Blinded by the Light

As a child, you may have been told, “Don’t spend so long in front of the TV… your eyes will go square!” – but what if the truth was more serious? A team at the University of Toledo, OH, USA, has found that blue light emitted by digital devices – and the sun – could permanently affect eyesight.

The research, led by Ajith Karunarathne, found that, when exposed to photoexcitation by blue light, the photoreceptor chromophore 11-cis retinal (11CR) and its photoproduct, all-trans-retinal (ATR), could irreversibly distort PIP2 (a plasma membrane-bound phospholipid), disrupting downstream signaling and inducing oxidative damage, ultimately leading to cell death (Figure 1)(1).

“When retinal absorbs blue light, it becomes excited with photon energy. It releases that energy to oxygen, which generates highly oxidative chemical molecules, oxidizing important signaling lipids and proteins in cells, leading to cytotoxicity,” explains Karunarathne. And the results were the same when the team introduced retinal molecules to other non-receptor cell types. “Many reports have indicated the likelihood of blue light being cytotoxic,” says Karunarathne. “Our work clearly shows cell death occurs when retinal molecules are present, even without photoreceptors.”

Given that photodegradation of this kind is linked with diseases such as AMD, can anything be done to avoid blue-light induced vision loss? “Avoiding prolonged exposure can help,” says Karunarathne, who also recommends sunglasses that not only block out UV light but also blue light, as well as advising against looking at cell phones or tablets in the dark.

Karunarathne has a worthy end goal in mind: “By learning more about the mechanisms of blindness, and searching for a method to intercept the toxic reactions caused by the combination of retinal and blue light, we hope to find a way to protect the vision of children growing up in a high-tech world (2).”