Li J, Yuan N, Chu WK, et al. - Researchers conducted this cross-sectional study to evaluate the impacts of exposure to secondhand smoke (SHS) on peripapillary retinal nerve fiber layer (p-RNFL) thickness in children. School children aged 6 to 8 years were consecutively selected from the population-based Hong Kong Children Eye Study (HKCES). Among the HKCES cohort (n = 3,103), nearly a third of children were exposed to SHS (35.4%, n = 1,097). Compared with those without exposure to SHS, children exposed to SHS had similar age, gender, BMI, birth weight, and axial length, but had lower family income and lower parental education level. Findings suggested an association of exposure to SHS in children with a thinner p-RNFL. In the future, a thinner p-RNFL can raise the risk of irreversible visual impairment. The findings provide evidence to recommend that children avoid SHS exposure.