As you are reading this, over 50% of the surface of your brain is being used to process the visual information coming in through your eyes. Each eye is constructed of over 2 million working parts and of those, the optic nerve contains between 770,000 to 1.7 million nerve fibers. Nearly 80% of sensory information coming into your body is the input to your eyes! We have more neurons dedicated to vision than our four other senses combined. Interestingly, if you receive conflicting information from your senses, your brain will use vision to over-ride the other sense almost every time (video showing this phenomenon at the end).
This recovery has led me to realize just how much I took for granted, especially my vision. How often do you stop and think, I am seeing this image perfectly in space because of the intricacies of the brain that created it? What happens behind the scenes is the subconscious system of the brain, allowing us to experience where we are at in space and our perception of the world around us. This information is a culmination of so many factors working together in the brain which then forms the 3D road map for us. The human body is amazing.
20/20 is looking at one visual function of the eyes, that being visual acuity. What about all of the other components that contribute to the visual system? The systems that make up our vision are so complex and involve various areas of the brain to produce the images and our perceptive abilities. After TBI, disruption and damage at different areas of the brain can occur. With so many areas of the brain contributing to our visual system, you can imagine if there is damage to any single part of the system, it can lead to visual dysfunction.
Following TBI, up to 90% of patients experience at least one oculomotor dysfunction (scanning and tracking) and up to 40% experience visual dysfunction (focusing and eye teaming) persisting beyond three months. Despite the prevalence, this is still often overlooked in patients.
I mentioned briefly in an earlier post that I had a quick referral to an optometrist for my visual deficits that became prominent immediately after the injury but continued to worsen as days and months passed. In the immediate days following my brain injury, I developed blurry and double vision. I couldn’t scroll on my phone or drive in the car without feeling dizzy and nauseous. I couldn’t track moving objects nor could I move my eyes without pain or move them quickly from one target to another without feeling off balance and experiencing double vision.
About two weeks following the injury I was seen by an optometrist who did two things on examination – checked my visual acuity and near point convergence (NPC). When your eyes come in to focus on a close target, that is called convergence (your eyes are converging). NPC is a measurement of the distance where maximum effort of convergence occurs, measured by a doctor moving a fixation stick from far to near and stopping when you no longer see one stick (it becomes double) or when one eye subtly deviates outward. The distance from the nose to that point is the NPC.
You can try this by holding a pen at arm’s length and slowly bringing it closer and closer to your nose. Wherever you start to see two pens or when one eye subtly deviates (if you have an observer), this is your NPC. This is commonly abnormal in patients following TBI. From these two tests, I was diagnosed with convergence insufficiency and accommodative insufficiency. I will explain these diagnoses later in this post. I was prescribed reading glasses (+ 0.50) to aid in focusing. The glasses had a tint to them to block blue light and help with light sensitivity.
I was advised to follow up again in one month to determine if I required vision therapy which we did end up starting one month later. Therapy occurred every two weeks consisting of a ten-minute appointment with the optometrist who observed me perform certain tasks. There was no objective data to show improvement and really no time to properly assess for improvement in a ten-minute appointment anyway.
My eyes continued to hurt, headaches persisted, blurry and double vision seemed to worsen. This carried on for 3-4 months with no notable progress at all. I thought that maybe there just wasn’t room for improvement of my eyes. We kept doing the same exercises over and over to no avail. It felt like I was banging my head against the wall over and over. It also felt like this therapy was a blanket approach – the same therapy used on every single concussion patient.
After stopping vision therapy, I traveled to Georgia where I stayed for one week and completed a brain rehabilitation program. That was the first time I had real, objective data of just how poorly my eyes were functioning. I’m going to explain this trip in detail in a later post. I returned from brain rehab with home exercises and felt better initially but as weeks went by, I could feel my body and eyes reversing back to the state I was in prior to the trip. I thought maybe I just needed more comprehensive care in person for my vision but I didn’t know where to look.
Like every other helpful treatment I’ve discovered, I was listening to a TBI podcast and one of the topics discussed was neuro-optometric rehabilitation. I wasn’t very familiar with this. The doctor in the podcast proceeded to talk about how important it is following a brain injury to find a provider who is specialized in neuro-optometric rehab and a great resource to find one is through the NORA (neuro-optometric rehabilitation association) database. A neuro-optometrist has special training in the neurological aspects of the visual system. The importance of a neuro-optometric examination as quickly as possible after brain injury was stressed.
