Over the past five years, dialogue surrounding the implications of concussions has been at the center of media headlines, optometric research, and movie scripts.
So why is there so much emphasis on these conversations especially surround concussion and eye problems? First, concussions are prevalent. While we mostly think of concussions in athletes, they are common across all ages, professions, and places. In fact, the most common cause of concussions are falls.
There are approximately 3.6 million reported concussions per year, but there is also a high number of injuries that we suspect go unreported. To put this into perspective, if we combine the yearly incidence of multiple sclerosis, HIV, and breast cancer, there are about 1.6 million reported cases per year compared to the 3.6 million reported concussions. It is estimated that about 30% of people will have a concussion by the time they are 21 years old.
Not only are these head injuries common, but they also can be serious.
While the underlying mechanism of concussion continues to be researched, we know that the trauma of acceleration and deceleration on the brain can lead to stretching of the neurons and diffuse axonal injury, which can potentially affect a variety of brain processes. Secondary damage may occur due to ischemia and a cytotoxic cascade, so we get an imbalance of neurotransmitters in the brain and, ultimately, cell death.
The increase in popularity of the topic has also given rise to misconceptions about concussions. Commonly, it is thought that a concussion is only serious if a person “blacks out,” however, only about 10% of brain injuries result in a loss of consciousness. The seriousness of the concussion is not determined by the severity of the hit, but rather by the person’s prior medical history. Historically, treatment protocol emphasized limiting activity and avoiding symptom triggers.
With new research and treatment plans, however, we now know that the best therapies are active, and too much rest can actually interfere with healing.
Additionally, there is no blood work or imaging that can confirm a concussion, so not only can they be challenging to treat, but they can also be difficult to diagnose.
Due to the presumed diffuse neuronal damage sustained during a head injury, several areas of the brain can be impacted. As such, there are six main types of concussion that can be identified based on symptoms, though patients can have more than one type simultaneously.
- Mood and anxiety
- Migraine headaches
- Ocular issues
Over 50% of the brain is directly or indirectly involved in visual processes, so it is not surprising that an estimated 70-82% of concussion patients present with visual symptoms.
These issues can range from dry eyes and photophobia to binocular dysfunctions such as convergence insufficiency and accommodative dysfunction. Therefore, optometrists are a crucial member of the treatment team!
Primary care optometrists have a few things they can do to help the patient’s healing process.
The first step is to cover, refractive error. It is common to see a refractive shift after a concussion, but it is important to prescribe with caution especially if the patient is experiencing increased myopia. Most of the time this “myopic shift” is just an over-acting accommodative system, so prescribing this extra minus is going to worsen symptoms.
Additionally, with presbyopes there are two core suggestions to avoid: no progressive lenses and no monovision contact lenses. Both of these correction types can be difficult for the brain to adapt to after a head injury and can actually make symptoms worse. Finally, when addressing dry eyes and photosensitivity patients should refrain from wearing their sunglasses inside as this will actually increase the sensitivity of the system once it is healed.
Many of the visual manifestations of brain injury are considered “hidden” issues, and they are not always apparent on a quick visual acuity or refraction. Therefore, it is up to optometrists to help diagnose the escalating number of patients who struggle to return to their normal daily activities after traumatic brain injury. As these sufferers continue to (rightfully) gain attention across medical journals and media outlets, optometrists must stay informed, rise to the need, and join this exciting conversation.