The impact of prism lenses can be life-changing for patients!
Through the use of neuro-optometric rehabilitation, the vision system can be retrained and visual symptoms that may stem from a traumatic brain injury can be resolved or even eliminated. This can include the use of eye-training exercises to rewire the brain and enhance visual function.
Window to the brain
Nanasy: Several years ago, I faced many of the visual sequelae of a traumatic brain injury (TBI) firsthand following a car accident. While the symptoms I experienced affected me greatly at work and home, they were by no means rare. I was experiencing the same symptoms that many patients endure, except they do so without proper access to treatment, and that reality caused me to alter my professional goals.
I made it my mission to find better ways not only to treat my concussion patients but also to educate other providers about how we can help this patient population return to learning, working, and playing faster and with potentially better outcomes. The visual system is often the missing component of a TBI treatment plan.
Nelson: The eyes are an extension of the brain. Because we have 2 eyes, they must coordinate together to produce a single image for clear vision. When both eyes are not properly synchronized, the brain attempts to correct the disparity and keep the images from each eye coordinated.
Unfortunately, an important nerve that keeps your eyes working together can also cause pain because it innervates the meninges, the lining of the brain, which has a lot of pain receptors. If both eyes must exert extra effort to work in concert all day long, your head lets you know by giving you a headache. These issues with eye misalignment can occur or escalate after a TBI, which can happen due to a variety of causes.
Contact sports are a major factor associated with TBIs. Results of one study show that the incidence of chronic traumatic encephalopathy (CTE) from head injuries and concussions in former football players is about 21%, 91%, and 99% among those who played in high school, college, and the National Football League, respectively.1 But sports are not the only cause of TBI. Accidents, falls, and everyday activities—even walking—can lead to injuries serious enough to cause trauma.
Nanasy: Athletes may not even have acute head injury; CTE can occur as a result of repetitive subconcussive injuries. Even though many of my patients are athletes, I also see many non-sports-related injuries.
One of my patients is a basketball player who hit his head while getting out of an elevator. I’m seeing him because he works with a sports medicine team that knows how to recognize the signs of concussion and the visual symptoms that follow. People associate concussions with sports, but it is important to remember that, as Dr Nelson points out, it could happen to anyone at any time.
What to look for
Nelson: Most patients with TBI go to their primary care physician and later to physical medicine and rehabilitation doctors. Those with blurry or double vision consult an optometrist. Neurologists are consulted only if patients have seizures or continued headaches, but it is important to evaluate both eyes and the brain. If I treat the headaches but no one is treating the eye alignment problem, I am just working uphill. However, when the eye misalignment is corrected, suddenly, things come back together and improve. The same is true on the flip side.
We evaluate the patients who come to our office for several functions, such as swallowing, talking, walking, memory, thinking, numbness, and focal weakness. Eventually, we discuss how they feel overall, and that is typically when the issue of headaches comes up.
The extent of eye misalignment can vary, with some patients having double vision and others having just enough dysfunction to cause pain but no other visual symptoms. Unless we are specifically looking for these symptoms and have the right tools to do so, we might not refer them to the optometrist or ophthalmologist. But neurologists know that headaches that arise from eye misalignment have different, more subtle symptoms than those arising from migraines.
Migraines are a 1-sided throbbing headache with nausea and sensitivity to light and sound. But the headaches that come from eye alignment are more like a pulling sensation in your eyes, an abnormal sensation of a band over them, and/or a lot of achy type pain in the back of your head and down into your neck. These sensations can be exacerbated when patients are using near vision, such as when reading a book or working on a computer.
While a patient with a TBI may be understandably concerned about how their leg is functioning, it is important to carefully monitor these minor symptoms, such as headaches, because treating these can improve their quality of life.
Nanasy: I agree. Interdisciplinary care is critical in TBI. We give the best care when we can identify the need for an appropriate referral. It can be easy to forget that vision is involved in so much more than reading a static 20/20 line. Vision provides adequate flexibility in the accommodation and vergence system. Vision also coordinates with the proprioceptive and vestibular systems to maintain spatial awareness and balance, guides our processing of motion with peripheral integration, and even plays roles in visual memory. If the visual system is overly burdened and cannot adequately compensate, this can sometimes slow overall recovery.
