What is blue light?

We hear more and more these days about “blue light” and how we are exposed to it from all sorts of sources in our modern day lives. 

Blue light is everywhere.  It is the main type of light from the sun, and as such we are exposed to it most days of our lives.  It is also the light emitted by screens and fluorescent lighting, a “manufactured light” that most of us are also exposed to daily. 

Blue light falls in the middle of the colour spectrum.  Ultraviolet light is at the high end of the spectrum with short wavelengths and very high energy.  At the other end of the colour spectrum are green, yellow and red lights which have progressively longer wavelengths and lower energy.  In the middle is blue light with light of around 380-500 nanometres.  (A nanometre is a measure of distance, used in this case to measure wavelength).    

Studies have shown that light is most dangerous to the eyes between 415-455 nanometres, which of course falls right into the blue area on the spectrum.

Light spectrum and our eyes
Ultraviolet light appears below blue light (shorter wave lengths and higher energy)

Where does blue light come from?

As we mentioned above, natural blue light comes from the sun.  There are some health benefits from exposure to natural blue light such as helping memory, elevating your mood and helping with your circadian rhythm.  Nature regulates our exposure to natural blue light through a simple process of only exposing us to certain amounts of it per day.

Manufactured blue light comes from man-made devices such as LED lighting, fluorescent lighting and screens including TVs, phones, computers, tablets, electronic readers and computer games.  Too much exposure to these sources of blue light can lead to issues with your eyes such as digital eye strain or macular degeneration.

Exposure to blue light

What can it do to our eyes?

There are a couple of main eye conditions we talk about when we discuss exposure to blue light.  One of them is digital eye strain and the other is macular degeneration.

Digital eye strain comes about when looking at digital devices for long periods of time. Blue light, being on that particular frequency identified as short wavelength, high energy, can pass through the eye to the retina, causing damage.  It’s not just the blue light though – studies show that we blink much less when looking at a screen, drying out our eyes and not allowing them an opportunity to relax.

Blue light may also play a part in macular degeneration, although there are many other risk factors we look at such as family history, smoking, diet and obesity.  Studies in laboratories have looked at the way blue light penetrates the retina and found that the damage resembles macular degeneration, but much more research needs to be done before a clear link is established.

Looking at screens can hurt your eyes

What about other coloured light?  Is that better for our eyes?

At the shorter end of the spectrum where there is ultraviolet light, too much exposure may lead to conditions such as cataracts, pterygium or photokeratitis.  The most straight-forward ways to protect your eyes from UV exposure is to wear sunglasses, wear a hat, avoid reflection of UV light (such as off bodies of water or the snow), and avoid looking at the sun directly.

At the other end of the spectrum, the wavelengths are longer and have less energy.  Red falls at this end, and studies are starting to be done to look at whether red light can help prevent or reduce damage to eyes, or even improve declining eyesight.  A study released in 2020 by the University College London found that, in older participants, looking at red light for a period of time may help to improve colour contrast sensitivity (ability to detect colours) and rod sensitivity (ability to see in low light). 

Take time away from screens for eye health

What should I do if I spend a lot of time with screens?

If your exposure to manufactured blue light is high, there are a few simple things you can do to give your eyes a bit of relief:

  • Blink!  We blink far less when looking at a screen so actively remembering to blink gives your eyes a quick break and a bit of moisture too.
  • Look away – Focusing on something in the distance every once in a while also helps to give your eyes a bit of a break.  We recommend following the 20/20/20 rule.  Every 20 minutes look at something 20 feet (6 metres) away for 20 seconds.
  • Take breaks – Take time away from screens – read a book instead of watching TV or go for a walk instead of playing a computer game.
  • Turn them off at night – Or use the night time function on your device to dim the brightness.

If you do feel that your eyes are sore or strained, that you have headaches or are worried that your vision is suffering due to the amount of screen time you are exposing your eyes to, make an appointment to come and see us.

This website does not provide medical advice.  It is intended for informational purposes only.  It is not a substitute for professional medical advice, diagnosis or treatment.  Never ignore professional medical advice in seeking treatment.  If you think you may have a medical emergency, immediately dial Triple 0 (000).


All About Vision, Blue light, what you should know, https://www.allaboutvision.com/en-au/digital-eye-strain/blue-light/.  Accessed February 2021.

All About Vision, Computer eye strain: 10 tips to get relief, https://www.allaboutvision.com/en-au/digital-eye-strain/get-relief/. Accessed February 2021.

American Academy of Ophthalmology, The sun, UV light and your eyes, https://www.aao.org/eye-health/tips-prevention/sun.  Accessed February 2021.

American Macular Degeneration Foundation, Ultra-violet and blue light aggravate macular degeneration, https://www.macular.org/ultra-violet-and-blue-light. Accessed February 2021.

Harvard Health Publishing, Will blue light from electronic devices increase my risk of macular degeneration and blindness? https://www.health.harvard.edu/blog/will-blue-light-from-electronic-devices-increase-my-risk-of-macular-degeneration-and-blindness-2019040816365#:~:text=Blue%20light%20from%20electronic%20devices%20is%20not%20going%20to%20increase,your%20health%20or%20circadian%20rhythm. Accessed February 2021.

Science News, Declining eyesight improved by looking at deep red light, https://www.sciencedaily.com/releases/2020/06/200629120241.htm. Accessed February 2021.

The Conversation, Blue light isn’t the main source of eye fatigue and sleep loss – it’s your computerhttps://theconversation.com/blue-light-isnt-the-main-source-of-eye-fatigue-and-sleep-loss-its-your-computer-124235.  Accessed February 2021.

What is blue light?
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