How Does Blue Light Affect Your Eyes?

by Emerson Ecologics

Affects of Blue Light

These days, we’re surrounded by blue light, one of the visible portions of the color spectrum. Blue light is not only emitted by our electronics (smartphones, tablets, TVs, etc), LED light bulbs and contains a higher concentration of energy at a shorter wavelength. Therefore, we’re inundated with it almost constantly — even after dark, lying in our beds, we stare at our smartphones. Given the prevalence of blue light in our lives, researchers are working quickly to determine just how this may affect our long-term health, both physically and emotionally. 

Blue light is most often associated with poor sleep or interrupted circadian rhythms, but there can be negative physical effects to the eye as well. “The more research we do, the more evidence we have that excess artificial light at night can have a profound, deleterious effect on many aspects of human health,” says and chief of the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital in Boston. “It is a growing public health concern.” 

Like any other evolving aspect of public health, we must learn how we can mitigate the damage already done and learn how to best protect ourselves from future damage. Here’s what you need to know about how blue light affects your eyes (as well as other aspects of your health) and what you can do to support eye health.

Blue Light and Circadian Rhythms

Eye strain is more common among people who spend copious amounts of time looking at screens (such as people who conduct a significant portion of their work on computers) because of blue light’s short wavelength, high frequency nature — it scatters quickly and can exhaust the eye as it tries to focus on the screen. 

“Common sense and inference leads us to believe there is reason for caution here,” says  , health coach and wellness podcaster. “Blue light, on the light spectrum, is very close to ultraviolet rays — the ones we try to protect against. So, sitting and staring at our devices (computers, TVs, cell phones) is, for our eyes, almost like sitting outside in the sun without sunblock.” 

Given the push for everyone to everyday, Trepeck’s analogy hits close to home. “There is potential for damage to the retina of the eye, the part of the eye responsible for vision, turning light into neurological signals which go to the brain for visual recognition,” she says. “Therefore, many will experience eye fatigue, headaches and other discomforts. More scientific research is needed, but I still recommend to my clients that we take preventative measures.”

However, most practitioners and researchers agree at this point that, while the light itself is not helpful (and potentially harmful), the major issue with blue light is how it affects our circadian rhythms.

found that “short-wave blue light with wavelength between 415 nm and 455 nm is closely related to eye light damage.” Furthermore, “this high energy blue light passes through the cornea and lens to the retina causing diseases such as dry eye, cataract, age-related macular degeneration, even stimulating the brain, inhibiting melatonin secretion, and enhancing adrenocortical hormone production, which will destroy the hormonal balance and directly affect sleep quality.”

Researchers point out that this is a particular concern at night time, and suggest the use of anti-blue light products, such as blue light blocking glasses, or films that can be placed over a smartphone, tablet, or computer.

is inclined to agree. “Evolution proceeded under the assumption that light meant daytime and darkness meant night,” he says. “Exposure to bright or white light after sunset messes with this natural rhythm, disrupting melatonin levels and sleep patterns. I advise limiting technology use in the hour before sleep.”

In other words, it’s better to be safe than sorry — especially when it comes to your ability to get a .

How Does Blue Light Affect Your Eyes?

In order to understand how blue light affects your eyes, both in the short and long-term, you must first understand how your eyes work, at least on a basic level. If we can recognize the function of each part of the eye and how they play a role in absorbing and processing light, we can learn how to protect ourselves from damaging light and habits that increase our risk of eye damage.

Cornea

The cornea is the first line of defense for the eye — it’s the clear portion of the front of the eye that covers and protects the iris and pupil. Its primary purpose is to direct and focus light that enters the eye so we can make sense of what’s in front of us. It is composed of cells and proteins, but no blood vessels.

“the survival rate of corneal epithelial cells after Blu-ray irradiation decreases, while blue light has been shown to increase reactive oxygen species (ROS) production in corneal epithelial cells, activate the ROS-nucleotide-binding domain, leucine-rich containing family, pyrin-domain containing-3 (NLRP3)-interleukin (IL)-1β signaling pathway, and trigger inflammation of human corneal epithelial cells (HCECs) induced by hyperosmotic pressure from NLRP3 and up-regulation of IL-1 beta secretion. Thus, mediated oxidative damage and apoptosis lead to further ocular inflammation and xerophthalmia formation.”

In simpler terms, what this body of work is saying is that blue light triggers a process that increases inflammation in the corneal cells, and that this inflammation can lead to vision issues, and cell death (apoptosis). 

