Mariam Malik ‘22
Blue light from electronic devices, such as smartphones and laptops, is of shorter wavelength on the light spectrum, thereby giving off higher amounts of energy. The harmful effects of absorbing too many light rays, such as UV and micro, have been researched and known. However, a recent study at Oregon State University on Drosophila melanogaster, the common fruit fly, shows the damaging effects that blue-light rays can have on the brain and retinas, and that it even expedites the rate at which one ages.
Lead researcher Jaga Giebultowicz utilized a group of fruit flies, separated by sex and maintained on diets of yeast, molasses, and cornmeal, to determine the effect that blue-light exposure has on their lifespans, brain, and retinal health. Researchers exposed fly colonies to twelve hours of blue-light daily, alternating with twelve hours of darkness. The control group of flies, however, experienced no light whatsoever, as researchers instead kept them in constant darkness through their adult stages, and handled them under red light. To determine retinal degeneration, the team of researchers determined photoreceptor cell survival on cross sections of the eye by counting the number of rhabdomeres, or the visual units of a photoreceptor. To observe effects on the brain, researchers took the average area of all vacuoles seen on parts of the brain. To measure a fly’s lifespan, one-hundred females or one-hundred males were held in vials in groups of twenty-five. Researchers also tested climbing ability for use as an aging biomarker. Flies were also assessed for locomotor movement and monitored for five cycles of twenty-four hours each.
After analyzing results from all genotypes and light conditions, Giebultowicz and his team found that the experimental group of flies had shorter lifespans compared to both the control flies and the flies that were exposed to light but had blue-light filtered out. Blue-light exposure to flies revealed damage in retinal cells and brain neurons and hindered locomotion, making them unable to walk on walls. Additionally, some flies in the experiment were born as mutants with no eyes, yet blue-light still caused damage, showing that blue-light does not have to reach the eyeball for it to cause damage to the brain. In terms of aging, certain genes, specifically ones that respond to stress and are protective, were turned on in old flies that were kept in light. Evaluating the spectrum and different light conditions revealed that conditions of light with blue-light filtered out slightly shortened lifespans, but exposure to only blue-light greatly diminished the flies’ lifespans.
Although humans have discovered ways to increase longevity throughout time, our exposure to blue-light is still increasing with harmful consequences. The researchers add that it may be possible to create a healthier spectrum of light for overall well-being. Until then, researchers advise to set up our technologies to block blue-light emissions and to wear eyeglasses with amber lenses to ultimately protect our retinas.
- T.R. Nash, et al., Daily blue-light exposure shortens lifespan and causes brain neurodegeneration in Drosophila. Npj Aging and Mechanisms of Disease 5, (2019). doi:10.1038/s41514-019-0038-6
- Image retrieved from: https://pxhere.com/en/photo/1176