Correlation Between Accommodative Facility and Light-Evoked Pupil Responses in Individuals with History of Mild Traumatic Brain Injury.

introductionPrevious studies have shown those with a history of a traumatic brain injury (TBI) have altered pupillary light responses compared with those without a history of TBI. Those with a history of TBI are also more likely to have accommodative deficits. We investigated the relationship between light-evoked pupil dynamics and accommodative function in individuals who have previously experienced a TBI.

methodsA total of 17 participants with a history of mild TBI were recruited. Pupil metrics were measured using a commercial pupillometer and included baseline diameter, latency, constriction amplitude, average constriction velocity, peak constriction velocity and peak dilation velocity. Accommodative function was assessed using clinical measurements of facility and amplitude. Pupil metrics were compared among those with versus without accommodative dysfunction.

resultsOne-way ANCOVA testing (controlling for age and time since most recent TBI) comparing groups with and without accommodative dysfunction showed that those with accommodative dysfunction had significantly larger light-evoked pupil constriction amplitudes (

conclusionsThe results of this small-sample study suggest that accommodative function and light-evoked pupillary dynamics are correlated in individuals with a history of TBI. Those with accommodative dysfunction showed greater pupil constriction amplitudes and velocities and this relationship may reflect shared autonomic or oculomotor mechanisms.