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The lowdown on blue light

Laura Graham - 2018/11/15


Blue light is all around us. It exists naturally in our environment from the sun and, in moderation, can be beneficial to us. Blue light helps to regulate our circadian rhythm, telling our body when it is time to be awake and when it is time to go to sleep. During the day it helps to boost our attention levels, reaction times and our mood. At night, when the blue light from the sun fades away, our body knows it is time to release the hormone melatonin that helps us to fall asleep.

However, blue light also exists in an artificial form in the digital screens of our smartphones, tablets, computers and televisions. The addictive nature of this type of blue light means we are increasingly spending more and more time staring at a screen and recent studies have shown that over-exposure to this form of blue light may have detrimental effects on our health, such as digital eye-strain, sleep disorders and an increased risk of macular degeneration.

The symptoms of digital eye-strain, also known as Computer Vision Syndrome, include sore, dry or itchy eyes; loss of focus, blurry vision or fatigue; headaches or neck pain and general physical discomfort after spending time in front of a digital screen.


Blue light from screens at night disrupts the circadian rhythm that causes the natural release of melatonin that help us sleep. The blue light tricks our brain into believing it is still daytime making it more difficult to fall asleep and to sleep soundly. Poor sleep and circadian disruption have been linked to more serious health problems, including an increase in obesity and depression.

The blue light from our screens - also known as high energy visible blue light (HEV) - has a wavelength of between 380nm and 500nm and is one of the shortest, highest energy wavelengths. Research has shown that prolonged exposure to the blue violet light between 400nm and 440nm can contribute to retinal damage and macular degeneration – the leading cause of blindness in industrial nations. A study out of the University of Toledo recently discovered that prolonged exposure to blue light from digital devices damages vision and speeds up macular degeneration by triggering poisonous molecules to be generated in the eye's light-sensitive cells.


Reducing your exposure to blue light from digital devices is key to protecting your eye health. To help combat digital eye-strain you can follow the 20-20-20 rule i.e.: for every 20 minutes of screen time, look at something 20 feet (6 metres) away for 20 seconds to give your eyes a break. For those times when being in front of a screen is unavoidable, protect your eyes by wearing a pair of blue light blocking glasses.


To ensure you get a good, restful night’s sleep it is advised to avoid looking at a screen in the dark and switch off all your devices at least an hour or more before you go to bed. Time to make your way through your reading pile instead!