The research, which was published in JAMA Ophthalmology, involved detailed ophthalmic examinations of children aged between six and eight.
The parents or legal guardians of the children were then asked about their smoking status.
Parents were asked if they or another member of the family smoked at home. They were also asked how long they smoked for and how many cigarettes they had each day.
Of the 1400 children, 941 had no exposure to secondhand smoking and 459 had some exposure to secondhand smoking.
Analysis of the results revealed that smoking exposure was linked to a thinner choroid by 8.3 micrometres (μm) in the central subfield, 7.2μm in the inner inferior, 6.4μm in the outer inferior, 6.4μm in the inner temporal, and 7.3μm in the outer temporal.
An increased number of family members who smoked and greater tally of daily cigarettes were both associated with a higher level of choroidal thinning in the study participants.
“These results support evidence regarding the potential hazards of secondhand smoking to children,” the authors emphasised.
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