Digital eye strain: Do blue light glasses work?

08 June 2021

Author: Kate Green

blue light blocking glasses

Impacts of ever-increasing screen time


Over the course of the pandemic, everyone has spent much more time indoors. For most of us, this has also led to a dramatic increase in screen time, particularly throughout the winter months. Whether that’s watching a film and playing video games to pass the hours, or chatting to distant family members on long FaceTime calls, screens became a huge part of our new pandemic lives.


Pre-lockdown, the average adult spent 8 hours and 41 minutes on digital devices each day. However, for some people, this number was much higher, particularly if their jobs required them to be sat in front of computer screens for 35-40 hours a week. This, teamed with using your personal smartphone during leisure time and watching a bit of TV after work, easily totals 12+ hours of exposure to screens each day. 1 in 3 people in the UK have actually noticed their vision deteriorating over the course of the pandemic as a result of increased screen time.


We’ve written previously about the impacts of too much screen time on our eyes and how you can identify the symptoms of Computer Vision Syndrome, but something that’s been discussed more recently on this topic is the effect of blue light glasses. Blue light blocking glasses are special glasses which are supposed to filter out blue light, purportedly protecting your eyes and preventing the onset of certain eye conditions such as age-related macular degeneration and other forms of retinal damage. But how much of this is true?


What is blue light?


Before we look at how blue light glasses work, and indeed whether they actually work, it’s important to understand what blue light is and how it enters our eyes. Sunlight is one of the biggest sources of blue light. Sunlight is actually made up of several different types of coloured light such as red, orange, yellow, green, blue, indigo and violet, but the spectrum of all of the colours combined is called white light. Each type of light has a different wavelength and level of energy.


Blue light has a very short wavelength and high energy levels which means that it can easily enter the eye and pass through the cornea, eventually reaching the retina. Some specialists have suggested that over-exposure to blue light can actually damage the light-sensitive cells in your retina, hence the negative discussions around the effects of digital screens and blue light in recent years.


However, the amount of blue light emitted from screens is much lower than the amount of blue light we’re exposed to every day, simply by being outside in the daylight. Recently blue light has gained a negative reputation due to its link to the use of digital screens, but is it possible that this is an issue due to the proximity of the screen and the number of hours people spend using digital devices, rather than a problem with the blue light itself?


How do blue light blocking glasses work?


Blue light blocking glasses are more popular than ever, particularly growing in popularity during the pandemic. In fact there was an 812% increase in searches over the past 12 months for ‘blue light glasses’ last year. Zenni, the large seller of blue light blocking glasses, says they sold almost 2 million pairs in 2020. Further to this, The Book Club eyewear company claim that their blue light blocking glasses sales shot up by 116% between March and April last year, compared to the same period in 2019.


It’s clear to see that something about blue light glasses works, whether it’s merely a placebo effect, or something more science-based. The lenses in blue light blocking glasses are specially designed to filter out blue light rays before they reach the retina. The lenses don’t correct for a prescription like traditional glasses, but rather have a clear lens with a subtle yellow tint. This counteracts the blue light and supposedly prevents the rays from entering the eye.


How effective are blue light blocking glasses?


Simply, there is no current research to suggest that blue light blocking glasses are at all effective in preserving your eye health. It has been claimed that they can improve your vision, help with any discomfort or sensation of fatigue in the eye, preserve macula heath, and improve your quality of sleep. Unfortunately, however, none of this has been scientifically proven.


Although some people claim that their blue light blocking glasses help their eyes feel less strained, there is still the question of whether or not blue light even causes eye strain in the first place. Some specialists suggest that it’s actually our behaviour when using screens that causes eye strain, rather than the effect of the blue light itself. These behaviours include constantly straining our eyes to read small text, blinking infrequently and irregularly, and focusing on just one distance, rather than using our eyes to focus on a range of objects and distances.


In fact, there are several regulations and guidelines in place to prevent the screens we use every day from emitting an unsafe level of blue light – so it is actually unlikely that the amount of blue light from our digital devices is significant enough to cause retinal damage.


There is some evidence, however, to suggest that blue light glasses may help you sleep better. Blue light has been known to block your body’s production of melatonin, the sleep inducing hormone. This is why most modern smartphones have a ‘night setting’ with a more yellow tinted screen colour, to counteract the blue light. In fact, a study conducted by the University of Houston in 2017 showed that blue light blocking glasses increased melatonin levels by almost 60% in their participants. This is probably the most effective use of blue light blocking glasses, as opposed to improving your vision or preventing eye disease. There is also some evidence to suggest that they potentially help reduce screen-induced headaches and stop tired eyes, but there are questions over whether these ailments even occur as a result of blue light exposure.


How can I avoid digital eye strain?


As it’s most likely that the majority of eye problems we associate with screens are actually a result of eye strain, rather than the impacts of blue light, it’s important to know how to alleviate the discomfort of strained eyes. You could implement some of the below suggestions to your daily life if you find yourself struggling with strained eyes following screen use.

  • Adjust brightness and contrast settings on your computer screen
  • Install matte screen covers to prevent glare
  • Zoom in to 120% or more when using a computer
  • Increase the font size on your phone
  • Use artificial tears to help with dry eyes


You can also use what eye care specialists call the 20-20-20 method. This is a set of exercises which helps you to exercise your eyes throughout the day and keep them lubricated, moving well, and regularly focusing at different distances. The process involves taking a break from your screen every 20 minutes to look at an object 20 feet away for 20 seconds. Doing this gives your eyes a rest from the screen and works to ensure that you’re not experiencing any eye strain induced by digital screens.

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