Blue-light-blocking glasses are simply that. They filter out a portion of the visible light spectrum with a wavelength between 400 and 450 nanometers (nm).
Blue light gets a bad rap because of its high energy and proximity to UV light on the electromagnetic spectrum (10-400 nm). UV light has long been linked to eye damage, but there is less evidence to show the potential harm with visible light. Because most LED devices have a peak emission of 400-900 nm, there’s a lot of concern over what can happen if you have prolonged exposure to the computers and devices that many of us use for hours on end.
From the American Optometric Association’s article Light and Eye Damage by Gregory W. Good, OD, PhD: “The most offending portions of the EM spectrum are the UV-A (315 nm to 400 nm), UV-B (280 nm to 315 nm), and “blue-light” portion of the visible spectrum (380 nm to 500 nm)”.
Thankfully, there’s little evidence to prove that blue light from LED devices is harmful. A study available on the National Institutes of Health’s website, Effects of blue light on the circadian system and eye physiology, sums up what we know nicely: “Although we are convinced that exposure to blue light from LEDs in the range 470-480 nm for a short to medium period (days to a few weeks) should not significantly increase the risk of development of ocular pathologies, this conclusion cannot be generalized to a long-term exposure (months to years).”
Researchers believe that more studies are needed on long-term exposure to low levels of blue light.
The fact is, with enough brightness and exposure time, all light can be damaging to the eye. LED devices are simply not bright enough to cause any harm.
Blue light isn’t always bad. A healthy amount of blue light is essential for maintaining your circadian rhythm, or sleep-wake cycle. But blue light also inhibits the body’s release of melatonin, keeping us awake during daylight hours.
Blue light deprivation (BLD) can lead to an increased risk of sleeplessness, depression, and insomnia. Like everything in life, balance is key. Blue light is necessary for our health.
Do Blue-Light Glasses Really Help?
It’s unlikely. There’s not much evidence to show that blue light from LEDs is harmful. Most blue-light-blocking glasses only filter 5%-40% of blue light.
For now, the American Optometric Association, American Academy of Ophthalmology, and American Academy of Sleep Medicine don’t recommend the use of blue-light-blocking glasses for any specific eye conditions or sleep disorders.
Instead, here are some things that may help maintain comfortable vision and healthy habits:
- Use the 20-20-20 rule: Take a 20-second break after 20 minutes of device use and look at something 20 feet away.
- Ensure you are wearing your correct prescription for glasses or contacts, working at an appropriate working distance, and maintaining good posture.
- Avoid screen time 2-3 hours before your bedtime.
- Use artificial tears and remind yourself to blink regularly to avoid dryness.
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