Researchers used an activity tracking device to objectively discover children are exposed to more light in the summer compared with school months, particularly the fall session. Sixty kids participated in the study, and their cycloplegic autorefraction and axial length were measured at baseline and one year later. 

While axial growth rate decreased with light exposure, it did not reach significance after adjusting for baseline axial length, age, sex, activity and parental myopia.

However, 33 parents also wore the tracking device during the same two weeks their child wore it, allowing the researchers to note the kids mimicked their parents’ behaviors. For example, parent and child time outdoors and sleep duration were both significantly correlated.

“Associations between parent and child behaviors suggest a potential mechanism for how myopia is transmitted from parents to children through patterns of environmental exposure, in addition to genetic factors,” the study says.

Ostrin L, Sajjadi A, Benoit J. Objectively measured light exposure during school and summer in children. Optom Vis Sci. 2018;95(4):332-42.