Blue light in the spotlight

With screen use at an all-time high, should we be worried about its lasting effect of on our health, asks Hattie Parish

- Hattie Parish

During the first lockdown, many Brits spent as much as 40 per cent of their day watching TV and online streaming services. And for many people, work and social lives also played out exclusively on devices, so that’s a lot of screen time.

No wonder, then, that our interest in blue light – also known as high-energy visible or HEV light – has soared in the past year, with online searches up 58 per cent.

The data shows we’re unsure of the negative effects on our health and the steps we can take to protect ourselves.

What is blue light?

Most of us know sunlight contains visible light rays as well as invisible ultraviolet (UV) ones. But visible light comprises a range of different coloured rays, which each carry different amounts of energy.

“Blue light is one of the visible parts of the electromagnetic spectrum so it’s one of the colours we can see,” says Romesh Angunawela, consultant eye surgeon at Moorfields Eye Hospital. “It has shorter wavelengths than any other visible colour. It’s close to UV, which is even shorter, but not visible to us.”

As well as being present in daylight, blue light is emitted by fluorescent lamps and LED devices such as computers, smartphones, TVs and tablets.

“Electronic devices tend to emit more light in that spectrum than natural light does,” says Angunawela.

This, plus the time we spend on our devices and their proximity to our faces, has health professionals concerned about the potential consequences.