Pupil size and anisocoria in children measured by the plusoptiX photoscreener

Purpose To investigate pupil size and the incidence of anisocoria in children at a single community-based practice using the plusoptiX A04 and A09 photoscreeners (plusoptiX GmbH, Nuremberg, Germany). Methods The medical records of consecutive patients <1 to 17 years of age who had received a comprehensive ophthalmological examination that included photoscreening with the plusoptiX were retrospectively reviewed. Data collected included sizes of both pupils, age, sex, laterality, and magnitude of anisocoria. Results A total of 1,306 patient records were reviewed. Of these, 1,057 (80.9%) had 0-0.4 mm of anisocoria; 219 (16.8%), 0.5-0.9 mm; 20 (1.5%), 1.0-1.4 mm; and 10 (0.8%), ≥1.5 mm. Magnitude of anisocoria appears to increase with age (P = 0.0073). Pupil size and age were positively correlated (P < 0.0001), that is, older children had larger pupils. Average pupil size of children <1 year of age was 5.0 mm; of children ≥16 years of age, 6.1 mm. When sorted into age buckets of 0-3, 4-7, 8-11, 12-15, and 16-17, this increase becomes apparent. There is no significant relationship between pupil size and sex (P = 0.14). Conclusions Our study of 1,306 children shows that pupil size increases through childhood, and that 19.1% of children in a clinical population have anisocoria >0.4 mm.