The study found that a previously overlooked phase of the pupil response to light, known as the late light-off response (LOR), predicted improvements in consciousness seven days later in patients with acute brain injury. In contrast, standard pupil measurements already widely used in intensive care units (ICUs), including the Neurological Pupil Index (NPi) and pupillary light reflex (PLR) latency, did not predict later gains in consciousness.

Predicting whether a patient will recover consciousness after a severe brain injury remains one of the greatest challenges in intensive care. While automated pupillometry is already widely used in ICUs to assess brain function, existing measures mainly capture the pupil’s immediate reaction to light and offer limited insight into longer-term recovery.