Cornea, Iris, Pupil, and Anterior Chamber
Central corneal thickness (CCT) decreases during the first 6–12 months of life (see the section Dimensions of the Eye). It then increases from approximately 553 μm at age 1 year to about 573 μm by age 12 years and stabilizes thereafter. CCT is similar in white and Hispanic children, whereas African American children tend to have thinner corneas.
Most changes in iris color occur over the first 6–12 months of life, as pigment accumulates in the iris stroma and melanocytes. Compared with the adult pupil, the infant pupil is relatively small. A pupil diameter less than 1.8 mm or greater than 5.4 mm is suggestive of an abnormality. The pupillary light reflex is normally present after 31 weeks’ gestational age. At birth, the iris insertion is near the level of the scleral spur, but during the first year of life, the lens and ciliary body migrate posteriorly, resulting in formation of the angle recess.
Pediatric Eye Disease Investigator Group; Bradfield YS, Melia BM, Repka MX, et al. Central corneal thickness in children. Arch Ophthalmol. 2011;129(9):1132–1138.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.