Nursery Lighting May Not Increase Risk of Nearsightedness
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.
Stone, who wrote in Nature the reply to the two new studies, is professor of ophthalmology at the University of Pennsylvania. He points out that the children he studied are younger and more severely affected. "There's a strong indication that there may be something about light-dark cycles and early-onset myopia," says Stone. Whatever that something may be, it is obscured when researchers look at older children, he says.
Earl L. Smith III, DO, PhD, reviewed the two new studies and the previous one. "Of all three studies, the Zadnik one has the largest subject sample and [is] one that is representative of the general population," he says. "The fact that they find no association [between night-light use and nearsightedness later in childhood] casts some doubt about whether the results of the original study apply to the general population." Smith is associate professor of optometry at the University of Houston College of Optometry.
Smith agrees with the new studies' authors: parents should be reassured that the warning about night-lights that received so much publicity last year needs to be moderated. "That warning?finds no support in these other two studies," he says.
But Stone holds firmly to the cautionary advice he and his colleagues published in their study last year. "Parents can't know if their child is going to be susceptible to something developing early or not, so I don't know why we would say anything different than what we recommended before," he says
- Contrary to previous findings, two new studies show there is no association between babies sleeping with a night-light and developing nearsightedness.
- The new research shows that parents who use night-lights in their children's rooms are more likely to be nearsighted, which would explain why the children are nearsighted as well -- because of genetic predisposition.
- Researchers from the original study stand by their findings and argue that the new studies looked at older children with less-severe nearsightedness, which could have obscured the results.