Answer: Shenanigans

            There were (and still are) some scary posts about how a nightlight will cause (important word here to note) poor eyesight. A 1999 study (Quinn et al., 2003) found a relationship between the use of nightlights and later vision issues. A big “however” here is that this study has been mostly refuted by more recent research that has routinely found no relationship between nightlight use and vision problems (e.g., Damian et al., 2012; Guggenheim et al., 2003). The earlier study mostly failed to account for at least one major factor that is a known cause of later vision issues—parental vision problems. Parents who have vision issues are more likely to use a nightlight to see and are also more likely to pass those vision issues to their children.

            The current consensus is that there is no link between nightlight use and impacts on later vision (Zadnik, 2001). If parents are concerned about their child's vision development, it appears that spending time outside in daylight can be protective (Gillies et al., 2022). Exposure to daylight, as well as the exercise the eye receives from looking at the horizon, appears to have a protective effect on the later development of vision problems.

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