If you work at a screen a lot and have visited an optician in recent years, chances are you’ve been recommended glasses with a blue light filter. What’s the theory behind these filters? And do these computer glasses actually work?
I regularly got these questions during my conversations with clients I help online to create an ergonomic and more comfortable home workstation. According to the latest research, there’s actually no evidence that these glasses prevent tired eyes or help you sleep better. But some people do benefit from them!
I’m not an optician or an ophthalmologist, but I want to give good advice about every tool that can improve a workstation. So here’s an overview of what I found.
Let’s start at the beginning:
Blue light has a high energy level
Visible light, such as sunlight, contains all the colours of the rainbow. Together, these colours make up the “white” light we see. Each colour in sunlight has its own frequency and energy level. Blue light has a short wavelength, a high frequency and a high energy level. It sits at the end of the visible part of the light spectrum, right next to light we can’t see (UV light).
The sun emits blue light, but so do the screens of your TV, phone, laptop and computer. The blue light from screens is only a fraction of what the sun emits, but many people use screens very intensively.
Light sources that are close to our eyes expose us to more blue light. So you’re exposed to more blue light when using a computer or smartphone than when watching TV (which is usually further away).
Blue light from your screen isn’t harmful
Blue light has a short wavelength and a lot of energy. It sits right next to UV light in the spectrum, but it’s something different: UV is invisible and is harmful, blue light is visible. In 2024, researchers concluded that one minute outdoors gives your eyes more blue light than about 24 hours of using your devices.
Screens, lamps and other light sources we use every day emit hardly any UV, so they pose no danger to your eyes.
There’s no proof that blue light filters work
In 2023, Cochrane (the gold standard for medical evidence) reviewed 17 studies. The conclusion: the evidence that blue light glasses reduce tired eyes from computer work (compared to computer glasses with “regular” lenses) is weak.
And do they help you sleep better? Six studies on this contradicted each other: three found better sleep scores with glasses that have a blue light filter, three found no difference. So it hasn’t been shown that they help you sleep better.
A good more readable source with many links to academic research, is this one from Specsavers.
Still, they work for some people
Still, blue light glasses work for quite a few people I’ve spoken to! How is that possible? Blue light, and other excessive light, can be genuinely unpleasant for some people. Even if there may be no scientific evidence, some things simply work for some people. I’m firmly convinced of that!
Alternative: adjust your screen colours
Instead of buying blue light glasses, you can also filter the blue light from your screen by changing your screen settings. For free :). On Windows this is called “Night light”, on Apple devices “Night Shift”, and on Android (depending on the brand) “Night Light” or “Eye comfort”. Many monitors also have a “low blue light” mode in their own menu.
What does help against tired eyes
Tired eyes are often caused by a combination of the following:
- You blink less when working at a screen, so your eyes dry out faster.
- When your eyes focus on something close by for a long time, the eye muscles tire more quickly.
- A screen that’s too bright or too dark, or a poorly lit room, also causes fatigue.
In my opinion, more important than computer glasses with a blue light filter is having good lighting (rule of thumb: match your screen brightness to the light in the room) and regularly changing focus.
The 20-20-20 rule (every 20 minutes, look at something at least 20 feet away for 20 seconds) is easy to remember but difficult to put into practice! Software that helps you take regular breaks drives many people up the wall, but it can definitely help.
But can’t do any harm
Medically speaking, there’s nothing harmful about blue light glasses. Some users I’ve spoken to say they find them difficult to get used to, and that they cause them stress. Then they backfire, and in that case, I’d of course advise against using computer glasses.
If they do work for you: keep using them! As with almost everything to do with your workstation: everyone is different, and different things work for different people.
Blue light glasses vs. computer glasses
Blue light glasses are often confused with computer glasses. But computer glasses don’t need to have a blue light filter. In principle, any pair of glasses can have such a filter in the lenses.
I rarely recommend blue light glasses
If you’re very sensitive to light or have trouble reading, I’d advise you to see an optician or ophthalmologist and consider computer glasses. I’ve rarely actively recommended computer glasses myself.
If your eyes bother you, I think it’s far more important and effective to take other measures so your eyes don’t get overworked and tired. See my tips above.
Frequently asked questions
Probably not. According to a 2023 Cochrane review (17 studies, 619 participants), blue light glasses may not reduce tired eyes from computer work, compared to regular glasses.
No. The blue light from a screen is only a fraction of what the sun emits. There’s also no evidence that blue light glasses protect your retina.
Yes, for free in your screen settings: Night light on Windows, Night Shift on Mac and iPhone. Whether that actually helps your eyes or your sleep is just as uncertain as with the glasses.
Computer glasses have lenses for used on a screen distance. A blue light filter is a coating that can be added to any glasses, but computer glasses don’t need to have one.
The British College of Optometrists, the professional body for optometrists, says opticians should tell customers there’s no strong evidence that blue light glasses help.