A new study has revealed how the blue light from smartphones, laptops and digital devices damages vision and can cause blindness.

Scientists say prolonged exposure to the light encourages cells in the eye to generate poisonous molecules that cause macular degeneration - an incurable condition that results in significant vision loss.

The study, undertaken at the University of Toledo, describes how blue light, which has a shorter wavelength and more energy compared to other colours, can gradually cause damage to the eyes.

Digital damage

Dr Ajith Karunarathne, an 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

Macular degeneration is caused by the death of light-sensitive cells in the retina.

Kasun Ratnayake, a PhD student at the University of Toledo who was 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.”

Dr Karunarathne said users of digital devices can protect their eyes in two ways - wear sunglasses that filter out blue light and avoid using mobile phones or tablets in the dark.