Is blue light really stopping you from sleeping?

Recent research suggests that blue light may not be the primary source of your tiredness and sleep deprivation


In the modern world, digital dominates. One study published in The Independent in 2018 found that UK office workers spend an average of 1,700 hours a year looking at a computer screen. And because of this, people are becoming increasingly concerned about the damage this might be causing.

In many instances, the blame is placed firmly on blue light. Electronic devices emit more blue light than any other colour, and this light is distinguishable by its short, high-energy wavelength which can damage the delicate tissue on the eye. It can also pass through the eye, directly into the retina. Many people who use computers for long hours complain of sleeplessness and fatigue.

However, is blue light the biggest concern for office workers? Or is there something bigger at play?

Our eyes are not defenceless — there is in-built protection in place

While we tend to think of blue light as something that exists purely in computer screens, the reality is that it’s present in nature as well. In fact, sunlight is made up mostly of blue light and, on a sunny afternoon, this light is almost 100,000 times brighter than your computer screen. Yet there has been little to no connection found between sunlight exposure and retinal disease.

Human eyes feature in-built protections. Our eyes feature macular pigments and the crystalline lens which has a natural blue-blocking ability. These structures are there to absorb blue light before it reaches your retina.

That’s not to say that blue light doesn’t have any impact

Blue light may not be actively damaging your retinas, but electronic devices can still have an effect. Blue light wavelength can disrupt your sleep–wake cycle due to your blue-light-sensitive cells (ipRGCs). These are responsible for telling your internal clock how light it is in your environment. So when you look at a bright screen, these cells tell your brain to be as alert as it would be during the day.

But these cells are also sensitive to the other coloured lights emitted from your screen, so cutting blue light alone won’t necessarily improve your sleep.

Another common complaint is that your eyes feel more tired after staring at a computer screen all day. But blue light isn’t solely to blame for this either, according to research. One 2019 study published in Optometry and Vision Science found that cutting blue light alone didn’t improve people’s comfort after a long computer session.

Reducing your tiredness requires more than blue light glasses

Blue light glasses are a popular option for people looking to reduce tiredness due to computer exposure, but they aren’t necessarily the most effective choice. Simply eradicating blue light isn’t enough to protect your eyes if you’re still practising the same potentially dangerous habits.

When we look at a computer, our blink rate drops from around 12 times a minute to six times a minute. This is part of the reason why our eyes feel dry and tired after staring at a screen.

One rule to bear in mind is the ’20-20-20’ rule, defined by the American Optometric Society as taking a 20-second break every 20 minutes to look at something 20 feet in the distance. This allows you to blink and relax your eyes. You can also use hydrating eye drops to restore the moisture in your eyes.

Your habits in the lead up to bedtime are especially important. In order to help your body relax during the evening, try to avoid bright screens in the hours before you turn in for the night. If you currently make a habit of scrolling on your phone before going to sleep, try to use this time in a different way. Reading a book or practising some simple meditation can help both your eyes and your mind relax, encouraging a healthier and more satisfying night’s sleep.

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