In brief: We’ve known for a long time that the blue light emitted from electronic devices such as smartphones isn’t good for us, harming our eyes and affecting users’ ability to get to sleep. But the true extent of the damage is quite shocking.
Research by the University of Toledo has found that long periods of exposure to blue light triggers the production of poisonous molecules in the eye’s photoreceptor cells.
Damage to these light-sensitive cells can lead to macular degeneration, an incurable condition that results in blurred or no vision in the center of the visual field, or “blind spots.” Age-related macular degeneration (AMD) is the leading cause of blindness in the US, affecting over 11 million Americans.
The problem is exacerbated when using a blue light-emitting device in the dark. We’ve seen plenty of incidents of people going temporarily blind after staring at their smartphones while in a darkened bedroom.
The researchers focused on a form of Vitamin A called retinal, which photoreceptor cells use to covert light into signals that get sent to the brain.
“If you shine blue light on retinal, the retinal kills photoreceptor cells as the signaling molecule on the membrane dissolves,” said researcher Kasun Ratnayake. “Photoreceptor cells do not regenerate in the eye. When they’re dead, they’re dead for good.”
Retinal that absorbs the blue light converts oxygen cells into a toxic molecule that kills the photoreceptor cells. The researchers injected the retinal molecules into other cell types, including cancer cells and heart cells, and found they died off when exposed to blue light. But the blue light by itself had no effect on the cells, neither did retinal that hadn’t been exposed to blue light.
“The retinal-generated toxicity by blue light is universal. It can kill any cell type,” said lead author and assistant professor in the UT department of chemistry and biochemistry, Dr. Ajith Karunarathne.
The researchers did find a molecule called alpha-tocopherol that can stop the cells from dying, but the natural antioxidant fails to protect older users who are more susceptible to macular degeneration.
If you want to protect your eyes, Dr. Karunarathne suggests wearing sunglasses/glasses that filter out harmful UV and blue light, using blue light filters on phones and monitors, and avoid using electronic devices with screens in the dark.