Pupillometry measures of autonomic nervous system regulation with advancing age in a healthy pediatric cohort

Purpose: To determine if variables of the pupillary light response mature with age and sex in a healthy pediatric cohort and the utility of pupillometry in assessment among pediatric participants. Methods: After 1 min in a dark room to establish baseline, pupillometry was performed on 323 healthy, pediatric participants (646 eyes; 2–21 years; 175 females). Variables included initial pupil diameter, pupil diameter after light stimulus, percent pupillary constriction, latency to onset of constriction, average constriction velocity, maximum constriction velocity, average dilation velocity, and time from light stimulus to 75% of the initial pupil diameter. Data analyses employed ANOVAs and non-linear regressions. Results: Analyses of age group differences revealed that participants 12–21 years old had a larger initial pupil diameter and pupil diameter after light stimulus, with males aged 12–18 years demonstrating a larger pupil diameter than all younger participants (ps < 0.05). Participants 12–18 years old had a slower maximum constriction velocity than participants 6–11 years old, with no sex differences (ps < 0.05). Furthermore, males aged 12–18 years old had a smaller percent constriction than males 6–11 years old (ps < 0.05). Regressions revealed that percent constriction and dilation velocity seemed to mature linearly, initial pupil diameter and ending pupil diameter matured quadratically, and the constriction velocity terms matured cubically. Conclusions: Results revealed maturation of the pupillary light response by age and sex in healthy pediatric participants. Given the value of the pupillary light response as a biomarker, the results provide normative benchmarks for comparison in health and disease, including opiate-exposed and concussion patients.