Prenatal Smoking Linked to Decreased RNFL Thickness

Researchers advise eye doctors to encourage pregnant women to quit smoking by counseling them on the potential risks to their child's visual health, including the increased likelihood of diminished RNFL thickness, which could predispose their children to long-term ocular issues and visual impairments. Photo: Getty Images. Previous studies established links between retinal nerve fiber layer (RNFL) deficits and factors such as lower birth weight and tobacco smoke exposure; however, the full implications of smoking during pregnancy on retinal health remain inadequately understood. To gain some clarity, a study published recently in Acta Ophthalmologica evaluated three independent birth cohorts to assess how maternal smoking patterns impact the RNFL in children. The findings highlighted a consistent negative association between maternal smoking and RNFL thickness across all cohorts.The following three cohorts—two Danish and one Australian—were included in the meta-analysis: Copenhagen Prospective Studies on Asthma in Childhood 2000 (COPSAC2000): Involved 411 children, with 269 analyzed; 35 had prenatal smoking exposure.Copenhagen Child Cohort 2000 (CCC2000): Included 1,229 participants aged 11-12 years, with 221 exposed to maternal smoking.Raine Study Generation 2: Followed 1,260 individuals over 20 years, with 269 experiencing prenatal smoking exposure.All participants underwent comprehensive eye examinations using optical coherence tomography (OCT) to measure RNFL thickness.The findings reflected a clear association between prenatal smoking and diminished RNFL thickness, suggesting that children exposed to smoking in utero may face a heightened risk of developing visual impairments and optic nerve diseases later in life. In the COPSAC2000 cohort, children whose mothers smoked during pregnancy presented with a mean RNFL thickness reduction of 8.1% compared to their non-exposed counterparts, with significant deficits particularly noted in the nasal (-10.0%) and inferior (-10.4%) sectors. Similar trends were observed in the CCC2000 and Raine Study cohorts, which reported maximum deficits of -8.4% and -8.9%, respectively, in the inferonasal sector among those exposed to maternal smoking.When the data were combined for a meta-analysis across all cohorts, the researchers noted an average deficit in RNFL thickness, revealing specific reductions in the superior (-7.1μm), nasal (-4.0μm) and temporal (-4.4μm) sectors. “Not only was maternal smoking throughout pregnancy associated with a general deficit in peripapillary RNFL thickness, but it also related to deficits in each sector (superior, inferior, nasal and temporal),” the researchers explained in their paper. They added that these results align with their findings from a prior study, “suggesting that the optic nerve is most vulnerable during prenatal life.”The link between prenatal smoking exposure and diminished RNFL thickness can be understood through existing research on smoking's detrimental effects on retinal health. In the discussion portion of their paper, the authors cited studies showing that smokers experience subnormal retinal blood flow, potentially impairing nutrient and oxygen delivery to retinal tissues. Additionally, subnormal retinal vessel density associated with nicotine exposure may exacerbate these vascular impairments. It’s also known that tobacco smoke contains oxidizing molecules that lead to oxidative stress and cellular damage in retinal tissues.“To protect offspring from smoking-related retinal nerve fiber damage, women considering pregnancy or already pregnant must be strongly counseled to quit smoking and offered support as well as nicotine replacement therapy if necessary,” the study authors concluded. “Knowing that susceptibility to optic nerve disease such as glaucoma is related to one's nerve fibre reserve, which shrinks with age and cannot be replenished, may be valuable messaging for encouraging women to quit for their child's eye health.”Click here for the journal source. Zhu L, Munch IC, Lee S-Y, et al. Prenatal and childhood exposure to smoking and retinal nerve fibre layer thickness: a meta-analysis of three independent birth cohorts. Acta Ophthalmologica. March 8, 2026. [Epub ahead of print].  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.