Damage from blue light exposure increases with age

According to a new study led by the Oregon State University (OSU), the damaging effects of daily, lifelong exposure to the blue light emanating from phones, computers, or household appliances worsen with age. Although the investigation was focused on the impact of blue light on the common fruit fly (Drosophila melanogaster), the findings could potentially be extended to humans too, since this model organism shares many cellular and developmental mechanisms with us.

The scientists examined the survival rates of flies kept in darkness and then moved at progressively older ages (two, 20, 40, and 60 days) to an environment of constant blue light. By focusing on the impact of the light on flies’ mitochondria – which act as cells’ power plants, generating adenosine triphosphate (ATP), a source of chemical energy – the researchers discovered that prolonged exposure significantly affected flies’ longevity, regardless of whether they were able to visually perceive this light or not.

“The novel aspect of this new study is showing that chronic exposure to blue light can impair energy-producing pathways even in cells that are not specialized in sensing light,” said study lead author Jadwiga Giebultowicz, an expert in circadian clocks at OSU. 

“We determined that specific reactions in mitochondria were dramatically reduced by blue light, while other reactions were decreased by age independent of blue light. You can think of it as blue light exposure adding insult to injury in aging flies.” 

The flies exposed to blue light showed damage to their retinal cells and neurons and had impaired locomotion. Surprisingly, even mutant flies that didn’t develop eyes displayed such impairments, suggesting that flies don’t need to actually see the light in order to be harmed by it. The damage caused by exposure to blue light was strongly age-dependent. 

“The same length of exposure to the same intensity of light decreases lifespan and increases neurodegeneration more significantly in old flies than in young ones,” said Giebultowicz.

While it is not yet clear whether these findings apply to humans too, there is a significant possibility that similar processes might be at play during humans’ exposure to blue light. 

“There are increasing concerns that extended exposure to artificial light, especially blue-enriched LED light, may be detrimental to human health. While the full effects of blue light exposure across the lifespan are not yet known in humans, accelerated aging observed in this short-lived model organism should alert us to the potential of cellular damage by this stressor,” Giebultowicz concluded. 

The study is published in the journal NPJ Aging. 

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By Andrei Ionescu, Earth.com Staff Writer