Why are some blue light glasses completely clear and why aren't ours?
The question comes up every week. And it's a good question. Because if the lens is really filtering light effectively, it shouldn't even be completely clear. When it comes to circadian rhythms, eye strain, and the right wavelengths, physics dictates the rules of the game. In this article, we'll explain clearly and with numbers why color matters and why not all "blue light blockers" are the same.
Why aren't North Ray lenses clear?
This is perhaps the most common question we receive.
“Wouldn’t a clear lens be enough?”
“I already have blue light protection on my glasses.”
And we completely understand why people think this way.
It would be wonderful if completely clear glasses could do the job inconspicuously.
But this is where physics (and a little bit of photobiology) comes into play.
And it's pretty ruthless.
👉 A clear lens simply cannot filter enough, or even the right wavelengths.
Clear lenses: a good idea, but little effect
Most clear blue light glasses and eyeglass coatings typically filter out about 5–20% of blue light. And mostly from that edge of the spectrum, around 400–420 nm.
That sounds nice.
But at the same time:
- 400–450 nm wavelength affects eye strain, glare and digital fatigue
- The 460–490 nm wavelength affects alertness and melatonin production
- 500–570 nm (green) is the brain’s “day mode” signal
...and all of this comes through clear glasses almost unnoticed.
So the end result is often: “really nice glasses”, but the body doesn't really notice any difference.
When you want the right effect, you need color
If you really want to block light, a coating alone isn't enough. The light has to be absorbed by the lens material. And that can only be achieved with pigment. In other words: if the lens is to work properly, it has to be yellow, orange, or red. That's not a design choice. It's physics.
During the day: less stress, feeling refreshed
We don't want to make your day dark. We just want to eliminate that sharp "blue light spike" that makes your eyes squint at the screen. That's why our daytime lenses:
- blocks approximately 80–85% of blue (400–500 nm)
- especially cuts 400–450 nm almost completely
- allows most of the green light to pass through
In practice, this means: less stinging, less strain, a softer feeling on the eyes, but still a bright and energetic day. And this level of filtration is simply not possible with a clear lens.
In the evening: the game changes
When the sun goes down, the body starts to crave a different message. It’s no longer “the day continues,” but “now it’s time to calm down.” At this point, blue alone isn’t the whole story. Green light (500–570 nm) also keeps the brain awake.
That's why evening glasses attenuate both:
- blocks 93–98% of blue
- attenuates about 65% of green
This is the moment when many people notice: “oh, now I’m naturally tired.” And the clear lenses?
They practically do not apply to green at all.
At night: minimal stimulus
Then there are those moments when the day is really over. The last hour before bed. Late screen time. Waking up at night to go to the kitchen or with the baby. Then the goal is no longer “a little less light”.
But the clearest possible message to the body: it's night time. Night glasses:
- blocks approximately 99% of blue and green light
- practically cuts off almost the entire biologically activating spectrum
When both blue and green light are minimized, the brain no longer receives the “day” signal at all. Melatonin production is allowed to continue in peace, and the body does not wake up again unnecessarily.
If I could sum all this up in a few points...
The clear lens offers little comfort.
The spectrally controlled lens provides the correct biological effect.
That's why our lenses are colored.
Not because it looks like “biohacker glasses”.
But because that's the only way light can truly be filtered.
Light is not just brightness. It is information for the body.
In the morning it says: wake up.
During the day: stay refreshed.
In the evening: calm down.
At night: sleep.
When you understand that different wavelengths are different messages, the color of the lenses starts to feel logical, not special.
For us, spectra, percentages and measurements are everyday things, but in the end it's all about one thing: that that light supports your rhythm and does not fight it.
👉 If you want to take a closer look at the numbers and spectrum curves, we've compiled them here:
