What is Blue Light?
When you were growing up, you might have heard the phrase, “if you watch too much TV, you’ll get square eyes”. Let’s face it, mum or dad would probably be shocked if they saw how much time you spent in front of a screen today.
Whether it’s watching Netflix, flicking through Linkedin or putting together a spreadsheet, all these activities have one thing in common: screen time.
Today, we’ve all pretty much come to accept that digital devices and screens are a part of everyday life. But you might be wondering, what does all this screen time mean for our eyes?
If you’ve ever Googled the subject, you probably came across the term ‘blue light’. Yes, screens emit blue light. But is it all bad?
In this article you’ll learn about blue light, what it means for you and tips to help you manage your exposure.
- What is blue light?
- Blue light exposure in modern life
- Why (some) blue light can be good
- Views on high-energy visible light
- Reducing your blue light exposure
What is blue light?
Blue light isn’t some special form of light that only comes from computers and LED lights - it’s actually all around us. In fact, sunlight is the main source of blue light. When you walk outside during the daytime, you’re exposed to blue light.
The blue light emitted by the sun is the reason we see the sky as blue. It's these light waves that get reflected and bounced around the most by the Earth’s atmosphere.
The light spectrum consists of UV, visible and infrared light. Visible light accounts for 50% of the light spectrum and, as the name suggests, it’s the only part of light that can be detected by the human eye (UV and Infrared Light are both invisible). These different colored light rays contain different amounts of energy.
Light is measured in wavelength, the units of which are nanometers (nm) and millimetres (mm). Visible light has a wavelength range in the region of 400 to 700nm, with high energy visible (HEV) light falling somewhere between 400 - 500nm. It’s called high energy visible light because the blue/violet band of the visible spectrum has a particularly high frequency.
In today’s world, there are an increasing amount of artificial sources of blue light and we interact with many of them on a daily basis. Think digital display screens on laptops, tablets and smartphones.
The fact we spend most of our waking lives using screens - and at such close proximity - has eye doctors and other medical professionals concerned about the effects.
Blue light exposure in modern life
One problem is that our eyes aren’t really designed to be good at blocking blue light. It’s why blue light has been linked to something called Computer Vision, a condition which encompasses a range of symptoms including headaches, blurred vision and eye strain amongst others.
What’s undeniable is that our habits have changed dramatically in just the last few years. Widescreen TVs, laptops and smartphone usage are all relatively new phenomenons. Now it’s normal to be using a screen for most of the day.
Today, manufacturers use brighter LED lights because they are more efficient. LED screens are also thinner, lighter, longer-lasting and have a better color resolution. But, it’s these brighter LED lights - along with modern day habits - that expose us to more blue light than ever before.
Why (some) blue light is good
Blue light isn’t all bad though. You might be surprised to hear that blue light is actually good for us in some ways.
Research shows that HEV light - in the right amounts - promotes alertness, boosts memory, improves cognitive function and elevates mood.
It’s these positive effects that are behind the reason why people use HEV to treat Seasonal Affective Disorder (SAD), a type of depression resulting from lack of daylight during winter months.
Mood changes can be common during the winter months, where sunlight is reduced. But for people with SAD it can result in more severe mood alterations. Studies have shown that blue light can help alleviate some of those symptoms.
Without us even realising, it helps regulate our sleep / wake cycle and biological clock if we’re exposed to it in the right doses, at the right time. Being exposed to blue light during the day actually determines our circadian rhythm.
Views on high-energy visible light
It’s fair to say there is growing concern about the effects that screen use is having on our lives.
Research on blue light is in its early stages so scientific proof is still limited to short-term findings. Much like other modern phenomenons such as vaping, there is not enough long-term data to back claims with evidence.
One thing all experts agree on is the role exposure to blue light plays in regulating our sleep patterns. The amount of artificial LED lighting we are exposed to has increased in terms of time, intensity and proximity.
Some organizations are starting to become more vocal about the harmful effects posed by HEV light exposure.
Chief Medical Officer for England, Dame Sally Davies has called for more research: “I note “there is increasing public and policy concern about the impact of computer/smartphone screen use, and ‘blue light’, upon human health. Research is on-going and this is an important area of investigation, particularly given children’s use of social media via smartphones, increasing their exposure to potential risk”.
More seriously, the Barcelona Institute of Global Health has linked blue light exposure to increased risk of breast and prostate cancer.
For some perspective, it’s worth taking into account that smoking was once considered healthy and heroin used to be used in cough syrup. Sometimes it takes time for the research to catch up to the reality.
Reducing your blue light exposure
Fortunately, if you want to reduce your exposure to blue light, there are a few easy ways you can moderate the amount of artificial HEV light you come into contact with:
- Use an app: Software like f.lux can reduce the amount of blue light that is emitted by your monitor. It works by adjusting the color temperature on your digital display. Best of all, it’s free. There are a few things to consider though. Since f.lux works by changing the color temperature of your screen - which can be relaxing for your eyes - viewing your display in a yellowish hue can be disruptive in some situations. If you’re doing any work or activity that involves seeing the colors on the screen for what they actually are (graphic design, for example), then fitting f.lux around your routine can be a challenge.
- Computer glasses: Blue light blocking glasses are another great way to reduce blue light exposure. At LUMES we offer blue light blocking glasses that come with transparent lenses. The reason our glasses come with transparent lenses is for two main reasons. Firstly, color perception won’t be affected but a considerable % of blue light will still be filtered. Secondly, transparent lenses blend with your style. Most people don’t want to walk around in glasses with yellow lenses and we don’t expect you to either. LUMES lenses are also anti-glare too, which will keep your eyes feeling more relaxed.
- Step away from the screen: Take a break from your screen every now and again. This will reduce the amount of blue light you’re exposed to during the day and it will also give you the added benefit of some exercise too. A good way to remember to take breaks is the 20-20-20 rule: it recommends that every 20 minutes, you look at something 20 feet away for at least 20 seconds. Use Google Chrome? Try out the LUMES 20-20-20 timer extension.
- Power down at night: The evening is a great time to reduce your blue light exposure. If your work involves screen use then it can be challenging to limit HEV light exposure during the day. However, when you're relaxing at home, why not keep the hours before bed blue light free.