Normal pupil size and anisocoria in newborn infants.

The incidence of anisocoria in the newborn period is not well described. Additionally, the normal range of infant pupil size is not well defined. Eight-eight healthy newborns were evaluated. Pupil size and color were obtained from photographs. The mean (+/- SD) pupil size was 3.8 +/- 0.8 mm. There was no statistical difference between right and left eyes. A statistically significant difference in pupil size was found between blue and brown eyes. The incidence of anisocoria was found to be 21%. No difference was greater than 1.0 mm. The incidence of anisocoria was no different on the basis of eye color.