Eye Test May Predict Return of Consciousness After Severe Brain Injury

Early, reliable prediction of recovery is central to guiding goals of care, sedation strategies, and rehabilitation planning in the intensive care unit. Current bedside tools focus on immediate pupillary reactions and offer limited insight into longer-term outcomes. To help address this challenge, researchers have identified a brief eye-based measure that may forecast return of consciousness days in advance.

The late light-off response (LOR) was evaluated by teams from Copenhagen University Hospital Rigshospitalet and the Danish Technical University using a handheld automated pupillometer. LOR describes a later phase of the pupil’s response that occurs after the light stimulus has ended. The work was presented at the European Academy of Neurology Congress 2026 and centers on extracting prognostic information that routine pupillary indices may miss.

The study included 250 intensive care patients with impaired consciousness after traumatic and nontraumatic brain injury, along with 30 age- and sex-matched healthy controls. Patients underwent daily automated pupillometry and neurological assessments for up to 20 days. LOR latency independently predicted improvement in consciousness seven days later after adjustment for baseline neurological status, time since injury, sedation, and injury type. The signal did not correlate with same-day responsiveness, indicating it may reveal recovery potential not evident at the bedside. 

The association appeared strongest in patients not receiving sedatives and in those with anoxic-ischemic brain injury, a condition in which the brain is deprived of oxygen and blood flow. Investigators emphasized that these subgroup findings were exploratory and require confirmation in larger, multicenter cohorts. Because handheld automated pupillometers are already common in intensive care units, the approach could be comparatively straightforward to adopt if validated, and the assessment takes only 13 seconds per eye.

“Current tests of pupillary function tell us how the brain is responding in the moment, but the late light-off response may provide clues about the brain's potential for recovery. This could help us better understand which patients may improve in the days ahead,” said Dr. Poul Laigaard, lead author, Copenhagen University Hospital Rigshospitalet.

“We believe this is an important observation that deserves further investigation. Larger, multicenter studies are needed to determine whether this approach could be used routinely for bedside monitoring and prognosis,” said Professor Daniel Kondziella, senior author of the study.

Related Links
Danish Technical University
Copenhagen University Hospital Rigshospitalet