What is blue light and is it harming us?


by Shona Wilkinson

What is blue light and is it harming us?

In this article, we will be discussing blue light - what it is and the ongoing debate about whether it really causes potentially harmful effects. 

Although heavily debated and discussed, many people are still unaware of exactly what blue light is and whether it is bad for them or not.  

Read on to learn all about blue light and whether it is something we should be concerned about our exposure.

So what exactly is Blue light?

Ready for a quick science recap? Light is made up of electromagnetic particles that travel in waves. These waves emit energy and vary in length and strength. The shorter the wavelength; the higher the energy. Every wavelength is represented by a different colour, and together these wavelengths make up the electromagnetic spectrum.

The human eye is sensitive to only one part of this spectrum: visible light. Visible light is that part of the electromagnetic spectrum that is seen as colours: violet, indigo, blue, green, yellow, orange and red.

Blue light waves are among the shortest, highest-energy wavelengths in the visible light spectrum. Because they are shorter, these blue wavelengths flicker more easily than longer, weaker wavelengths. This kind of flickering creates a glare that can reduce visual contrast and affect sharpness and clarity. It is thought that this flickering and glaring may be one of the reasons for eye strain, headaches, physical and mental fatigue caused by many hours sitting in front of a computer screen or other electronic device.

It is, however, important to note that there is a natural blue light which can be very beneficial for us. When we are outside, light from the sun travels through the atmosphere. The blue light wavelengths collide with air molecules making blue light scatter everywhere. This is what makes the sky look blue! In fact, the largest amount of blue light we come into contact with comes from sunlight. Blue light is important to us in its natural form, as our body uses it to regulate our natural sleep and wake cycles - known as our circadian rhythm. We know that blue light also helps boost alertness, increases the feeling of well-being and can help heighten reaction times.
So we can see that natural blue light is important - not only does it provide basic illumination to our world, but blue light also helps to increase feelings of well-being. It is important to note that blue light - whether natural or not - may still cause eye damage.

Blue light from screens

As mentioned, blue light is a natural part of life and can be beneficial for our health and wellbeing. Problems are thought to occur due to the increased amount of blue light we are exposed to nowadays.  

Sources of blue light which aren't natural can include blue light from:

  • smartphones
  • laptops
  • tablets 
  • LEDs 
  • LED televisions 
  • fluorescent lights

Many of today’s electronic devices use LED technology. LED back-light technology enhances the screen brightness and clarity. Unfortunately, the LEDs emit very strong blue light waves.  

How many hours do you spend in front of a digital screen? Most of us spend the majority of our waking hours in front of a digital screen. In fact, studies suggest that 60% of people in the UK spend more than 6 hours a day in front of a digital device! This has led to concerns about our blue light exposure levels - especially for our children who are thought to absorb more blue light than adults as they are not yet fully developed. Children start being regularly exposed to blue light from electronic devices as young as two years old so their exposure is much greater by the time that they are adults compared to older generations.  

Can blue light cause eye damage?

Many people are concerned about the impact of blue light on our eye health. This is even more of a worry now for some people, due to the increased amount of time we spend in front of blue-light emitting screens and how close we are to these throughout the day.  

One of the principle concerns about blue light is the role it is thought to play in the development of age-related macular degeneration. People with a higher risk of age-related macular degeneration are advised to protect their eyes from excess blue light exposure. Halogen lights are often recommended as an alternative to other different types of lighting as they emit less blue light.

Another group that could be compromised by blue light is those who have had cataract surgery. This is because they may not have as much natural protection against blue light.

It is worth bearing in mind though that experts clash on whether blue light affects our eye health or not. Some researchers argue that blue light does not affect our eye health at all. They claim that compared to the risk to eye health from smoking, cardiovascular disease, high blood pressure and being overweight, exposure to blue light from electronics is negligible. They also state that current evidence does not support the use of blue-light-blocking lenses to protect the health of the retina. However, a paper published by The American Macular Degeneration Foundation reported that “the blue rays of the spectrum seem to accelerate age-related macular degeneration more than any other rays in the spectrum”.

