Uroš Bole, PhD

Mar 27, 2019

12 min read

Which Blue Blockers Really Do Work & Why [Science-Backed] 2019

You want the best blue light blocking glasses. A pair that will work. For you!

So, you google something like: best blue light glasses.

But to your surprise:
Not one mention of how glasses block blue light (spectral transmission)!?
In any of the TOP 10 articles!

Some do mention % of blue light blocked. But that’s to fool you (more in a minute).


Because, as you’d expect:

So you search on … OK, maybe you don’t … I did.

I know it’s crazy, but:
I reviewed Top 10 articles for 14 different queries.

NOTE: All 14 queries (if you care):
Best blue light glasses, Best gaming glasses, Best computer glasses, Best glasses for computer eye strain, Best glasses for computer screens, Best blue light filter glasses, Best anti-blue light glasses, Best blue light blocking glasses, Best computer glasses blue light, Best migraine glasses, Best glasses for computer, Best blue blockers, Best anti blue ray glasses, or Best blue blocking glasses for sleep.

That’s 57 unique blue light blocking glasses review articles! (Excluding vendors’ sites like Gunnars glasses, Amazon, Felix Gray, Zenni, Swannies glasses, …)

Still nothing. Not a single mention of spectral transmission!

So, when you shop for blue light blocking glasses you are buying a pig in a poke.

But it gets worse:

Most shoppers don’t know which blue blockers will work for them! Do you?

What’s going on and they don’t want you to know about

— Science doesn’t know what the best blue blockers are. Not yet.
— Vendors take advantage of the resulting ambiguity.
— Popular media promotes vendor’s stories (can’t blame them). And,
— You get superficial articles and buy blue blockers that don’t work for you. (Unless you are lucky. Or only need a placebo).

Best part:
— You can hack your best blue light glasses.

What no-one’s told you [unless you read neuroscience]

This is an optician’s frustrated comment:

It’s been on a forum for eye care professionals. Since 2014!

Yet, to date, no-one argued!

Why not?

Because it is true:

Around about that time top 14 neuroscientists published this paper:

It’s a review of everything known about the biological and behavioral effects of light, particularly blue light.

A few quotes (translation follows):

Light is a potent stimulus for regulating circadian, hormonal, and behavioral systems.

The neurophysiology (…) reveals the challenges in producing a method of spectral weighting that would be suitable for all circadian, neuroendocrine and neurobehavioral responses under all conditions. (…) the spectral sensitivity of this photoreceptive system is fundamentally context-dependent.

Simple prescriptions are as likely to do harm as well as good, and even experts may have divergent ideas about best practice under some situations.

For reasons outlined above, it is not yet possible to predict the non-image-forming impact of a given illuminant based upon its intensity and spectral composition.

[source: Trends in Neurosciences (2014)]

Bottom line (translation):
Blue light can have positive and negative effects.

Spectral composition of light is the key to positive effects.

How to filter blue light depends on many things, including:
— how your brain processes light signals
—your lighting conditions
and artificial light-sources (different scenarios might call for different blue blockers)
— your specific problem with blue light

Now you might be wondering:

Haven’t things changed since 2014?

Well, yes and no:

What is still true today

Since 2015 I’ve been studying blue light and blue light filters. And keeping up with new, relevant research. That -by no means- makes me a vision neuroscientist [disclosure].

But, my blog readers kept writing and asking two fundamental questions:
— Do blue light glasses work? and
— Which blue blockers should I get?

I was always unhappy with my answer. But, as you’ve seen above, the truth is:
It depends … on many many things …

So, I’ve craved for the news:
The decoding of blue light filter glasses

What I am trying to say is:
When they figure it out, I’ll be among the first ones to find out.

A lot of things are very different in 2019

The awareness of blue light has increased:

Blue light filters have become more popular:

And so have blue light blocking glasses:

Of course:

In 2014 the choices were few. Most blue blockers were not exactly stylish. Like, for example, orange Uvex safety goggles.

Blue blocking prescription or reading glasses were extremely rare.

Today you have lots of options. And many blue blockers look good!

For example, on Amazon* you get to choose from:
— 40,000+ Night glasses
— 10,000+ Gaming glasses
— 20,000+ Computer glasses
— 4,000+ Blue light filter glasses
— 4,000+ Blue light blocking glasses
— 1,000+ Blue blockers
— 399 Migraine glasses
— 8,000+ Sleep glasses
— 4,000+ Blue block sunglasses
* As of March 20, 2019 (click above for up-to-date data)

That’s a lot of blue light blocking glasses! On Amazon alone!

