Prenatal tobacco exposure and visual disorders in children

Maternal smoking during pregnancy is associated with adverse fetal and perinatal outcomes and may also affect visual system development in offspring. Increasing evidence suggests that prenatal tobacco exposure may also be associated with abnormalities of visual system development in children. However, the extent to which these associations reflect direct effects of tobacco exposure versus indirect pathways mediated by adverse perinatal outcomes remains uncertain. This narrative review summarizes the available evidence regarding the association between prenatal tobacco exposure and visual abnormalities in children, with particular emphasis on retinopathy of prematurity, strabismus, refractive errors, retinal nerve fiber layer abnormalities, and optic nerve hypoplasia. The most consistent evidence concerns retinopathy of prematurity and strabismus, although interpretation is complicated by prematurity, fetal growth restriction, neonatal morbidity, and residual confounding. Evidence regarding refractive errors and amblyopia is less consistent, while data on structural visual pathway abnormalities remain limited. Proposed mechanisms include vascular dysfunction, altered cholinergic signaling, oxidative stress, inflammation, and impaired neurodevelopment. Conclusion : Prenatal tobacco exposure may be associated with selected functional and structural abnormalities of the developing visual system. The strength of evidence varies substantially by outcome, and available data do not establish that prenatal tobacco exposure independently causes all reported visual disorders. Future studies should use objective exposure biomarkers, longitudinal designs and analytical approaches that distinguish direct effects from pathways mediated by prematurity and fetal growth restriction. Smoking cessation during pregnancy remains an important preventive intervention. What is Known: • Maternal smoking during pregnancy is associated with prematurity, low birth weight, and adverse fetal neurodevelopment. • Prenatal tobacco exposure has been associated with selected pediatric visual disorders, particularly retinopathy of prematurity and strabismus, although the strength, consistency, and independence of these associations vary across studies and may be influenced by confounding and mediation through prematurity, fetal growth restriction, and neonatal morbidity. What is New: • Emerging evidence suggests that tobacco exposure may also be associated with structural abnormalities of the visual pathway, including retinal nerve fiber layer thinning and optic nerve abnormalities. • Recent genetic and mechanistic studies provide additional support for biological plausibility but do not eliminate the possibility of residual confounding or shared genetic and environmental influences. • The interpretation of associations with visual outcomes should distinguish potential direct effects of tobacco constituents from indirect pathways mediated by prematurity, fetal growth restriction, and neonatal morbidity.