Nursery Lighting May Not Increase Risk of Nearsightedness
March 8, 2000 (Lake Tahoe, Calif.) -- Parents concerned about whether
night-lights are safe will be reassured by two studies published in
Nature this week. The new research contradicts a study that appeared in
the science journal last May implicating nighttime lighting in the bedroom of
children under age 2 as a risk factor for myopia or nearsightedness.
Both new studies found that myopia occurred just as often in infants who had
slept in the dark as it did if they had slept with a light on. Another
important finding was that there was a link between the use of light at night
and whether the parents had myopia.
This is significant, because children of myopic parents are more likely to
develop nearsightedness later in life. In other words, having a nearsighted
parent is the risk factor -- not whether a light in the children's bedroom is
on while they're sleeping.
"Parents should light their nursery in a way that they're comfortable
with and not worry about that decision," Karla Zadnik, OD, PhD, tells
WebMD. Zadnik was the lead researcher of the Ohio State study involving more
than 1,200 school children and their parents.
She found that about 18% of the children in her study group developed myopia
around the age of 10. After analyzing questionnaires completed by the parents,
Zadnik found no significant difference in myopia incidence between those
children who slept under three different lighting conditions as infants and
toddlers. However, Zadnik says, "Nearsighted parents say, 'Yes, we use
night-lights.' It may be because they don't see as well at night or they're
more insecure about how they see at night."
Researcher Jane Gwiazda, PhD, of the New England College of Optometry study,
also in Nature, tells WebMD that she also looked at the parent's vision
problems as well as asked them to answer questions about lighting in the
bedrooms of their children when they were infants. Her results were very
similar to those of Zadnik. "I feel very confident in saying there is no
association between nursery lighting and the development of myopia. Parents
should not worry about turning on a light at night. They should be comfortable
with whatever conditions they need to have in the child's bedroom."
In a reply to the two new studies, the authors of the original University of
Pennsylvania study, which found that lighting in early infancy does affect the
chances of developing myopia, point out that the children they evaluated did
have an unusually high incidence of myopia and, therefore, could be predisposed
to a more severe form of nearsightedness.
"There may be genetic differences in light sensitivity or in response to
light. ... Myopic parents turn on the lights, and their children may have a
sensitivity to it," author Richard A. Stone, tells WebMD.