Purpose: To determine scotopic pupil diameter in a normal pediatric population.
Methods: Scotopic pupil size was measured in 166 eyes of 83 children with a mean age of 6.01+/-4.11 years (range 0.51-14.26 years) using the light and hand-held Colvard infrared pupillometer. Measurements were performed under dim illumination after 2 min of dark adaptation. The Colvard infrared pupillometer utilizes light amplification technology to determine scotopic pupil size.
Result: The mean scotopic pupil diameter was 6.06+/-0.95 mm (range 4.0-8.5 mm) in the right eyes (OD) and 6.11+/-1.02 mm (range 4.0-8.5 mm) in the left eyes (OS), and 6.09+/-0.98 mm (range 4.0-8.5 mm) for both eyes (OU). An increase in mean scotopic pupil size with age was detected, with a peak of 7.28+/-0.42 mm at the age of 10-11 years. The correlation coefficient for age and scotopic pupil diameter was 0.51 OU (OD 0.52, OS 0.51), and the correlation coefficient for objective refraction (spherical equivalent) and scotopic pupil diameter was 0.05 OU (OD 0.01, OS 0.08).
Conclusions: The scotopic pupil diameter in a pediatric population increases with age until the age of 11 years and then decreases again.