And the figures have grown by about 30%. In only 3 months!

Here’s how this growth can happen:

Ambiguity: Happy selling (& buying)


Unfortunately, you can’t always count on the marketers to have your best interests in mind. Which glasses they recommend as best blue blockers may depend on profitability.

Blue blockers’ vendors have come up with a series of half-truths to convince you to buy their products.

For example:

Different blue blockers’ tints — same promises

Orange lenses block a lot more blue light than “clear” ones.

I am using "clear" with quotation marks. Because "clear" blue blockers are not as clear as regular clear glasses. Although, their color distortion is the least noticeable. That's because they block blue light the least.

As you might know, blue light is from about 380 to about 500nm.

Orange glasses might block all blue light and beyond — up to about 540nm, like this:

Such glasses are truly 100% blue light blocking glasses.

“Clear” blue blockers might block 100% of blue light only up about 400nm:

These two transmission spectrograms belong to real glasses. The brands are not disclosed because the argument may not apply to them.

The difference with orange glasses is huge. These block only 20-50% of blue light beyond 420nm.

Yet, vendors may promise the same benefits in both cases. Protection from:
—digital eye strain,
—screen glare and reflections
— headaches,
— dry eyes,
— insomnia, …

Both orange and “clear” glasses do deliver on those promises. Some of the time. It’s obvious from positive customer reviews.

But, there are also many negative reviews.

So, as you’d expect (based on science) the same glasses that filter blue light can’t be the best for everyone.

The question is: Will orange, amber, pink, yellow, or “clear” blue blockers work for you?

Another example:

Presenting “clear” glasses as powerful blue blockers

“Clear” glasses that filter blue light often claim “up to 100% of blue light blocked” (or similar).

Have you thought about what that might mean?

Below you can see spectral transmissions of a few clear lenses and “clear” blue blocking lenses:

Take the intermittent blue curve (red arrow). It blocks:
— 100% of light below 400nm, and
— very little above 400nm
(blue light is ~380-~500nm).

As you can see, it is true:
Such glasses do block blue light. Up to 100%!

You can also see (blue box) that those are regular, clear glasses!

Digital screens and ordinary light bulbs don’t emit any light below ~420nm.

Bottom line:
They want you to think you are getting lots of blue-blocking power.
Also with deceiving names like Blue Zero (see blue box in the graphs above).

1. so you buy, and likely also
2. to influence how you feel once you put the glasses on.
(With that “100% blue block power” or “Blue Zero” in mind you are more likely to “feel” the desired improvement).

A possible placebo effect?

—Who knows? … Who cares? … They don’t (as long as you buy their blue blockers).

This is not to say that “clear” blue light blocking glasses don’t work. They do. For those who are not very blue light sensitive.

Want to know the worst part?

Here is the latest trick. It sells like crazy:
#1, #2, and #3 sellers in Computer Blue Light Blocking Glasses category on Amazon use it!

(Ranking may change: data from March 22, 2019)

This is how it works:

They show you an image, like this one:

…and a video of a test with a blue light sensitive card and a blue light torch.

Their “clear” blue blocking lens (right) blocks all or lots of blue light. Unlike a regular clear lens (left).

Best part:
If you buy their glasses, they also send you a torch and a testing card. So you can test those blue blockers yourself!

Convinced? 100%! You must admit it! These “clear” blue blockers DO block blue light! All blue light!

— the torch only emits certain wavelength(s) of blue light, say 390–400nm, or
— the card is only sensitive to low wavelengths (say 390–400nm). But not higher blue light wavelengths (400–500nm).

As you know by now it must be one or the other. Because “clear” glasses that filter blue light can block 100% of light at most up to ~420nm.

Are you being misled? … Again?

— Who knows? … Who cares? … They don’t (as long as you buy their blue blockers).

Last example:

What if “clear” blue light blocking glasses are plain clear glasses?

A great majority of blue blockers sold are “clear”. For example:
83 out of 100 best sellers in computer blue light blocking glasses category on Amazon (data from March 15, 2019).

Do huge sales volumes and positive customer reviews mean that most of us are:
— mildly blue light sensitive? Or,
— plain happy with a placebo?

—Who knows? … Who cares? … They don’t (as long as you buy their blue blockers).

Here is the worst part:
78 of those 83 “clear” Amazon’s best sellers appear completely clear in the images (as measured with color detection software).

