Blue Light Glasses: When to Wear Them & Why

There's Only One Reason to Block Blue Light During the Day

It's not to protect your sleep. It's not to reduce eye strain in some vague, general way. And it's definitely not to block all blue light.

We keep saying it, and we’ll never stop: your brain needs blue light during the day to function properly. But there’s nuance!

The one reason to block blue light (but not all of it) during the day: a narrow band of harsh dark blue light (around 430–450nm) sits at the peak of what photobiologists call the blue light hazard function. This is a well-established band that carries the most phototoxic potential for the retina. The curve has been mapped for decades, and it peaks right around 435–440nm.

That same narrow band happens to be exactly where LED screens and standard white LEDs concentrate their blue output. The blue pixels in your screen are fairly wideband, but their peak emission lands squarely on the hazard peak.

Here's the thing… this wavelength range doesn't sit at the peak of any useful biological receptor.

It's not what sets your circadian clock. It's not what activates the light-responsive opsins in your skin and body. It's biologically expensive and biologically unproductive. But we’re drowning in it.

That's the narrow range of blue light worth filtering out during the day. Just that band. Nothing more.

Most Blue Light Glasses Get This Wrong

Too little: Clear or nearly clear lenses that claim to block "blue light" but filter only 5–10% across a broad range. They may look great, but they do almost nothing. If you can't tell you're wearing them, neither can your biology.

Too much: Yellow, orange, or red-tinted lenses that cut deep into the blue and green range. These block not just the hazard band, but the sky blue light (~480nm) your brain uses to maintain daytime alertness.

These lenses suppress the circadian signal that keeps you awake and focused. Wear them during the day and your biology starts shifting toward evening mode. You might feel mellow, but that's not protection. That's your biological clock being told the wrong time.

The ideal daytime lens blocks the narrow hazard peak and leaves everything else alone.

During the day we WANT the sky blue (cyan) circadian signal and the violet range that serves light-responsive opsins throughout the body.

Golden Glo: The Daytime Lens

That's what our Golden Glo lenses are designed to do.

These block out the peak of the blue light hazard range where screen output is strongest and least biologically useful, but keep some of the circadian driving light on either side.

The circadian signal still gets through and you’re not getting drowsy wearing these.

Granted they don’t allow as much cyan and violet as unfiltered light, but the circadian response is deeply nonlinear: even partial transmission at the right wavelengths provides a meaningful daytime signal.

Going from zero violet and cyan (most blue blockers) to some is a far bigger biological jump than going from some to full.

When to wear Golden Glo glasses:

• Working at a computer indoors
• Heavy screen use during the day
• Afternoon through early evening under artificial lighting
• Early mornings when a bright screen feels like too much

When to take them off: Any time you’re outside (even when using a phone!). Sunlight is the best light your biology can get and it’s orders of magnitude more intense than any screen, naturally balancing out the light from the screen.

Golden Glo's job is to clean up indoor light, not to filter natural light. Whenever you can get outdoors, take them off.

Colors stay mostly natural with a subtle golden warmth. Screens and harsh indoor lights feel noticeably less glaring. But the key is you don't get drowsy wearing them because the daytime signal is still intact.

Blue Light Blocking at Night: When to Block Everything

Once the sun goes down, your body expects true darkness.

During the day, you want to bask in the circadian signal while filtering the hazard band.

In the evening, you want to shut the circadian signal down. That's how your brain knows it's time to produce melatonin and prepare for sleep.

The problem is every screen and indoor light in your environment is still broadcasting "DAYTIME!!" Hotel rooms, airport terminals, your phone, your TV, all of these send the same wake-up signal to your brain, hours after the sun has set.

Research from Harvard found that ordinary room light before bed suppressed melatonin onset in nearly every person tested and shortened melatonin duration by about 90 minutes. And that's just standard room lighting, screens can be far worse.

This is the only time you want aggressive, broad filtering. Blue and green “melanopic” light from ~420nm to 550nm suppresses melatonin. Proper evening glasses need to block this entire band.

