What is blue light?
All of the light we see falls somewhere along the rainbow-colored visible light spectrum.
The light of each color has a different wavelength. Blue light is on the lower end of the spectrum, with wavelengths between about 380 and 500 nanometers.
Light with shorter wavelengths has higher energy. So, blue light is also called high-energy visible (HEV) light.
Digital electronic devices emit blue light that can cause eye strain and may lead to eye problems over time.
The sun is the largest producer of blue light. Scattered blue light in the atmosphere is what makes the sky look blue.
Digital screens, like the ones on our phones, TVs and computers, also emit blue light. Though they produce less intense blue light than the sun, we stare directly at these artificial sources for hours at a time, which concerns many eye doctors.
What does blue light do to your eyes?
Blue light may also worsen or contribute to rarer effects like ocular migraines.
When blue light enters your eyes (especially late in the day), it sends a signal to your brain to stay awake by disrupting the production of the natural hormone melatonin. When melatonin production is out of whack, so is your sleep schedule.
However, research isn’t clear about potential eye damage from blue light emitted by electronic screens. Since their blue light is so much weaker than the sun’s, we don’t know for sure if it can or will have the same harmful effect.
Is blue light bad?
Yes and no — blue light can be both good and bad.
Blue light is a little like UV radiation. The sun’s UV rays can be a great thing in moderation, leading to healthy vitamin D levels and overall well-being. But if you overdo it, you could experience damage to your skin and eyes.
Blue light is one of the primary elements regulating circadian rhythms (sleep cycles). Blue-tinted daylight tells the brain to stay awake. But too much blue light (especially late in the day and before bedtime) may interrupt your sleep cycle and cause eye strain.
Researchers at Harvard found that 6.5 hours of blue light exposure had twice the negative impact on sleep cycles when compared to the same amount of exposure to green light.
We don’t know for sure whether long-term digital blue light exposure can permanently damage the eyes or not. It may take decades to know for sure. But because people are spending more time than ever staring at screens these days, many eye doctors recommend caution.
SEE RELATED: What is computer vision syndrome?
Do blue light glasses block all blue light?
They can, but they usually don’t — and for good reason.
Lenses that block 100% (or close to 100%) of blue light have a deep orange or amber tint, greatly changing the way everything looks around us.
However, lenses with 10% or 20% protection can appear almost clear. These usually make more sense for all-day wear. Many computer- or gaming-specific glasses have visibly yellow lenses, since they tend to block around 50% or 60% of blue light.
You may want to experiment with different levels of protection to see what works best for you.
Can you wear blue light glasses all day?
Yes, blocking blue light all day will not hurt your vision.
But be aware that blocking too much blue light may have the reverse effect on your alertness, making you feel groggy earlier in the day. This is especially true for high-percentage lenses, but these are often taken on and off during long screen sessions.
If you feel more tired wearing high-percentage blue blocking glasses, consider stepping down to a lower percentage.
What’s the difference between blue light glasses and computer glasses?
Most computer glasses are also blue light glasses, but not necessarily the other way around.
Computer glasses usually have a higher degree of blue light protection plus slight magnification to further reduce eye fatigue. Computer glasses with magnification act like reading glasses, except they optimize intermediate-distance vision instead of near vision, and they have blue light protection.
If these specialized glasses work for you, the additional comfort can translate into increased work productivity.
Gaming glasses also tend to include slight magnification and mid-range blue light protection.
Clear everyday blue light glasses may be better for general use and minor eye fatigue. These lenses block a low degree of blue light and offer more flexibility in terms of style and facial fit.
If you’re not sure how to find the best computer glasses for your needs, it’s always a good idea to consult with your eye doctor.
Are there other ways I can reduce eye fatigue?
Absolutely. Free programs like f.lux or your phone’s “night shift” and dark modes can also reduce the amount of blue light that reaches your eyes.
Practicing the 20-20-20 rule is another great way to reduce computer eye strain: For every 20 consecutive minutes of screen time, take a quick break and look at an object 20 feet away for 20 seconds. This gives the tiny muscles inside your eye a well-deserved break.