Blue Light Health Effects: What the Science Says

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Medically reviewed by Dr. Alex Keller, ND – Written by Laura Dan, BSc, NDTR

Do you have trouble falling asleep at night? If so, your digital devices might be to blame. Artificial blue light, most commonly emitted from sources such as fluorescent lights, smartphones, and televisions, can have damaging health effects on your eyes and may impact sleep quality. (29)

What is blue light?

Blue light, emitted by both the sun and artificial light sources, is a defined range of light from 415 to 455 nanometers (nm) on the visible light spectrum. (29) This type of light is a short wavelength, meaning it produces greater amounts of energy compared to other visible light. If you’ve ever wondered why the sky is blue, it’s a result of the shorter wavelengths of blue light that easily scatter light in the earth’s atmosphere as they collide with air and water molecules. (6)

Sources of blue light

Industrialization and modern life have resulted in significant changes in the way we live. In developed countries, natural sunlight exposure has become less frequent, and exposure to artificial light has increased. (5) Artificial blue light is all around us, from the light bulbs we use to brighten our homes, to the smartphones we use to stay connected.

Sources of artificial blue light include:

  • Digital screens (e.g., computers, smartphones, tablets, and televisions)
  • Fluorescent lighting
  • Light-emitting diodes (LED) (28)

Did you know?
Two-thirds of adults aged 30-49 and 37% of adults aged 60 and over, spend at least five hours per day on digital devices. (27)

Negative effects of blue light exposure

While artificial light has proven to be useful in our modern daily lives, excessive exposure poses some health risks.

May cause eye damage

Chronic (long-term) blue light exposure increases your risk of developing several eye conditions. (29)

Blue light can damage eyes when light passes through the cornea and lens and reaches the retina. The lens protects the retina by absorbing blue light; however, this protective effect can result in the formation of cataracts. Cataracts are characterized by cloudy, discolored lenses and may lead to total blindness over time. (29)

Furthermore, staring at blue light-emitting screens may cause you to blink less often, which can lead to eye strain and eye dryness. (19)(24) Regular blinking is necessary for normal tear distribution and to protect the eye surface. (2)

One of the most common conditions related to chronic blue light exposure is age-related macular degeneration, which is the leading cause of vision loss in North America and results from the deterioration of the macula (central area) in the retina. (29) The retina detects light and converts it to electrical impulses that travel through the optic nerve to the brain.

Impacts sleep quality

Nighttime exposure to blue light can also impact blood pressure and body temperature regulation by disrupting the circadian rhythm. (15) The circadian rhythm is your body’s internal clock, which regulates your sleep-wake cycle.

When the sun sets, the retina in your eye detects the shift from light to dark; this signals the pineal gland in the brain to produce melatonin, a hormone responsible for regulating your sleep-wake cycle. As melatonin levels in the blood increase, mental alertness decreases, and you begin to feel sleepy. Once the sun rises and you are exposed to light melatonin production slows down, heightening mental alertness. (16)(12) When melatonin production is altered by inappropriate light exposure, the circadian rhythm is disrupted. (7)

Exposure to blue light sources during evening hours stimulates the brain and interferes with the body’s natural response to secrete melatonin. Without sufficient melatonin levels, the circadian rhythm is disrupted, affecting sleep quality, and makes it difficult to fall asleep. (29)

May accelerate skin aging

Some research suggests that blue light may harm skin by contributing to skin cell damage and aging. Exposure to light from electronic devices promotes oxidative damage in skin cells, further accelerating skin aging. (10)(5) Studies have also shown that blue light may cause more skin pigmentation than ultraviolet light (UV) from the sun. (14)

Are there any benefits of blue light?

Blue light does offer some health benefits; however, timing is key. Daytime blue light exposure increases alertness and helps regulate the circadian rhythm. Research suggests that blue light may improve memory and cognitive function. (9)(4) Daytime blue light from natural and artificial sources may also have mood-boosting effects. (11)

Blue light therapy has shown effectiveness in relieving symptoms associated with some conditions, including:

Reducing the negative effects of blue light exposure

Outlined below are some practical solutions to reduce exposure to artificial blue light and mitigate some of its harmful effects.

Increase lutein and zeaxanthin intake

Lutein and zeaxanthin are types of carotenoids that have antioxidant properties. These carotenoids accumulate in the lens and retina of the eyes and absorb blue light. (29) The accumulation of lutein and zeaxanthin help protect your eyes from oxidative damage caused by free radicals. (25)

As we age, conditions affecting the eyes, such as macular degeneration and cataracts, are more common. Diets rich in lutein and zeaxanthin can slow or prevent the progression of age-related eye disorders. Lutein and zeaxanthin are found in many green, yellow, and orange-colored foods, such as kale, spinach, carrots, cantaloupe, grapes, and egg yolks. (1)

Supplementing with lutein and zeaxanthin has been shown to be effective in restoring antioxidant levels in the eyes. (3)(23) Speak to your integrative healthcare practitioner for specific guidance and recommendations.

man looking at his laptop at night

Emitted by the sun and artificial light sources, blue light falls into a defined range of light from 415 to 455 nanometers (nm) on the visible light spectrum.

Wear blue light-reducing glasses

Blue light-reducing glasses, available with clear or amber-colored lenses, are a safe and effective tool for reducing blue light exposure. They partially filter short-wavelength light without significantly impairing vision. (22)

One study investigated the effects of amber-colored lenses and found that wearing blue light-reducing glasses with amber lenses for the two hours leading up to bedtime significantly improved sleep quality and total sleep time. (26) Another study tested the effects of blue light-reducing glasses on adolescents who use LED screens for several hours a day. Individuals who wore blue light-reducing glasses had higher levels of melatonin and were able to fall asleep faster. (21)

Minimize screen time after sunset

When possible, avoid using digital devices once the sun goes down. To optimize sleep, remove any blue light-emitting sources from your bedroom, particularly computers, televisions, and smartphones. Research suggests that eliminating or reducing blue light exposure with blue light-reducing glasses, for three hours before bed, is ideal for optimal sleep. (8) Start by avoiding screens 30 minutes before bed and gradually increase the amount of time away from screens. (17)

woman in bed at night looking at her phone, phone light illuminating her face

Blue light can have a negative effect on sleep. Minimize the use of blue light-emitting devices after dark.

Enable blue light filters on your devices

Many computers, smartphones, and tablets offer settings that allow you to adjust the color warmth of the device’s screen. These filters reduce the amount of blue light emitted from the screen. One study found that light-blocking software for digital screens improved sleep quality and cognitive function in night shift workers. (20)

Check the settings on your devices and consider opting for automatic screen adjustments, which alter the screen warmth according to the time of day. If your computer, phone, or tablet doesn’t have a blue light filter setting, there are several downloadable apps to help reduce blue light.

The bottom line

Chronic blue light exposure can have lasting negative impacts on health, particularly affecting sleep quality and eye health. Negative effects can be mitigated by minimizing screen time, filtering blue light, eating a diet rich in carotenoids, and supplementing with lutein and zeaxanthin. Do your best to minimize the use of artificial blue light-emitting devices, especially during evening hours.

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