Blue light and sleeping patterns

As discussed earlier, blue light helps our body regulate our natural sleep and wake cycles.  The most obvious example of this is the sun keeping our internal clock aligned with the environment.  

We also know that exposure to light suppresses the secretion of melatonin (our sleep hormone).  Even a very dim light can interfere with our circadian rhythm and melatonin secretion. Our circadian rhythm dictates when we sleep and wake up in accordance with the environment we are in. For example, even a night light could have an effect on melatonin secretion which can affect our sleeping patterns and any light at night could be enough to prevent some people from getting enough quality sleep.

So does blue light affect our sleep?

Whereas there are differing views and opinions about whether blue light affects our eye health, the evidence that it affects our sleep patterns is widely agreed upon.

While light of any kind can reduce the secretion of melatonin, blue light at night has a significantly greater impact of suppressing melatonin production. Much research has been conducted and demonstrates that exposure to blue light at night reduces our melatonin levels which will, therefore, affect our sleep patterns. Exposure to blue light at night tells our body that it is still daytime and not time to sleep. This can mean that you are more likely to stay up later and find it harder to fall asleep when you should - no matter how hard you try. Some people who can’t nod off will reach for their phone or tablet to pass the time, potentially making the problem even worse!

So how can I protect myself from blue light?

Remember that blue light does have some positive effects during the daytime as it can raise our alertness and our attention span and stop us feeling tired.  

Also, remember that the claims that blue light can affect our eye health are not totally proven yet and are still under debate.  

We know for sure that blue light exposure in the evening can be detrimental to our health and affect our sleep. Fortunately, there are some steps you can take to help reduce this exposure.  

Consider some of these lifestyle habits

  • Avoid screens for a few hours before bed. This is the best way to stop blue light from distorting your sleeping patterns - exposure to blue light in the evening only keeps people awake longer and makes sleep cycles more inconsistent. Try to avoid any screen time use at least two to three hours before bed - remember that this includes smartphones! 
  • Adjust the brightness of your screen - reduce or increase the brightness to match the ambient light levels so that your eyes don’t have to deal with the contrast. 
  • Reduce your screen time. The best advice for protecting yourself against artificial blue light is to just avoid it as much as you can - easier said than done!  You can set time limits for yourself when using phones and laptops though.
  • Replace your night light - Some people use night lights (if they have children, for example). Consider using dim red lights instead. Red light doesn’t shift circadian rhythms or suppress melatonin as much.  
  • Buy some computer glasses. These products are now widely available. Yellow tinted glasses will deflect more blue light from reaching the eyes, and can reduce the strain screens put your eyes under.
  • Invest in a screen filter. These handy filters which can be attached to laptop and phone screens filter out more of the blue light coming from your devices.
  • Get in the daylight! - Expose yourself to lots of natural light during the day. This may help you sleep better at night and keep you more alert during the day.  
  • Adopt the 20-20-20 rule - Every 20 minutes, take a 20-second break and focus your eyes on something at least 20 feet away. This simple rule will give your eyes a break and reduce eye strain and other computer-related eye stress and is often recommended by eye experts.
  • Eat oily fish - Omega-3 is known to benefit eye health in general, and has been shown to reduce the likelihood of you developing macular degeneration. Consuming more Omega-3 could be a useful way to protect against eye damage. Omega-3 can be found in oily fish such as sardines or anchovies. If you don’t eat oily fish in your diet consider taking a good quality Omega 3 supplement.

If you enjoyed reading this article, you might like Eye vitamins - Nutrition for your eyes.

Post author

Shona Wilkinson

Shona Wilkinson is a Registered Nutritionist who works as an independent consultant and health writer for national magazines and broadsheet newspapers as well as frequently being invited to speak on national radio. She advises nutritional brands and retailers on the health industry market, compliance and product development.