it did not help that there was usually a TV running in the background, which served as a stimulant. Sarah is not sure whether the blurred vision faded overtime as in cured, or the brain had adjusted and made the problem more manageable. Nonetheless, she stopped complaining of blurred vision a few years after her hemorrhagic stroke. I honestly considered it a cure when there was no complaint, whether the problem resolved itself or the eyes and brain learned to adjust by working together. In any case, we were thankful.
The trickiest problem of all was Sarah’s field of vision loss- a problem that has proved over the years to be very complex, with additional impact and symptoms.
Fast forward, after Sarah’s advanced studies in the field of neuro-psychology, she started to have a better understanding of this puzzle. Now she knows that her brain is overworking while overcompensating in the field of vision loss, and how this has contributed to those aura migraines. She has also realized that in the mental arena, her mind tries to reconcile what it sees with what it already knows. This explains some of her struggle in once mastered skills like reading comprehension, writing composition, and verbal expression.
Compounded symptoms –
When you have a brain injury, the associated symptoms are compounded by vision issues in two ways. First, the added symptoms caused by the vision issue, such as blurry vision, double vision, field vision loss, vision balance disorder, and depth perception. Second, those vision issues will likely cause the brain to overwork and may lead to overcompensation and additional symptoms. But the brain is already injured, overworking and overcompensation add more pressure on the brain to perform. The result is usually a host of confounded symptoms and total exhaustion, mentally and physically. So, what should you do?
Remedies
First, along with brain scans, you need a good neuro-ophthalmologist assessment in order to get a clear picture of your vision issues. Second, you need to make sure that you have a neuropsych assessment, in order to understand how well the brain is functioning after your brain injury, and given your vision issues. Now that you have these reports, make sure to follow the recommended treatment. As for the symptoms, there are things that you can do in order to decipher through and minimize those symptoms. To start, keep a log of symptoms, dates, times, severity, and the activities involved prior to those symptoms. Finally, review periodically with a caring and knowledgeable family member, or caregiver, and look at both reports and symptoms for clues. This may not come easy or right away, but you will eventually learn of activities and lifestyle adjustments that will help minimize those symptoms and keep things manageable.
Note – Balance is a complex task. The human head is very heavy, and our bodies use multiple systems to keep our heads upright and to move through space on our two legs. These interrelated systems working as a team are the vestibular (inner ear) system, the visual (eyes) system, and the proprioceptive (muscles & body movement sensory) system. So, when brain injury results in any vision disruption, this can contribute to walking and balance issues. We will cover more on this under “Balance & Reaction”.