What Are the Sources of Blue Light

What Are the Sources of Blue Light

Nowadays, you’re bombarded by blue light. Every time you look at your phone, your TV, your computer, your tablet or spend time under an energy-efficient fluorescent bulb or LED light, you’re bathed in the short, high-energy wavelengths of blue light [1]

You’ve probably heard that all this blue light from electronic devices can interfere with your sleep and strain your eyes, and that’s true [2;3]. But not all blue light is bad.

The sun produces blue light too. When the blue light from the sun collides with air molecules, it casts blue light everywhere, and that’s why the sky is that beautiful shade of blue [1]. Like anything, blue light is okay in moderation.

In fact, during the daytime, blue light can have certain benefits. Studies show it can improve reaction time, increase your attention span and enhance your mood during the daylight hours [2]. The problems associated with blue light happen because we’re exposed to blue light all day long and all evening long too. Studies show that most people spend as much as 6 hours per day in front of electronic devices [4]. That’s a lot of blue light, and it can take a toll on our sleep-wake cycle and our eyes.

Exposure to any type of light at night decreases the amount of melatonin your body produces [2]. But research shows that blue light hampers melatonin production the most [2]. Melatonin is a hormone that plays a role in your sleep -wake cycle [5]. If you don’t produce enough at night, you’ll have trouble sleeping [6].

If you’ve ever spent a long day working on the computer, you’ve probably experienced the eye-related side effects of blue light firsthand. Too much blue light can strain your eyes, making them feel sore, irritated or dry. It can even contribute to more serious eye diseases, like macular degeneration [7].

Why is blue light bad for your eyes?

When you look at blue light, it penetrates your retina, the layer of tissue inside your eye that processes light and sends visual signals to your brain that tell you what you’re seeing [8]. Research shows that shorter wavelength lights, like blue light, are more likely to damage your retina [9]. These changes in your retina could contribute to macular degeneration, glaucoma or retinal degenerative diseases [10]

Part of the reason blue light damages your retina is because of its effect on macular pigment, protective pigments found in the center of your retina. Macular pigment is made up of three carotenoid antioxidants you get from your diet: lutein, zeaxanthin and meso-zeaxanthin [11]. Blue light can affect the amount of macular pigment you have in your eye, and low levels of macular pigment are associated with a higher risk for macular degeneration [11].

In today’s world, we’re confronted with so many sources of blue light daily that it’s hard to maintain moderation when it comes to blue light. So, what should you do about all the blue light in your life?

To keep your sleep-wake cycle on track, it’s wise to stop using electronic devices two to three hours before you head to bed. To protect your eyes, you can decrease your screen time as much as possible, and wear blue-light filtering, yellow-tinted computer glasses whenever you have to stare at screens for long periods of time [12].

These simple steps will reduce your exposure to blue light and decrease your chance of developing eye strain. But you can also promote eye health in other ways. Antioxidant supplements that contain lutein, zeaxanthin and meso-zeaxanthin are known to support good vision and help eyes age healthfully. However you choose to care for your eyes, make sure you’re protecting them from all that blue light they’re bombarded with daily.


[1] http://www.bluelightexposed.com/#where-is-blue-light-found

[2] https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side

[3] https://www.aao.org/eye-health/tips-prevention/should-you-be-worried-about-blue-light

[4] http://www.bluelightexposed.com/#bluelightexposed

[5] https://nccih.nih.gov/health/melatonin

[6] https://sleepfoundation.org/sleep-topics/melatonin-and-sleep

[7] http://www.bluelightexposed.com/#where-is-the-increased-exposure-to-blue-light-coming-from

[8] https://www.healthline.com/human-body-maps/retina#1

[9] https://www.aoa.org/Documents/CRG/Blue%20Light%20and%20Eye%20Damage.pdf

[10] http://www.bluelightexposed.com/#blue-light-and-macular-degeneration

[11] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3725486/

[12] https://www.preventblindness.org/blue-light-and-your-eyes