The Chemistry of How Blue Light Accelerates AMD
Thursday, August 16 2018 | 05 h 51 min | Vision Science
Chemists at the University of Toledo say they have found the mechanism that explains how blue light from digital devices can transform retinal molecules into harmful forms that lead to age-related macular degeneration.
“We are being exposed to blue light continuously, and the eye’s cornea and lens cannot block or reflect it,” Dr. Ajith Karunarathne, assistant professor in the UT Department of Chemistry and Biochemistry, said. “It’s no secret that blue light harms our vision by damaging the eye’s retina. Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop.”
According to the paper published in the July edition of Scientific Reports, the culprit is a photoreceptor chromophore called 11-cis retinal (11CR). Upon exposure to blue light 11CR transforms to all-trans retinal (ATR).
When exposed to blue light, 11CR and ATR bind to and disrupts the membrane bound phospholipid named PIP2, eventually leading to cell death. The presence of 11CR on its own did not cause any cell death, nor did exposure to blue light without the presence of 11CR/ATR, but blue light in combination with the chemicals did lead to cell death.
“It’s toxic. If you shine blue light on retinal, the retinal kills photoreceptor cells as the signaling molecule on the membrane dissolves,” Kasun Ratnayake, a PhD student researcher working in Karunarathne’s cellular photo chemistry group, said. “Photoreceptor cells do not regenerate in the eye. When they’re dead, they’re dead for good.”
The news isn’t all bad, however. Alpha tocopherol, a natural antioxidant, can prevent the cells from dying. But as people age they produce less of this antioxidant and our eyes lose this natural protection.
Karunarathne advises that people should wear UV and blue light filtering sunglasses while outdoors, and avoid looking at digital devices in the dark.
*pictured in the image above: Dr. Ajith Karunarathne
