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The blue light spectrum is an essential part of the visible spectrum with wavelengths of about 400-480 nm. [1] Blue light is primarily generated by Light-Emitting Diodes (LED) lighting and digital screens, it has now become prevalent in the world around us. [2] LED lighting creates white light by combining blue light with other wavelengths ...
- Overview
- What is blue light?
- What does blue light do to your eyes?
- Risks and side effects of blue light exposure
- Health benefits of blue light
- How to limit blue light exposure
- Takeaway
Blue light usually comes from the sun but also from digital screens and LED lights. Some experts believe artificial sources may be causing eye damage in humans, but animal studies are inconclusive.
Chances are, you’re reading this article on a device that emits blue light. With the amount of time people spend in front of screens reaching record highs, should you be concerned about the blue light streaming into your eyes?
The world is pulsing with electromagnetic energy. It travels around us, and even through us, in waves.
The waves vary in length, with the longest being:
•radio waves
•microwaves
•infrared
•ultraviolet (UV) waves
Your eye is equipped with structures that protect it from some kinds of light. Your cornea and lens protect the light-sensitive retina at the back of your eye from damaging UV rays, for example.
Those structures don’t keep out blue light. And you’re exposed to a lot of it — the natural blue light from the sun far exceeds the amount from any one device.
Nevertheless, some eye health experts have expressed concern about exposure to blue light from backlit digital screens and devices. This is because people spend so much time using them at such a close range.
A 2020 study published in the Indian Journal of Ophthalmology found that during COVID-19 lockdowns, for example, 32.4 percent of the study population used a blue-light-emitting device 9 to 11 hours per day. Another 15.5 percent used the devices 12 to 14 hours per day — a sizable increase in screen time, probably due to changes in the way people work during the pandemic.
So far, research does not appear to validate the concern about blue light eye damage. While some animal studies have shown that blue light can damage cells in the retina, eye doctors say there is little proof that blue light damages the retina of the human eye.
One recent exception: Doctors reported that a woman who used an LED face mask to improve her skin had distorted vision and a retinal lesion afterward. However, it’s difficult to say whether blue light, red light, or infrared light caused this damage because the face mask included all three.
Blue light and macular degeneration
Age-related macular degeneration (AMD) is the number one cause of sight loss in people over 50 years old, according to the American Academy of Ophthalmology (AAO). It happens when a structure in the back of your eye, the macula, becomes damaged as you get older. The result is that you lose the ability to see the center of your field of vision. You may still be able to see things on the periphery. But details and objects in the center of your sight lines may become blurry and, over time, more difficult to see. Animal studies and lab studies have raised questions about whether blue light could speed up the process of macular degeneration. Still, eye doctors and researchers do not think there is a verifiable link between using LED or blue-light-emitting devices and AMD. Similarly, a 2018 research review also concluded that there was no evidence blue-light-blocking lenses lessened the chance that someone who has had cataract surgery would later develop macular degeneration.
Blue light and digital eyestrain
Using digital devices up close or for long periods can lead to digital eyestrain. Research has shown that when people use computers, laptops, and other digital devices, they tend to blink less often than normal. Fewer blinks can mean less moisture. Digital eyestrain means different things to different people, but is generally related to the focusing system of the eyes. When your eyes are strained from staring at a blue-light-emitting screen, you might notice: •dry eyes •sore or irritated eyes •tired eyes •headaches •facial muscles fatigued by squinting Blue light scatters more easily than most other visible light. This may make it difficult for your eye to focus when receiving blue light. Instead, your eye may digest blue light as poorly focused visual static. This reduction in contrast may make it more difficult for your eye to process blue light, potentially contributing to eyestrain. Still, there isn’t much research to confirm that blue light directly leads to eyestrain. More high quality studies are needed.
