Short answer: put blue light glasses on two to three hours before bed and keep them on until lights out. The lens matters as much as the timing: clear and yellow lenses let too much blue light through for the evening, so choose an orange or red lens. Our orange SleepAid lens blocks 99% of light across 380–550nm, and our red SleepAidMax lens blocks 99.7% across 380–580nm. Treat them as one part of a wind-down routine, alongside dimmer, warmer lighting.
Below: why evening light matters, how long before bed to wear them, which lens to choose, and what else makes a difference.
Why Light Matters in the Evening
Blue light is the part of visible light between roughly 400 and 500nm. The sun is by far the biggest source; screens, LED bulbs and fluorescent lighting give off blue light too, at much lower levels.
During the day, blue light helps you feel alert and keeps your body clock on time. In the evening, bright, blue-rich light can delay the rise of melatonin, the hormone that tells your body it's getting dark. That's why the light you're around in the last few hours before bed matters, whether it comes from a screen or the ceiling.
How Long Before Bed Should You Wear Them?
Two to three hours is the usual guidance. Melatonin normally starts to rise a couple of hours before your usual bedtime, so that's the window to cut blue light.
- Put them on: around sunset, or two to three hours before you plan to sleep, whichever is later.
- Keep them on until lights out: taking them off to brush your teeth under a bright bathroom light undoes some of the benefit.
- Be consistent: wear them every evening, not just now and then, and keep a regular bedtime.
Which Lens to Wear Before Bed
Lens color tells you roughly how much blue light is filtered. Here's how our lenses compare, as measured by Micro-Light Optics:
- Clear (InvisiAid): blocks 35% across 400–500nm. Made for daytime screens; not enough for the evening.
- Yellow (ScreenAid): blocks 60% across 400–500nm. A daytime lens that still lets through around 40% of blue light.
- Orange (SleepAid): blocks 99% across 380–550nm and lets through 48% of visible light (ISO 12312-1 Category 1). The one to wear for the two to three hours before bed.
- Red (SleepAidMax): blocks 99.7% across 380–580nm and lets through 22% of visible light (Category 2). Best for the last hour before sleep, or if you want the strongest filter.
Not sure which suits you? The Lens Finder takes a minute. There's more on orange lenses in our guide to orange lens blue light glasses.
What the Research Shows
In a University of Houston study published in Ophthalmic & Physiological Optics, 22 people aged 17 to 42 wore short-wavelength-blocking glasses for three hours before bed for two weeks, while using their devices as normal. Their nighttime melatonin levels rose by about 58%.
That's a small study, and research on blue light glasses overall is mixed: results vary with the lens, the timing and the person. What's well established is that bright light in the evening delays the body clock, and that cutting it helps the body get ready for night. Sleep depends on much more than light, so glasses are one part of the picture, not a fix on their own.
What Matters as Much as the Glasses
- Room lighting: switch off bright overhead lights in the evening and use dim, warm lamps instead.
- Screen settings: turn on night mode and lower brightness after sunset.
- A regular schedule: going to bed and getting up at the same time every day keeps your body clock steady.
- Morning daylight: getting outside early in the day helps set your body clock for the evening.
- Caffeine and late meals: both can keep you up, whatever you wear.
Tips for Wearing Them
- Keep them by the couch or bed so putting them on becomes part of your routine.
- Expect colors to look different. Orange and red lenses shift colors strongly, so skip color-sensitive tasks while wearing them.
- Don't drive in them. Orange and red lenses let through too little light for driving at any time of day.
- Give it a few weeks. Wear them every evening for two to three weeks before judging how they fit your routine.
Frequently Asked Questions
How Many Hours Before Bed Should I Wear Blue Light Glasses?
Two to three hours, and keep them on until lights out. The University of Houston study used three hours.
Which Color Lens Is Best Before Bed?
Orange or red. Clear and yellow lenses are made for daytime and let too much blue light through for the evening.
Do I Need to Wear Them if I'm Not Using a Screen?
Yes, if the room is brightly lit. Overhead LED lighting gives off blue light too, so the glasses help whether you're on a screen or not.
Is Blue Light Bad for Your Eyes at Night?
No. The American Academy of Ophthalmology says the light from screens doesn't damage the eyes. The concern in the evening is your body clock, not your eyes.
Can I Drive Home Wearing Them?
No. Orange and red lenses are not for driving. Take them off before you get behind the wheel.
Conclusion
For the evening, timing and tint go together: wear an orange or red lens for the two to three hours before bed and keep it on until lights out. Pair it with dimmer, warmer lighting, night mode on your devices and a regular bedtime, and you'll cut most of the blue light your evenings would otherwise bring.
Shop SleepAid orange lens glasses and SleepAidMax red lens glasses, or use the Lens Finder.
