Biyik KZ, Tideman JWL, Polling JR, et al. - Among 9-year-old children, researchers explored the connection between clinical and perinatal features and subfoveal choroidal thickness. Data were included from the population-based Generation R cohort, whose participants had cycloplegic refractometry, ocular biometry, height, weight and subfoveal choroidal thickness measurements using a swept-source optical coherence tomography instrument. Using medical records, birth parameters were obtained. Using multivariate regression models adjusted for age, ethnicity and sex, statistical analyses were performed. The study sample consisted of 1,018 children with a mean age of 9.9 ± 0.3 years and a mean cycloplegic spherical equivalent refraction of 0.80 ± 1.1 D in boys and 0.81 ± 1.4 in girls. In girls, the subfoveal choroid was thicker than in boys, and a thicker subfoveal choroid was associated with higher body height, higher birth weight and a larger size for gestational age. Smoking was correlated with a thinner choroid until the moment that pregnancy became known. Alcohol consumption did not have a detectable effect. In longitudinal studies, the implications of these findings for myopia development need to be further evaluated.