Blue light from smart phones and digital devices could raise risk of blindness

By Dr. Ananya Mandal, MDAug 10 2018

According to researchers, the blue light from laptops, smart phones and other digital devices, could raise the risk of blindness. The study appears in the latest issue of the journal Scientific Reports.

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The new study comes from a team of researchers at the University of Toledo in the US who showed that a long term exposure to the blue light can raise the levels of certain poisonous molecules released within the light sensitive cells of the eyes leading to macular degeneration. Macular degeneration is a progressive and incurable condition that leads to blindness. It affects around 2.4 percent of the UK population and commonly affects those in their 50s and 60s and leads to vision loss. The loss of vision occurs due to deaths of the light sensitive cells of the retina.

The researchers explain that the blue light emitted from the digital devices has a shorter wavelength and more energy compared to other forms of light and this can cause damage to the eyes. Dr Ajith Karunarathne, an assistant professor in the university’s department of chemistry and biochemistry explained that this blue light is constantly affecting the cornea and the lens that cannot block or reflect it. With time it can damage the retina. He explained that their experiments have shown that this exposure can lead to slow macular degeneration and a new therapy is developed to block this effect.

Kasun Ratnayake, a PhD student at the University of Toledo and one of the authors of the study explained that if the blue light is shone on the retina, it kills the photoreceptor cells of the retina and the signalling molecules called retinal on the retinal membrane dissolves. The photoreceptors cannot function without the presence of the retinal molecules. Retinal is a form of vitamin A that changes shape when exposed to light rays.

Ratnayake said once these photoreceptor cells are dead, they are dead “for good” and cannot be regenerated. These retinal molecules were them introduced into other cell types of the body such as heart cells, nerve cells, cancer cells etc. These molecules killed the cells when exposed to blue light. Retinal without blue light or blue light without retinal could not kill the cells. Both were necessary to kill the cells. Karunarathne said their experiments showed that the toxicity from retinal that is triggered by blue light can kill any type of cell.

The team also found that alpha-tocopherol - a natural antioxidant from vitamin E can protect the cells from dying due to retinal and blue light exposure. However this protection is not seen in ageing populations. The researchers say that the damage is most likely to be seen in the ageing population. Dr Karunarathne says that blue light can be filtered with sunglasses which filter both UV rays as well as blue light. They advise against browsing on mobile phones, laptops or tablets in the dark.