Characteristics of the iris in 100 neonates.

To better characterize the appearance of the iris at birth, we studied certain iris features of 100 normal newborns with slit lamp biomicroscopy. We noted the iris color, crypt-structure, and vascularity of the collarette and periphery of the iris. These features were considered in light of the child's birthweight, postnatal days of age, sex, and race. Iris vascularity correlated significantly with postnatal age at examination, and stage of crypt development was more advanced in males, and more evident in the blue and gray irides. Males also had a more advanced stage of iris development. In addition to our previous finding that iris vessels of cocaine intoxicated neonates were more tortuous and dilated than a control group, this study suggests that such vessels may also be more commonly found in sickly infants.