Pupil size increases through childhood

This large retrospective study found that pupil size increases through childhood, beginning to level off around age 10, and that nearly 20 percent of children have anisocoria of >0.4 mm.

The authors reviewed the charts of 1,306 consecutive patients <1 to 17 years of age who had received a comprehensive ophthalmological examination that included photoscreening with a plusoptiX device at a single, community-based practice.

Of these, 1,057 (80.9%) had 0 to 0.4 mm of anisocoria, 219 (16.8%) had 0.5 to 0.9 mm, 20 (1.5%) had 1.0 to 1.4 mm, and 10 (0.8%) had ≥1.5 mm. The magnitude of anisocoria appeared to increase with age.

Pupil size also increased with age. The average pupil size was 5.0 mm in children <1 year of age and 6.1 mm in children ≥16 years of age. There was no significant relationship between pupil size and sex.

The authors note that this study was limited by the comparatively small number of subjects aged 12 to 17 years.