For patients with TBI, the visual system can have a hard time compensating for minor imbalances or misalignments that were previously corrected automatically—for example, a phoria or a hyperopic refractive error. The additional strain on the system can make it feel as if you are holding a 10-lb weight all day long. Eventually, you tire out, and that can result in symptoms such as blurry vision, headaches, and visual integration or ocular-motor dysfunctions.
Patients may not have double vision, but they could be near the point of having it. When this happens, the trigeminal nerve is fighting through it, flaring all the headaches and the feeling of discomfort during tasks that require near vision. A small amount of help to control eye posture and take excess strain off their visual system can help patients get better that much faster.
A better way to see
Nanasy: Contoured prism lenses (Neurolens) provide the right amount of prism to take the extra weight off the brain. I had been prescribing small amounts of prism for several years before discovering the availability of a contoured prism. Patients with concussions would sometimes need multiple pairs of glasses: one for distance, sometimes with prism, and another one for near work, with a larger amount of prism. This patient population sometimes finds it difficult to switch between multiple pairs. Even more important, I love having consistent eyewear that offers them both clarity and comfort at all distances. Typically, I have patients who are good candidates for these glasses wear them for 2 weeks and then come back and see me. Their symptoms are almost always dramatically improved.
Nelson: I remember my first encounter with contoured prism lenses. It was 2011, and one of my patients walked in with what she called “headache glasses.” Knowing that patients with migraines will do a lot of things to make their headaches better, I contacted the optometrist who prescribed them and got the conversation going.
At that time, I had patients with chronic headaches who had been treated with all the tools in my armamentarium, but they were unresponsive. Collaborating with my optometrist colleague and keeping track of our patients together became a fruitful endeavor over the years. Today, I could not imagine practicing without contoured prism lenses. I need them.
One particular challenge in treating patients with TBIs is that they are often previously healthy and active people who are not used to being sick and therefore reluctant to consult a doctor. Another challenge is managing their expectations with the aspects of their condition that cannot be fixed because of the irreversible microscopic changes in the brain. But eye misalignment can be treated, leaving room to address other aspects of their TBI-related issues and quality of life. If a patient is in school, their work will be easier because their brain is not strained by their visual system. And if school and work are easier, all their other symptoms will be easier to tolerate. It will be easier to get more physical therapy, more exercise, and whatever they need.
The most impactful aspect of treating patients with TBIs, for me, is knowing that I can help change their lives. Some of my patients had issues with their visual system even before TBIs, and some have truly never known life without a headache or eyestrain, so treating eye misalignment makes everything easier. I hear it all the time: “Neurolenses changed my life.”
Life-changing lenses
Nanasy: The impact of prism lenses can be life-changing for patients who found their way to me after a traumatic time, having dropped out of college or being unable to work since their injury. I have had people who came down the hallway holding onto the wall leave my room standing upright after I give them just a diopter of prism in a trial frame.
More awareness is key to changing our standards of care. Often, patients and other providers do not realize the impact of visual systems on symptoms. Take, for instance, dizziness. Think of a stationary walkway with simulated spinning motion projected on the walls at an amusement park. The vestibular system says, “We aren’t moving,” but if the peripheral visual system thinks you are moving, you walk down the hall off-balance. If a vestibular problem is suspected, a huge step forward would be to at least consider a referral to an eye care provider. You can train saccades and do pencil push-ups all day, but if there is an underlying refractive or prismatic prescription left uncorrected, we are delaying the best possible recovery.
Nelson: My patients often tell me that I am the first one who has ever told them about issues resulting from eye misalignment, and that should not be the case, particularly when the therapy is not yet another drug added to the list of medications that patients take. There’s a way to treat it. So, there is no good excuse not to. We should be looking for it.
Carol Nelson, MD
Nelson is a neurologist in Sioux Falls, South Dakota, specializing in treating headaches. She has no financial disclosures related to this content.
Amanda Nanasy, OD
Nanasy, an optometrist specializing in sports medicine, is director of the Florida Institute of Sports Vision in Pembroke Pines, Florida. She has no financial disclosures related to this content.
References
1. McKee AC, Stein TD, Kiernan PT, Alvarez VE. The neuropathology of chronic traumatic encephalopathy. Brain Pathol. 2015;25(3):350-364. doi:10.1111/bpa.12248
