Blue Light Could Damage Cells In Your Eyes

During daylight, blue wavelengths can be beneficial, an important role in setting mood and attention. Besides sunlight, most of the light we are exposed to via digital devices is also blue. For example, the most common type of LED used in electronic devices is a white-light LED, which actually has a peak emission in the blue wavelength range up to 490 nm). Our eye’s cornea and lens are unable to block or reflect blue light.

Increasing evidence suggests that blue light is damaging. It can suppress the secretion of melatonin and wreak havoc on our circadian rhythms, and recent studies have shown that extended exposure to blue light can damage the retina.

Now, new research from the University of Toledo demonstrates that when blue light hits a molecule called retinal, it triggers a cascade of chemical reactions that could be toxic to cells in the retina of the eye.

However, researchers discovered that when HeLa cells -- which were used as a substitute for photoreceptor cells -- were exposed to blue light in the presence of retinal, this triggers a distortion in an important protein in the cell membrane. This was followed by an increase in both oxidative damage and calcium levels in the cells.

"It's toxic," says Kasun Ratnayake, a PhD student who was also involved in the study. He says the findings suggest that "if you shine blue light on retinal, the retinal kills photoreceptor cells as the signaling molecule on the membrane dissolves."

"Photoreceptor cells do not regenerate in the eye," he adds. "When they're dead, they're dead for good."

The researchers suggest that progressive destruction of light-detecting cells in the eyes due to prolonged exposure to blue light could therefore contribute to age-related macular degeneration, which is a leading cause of blindness.