Impact of birth parameters on eye size in a population-based study of 6-year-old Australian children

PURPOSE: To study the effect of birth parameters, including birth weight, birth length, and birth head circumference on ocular dimensions in 6-year-old children. DESIGN: Cross-sectional study. METHODS: A stratified random cluster sample of 6-year-old Sydney school-students (n = 1765) were participants in this study. Children had ocular dimensions measured with non-contact methods (Zeiss IOLMaster, Zeiss, Meditec-AG, Jena, Germany). Information on birth weight, height, and head circumference was derived from a questionnaire. RESULTS: After adjusting for cluster, age, and gender, children with birth weight <2500 g had mean axial length 22.46 mm (95% confidence interval [CI], 22.20-22.72) and mean corneal radius 7.70 mm (CI 7.61-7.79). This compared with axial length 22.80 mm (CI 22.70-22.90) and mean corneal radius 7.85 mm (CI 7.81-7.89) for children with birth weight <4000 g. Axial length and corneal radius were also related to birth length and head circumference. Refraction, however, was unrelated to birth size. CONCLUSION: Birth parameters have a lasting effect on eye size but not on spherical equivalent refraction.