Blue light and sleep
While the jury is still out on the long-term effects of blue light on human eye health, there is more consensus around the effects blue light has on your sleep-wake cycle. Light sensors in your eyes and even in your skin can perceive the difference between the intense blue light waves of bright daylight and the warmer, redder tones that signal the day is ending. When the light around you eases into those sunset shades, the sensors in your eyes prompt your body to release your body’s natural stores of melatonin, the sleep-inducing hormone. A small 2015 study found that when people are exposed to blue light in the evening hours, their bodies don’t release as much melatonin, and their sleep cycles are delayed or disrupted. According to a 2019 review, when blue light disturbs your sleep cycles, other problems can also develop: •an elevated risk of hormone-related cancers, such as breast and prostate •lower levels of leptin, a chemical that signals fullness after meals •metabolic changes, especially blood sugar
Help you stay alert
A small 2018 study has shown that exposure to blue light can perk up your reaction time and stimulate alertness when you’re not at your peak performance time of day.
Boost memory and cognitive function
Participants in a small 2017 study who had a 30-minute blue light “washout” period performed better on verbal memory and memory consolidation tasks afterward. Study participants who had an amber light “washout” didn’t perform as well.
Potentially improve seasonal depression
Blue light therapy is now one of the go-to treatments to relieve seasonal depression. Researchers have found that it’s also an effective treatment for depression that isn’t seasonal, especially when combined with antidepressant medications.
Practice the 20/20/20 strategy
While you’re using a device that emits blue light, stop every 20 minutes to focus on objects that are around 20 feet away. Study those objects for 20 seconds before you return to your up-close viewing.
Keep your eyes moist
Eye drops, such as artificial tears, and room humidifiers are all good ways to keep your eyes from becoming too dry and irritated while you’re using blue-light-emitting devices.
Use eyeglasses with the right prescription
Squinting at screens for long periods isn’t recommended for the overall health of your eyes. If you wear prescription eyeglasses to correct your vision, make sure you’re wearing a prescription intended for the distance between your eyes and your screen — ideally an arm’s length away. Most glasses are formulated for longer distances.
Blue light is part of the natural electromagnetic energy spectrum. Most of your exposure to blue light is from the sun, but some health experts have raised questions about whether artificial blue light could be damaging your eyes.
Some studies have shown that blue light damages cells in laboratory animals. So far, there isn’t much research that indicates blue light from digital devices and LED screens damages human eyes.
Prolonged digital device use leads to digital eyestrain, though, so it’s a good idea to take frequent breaks if school or work involves hours of screen time.
Blue light can also interfere with your body’s internal sleeping and waking cycles, too, so you may want to stop using your devices before bedtime or switch to an amber-light mode.
Feb 12, 2024 · Blue light is located in a narrow band near an outer edge of the visible spectrum, with wavelengths close to those of ultraviolet light. Blue light triggers your eyes to react, especially the lens ...
Jan 16, 2021 · Spectrum is Latin for “appearance” or “apparition” and Newton used the term to describe the rainbow spectrum produced by sunlight passing through a prism. Sunlight is a form of white light, which is the color you get when all of the wavelengths of light blend together. Newton saw the colors red, orange, yellow, green, blue, and violet.
Feb 27, 2019 · This greater degree of scattering of blue light is what makes a cloudless sky look blue. 3. Our eyes are not very good at filtering blue light. Structures in the front half of the eye (the cornea and lens) are very effective at preventing UV rays from reaching the light-sensitive retina at the back of the eyeball.
The light that human eyes can see, as it bounces off objects, has wavelengths of between 380 and 700 nanometres. Within this spectrum, running from violet to red, blue light vibrates with almost the lowest wavelength (400 to 450nm) but almost the highest energy. There couldn’t be anything more ordinary than blue light.
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Oct 19, 2023 · The strong energy of blue light is what allows it to pass easily through the cornea and lens of our eyes. Blue light has the shortest wavelength in visible spectrum, and therefore also has the most energy and is the most harmful. Prolonged exposure to this slowly deteriorates the retina. Limited exposure to blue light isn’t all that bad.