This was in April of 2019, six months after my injury. I looked in the NORA database and found there was a center very close to home, The Vision Development Team. I looked into it – another treatment that would be solely out of pocket. Could this be worth a shot? I decided it was definitely worth it. Unfortunately, the optometrist I had been seeing for months prior had no experience in neuro-optometric rehabilitation. Vision therapy with that optometrist was solely focused on the eyes, and not how the eyes and brain were working together.
I called and scheduled the first available appointment at The Vision Development Team, about two months away. The appointment was scheduled for June 13, 2019. My hospitalization with the pneumothorax happened the day before this appointment. I cried because I was so upset that I would miss the appointment I had been waiting so long to go to. I begged to be released from the hospital temporarily to make the appointment (this was ridiculous). I was desperate to get my vision better and felt like waiting was wasting more time.
The Appointment at The Vision Development Team
My appointment included a thorough history of the injury and symptoms followed by a complex sensorimotor examination and neurovisual assessment. The exam didn’t just look at the eyes, it assessed how the eyes and systems of the brain work together. The best part other than giving me objective data showing my visual deficits was that they weren’t just addressing my eyes at this appointment – they were addressing all of the systems that construct me.
The exam started with the basic visual acuity test. Surprise, I have 20/20 vision. Oh, how I wish that meant everything were perfect. We then carried on to the more complex sensorimotor and neurovisual assessments.
This exam was comprehensive and included evaluation of oculomotor function, accommodation, binocular function, peripheral awareness, depth perception and spatial processing, visual-vestibular testing, balance and primitive reflex testing. In short, this is testing: how your eyes work together (eye teaming), your ability to track objects in space, your ability to sustain and shift focus, function of spatial processing (where things are at in space, our 3D road map), how the inner ear and balance system is functioning (vestibular system), if any primitive reflexes have re-emerged, and how the peripheral system is working.
I knew there was a lot wrong but what I discovered after all the testing was a lot to take in. I felt overwhelmed and defeated at first because so much was wrong but that turned into hope because we finally identified the target areas that needed to be rehabbed.
The eyes are supposed to work as a team. Just as other parts of the human body are not intended to operate independently of each other, the same applies to the eyes. It is necessary for the eyes to work in tandem and when this doesn’t happen as in my case, a multitude of issues surface. While each eye may individually be considered “healthy,” they are unhealthy in that they do not coordinate with each other and the communication system to the brain is impaired.
The exam showed I have binocular dysfunction or impaired eye teaming. I was diagnosed with convergence insufficiency (CI). This diagnosis means the eyes are not working together to focus on a target up close. Together, the eyes must turn inwards to view objects at near under normal circumstances. CI results when the eyes aren’t in sync and don’t move at the same time to focus on a target. This can result in the words appearing to move while reading as well as lead to blurred/double vision, impaired concentration, eyestrain, drowsiness, and headaches.
Another diagnosis is accommodative insufficiency (AI). AI involves the inability of the eyes to focus properly on an object and switching between looking at an object afar to an object near. An example of your eyes needing to accommodate is looking at the speedometer of your car and quickly looking out at a traffic light in the distance. If there is an insufficiency, when you make that quick movement of focus, there could be a lot of blurriness, double vision or motion intolerance.
I was found to have vestibular dysfunction. The visual system works very closely with the vestibular system of the inner ear that provides equilibrium and balance. When your head moves, your eyes need to adjust to the movement quickly in order to still be able to focus. Dysfunction in the two systems leads to motion intolerance, feeling off balance, dizzy and blurred/double vision.
Aside from the above issues, I had impaired peripheral awareness as well as impaired spatial processing seen with diminished hand eye coordination, depth perception and delayed reaction time.
A neurological phenomenon that I wasn’t aware of was present – suppression of one or both eyes alternating suppression. Most prevalent, however, is suppression of my left eye. This is a natural protective mechanism of the brain in an attempt to make sense of the visual information that is coming in. If you experience double vision, the brain adapts by disregarding or ignoring the visual signal provided by one eye or suppressing it. My eye suppression is a compensatory mechanism of my brain from prolonged periods of double vision.
For example, a healthy pair of eyes align and point towards the same object in space and see an equally clear image. The brain then uses small cues to determine the size, shape and depth of the object. The two images of each eye then combine to produce what you see in space. In a pair of eyes that have poor teaming, one eye may produce a blurry or double image so the brain struggles to combine the blurry image of one eye with the clear image from the other eye. The brain becomes confused and to compensate, it uses the good input from the healthy eye only and ignores the input from the blurry eye. This creates a strain on the muscles in the eye due to the overcompensation which can lead to headache, dizziness, nausea and unsteadiness.
