A new CU Anschutz study finds that specialized eye movement tests can reveal subtle brain changes in veterans more than 10 years after a concussion. The work could reshape how clinicians track recovery and tailor long-term care for mild traumatic brain injury.
Subtle changes in how the eyes move may reveal that the brain is still working differently more than a decade after a concussion, according to new research from the University of Colorado Anschutz Medical Campus.
In a study of military veterans, researchers at the CU Anschutz Marcus Institute for Brain Health found that specialized eye movement tests picked up lingering differences in attention, processing speed and impulse control long after typical concussion symptoms had faded.
The findings, published in the Journal of Neuro-Ophthalmology, suggest that even so-called mild traumatic brain injuries can leave a quiet but measurable imprint on brain function.
Mild traumatic brain injuries, often called concussions, are common in the military and in civilian life. They can result from blast exposures, sports collisions, car crashes and falls. Most people recover within weeks or months, but a significant minority report ongoing issues with concentration, memory, fatigue or mood.
The new study points to the eyes as a powerful window into those hard-to-see effects.
“The eyes are directly connected to brain networks that control attention, information processing and decision-making,” lead investigator Jeffrey Hebert, an associate professor at the CU Anschutz School of Medicine and director of research for the CU Anschutz Marcus Institute for Brain Health, said in a news release.
The research team evaluated 78 military veterans: 38 with a history of mild traumatic brain injury and 40 without. All participants completed a series of eye movement tasks along with cognitive tests designed to measure executive functions such as attention, processing speed and self-control.
The eye tasks were not simple vision checks. Some required participants to quickly look away from a visual target instead of toward it, which tests the ability to suppress an automatic response and follow instructions. Others involved rapid visual recognition and saying aloud what was seen, which taps both visual and verbal processing.
Because these tasks rely on complex networks spread across multiple brain regions, they can be sensitive to subtle disruptions that might not show up on routine exams.
“By studying how someone’s eyes move during a cognitively demanding task, we can detect subtle brain changes that might not appear on a standard bedside exam or brain scan,” Hebert added.
Compared with veterans who had never had a concussion, those with a history of mild traumatic brain injury were more likely to show slower and less accurate eye movements. They also tended to perform worse on some attention-based tasks. Importantly, some of these differences were still detectable more than 10 years after the original injury.
Hebert noted that repeated mild injuries, even when each one seems minor, may add up over time. The brain can often adapt, but the adaptations may come with trade-offs that only show up under pressure, such as in visually complex or fast-paced environments.
“Even when someone feels recovered, their brain may still be working differently behind the scenes, especially during visually demanding tasks and in busy environments,” added Hebert. “Objective eye movement testing gives us a measurable way to assess these often covert problems.”
That objectivity matters in concussion care. Many standard imaging tools, including MRI, often look normal after a mild brain injury, even in people who continue to struggle.
“Standard imaging tools such as MRI scans often appear normal after mild brain injury, making persistent symptoms difficult to verify objectively,” Hebert added.
The new findings suggest that cognitively challenging eye movement assessments could give clinicians another way to validate patients’ concerns, better understand ongoing cognitive issues and tailor rehabilitation strategies, according to Hebert. For example, if testing shows specific weaknesses in impulse control or processing speed, therapy can target those skills more precisely.
While the study focused on military veterans, the implications extend far beyond the armed forces. Athletes, first responders and civilians who have experienced concussions could also benefit from more sensitive tools to track brain function over time.
The researchers emphasize that most people do recover well from mild traumatic brain injury. The goal is not to alarm patients, but to identify the smaller group who may need extra monitoring and support.
By catching lingering effects early, clinicians may be able to adjust work or school demands, recommend targeted therapies or simply follow patients more closely to ensure they continue to improve rather than plateau or worsen.
Future studies at CU Anschutz will explore whether adding these eye movement tests to routine concussion evaluations can help doctors more accurately diagnose mild traumatic brain injury, track recovery and guide treatment decisions over the long term.
As awareness of concussion risks grows in sports, the military and everyday life, tools that can reveal how the brain is really functioning — not just how it looks on a scan — may play a key role in protecting long-term brain health.
Source: University of Colorado Anschutz