Retinal nerve fiber layer (RNFL) defects are a defining feature of optic neuropathies and have been implicated in a few neurodegenerative disorders, including multiple sclerosis,1 Alzheimer disease,2 and Parkinson disease.3 Ashina et al4 conducted a prospective study observing 1406 children recruited from the Cophenhagen Child Cohort over 10 years. They showed that children of mothers with a history of smoking during pregnancy had a mean reduction in average circumpapillary RNFL thickness of 5.7 μm, adjusting for axial length, birth weight, and other covariates, compared with children without such history. Smoking during pregnancy has a detrimental effect on fetal development, including a higher risk of birth defects, low birth weight, and development of cognitive and behavioral problems.5 Although a difference of 5 to 6 μm in average circumpapillary RNFL thickness is unlikely to translate into a detectable difference in visual function in children aged 12 to 13 years, the risk of subsequent development of visual impairment should not be overlooked.