Primitive reflex testing was also something I wasn’t familiar with prior to this appointment and the rehab that followed. Our primitive reflexes are automated responses to a stimulus, sensed by our neurons which then produce a response which is our involuntary action. We have many reflexes, some that are acquired throughout our lives and others that we are born with (innate, primitive). These primitive reflexes we exhibit as babies are a survival response and are integrated into our nervous system within the first year of life. As we hit each developmental milestone, a sense of safety is reached and different reflexes are inhibited by the developed higher brain areas.
Once the primitive reflexes are integrated into our nervous system or disappear, their purpose has been served and they are then stored. Brain injury threatens survival resulting in the reflexes that were once stored to be triggered to reappear. The brain reverts back to that primitive state. Re-integrating the reflex is important as it helps re-connect the sensory systems and regain normal visual functions.
The moro reflex in infancy is stimulated by any sudden movement of the neck. This results in the “startle response.” This survival instinct helps the baby cling to the mother. It is developed at about 28 weeks gestation and typically integrates and disappears around 4 months of age. If the moro reflex is activated in adult life it can lead to dysregulation of the autonomic system, hypersensitivity to external sensory stimuli, anxiety, visual perception and oculomotor dysfunction, and vestibular problems. Through testing, it was found that my moro reflex became active again due to the brain injury.
Neuro-optometric rehab was prescribed, which I continue to this day. A customized plan tailored to me was made – not a blanket approach used on every concussion patient. This is so important because no two concussions are the same.
Neuro-Optometric Rehab: A Work in Progress
It can be difficult for the brain to unlearn some of these behaviors but the good news is the brain exhibits neuroplasticity which means it has the ability to form new connections and heal. Did you know your hippocampus generates at least 700 new neurons a day? That’s pretty cool.
Neuro-optometric rehab focuses on plasticity by using prisms, filters, lenses and more to help stimulate various parts of the brain. This is unlike routine eye care or refractive care that can be fixed with glasses. The therapy I first received following my injury was focusing solely on the eyes and not how the eyes and brain worked together.
Walking into vision rehab often feels like walking into a jungle gym or a playground. Most appointments I am there in the big therapy room with little kids. Every rehab appointment feels like I’m channeling my inner child, which is what makes it so enjoyable.
Though painful at times, and I mean very painful, going to vision rehab can be a fun experience. My doctor works with the vision therapist to tailor a plan for me and adjust it through time as my progress is tracked. My vision therapist knows how competitive I am and incorporated many activities where you can set records. Not only was this motivating for me but it was a great way to track progress and see if I could beat my own scores each week.
We have done so many different vision exercises that I can’t possibly explain all of them here. My initial vision exercises were single eye exercises as I patched one eye. As I progressed, we slowly added in movements and eventually no patch.
To re-integrate the moro reflex we have done a lot of breathing techniques and relaxation exercises. This ties into the autonomic dysfunction that occurs following brain injury leading to a heightened and prolonged fight or flight state. The breathing techniques seemed a little silly at first and were sort of embarrassing with someone watching but it actually works. The breathing techniques used are called hisses and hums. Take a deep breath in, breathe out slowly and as you breathe out, you make a hum or hissing noise. This allows stimulation of the vagus nerve which in turn stimulates the parasympathetic nervous system (relaxation). We were able to reintegrate this reflex to the point where it was no longer present for about a year but unfortunately it re-surfaced after a recent traumatic day of testing.
Another helpful tool not only for the moro reflex but also easing the eyes after difficult rehab sessions is Syntonic phototherapy. When light travels through the eye it reaches the brain, specifically the hypothalamus and pineal gland. These areas are important for regulating various functions and studies have shown that by stimulating them with specific frequencies of light, it can have positive effects. I have done a lot of work with Upsilon Omega (a blue shade) that is supposed to help stimulate the parasympathetic system and restore balance of the autonomic nervous system.
To help with the vestibular system, we have done exercises with head movements which are still extremely challenging. As of late, we have had to put a hold on those more advanced exercises but hopefully I will progress to that point again soon.
Through time, we have also incorporated auditory processing through a program called the Integrated Listening System. I have done this while performing vision exercises to integrate the senses which has been a major area of disconnect. This is extremely challenging as I still have many issues in conversations with side noises, busy environments and becoming startled by unexpected noises and sounds. The intense tinnitus continues to be an issue.
It turns out that the glasses initially prescribed by the first optometrist I saw were not what I needed. After the neurovisual exam, I was prescribed prism glasses with binasal occlusion. Binasal occlusion is a partial covering of the visual field of both eyes to reduce the amount of visual stimuli that my brain has to process that is coming in. Prisms take into account how the brain and eyes are working together and can help stimulate those affected areas and improve vision, balance and spatial processing. Prisms are used for when the eyes aren’t working together to focus on a target which can lead to double vision. The prisms bend light that travels into the retina, allowing the eyes to remove the double vision and perceive it as one image.
