A quick eye test performed at a patient’s bedside may soon help doctors predict whether someone with a severe brain injury is likely to regain consciousness.
The findings come from new research presented at the European Academy of Neurology (EAN) Congress 2026. Although the study is still at an early stage, it offers hope for improving the care of patients who are unconscious after a serious brain injury.
Severe brain injuries can happen after road accidents, falls, strokes, lack of oxygen after cardiac arrest, or other medical emergencies. Some patients wake up quickly, while others remain unconscious for days or weeks. Doctors and families often face heartbreaking uncertainty because it is very difficult to know who will recover and who will not.
Today, intensive care units already use small handheld devices to shine a light into a patient’s eyes. The device measures how the pupils react. These tests help doctors monitor brain function, but they mainly show what is happening at that moment. They do not reliably predict how a patient may improve in the coming days.
Researchers from Copenhagen University Hospital Rigshospitalet and the Technical University of Denmark wondered whether another part of the eye’s reaction had been overlooked. Instead of focusing only on how the pupil becomes smaller when exposed to light, they studied what happens after the light is turned off. This delayed change is called the late light-off response.
The team studied 250 patients with disorders of consciousness caused by both traumatic and non-traumatic brain injuries. They also included 30 healthy volunteers for comparison. Patients received daily eye measurements and neurological examinations for up to 20 days while staying in intensive care.
The researchers found that the timing of the late light-off response could predict whether patients would show better levels of consciousness seven days later.
Importantly, the result remained significant even after taking into account injury severity, sedation, time since injury and the type of brain injury. Traditional measurements, including the Neurological Pupil Index and the standard pupillary light reflex, did not predict later improvement.
The researchers also noticed that the new measurement seemed especially useful in patients who were not receiving sedative drugs and in people whose brains had been injured because of a lack of oxygen and blood flow. However, they stressed that these findings came from smaller groups and still need confirmation.
Another advantage is speed. The handheld device already exists in many intensive care units, and each eye takes only about 13 seconds to test. If future studies confirm these findings, hospitals may not need expensive new equipment.
The study has important strengths. It included a relatively large number of patients and followed them repeatedly over many days instead of relying on only one examination. The researchers also adjusted for several factors that might affect recovery.
However, there are limitations. The research was presented at a scientific conference rather than as a completed peer-reviewed journal article. It shows that the eye test is linked with later recovery, but it does not prove that the pupil response causes recovery or that it will accurately predict outcomes for every patient.
Larger studies involving hospitals in different countries are still needed before doctors can rely on this test in everyday practice.
Overall, this research offers an encouraging new direction. A simple 13-second eye test may eventually help doctors better estimate recovery potential and give families more accurate information during one of the most difficult times of their lives.
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Source: Copenhagen University Hospital Rigshospitalet.
