In the spotlight

out most blue light wavelengths.” The problem, he explains, is the relatively modern condition of having so much blue light close to our eyes for such prolonged periods.

“The concern is that we’re exposing ourselves to too much. It’s due to this that many of the lens implants we now use contain blue light filters.”

SKIN

Just as UV light can affect our skin, so too can blue light. One 2010 study compared the effects of both types of light on skin, and while skin exposed to blue light showed no signs of cancer growth, it did show more dark patches, called hyperpigmentation.

Another lab-based study found that just one hour of screen exposure was enough to increase free radical production, which can contribute to hyperpigmentation and skin ageing.

As with eye health, more research is required to ascertain the extent of the effects.

SLEEP

You probably feel a twinge of guilt when checking your smartphone in bed – we all know devices should be kept out of the bedroom.

“There’s clear evidence blue light exposure can affect sleep patterns and circadian rhythms,” says Angunawela. While blue light in the day helps regulate our sleep/ wake cycle, studies show that exposure at night suppresses the secretion of melatonin – the hormone we need for sleep – more than any other kind of light.

Lack of sleep has been linked to increased risk of depression, as well as cardiovascular problems and Type-2 diabetes.

The bottom line

When it comes to us fully understanding the lasting effects of blue light, it is a waiting game.

“These issues are theoretical because we think long-term exposure will be problematic, but at the moment we don’t have enough long-term data,” says Angunawela.

“But the day-to-day eye fatigue and headaches – that’s already happening. It doesn’t do any harm to protect yourself, so it’s worth taking measures to do so.”

■■This feature is from the latest issue of Healthy magazine, available from hollandandbarrett.com and Holland & Barrett stores nationwide.