Can choroidal thickness distinctions be traced back to perinatal characteristics? A new study says so. In a study of nine‐year‐olds, researchers found the subfoveal choroid was thicker in girls, as well as in all children with a greater body height, birth weight and gestational size.

The study included a total of 1,018 children (52.5% girls, 47.5% boys) with a mean age of 9.9±0.3. Mean cycloplegic spherical equivalent refraction was 0.80±1.1D in boys and 0.81±1.4D in girls. Participants underwent cycloplegic refractometry, ocular biometry, height, weight and subfoveal choroidal thickness measurements using swept‐source OCT. The team obtained birth parameters using medical records and performed statistical analyses using multivariate regression models adjusted for age, ethnicity and sex.

The study authors discovered that the subfoveal choroid was 17μm thicker in girls (298±60.6μm) than in boys (281±55.0μm), with a difference of 9.1μm after adjusting for age, ethnicity and axial length. They note that subfoveal choroidal thickness decreased as ocular axial length (-16.2μm/mm) and myopic refraction increased (-10.0μm/D). On the other hand, it increased as body height (1.3μm/cm), birth weight (13.0μm/kg) and gestational size increased (8.2μm/kg).

The researchers also found that smoking up until the time that pregnancy became known was associated with a thinner choroid. There was no detectable effect of alcohol consumption, adding that the distributions of axial length, refraction and choroidal thickness were narrower than in older populations.

Biyik KZ, Tideman JWL, Polling JR, et al. Subfoveal choroidal thickness at age 9 years in relation to clinical and perinatal characteristics in the population-based Generation R Study. Acta Ophthalmologica. August 6, 2019. [Epub ahead of print].