Age and refractive status could influence the changing characteristics of choroidal thickness, according to study based in Shanghai. The researchers determined that thickness changes were different and varied by age in the participants who did or did not have a myopic shift.

The study analyzed the one-year change in choroidal thickness and its association with age and refraction in 756 children. It noted significantly greater reduction of choroidal thickness in children ages six to nine (-9±25μm) and for those with a myopic shift (-12±25μm). However, there was a larger increase in adolescents ages 10 to 13 without a myopic shift (9±23μm).

The researchers noticed a marked decrease in the choroidal thickness for newly developed myopes compared with persistent non-myopes and persistent myopes. The association of changes in choroidal thickness with changes in axial length was inconsistent once myopia occurred, especially for children with moderate to high myopia at baseline compared with those with mild myopia.

The study concluded that some compensatory mechanisms of choroidal thickening might exist to counteract the thinning effect of axial elongation in mild myopes but not in moderate to high myopes. Still, the rapid reduction of choroidal thickness among newly developed myopes associated with rapid axial elongation may serve an important role during the onset of myopia.