How a TBI Can Affect Your Vision
In cartoons, traumatic brain injury (TBI) is typically depicted in silly, exaggerated ways, often with stars swirling around the head of someone who’s too dazed to move. It’s probably not their intention, but animators have gotten a few details right about head trauma: It’s painful. It may knock you unconscious. And seeing stars or flashes of light immediately after you’re injured is a common way that TBI can affect vision.
TBI can be mild, moderate or severe, depending upon the injury you endure and the extent of damage to different brain structures. Vision changes often occur because of your brain’s significant role in the process of seeing. In fact, more than half of the brain’s pathways are involved in processing visual information, making vision especially vulnerable after head injury.
“When we look at an image, that’s largely our brain creating that image,” said Steven Rauchman, MD, a California-based ophthalmologist and TBI specialist. “The eyes let in light. It goes through the optic nerve, has a few deviations and ends up in the occipital lobe, the visual processing center at the back of the brain, then spreads throughout the brain. You can imagine how global injuries to the head can affect visual processing.”
From there, signals travel along specialized pathways that help us identify objects, track movement and orient ourselves in space, functions that can all be disrupted after TBI.
Vision-related TBI symptoms may be obvious or subtle, depending on the nature of the injury. “The visual aspect often takes the back seat to headache, nausea, vomiting or dizziness, if it’s an emergency physician seeing you initially,” said TBI researcher Allison Reiss, MD, associate professor of medicine at NYU Grossman Long Island School of Medicine. “The concern about vision tends to be later, when it doesn’t get better.”
The Link Between Trauma and Your Eyes
Your brain is surrounded by fluid that cushions it from mild bumps on the head. When the trauma force is too great, your brain collides with your skull, sometimes ricocheting back and forth. The jolt can make nerve cells misfire, which makes you “see” stars. These brief flashes, known as “phosphenes,” occur when mechanical force stimulates visual neurons directly—rather than through light entering the eyes.
Every year, 1.7 million people experience TBI. About 80% are mild, including concussions, which are associated with sports injuries. Causes of more complex TBI include car accidents, falls, gun violence and military service.
Head trauma can damage brain structures that are integral to vision, like the optic nerve or the oculomotor nerve, which controls muscles responsible for eye movement.
“If the nerves that control the eye muscles aren’t working correctly, it can cause double vision or trouble tracking, reading left to right,” Dr. Reiss said. “Your eyes have to coordinate for those things, plus depth perception.”
Any injury that’s forceful enough can cause brain bruising and inflammation, which can affect vision.
“Inflammation is your body’s attempt to repair damage, which brings swelling, but the head is a closed space,” Dr. Reiss said. “Swelling compresses things, which can bring more damage.”
Classifying Vision-Related Symptoms
There isn’t a universal experience for people with TBI and vision changes.
“There’s a lot of fluidity in the way symptoms are described,” Dr. Rauchman said. “A lot of symptoms of mild TBI are subjective, so there aren’t hard findings. And what some people call mild TBI, other people call moderate.” This can make diagnosis challenging, particularly when standard imaging appears normal but people continue to have problems with their vision.
People with concussions or mild TBI may experience:
- Blurry vision
- Double vision
- Briefly seeing stars
- Light sensitivity
- Difficulty reading or tracking
People with moderate or severe TBI may experience the above-mentioned symptoms, plus:
- Floaters and flashes, which might indicate damage to the retina
- Drooping eyelids, which may suggest damage to the muscles that control eye movement
- Unresponsive pupils or one dilated pupil, which may indicate significant bleeding in the brain—which is a medical emergency
- Poor depth perception
- Poor contrast sensitivity
- Losing part of the visual field, which is the total area you can see.
TBIs that eliminate portions of the visual field can cause unique challenges. “Kids looking at school materials could only be getting half the information,” said Bradley Sewick, PhD, a Michigan neuropsychologist. “Men come in and they’ll shave on the right side but not the left side of their face; it’s like a line right down the middle, but they’re not aware of it.”
This pattern may reflect visual field loss (hemianopia) or visual neglect, a condition in which the brain fails to attend to one side of space despite intact visual structures.
Seeking a Diagnosis
People with TBI and vision changes may visit the emergency department, a neurologist or an ophthalmologist. They may also see a neuropsychologist for a comprehensive cognitive assessment, to find out which brain regions have been affected. Neuropsychological testing can help differentiate between primary eye disorders and disruptions in visual attention, spatial processing and perceptual integration caused by brain injury.
“There’s a sensory and motor examination and visual perceptual tests,” Dr. Sewick said. “We make a determination, based upon the complaints of the patient and their performance on the objective measures in the visual perceptual motor testing, how they’re seeing things which may be distorted. Basic vision may be intact, but associated functions, such as spatial awareness and three-dimensional perceptual functionality, may be disturbed.”
When a head injury damages nerves in the brain, they release proteins into the bloodstream; their presence indicates TBI. In 2024, the U.S. Food and Drug Administration (FDA) approved a blood test that can identify neural proteins in the blood within 12 to 24 hours of head trauma, to diagnose TBI and determine the severity of the injury.
“If the test is negative, you don’t need a CT scan,” Dr. Rauchman said. “The problem is emergency departments don’t always administer this test; they go right to the CT scan.”
Current Treatments
Providers can’t predict the course of TBI-related vision changes. Some resolve quickly; others linger for months or years. But treatment can help attenuate symptoms.
Neurologists, ophthalmologists and neuropsychologists may recommend:
Vision rehabilitation therapy. Neuro-optometrists usually provide this intervention, a personalized treatment plan that includes exercises to help people with TBI improve their ability to focus, read more easily, move the eyes in unison, address depth perception and manage other symptoms.
Corrective lenses. Tinted or filtered lenses may ease light sensitivity and contrast sensitivity. Prism lenses may improve double vision and other issues caused by eye misalignment.
Lifestyle modifications. Small tweaks may help you manage vision problems: Use a larger font size on your phone. Close your blinds midday, to keep bright sunlight from your field of vision. Look up from your screen every 20 minutes to rest your eyes.
Future Treatments
Researchers are investigating new ways to treat vision changes caused by TBI. Possible therapies that could arise in the future include:
Virtual reality. Incorporating a combination of artificial intelligence and tech gear could add a new dimension to vision rehabilitation therapy. “It could be helpful, making therapy more entertaining and fun, less work,” Dr. Reiss said. “If it’s given to people at home, it could supplement in-person sessions and provide treatment options to people in rural areas.”
Medication. One day, providers may be able to prescribe a treatment to improve or prevent vision loss after TBI. However, nothing has been developed yet to send for FDA approval anytime soon. “It takes a long time and a huge investment to see if a drug helps,” Dr. Rauchman said. “They’ve tried different drugs, and they don’t help so far.”
Some researchers are working to identify drugs to protect retinal ganglion cells, which are specialized cells that send signals from the retina to the optic nerve. When they’re damaged during TBI, they can’t transmit crucial information between the brain and eye. (They also can’t repair themselves.)
Stem cell therapy. In the future, neuron stem cell therapy could be used to repair TBI-related vision damage. Stem cells transplanted to the injury site would function the way the original cells had, improving vision.
“We’re not very far along, but I think we’re on the right track,” Dr. Reiss said. “In the UK, they are about to start a human trial to restore hearing with stem cells and cochlear implants. I don’t dismiss it.”
While research continues to evolve, recognizing and addressing vision changes after TBI remains a critical part of protecting long-term brain health.
