How to Recognize the Indicators of a Brain Injury

The brain is a 3 lb command center that relays neurotransmitters back and forth to every part of the body, while in the process consuming about 20% to 30% of the calories in our diet.¹ An injury to this complex organ can lead to brain fog, confusion, inflammation, oxidation, headaches, memory loss, double vision, light sensitivity, balance issues, difficulty falling asleep, and even trouble with speech, taste, or smell.

Because the skull has sharp ridges, whenever whiplash or other injury occurs to the brain, it sloshes around the cerebrospinal fluid that it floats in and can potentially get nicked by those ridges. This can damage the neurons and cause blood vessels to stretch or tear, leading to bruising, lack of oxygen, increased pressure, and/or a buildup of tau proteins.

WHAT IS A MILD TBI?

A mild traumatic brain injury (TBI) is the most common form (see the Table for criteria to determine the severity of a TBI.)² The American Association of Neurological Surgeons defines a concussion or mild TBI as “an injury to the brain that results in temporary loss of normal brain function,” including “alteration of mental status or level of consciousness, that results from mechanical force or trauma.”³ The CDC estimates that 6% to 15% of athletes experience a concussion during their playing season.⁴ However, it is important to note that concussions and head injuries don’t happen only from participating in sports—they can also occur at home, while driving in a car, or as a result of a fall.

NONVISUAL EFFECTS OF A MILD TBI

Hormonal Imbalance

A TBI can cause hormonal imbalances because one of the main glands that tends to be affected is the pituitary gland, which is located in the center of the brain. The pituitary gland is considered the master gland because it moderates the release of hormones to all other glands in the body. Any involvement of the pituitary gland can lead to irritability, low energy and/or focus to perform daily tasks, anxiety, depression, or even thoughts of suicide. One study showed that 30% of patients may become agitated after a brain injury due to excess cortisol levels in their blood.⁵

It is also worth noting that women can experience reproductive challenges, such as pauses in their monthly cycles and issues conceiving and maintaining a pregnancy, after a TBI.⁶ According to one study, 48% of female participants did not have their period for up to 60 months post-TBI, and 68% had abnormal menstrual cycles.⁷

Sleep Problems

According to the National Institutes of Health, 30% to 70% of patients who experience a TBI have sleep problems.⁸ When someone is not able to sleep for an uninterrupted 7 to 9 hours each night, their brain cannot function to the best of its ability because the human growth hormones are not properly released, which happens during deep stages of sleep and is crucial for brain healing. This is also why it is important to advise patients not to use any tablets or cell phone devices for 1 hour before bedtime, as the blue light emitted by digital devices can suppress melatonin levels, which disrupts circadian rhythms and makes it more difficult to fall asleep.⁹

DIAGNOSING AND TREATING PATIENTS WITH MILD TBIs

When a patient experiences a mild TBI, the standard advice from most health care professionals is to avoid physical or mental stimulation, get a good night’s rest, and hope for recovery in a week. In reality, data show that 10% to 80% of patients who have had a mild TBI continue to experience chronic symptoms.¹⁰ In fact, 50% of patients report symptoms for up to 3 months after a mild TBI, and 10% to 15% report symptoms up to 1 year later.¹¹

A patient may be able to tell you that they have experienced an impact to their head, but your evaluation can help determine whether a mild TBI has occurred. (See Functional Vision Questions to Ask Your Patients for a list of questions you may consider asking your patient as part of your evaluation and Suggested Tests for Oculomotor Parameters for further testing to consider.) As optometrists, our focus when a patient experiences a TBI is to make sure their eyes are aligned appropriately, their visual acuity is good (especially at near), their depth perception and contrast sensitivity are normal, their pupils are responding appropriately to light and are not dilated, their color discrimination is normal, and their eyes are in good health internally and externally (see Ocular Symptoms of a Traumatic Brain Injury for a more detailed list of urgent vs nonurgent ocular symptoms).

Ocular dysfunction, including eye movement defect, has been documented in up to 69% of patients with a concussion,¹² so it is important for us to be able to help patients who experience such symptoms. A visual problem that is often obvious to spot is photophobia. In my experience, patients with a mild TBI may enter the examination room wearing a baseball cap or sunglasses—or both—because of how bothersome the light is.

CLINICAL PEARLS

Because patients can be light sensitive, never use cycloplegia for a final refraction with this population. If you prescribe glasses or contact lenses, you may notice that the patient will accept more plus than before, as they are having accommodative issues. Prescribing 0.25 D of vertical prism can take care of the “I know something is off” complaints. You may also want to prescribe the full astigmatism (if they did not have some before), because what their eyes were able to handle before the TBI without any astigmatism is now too much to handle.

In addition, you can prescribe a second pair of reading glasses instead of bifocals for the accommodative dysfunction. Line bifocals may be used for those who were wearing progressive lenses before and those who use the computer frequently. One can use a flat top/round segment for the computer on top with the bifocal on the bottom. Sometimes, binasal occlusion can work for those experiencing diplopia.

Advise patients to avoid using medicines such as aspirin or nonsteroidal antiinflammatory drugs for any pain management, as these can cause a brain bleed. In addition, when a patient is put on oral medications, this can cause changes to their refractive error or ocular motility and produce color vision defects or halos.

Have these patients follow up at 1 month, 3 months, and 6 months to monitor symptoms, as they may last longer than the typical 1 month recovery period. Children and adolescents may experience prolonged symptoms, with one study reporting that 69% of children and adolescents with a concussion had at least one associated vision disorder.¹³ Another study found that 62.5% of those with persisting symptoms after a mild TBI had vestibulo-ocular dysfunction.¹⁴

REFER ACCORDINGLY

As primary care providers, we are on the frontlines of our patients’ health care. We must be aware of the signs of a TBI and be sure to refer accordingly, whether it be to a vision therapy specialist, physical therapist, psychologist, neuro-optometrist, or all the above.

It is essential to seek care from all relevant subspecialties so the patient will be in better shape physically and mentally for the future.