Screen Light Damages Brain Cells

Even if it never reaches your eyes

Woman looking at phone

Woman looking at phone

Prolonged exposure to blue light from phones, computers, and household fixtures could be affecting your longevity—even if it’s not shining in your eyes. The experimental study with fruit flies found blue wavelengths produced by light-emitting diodes damage cells in the brain as well as retinas.


Blue Death

Published in Aging and Mechanisms of Disease, the study involved a widely used organism, Drosophila melanogaster, the common fruit fly, an important model organism because of the cellular and developmental mechanisms it shares with other animals and humans. The study looked at how flies responded to daily 12-hour exposures to blue LED light—similar to the prevalent blue wavelength in devices like phones and tablets—and found that the light accelerated aging.

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Flies subjected to daily cycles of 12 hours in light and 12 hours in darkness had shorter lives compared to flies kept in total darkness or those kept in light with the blue wavelengths filtered out. The flies exposed to blue light showed damage to their retinal cells and brain neurons and had impaired locomotion—their ability to climb the walls of their enclosures, a common behavior, was diminished.

Some of the flies in the experiment were mutants that do not develop eyes, and even those eyeless flies displayed brain damage and locomotion impairments, suggesting flies didn't have to see the light to be harmed by it.

Expresses Stress Genes

“The fact that the light was accelerating aging in the flies was very surprising to us at first,” said Jaga Giebultowicz, a researcher in the Oregon State University College of Science, who studies biological clocks, and professor of integrative biology. “We’d measured expression of some genes in old flies, and found that stress-response, protective genes were expressed if flies were kept in light. We hypothesized that light was regulating those genes. Then we started asking, what is it in the light that is harmful to them, and we looked at the spectrum of light. It was very clear cut that although light without blue slightly shortened their lifespan, just blue light alone shortened their lifespan very dramatically.”

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Natural light, Giebultowicz notes, is crucial for the body’s circadian rhythm—the 24-hour cycle of physiological processes such as brain wave activity, hormone production and cell regeneration that are important factors in feeding and sleeping patterns.

“But there is evidence suggesting that increased exposure to artificial light is a risk factor for sleep and circadian disorders,” she said. “And with the prevalent use of LED lighting and device displays, humans are subjected to increasing amounts of light in the blue spectrum since commonly used LEDs emit a high fraction of blue light. But this technology, LED lighting, even in most developed countries, has not been used long enough to know its effects across the human lifespan.”

Flies Know Best

Giebultowicz says that the flies, if given a choice, avoid blue light. In the meantime, there are a few things people can do to help themselves that don’t involve sitting for hours in darkness, the researchers say. Eyeglasses with amber lenses will filter out the blue light and protect your retinas. And phones, laptops and other devices can be set to block blue emissions.

Referencei Trevor R. Nash, Eileen S. Chow, Alexander D. Law, Samuel D. Fu, Elzbieta Fuszara, Aleksandra Bilska, Piotr Bebas, Doris Kretzschmar & Jadwiga M. Giebultowicz. Daily blue-light exposure shortens lifespan and causes brain neurodegeneration in Drosophila. npj Aging and Mechanisms of Disease, 2019 DOI: 10.1038/s41514-019-0038-6
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