BACKGROUND: Pupillary evaluation is a crucial element of physical exams. Noting size, reactivity, and consensual response is critical in assessing for optic nerve dysfunction. We aim to establish normative data for scotopic pupillary size and function in the pediatric population in a clinical setting. METHODS: Pupillometry was obtained prospectively for consecutive, normal patients < 18 years old being evaluated by Lurie Children's Ophthalmology. Quantitative data included maximum (MAX) and minimum (MIN) diameters, constriction percentage (CON), latency (LAT), average (ACV) and maximum (MCV) constriction velocities, average dilation velocity (ADV), and 75% recovery time (T75). Iris color was noted as light, intermediate, or dark. RESULTS: 196 eyes of 101 participants (42.6% male, ages 1-17 years, average age 10.3 years) were analyzed. Mean MAX was 6.6 mm (5.1-8.1 mm 95% CI); MIN was 4.7 mm (3.1-6.1 mm 95% CI); CON was 30% (17-42 95% CI); LAT was 230 milliseconds (160-300 ms 95% CI); ACV was 3.70 mm/sec (2.21-5.18 mm/sec 95% CI); and ADV was 0.88 mm/sec (0.38-1.38 mm/sec 95% CI). Age had a positive correlation with MAX, MIN, and CON. 84.2 and 95.8% of participants showed resting pupil asymmetry of ≤0.5 mm and ≤ 1.0 mm, respectively. CONCLUSIONS: Quantitative pupillometry can be a useful tool for screening pediatric patients. We sought to establish normative data in this group. We found males to have significantly greater MCV and CON than females (p < 0.05). Also, age had a positive correlation with MAX, MIN, and CON.