The Impact of Age on Quantitative Infrared Pupillometry in Healthy Children 1-18 Years

Abstract

OBJECTIVE: The goal of this study was to establish normative values under ambient light conditions for measurements of quantitative pupillometry in children. METHODS: This was a cross-sectional analysis of pupillometry values obtained in children. Quantitative pupillomentry measurements were obtained from children between 1 and 18 years of age being seen for either a well child check or other outpatient appointment. Participants were excluded if they were in pain, on any medication known to affect pupil size (i.e. opioids, stimulants), or had any chronic neurologic conditions. RESULTS: A total of 242 children were enrolled in this study, with pupillometry readings obtained from a total of 171 children after exclusions. Maximum and minimum pupil size increased slightly with age; however, the correlation was weak (r = 0.14 and r = 0.16). Similarly weak correlations with age also were observed for maximum constriction velocity (r = -0.12) and dilation velocity (r = 0.05). No differences were observed between males and females for any of the pupil parameters. Maximum (5.35 mm vs. 4.91 mm) and minimum (3.71 mm vs. 3.36 mm) pupil sizes were significantly larger in Whites than African-American participants. CONCLUSIONS: Pupil size and reactivity show little correlation with age, appear to be relatively independent of ontogeny, and therefore would not be expected to significantly impact further exploration in utilizing pupillometry as a biomarker across the pediatric age range. Differences in race should be taken into consideration when pupillometry is used in mixed populations.