Including #1, #2, and #3 best selling blue blockers mentioned above!

Could these 78 be just normal, plain clear glasses?

— Who knows? … Who cares? … They don’t (as long as you buy their blue blockers).

Now, let’s not jump to conclusions:
Because an image may not be a perfect reflection of reality. But:

Take a closer look at the graph you’ve seen above already:

Compare the black curve (black arrow) to the intermittent blue curve (red arrow):
— they are almost identical up to about 410nm.
— beyond 410nm the black one blocks about 20% less blue light.

Now, this is crazy! Or inconsistent? Or deceiving?

According to this vendor:
— the lens that blocks 20% more blue light is a regular clear lens (blue box: “1.67 Clear”), while
— the lens that blocks less blue light is a “clear” blue blocker. With a bold name: Poly Blue Zero!

Bottom line:
Could it be that some (or all) of these 78 are normal, clear glasses—sold as blue light blocking glasses!?

—Who knows? … Who cares? … They don’t (as long as you buy their blue blockers).

Popular media spreads ambiguity

Another big change since 2014:
Popular media writes about best blue blockers. And Google favors big online media. So these are the stories you see in the searches.

Of course, the journalists couldn’t get all the way down to the nitty-gritty of blue blocker glasses.

Who’s got the time for it?

They spend about two days on those articles (my guesstimate of an average):
—a day or so for research. Including a list of 3–12 best anti blue ray glasses. (Outlier: an author who spent a entire week wearing blue-blocking glasses). And
— another day to write their best blue light glasses stories.

Then on to the next topic.

It’s normal. (Their income depends on the number of articles they write).

Now, remember the article that 14 neuroscientists authored. They’ve spent their careers focusing only on light and its effects.

So, there’s some 280 years of research in that article! (I am guessing an average of 20+ years/scientist).

The difference is huge! 2 days vs. 280 YEARS!

The scientists know what they don’t know and say it. While the journalists…!?

Bottom line:

Does anyone care about the best blue blocker glasses for you?

Yes. There are some that do care.

For one, I do. Among other things, because of the questions from my blog readers, I told you about.

I couldn’t accept:
It depends … on many many things …
as the best answer to:
Which blue light blocking glasses should I get?

So, I developed a way to figure out the best blue light blocking profile for you.

Which is why I also have a conflict of interest.
Disclosure: I sell the blue light test kit below.

But my primary motivation has been to help you get your best blue blockers. Or to help you find out you don’t need them.

How to find the best blue light blocking glasses

Let’s look at a similar example:

Suppose you need(ed) new prescription glasses. What do you do?

You go to have your eye-sight checked.

They use sophisticated instruments to measure what prescription you need. But that’s an estimate.

So, next, they pull out their prescription test kit. An amazing selection of lenses!

You try different strength lenses and settle for the ones that work best.

This is key:

Finally, you order prescription glasses based on that information.

To find the best blue light filter for your eyes, do something similar:

And remember:
It’s YOU who has the final say!
Because only you can know how a filter makes you feel.
(As with prescription glasses — only you know how well you see).

There are three different ways to test blue blockers:

Testing with a blue light filter app

You can do a blue light sensitivity test for free with f.lux.

Set it to 2700K or so by moving the slider— see my red arrow:

Your screen will turn yellowish. Which is why it emits less blue light.

Do your eyes feel better with f.lux on?

Then you could be blue light sensitive.

Play with the app settings.

Now, a blue light app is not exactly the same as blue light blocking glasses. Here are the two options for blue light testing with eyewear:

The ideal blue light filter testing scenario

Find a nearby ophthalmologist, optometrist, or a blindness/low vision agency.

Make sure they stock blue light filters for light sensitivity testing. Also, they should lend their anti blue light glasses for various days:

TIP 1: 
Your first impression of a blue light filter may be misleading. Some conditions may need more testing time. For example insomnia, eye dryness, migraines, AMD, … even computer eye strain. Plan on testing each filter for a while.
TIP 2:
Watch out also for negative side effects: nausea, eyestrain headaches, ...

The most convenient testing scenario

This is what our blue light test kit looks like:

And the corresponding blue light blocking glasses buyer’s guide. It takes you through the process in three simple steps: test, select, order.

That’s it! Now you know blue blockers do work. But not all blue light glasses will work for you under any conditions.

You also know how to find those that will.

Let me know in the comments which blue light sensitivity test option are you going to try: f.lux, low vision agency, or blue light blocking glasses test kit?