Why Blue Light Is So Bad: The Science — And Some Solutions

Amber Case
7 min readJul 24, 2018


Why the Color of Technology Must Change” touched on the health issues caused by the pervasive use of blue light and blue screens in our technology devices. After Fastco Design featured my essay, I got in touch with Bill James of Healthe, a Minnesotan company that’s integrating blue-filtering technology into the everyday products we use. Our conversation delved into the problems associated with prolonged exposure, the industry’s efforts to address it — and some steps we all can take, to minimize these health issues.

How Light Affects the Body

Image via All About Vision

Understanding the physics of light and how it interacts with the human eye is the first step to understanding why too much of it can be bad for us.

All light is waves, and different colors have different energies. Towards the beginning of the visible spectrum is red light, made up of low energy waves. This light is easier on our eyes, especially at night. As we get closer to the higher energy side of the spectrum, light becomes more tiresome for our eyes to process. Blue light occupies the highest energy portion of the visible spectrum. It penetrates all the way to the retina in the back of the eye.

Anything above 380 nanometers is not visible to the human eye and cannot be seen. While invisible, these frequencies can still be useful. Some epoxies used in dental work use ultraviolet light to accelerate the chemical process of fixing teeth. Tanning beds use these frequencies to artificially increase tan color (though of course you wouldn’t want to be bathed in it for hours, or you could develop significant health problems).

High energy light is crucial to everyday life. We get high energy visible light from the sun, and it helps us regulate our sleeping patterns. During the daytime, the light that comes into our eyes releases enzymes in the morning, bringing melatonin levels down and helping us wake up. A consistent cycle of rest and wake, regulated by melatonin, comprises our circadian rhythm.

This cycle can easily be disrupted. Fly to another country, or stay up too late, and the rhythm can change. Shift into blue light use, and disruption can easily occur. Artificial blue light before bed reduces the amount of melatonin being released in the body. Too little melatonin, too late, can prevent sleep and lead to exhaustion.

How Blue Light Hurts the Body

Photo via Wikimedia Commons

Artificial blue light, the kind associated with LED and screen-based OLED illumination, operates on a different level of the spectrum, in the 380–500 nanometer range. The 415–455 nanometer range is the most harmful — what’s called high-energy visible light, or HEV — and it’s where digital blue light from laptops, tablets and mobile phones operate. Sunglasses are designed to block light in this range — as are welding helmets! But the tech industry has been slow to adjust. “Apple for sure doesn’t build to that standard,” Bill pointed out.

It’s no surprise that nearsightedness is the number one eye issue in the world right now. In 2016–2017, we spent an average of 10.4 hours on our devices a day. It’s why many if not most of us deal with eyes that feel “shot” — dry, itchy, sometimes accompanied by a headache, what’s occasionally called “computer vision syndrome”.

Photo by Steve Paine

Different age levels require different levels of protection. Children under the age of 14 who use tablets and phones with high energy light are at special risk. Until 14, their corneas aren’t fully developed, and lack the protection of adult eyes — especially if they’re constantly in front of a device. Increased and prolonged exposure to HEV is a contributing factor to increased diagnoses of nearsightedness among children.

Adults have their own issues to deal with. As we age, our eyes “remember” and retain energy. Blue light not only penetrates all the way to the retina in the back of the eye, it builds up over time. The cumulative effect causes eye strain, dry eye, and unnecessary exhaustion.

Because of its temperature and frequency, blue light tends to affect both the retina and the cellular anchors, leading to early onset of Advanced Macular Degeneration, an issue which must be corrected through surgery. Consistent melatonin disruption has also been linked in recent studies to an increased risk of obesity and some cancers.

Industry Solutions to the HEV Dilemma

Fortunately, many device companies are aware of the health risks from blue light, and are implementing solutions. Bill James’ works at Healthe, Healthe, which develops a dye that mitigates blue light and can be layered on glass or clear adhesive. They’re partnering with glass companies that produce the majority of glass for automotive applications, meaning we should see commercial applications of blue-light filtering technology in our own devices in the near future. (You can also buy blue-filter covers for your laptop, mobile phone and VR goggles at the Healthe webstore.)

We can also expect to see new phone releases later this year that integrate blue light-reduction dye, and the Consumer Electronics Show in January 2019 will show off commercial grade products which incorporate these features.

Product designers should help accelerate this change by working with companies to integrate HEV-blockers right into the screens of the products they create. Also consider indicator colors on connected electronic devices; a warm orange will always be more welcome than a bright blue.

Reducing Blue Light Damage — A Checklist

Until the tech industry fully addresses the problems caused by blue light, there’s a number of steps we can take — in our household, and in our civic halls:

Via Digital Trends

Your home: “Smart” appliances like refrigerators often boast a touchscreen with bright blue display. Consider adding a small “drape” or other cover to put over appliance screens, so they doesn’t blast you into insomnia, when you go into the kitchen for a late night glass of water. Appliances with LED-based bulbs are another common culprit — a topic I’ll cover in my next post.

Your laptop and appliances: Use Flux at night to slowly decrease your computer’s blue glow as the sun sets. Buy a glare-reducing protective screen cover. Don’t buy electronics with lots of blue light — of if you do, cover the bulbs. Use blue-light protective glasses at night if you can’t avoid using your devices, or can’t entirely block out blue light in your environment.

Your glasses and contacts: Talk with your optometrist about purchasing eyeglasses or contact lenses with HEV filters already built in. It’s a good idea if you plan to use your devices all day, without many breaks. You can also wear special computer glasses. TrueDark is an eyewear company that sells blue-light blocker glasses that look just like regular glasses. The company just announced two clear-lens blue-light filter glasses that block around 40% of high energy visible light. TrueDark also produces special night-time glasses that filter out all high energy visible light that you can wear over your glasses to block out 100% of blue light caused by LED lights, devices, and streetlights an hour before bedtime for optimum sleep.

Your mobile devices: iPhone users can use Night Shift (under Settings > Display) and the less-known Color Tint feature; Android users can download Twilight for their screen-dimming needs. If you can’t help bringing your phone to bed, wear HEV blocking glasses, put a blue filter screen on your phone, or place it face down while it plays; play a movie or ambient white noise, or podcast clips to listen to while falling asleep. Or better yet, drift off while reading an analog book: It will force your brain to imagine, and that effort will wear you out more than the instant simulation brought by the visual nature of our devices.

Photo by Brad Flickinger


Your kids and your state representatives: We are seeing legislative activity around the health issues of device use. Maryland recently issued guidelines on screen time for kids in schools, and did California. Parents and teachers can get ahead of this trend by requiring kids to use blue light filters on their phones, laptops and tablets, or simply by limiting technology use before 14 years old. It is especially important for children to use protection from blue-lights before bedtime.

More than all this, we also need to promote a general understanding of how widespread this blue light problem is, and do everything that we can to insure it’s fully addressed in the next few years. Babies born now are designated for a life spent entirely in front of screens; at minimum we can do what we can to minimize the ocular suffering they’re destined to face.

My own sleep patterns have improved significantly after I started wearing blue-blocking glasses. My eyes were less tired, and I had clearer vision. As a heavy computer user, I want to ensure I can still see well and do my best work, and I look forward to buying more accessories to support this process over time!

Thanks so much to Bill James of Healthe/EyeSafe and Megan Soffer from TrueDark for help with this article. Do blue-blocking glasses, apps and screen protectors help you? I’d love to hear your feedback.



Amber Case

Design advocate, founder of the Calm Technology Institute, speaker and author of Calm Technology. Former Research Fellow at MIT Media Lab and Harvard BKC.