Lens

The lens is a biconvex, ellipsoid shape, which means that it’s a bit like a sphere, but elongated. When light enters the eye through the cornea, the lens actually changes shape, which focuses images. This works in a very similar way to how the lens of a camera works. Think of a professional camera lens — it’s longer and twists back and forth. As you do so, the image becomes clearer or more blurry, depending on which direction the lens is turned. This is the same thing that the lens in your eye is doing, all day, every day and in order to accomplish this, it uses the light that the cornea focuses.   

, the structural proteins, enzymes, and protein metabolites in the lens absorb shortwave light, such as ultraviolet (UV) rays and blue light. “These substances and derivatives are added to the lens’ protein to produce yellow pigments in the lens’ protein, causing the lens to gradually darken and turn yellow. The absorption of blue light by the lens increases significantly, thus blocking potential blue light retinal damage.”

So in this regard, our eyes are quite literally trying to adapt to protect themselves, which can lead to different problems. “When it exerts its protective effect on the retina, the lens has to undergo a decrease in transparency or color change, which leads to cataract formation.”

Retina

The retina is the thin membrane lining the inside of the back of the eye, right against the optic nerve. It takes the light focused by the cornea and lens, and then converts it into neural signals that the brain will understand, and transmits them to the brain via the optic nerve.

The cornea and lens block the vast majority of UV rays from reaching the retina. However, these first two defenses of the eyeball structure are not as effective with artificial blue light (not the light coming from the sun). Therefore, doctors are growing more and more concerned that the amount of time we spend staring at screens will of vision loss later on in life. 

“Blue light exposure may increase the risk of macular degeneration, which is the leading cause of severe, permanent vision loss in people over age 60,” says . “It happens when the small central portion of your retina, called the macula, wears down. The fact that blue light penetrates all the way to the retina is important, because studies have shown that too much exposure to blue light can damage light-sensitive cells in the retina.”

It’s important to note that not all blue light is “bad,” but we’re exposed to it so frequently (and for long intervals) that the compounding effect may be making the possibility of damage greater than before we all had smart devices.

The good news is that there are plenty of ways for you to protect your eyes and reduce your exposure to blue light.

The Benefits of Blue Light Glasses

Many companies are making glasses with lenses specifically designed to reduce the blue light entering our eyes. In some cases, these are simply frames with no corrective lenses, but prescription glasses can also be made to block the light. Essentially, it tints the blue light back to yellow. These glasses are great options for people who work on computers all day, or spend a good portion of time using screens.

“Blue wavelengths are known to cause oxidative damage to retinal cells, and a lifetime of exposure does appear to contribute to cataract formation and the development of macular degeneration,” says Ticho. “The natural human lens filters out most harmful blue and ultraviolet rays. When the lens is removed — in cataract surgery — the loss of this natural barrier was found to contribute to retinal degeneration.” 

Additionally, some doctors recommend blue light glasses after cataract surgery because the “cloudy” nature of the eye is no longer blocking UV rays. However, there is also good news on that front — Ticho says that science is catching up with our screens” “Intraocular lens implants now include a coating to filter out harmful wavelengths.”

Reducing Blue Light Exposure and Damage

Aside from blue light glasses, doing whatever possible to reduce the number of hours you spend on devices will be beneficial for eye health. For example, choosing to read physical books, or using an e-reader that does not use blue light is a good alternative to reading on your phone or tablet. Furthermore, be sure to turn off the TV and listen to music instead (even if the music is played from a screen, you don’t have to be looking at it).

Here are some other ways you can take care of your eye health and reduce potential damage from blue light exposure:

  • When you’re outside, be sure to wear sunglasses that block both UVA and UVB rays to protect your eyes from the sun. 
  • Use artificial tears to keep your eyes moisturized and lubricated.
  • Use warm light bulbs in your home.
  • Use the “night” setting on your smartphone, which tints yellow instead of blue after a certain time of night (which you can customize).
  • Buy a screen cover for your computer or tablet. In a doctor’s office setting, you may already have screen protectors for privacy. For home devices, consider getting protectors to block the blue light.
  • Set strict standards for yourself in terms of unnecessary screen time. 

Supplements for Blue Light Protection

In order to protect your eyes from potential damage, you can choose to supplement your diet with a number of vitamin, mineral, and other supplement ingredients that have been linked to supporting eye health, including the following:

  • Lutein
  • Zeaxanthin
  • Zinc
  • B vitamins
  • Omega 3s
  • Vitamin C
  • Vitamin A
  • Vitamin E

Protecting Eye Health

To some extent, time will tell how greatly all our screens are affecting our eye health. In the meantime, we can take multiple measures to protect our eyes, such as limiting our time staring at screens, wearing glasses that block blue light, wearing sunglasses when it’s sunny outside, eating healthy foods that provide important nutrients, and supplementing when necessary.

Are you interested in learning more about eye health? Check out these articles with additional pro tips: