Scientists have discovered how blue light from smartphones, laptops, and other digital devices damages vision and can speed up blindness, according to a study by the University of Toledo in the US.
The research reveals that prolonged exposure to blue light triggers the creation of toxic molecules in the eye's light-sensitive cells, leading to macular degeneration—an incurable condition affecting central vision. Blue light, with its shorter wavelength and higher energy, gradually harms the eyes.
Dr Ajith Karunarathne, assistant professor in the university's department of chemistry and biochemistry, said: 'We are being exposed to blue light continuously and the eye's cornea and lens cannot block or reflect it. 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.'
Macular degeneration affects around 2.4% of the adult population in the UK, particularly those in their 50s and 60s, and is caused by the death of photoreceptor cells in the retina. The researchers found that blue light causes retinal, a molecule needed for vision, to set off a chain reaction that produces toxic molecules in photoreceptor cells.
Kasun Ratnayake, a PhD student involved in the study, said: 'If you shine blue light on retinal, the retinal kills photoreceptor cells as the signalling molecule on the membrane dissolves. Photoreceptor cells do not regenerate in the eye. When they're dead, they're dead for good.' The study also found that a natural antioxidant called alpha-tocopherol stops cell death but offers no protection to older people or those with suppressed immune systems.
The researchers advise wearing sunglasses that filter UV and blue light outdoors and avoiding browsing on mobile phones or tablets in the dark. The study is published in the journal Scientific Reports.
