What Actually Separates Them: Green Light
All three tints are trying to block the light that keeps your brain in daytime mode. The catch is that two wavelengths matter, not one. Blue light around 460nm is the main melatonin suppressant, but green light around 555nm suppresses it too, nearly as much Gooley et al., 2010. Screens and LED bulbs put out both.
So the real question for any sleep lens is simple: how much of the blue-and-green range does it actually block? That one answer is what separates clear, amber, and red.
| Lens | Blue light | Green light | Best for |
|---|---|---|---|
| Red (Freddie) | Blocks 99% | Blocks 99% | The hours before bed |
| Amber | Blocks most | Passes through | Evening, partial |
| Clear | Filters ~10% | None | Daytime screens |
Clear Lenses: Built for Daytime
Clear blue-light glasses filter a small slice of blue, often ~10%, and let green through entirely. They're made for comfort during long daytime screen sessions, not for sleep, and the sleep research on them is mixed Luna-Rangel et al., 2025.
If you want to cut some glare at your desk, fine. For the hours before bed, they barely touch the light that matters.
Amber Lenses: Better, but They Miss Green
Amber is the classic blue blocker, and it's a real step up from clear. It blocks most blue light, and there's evidence it helps. In one small study, people who wore amber lenses for two hours before bed reported better sleep than those in clear lenses Burkhart and Phelps, 2009.
The limit is in the tint. Amber blocks blue but lets a lot of green through, and green suppresses melatonin too. So amber does part of the job and leaves the rest on the table.
Red Lenses: The Full Evening Range
Red is the only tint that filters the fuller range, blue and green both, up to the wavelengths that most affect your internal clock. That's the whole reason it looks so different through the lens. It's removing more of the light.
Freddie's red lenses block 99% of blue and green, so nothing in that range slips past the way it does with amber. For the last stretch of your evening, that coverage is the point.
So Which Should You Pick?
It comes down to when you're wearing them. For daytime screens, clear is fine. For the evening, amber beats clear but leaves green on the table.
For the hours before bed, red filters the most of the range that keeps you up, which is why it's the choice for a bedtime lens. Pick for the time of day, and for sleep the answer is red-lens sleep glasses.
Common Questions
Is amber good enough, or do I need red?
Amber helps, and it's better than clear. But it lets green light through, and green suppresses melatonin too. Red filters both, so for the hours before bed it removes more of the range that matters.
Why do red lenses look so much darker?
Because they're blocking more. The deeper tint is the blue and green light not reaching your eyes. Most people stop noticing within a few minutes.
Can I wear red lenses during the day?
They're made for evening indoor use. The tint shifts how colors look and how you see brake lights, so don't drive in them.
Do clear blue-light glasses do anything for sleep?
Not much. They filter a little blue and no green, and the sleep research on them is mixed. They're built for daytime screen comfort.