Pupil responses controlled by light-sensitive eye cells in people with traumatic brain injury

Pupil constriction amplitude was significantly less in traumatic brain injury (TBI) patients compared to control subjects for both red and blue stimuli.

• For red and blue stimuli, constriction amplitude and the post-illumination pupil response were not significantly different between TBI patients and control subjects.
• Pupil constriction amplitude attenuated over time for red stimuli and potentiated over time for blue stimuli across all subjects.
• Constriction and redilation velocities were similar between TBI patients and control subjects.
• Age-related differences in baseline pupil size may contribute to the observed decrease in pupil constriction amplitude in TBI patients.
• Responses to blue stimulation suggest no selective damage to intrinsically photosensitive retinal ganglion cells.

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