Prisms have also been incorporated into rehab. We have worked on balance and spatial processing at vision rehab using various prisms as I have to balance and walk on a walking rail. It feels as if my body is being pulled to one side or the room is slanted. We have made some progress in that I am not constantly falling off of the rail. The goal is to help the eyes and brain to learn to work together again.
Vision rehab has been quite the journey, with many setbacks but also many small victories. It’s easy to feel defeated and stuck during the setbacks but I’m learning to feel all of my emotions and get it all out and then start focusing on how I’ll get out of it and move forward. While I still have a lot of progress to make, I am extremely grateful for the small victories made along the way. My biggest goals of vision rehab have not been achieved yet but I am keeping the faith and hope these goals will be reached and when that day happens, I will probably cry first and then celebrate by going for a drive while listening to good music. This is something I dream about!
Find a NORA Provider Here:
If you experience vision issues following a concussion and are told you’re fine because your vision is 20/20, find a different provider and find one that understands the neurological aspects of vision!
Find a NORA provider here.
To see my amazing group of people at The Vision Development Team, go here.
To All My Healthcare Provider Friends:
It’s important to note that visual dysfunction following brain trauma is due to damage in the brain at the axonal level. The visual dysfunction is not an eye issue – it is a global connection issue and disruption at various levels of the brain.
Despite the prevalence following TBI, vision problems are still frequently overlooked in the concussed patient. Always check near point convergence when evaluating concussion patients. This should be done at the first assessment. Failure to recognize this issue early on can lead to worsened and prolonged outcomes. This is a good predictor of outcomes including the development of post concussion syndrome.
Research suggests abnormal near point convergence contributes to many other post concussion symptoms as well as cognitive impairment. In this study, patients with convergence insufficiency performed worse on reaction time, processing speed, verbal memory as well as post concussion symptom scores as compared to the normal group. Early recognition is key to getting the patient the proper help they need with a neuro-optometrist. It is good to have a resource who deals with concussions and is trained in neuro-optometric rehabilitation. I would check the NORA database for providers near you so you have a good referral system ready.
The systems of the brain work so intricately and it’s important to recognize these problems early on. If you refer your patient for vestibular rehab and they have undiagnosed visual dysfunction, they will likely not progress or will initially progress and then plateau because it requires proper function of the visual system to be successful. Your patient may have auditory processing deficits which could also affect the visual system. This is why it’s important to look at all systems and have a comprehensive neurovisual assessment prior to starting other therapy modalities. The systems are so tightly connected so why are we constantly isolating them from each other and never putting them back together?
Lastly, medications will not solve the visual dysfunction. It seems we are always searching for the quick fix for our patients in the form of various pharmaceuticals which don’t address the underlying problem. Treating visual dysfunction requires time, repetition and rigorous exercises in vision rehab – something a pill will not touch. Remember, 20/20 isn’t enough and doesn’t reveal the whole story.
The McGurk Effect
As I mentioned earlier, if there is conflicting information from your senses, your brain will use vision to over-ride the other sense almost every time. The McGurk Effect is this perceptive illusion that occurs if there is a conflict between what you hear and what you see as someone moves their mouth and lips. I find it fascinating. It just shows you how important vision is in processing information. This video is really neat and shows you what this exact effect is.
- Oculomotor Treatment in Traumatic Brain Injury Rehabilitation: A Randomized Controlled Pilot Trial, 2019, DOI: 10.5014%2Fajot.2020.026880
- Vision Diagnoses Are Common After Concussion in Adolescents, 2015, DOI: 10.1177/0009922815594367
- Vision Therapy for Post-Concussion Vision Disorders, 2016, DOI: OPX.0000000000000935
- Vision Disturbances Following Traumatic Brain Injury, 2002, s11940-002-0027-z
- Near Point of Convergence After a Sport-Related Concussion: Measurement Reliability and Relationship to Neurocognitive Impairment and Symptoms, 2015, DOI: 10.1177/0363546515606430
- Organization of Visual Areas in Macaque and Human Cerebral Cortex, 2002
- Task-dependent representations of stimulus and choice in mouse parietal cortex, 2018, DOI: 10.1038/s41467-018-05012-y
- Study guide: brain injury rehabilitation, pain rehabilitation, 1998
- Dynamics of hippocampal neurogenesis in adult humans, 2013, DOI: 10.1016/j.cell.2013.05.002