Nightshades: Proper Evening Lens

This is exactly what the Nightshades are built for. They block 98.5% of this blue and green melanopic sleep disrupting light.

When to wear them:

• 1–3 hours before bed, especially under indoor lighting
• Watching TV, using your phone, or on a laptop in the evening
• In brightly lit environments at night like hotels, airports, restaurants
• During travel, particularly in the protocols described in our jet lag travel guide
• On overnight flights

When to take them off: Right when you're laying down to sleep. Or when you’re in a room illuminated by only red light.

Most common red or orange blue blockers filter only a fraction of the relevant spectrum. If the lenses look almost clear, the filtering is minimal.

A note on usability: Nightshades allow a tiny fraction of violet light to pass through. This enables dramatically improved color perception in the worst lit environments vs pure red lenses, with only a minimal tradeoff in stimulation.  The best blue blockers are the pair you actually use. This is our 1.5% tradeoff.

A Note on Lens Color

You'll see blue-light glasses marketed by color as “yellow”, “orange”, or “red”. But the tint you see doesn't tell you what the lens is doing spectrally.

Two lenses can look similar and have very different transmission profiles. One might block the hazard band precisely. Another might let most of it through while cutting useful daytime wavelengths instead.

The only way to know what a lens does is to look at its transmission spectrum (the graph that shows exactly which wavelengths pass through and which don't.)  We publish ours because the data tells a clearer story than the color of the lens ever could.

When to Wear Blue Light Glasses: A Daily Guide

Morning: No glasses. Get sunlight. If you're at a screen early and it feels harsh, Golden Glo lenses take the edge off without suppressing your wake-up signal. But really, do all you can to get some morning daylight.

Midday: If you’re outside? No glasses. Working inside at a screen? Golden Glo. Again, take sun breaks as often as possible.

Afternoon to Early Evening: Golden Glo while working indoors. This is the sweet spot. Afternoon is when most people are under artificial light for extended periods.

1 to 3 Hours Before Bed: Transition to Nightshades. The goal shifts from "filter the hazard band" to "protect your melatonin."

Evening: Nightshades on any time you're exposed to screens or blue rich indoor lighting. Pair with your Red Portal or Sky Portal Mini on Deep Amber for a room environment that works with your biology instead of against it.

Quick Comparison

The Simplest Way to Think About It

Two blue light glasses. Two different biological circumstances.

Golden Glo: Blocks what your eyes don't need from screens. Keeps what your brain needs to stay alert.

Nightshades: Tells your brain the day is over, even when every light in the room disagrees.

Go outside with no glasses during the day whenever you can. There’s no replacement for the sun.

Want to learn more about how light affects your body? Read our complete guide to red light therapy benefits or our guide to beating jet lag with light.

This guide is for educational purposes. Chroma eyewear products are general wellness accessories designed to support your body's natural light responses. They are not medical devices and are not intended to diagnose, treat, cure, or prevent any disease.

Frequently Asked Questions

Can I just wear the Nightshades or other red glasses all day? You could, but you'd be filtering out the light your brain needs to stay alert and maintain a healthy circadian rhythm during the day. The Nightshades are intentionally aggressive, exactly what makes them effective in the evening. During the day, the Golden Glo blocks the hazard wavelengths without fully suppressing the signals that keep you sharp.

Do you need blue light glasses? Most everyone does. If you're choosing just one, pick the Nightshades. Evening light management has the biggest impact on sleep quality. But if you spend significant time at screens under indoor lighting, the Golden Glo addresses the daytime problem of too much harsh dark blue light.

Why do cheap blue light glasses look almost clear? Because they barely filter anything. Most block almost zero blue light. They're designed to look like regular glasses, not to meaningfully change what reaches your eyes.

Will the Golden Glo make my screen look yellow? There's a subtle golden warmth. You'll notice it for the first few minutes, then your eyes adapt and colors look mostly natural. Significantly less tinted than the Nightshades.

I use Night Shift / f.lux on my devices. Do I still need glasses? Software filters help, but they only address your screen, not the room lights. Further, most software modes don't filter aggressively enough. They're a good start, but glasses handle the full environment.