When you turn on most digital devices, their screens vibrantly illuminate so that you can see easily in a variety of light settings. However, the visible light that comes from your screen is more complex than you might think.
There are many common concerns regarding the blue light that emanates from device screens.
When pondering the many mysteries and misconceptions surrounding blue light, you might ask yourself:
- What kind of light is it?
- Will it damage my eyesight?
- Should I worry about my long-term exposure to blue light?
You can put your mind at ease. While there are reasons to pay attention to the ways blue light may be harmful, there is no cause for alarm.
What is blue light?
The simplest blue light definition is a high-intensity, short wavelength range of visible light on the spectrum. Blue light is a high-energy, visible (HEV) light; falling in the same category of visible light as violet.
All visible light falls on a color spectrum based on the frequency of a wavelength and energy levels produced by each color.
High-energy waves have short lengths and low-energy waves have long lengths. High-energy, short-length waves like ultraviolet rays are invisible to the eye but fall on the same spectrum.
Darker colors like violet and blue are the closest to UV wavelength and strength. Lighter colors like red and yellow are on the opposite end of the spectrum with longer wavelengths and lower energy levels.
The sun, the lights, and the computer. How much is too much?
While we tend to only think of blue light coming from display screens, it’s naturally produced by the sun. Even indoors, fluorescent and LED light bulbs are sources of blue light.
Whether you’re aware or not, you’re surrounded by blue light all of the time. Most computer monitors, cell phone screens, and flat-screen TVs are additional sources of blue light. This is because white light LED combines with blue LED to create a solid-state light which uses significantly less energy and power than alternative sources of light, making it ideal for electronic devices.
Even though we are surrounded by blue light in our natural environment our whole life, it’s our digital environment that causes excess exposure and the need for concern.
Is blue light harmful?
Blue light is harmful the same way having too much sodium in our diet is harmful. Our bodies are naturally adept at absorbing and dealing with blue light exposure, but like anything else, too much can be detrimental.
Blue light exposure can be helpful in some circumstances. If you have trouble waking up in the morning or focusing, a source of blue light can assist with both.
But is blue light harmful to the eye? While our skin doesn’t have much of a problem absorbing and dealing with blue light, our eyes don’t have the same level of protection or filtration.
Because the wavelength of blue light is short and powerful, it can penetrate past the cornea to reach the retina, which is the most light-sensitive part of your eye.
1. Eye strain and headaches are trouble signs
One of the most common side effects of blue light exposure is digital eye strain. If you stare at a computer screen for too long, you may start to experience pain in your eyes and headaches.
Digital eye strain, also known as computer vision syndrome, may lead to dry, sore, red eyes and blurred vision. With enough prolonged exposure, blue light can harm your eyes and lead to macular degeneration - causing damage the same way UV rays would.
However, avoiding permanent damage to your eyesight is fairly easy because it takes a significant amount of prolonged, repetitive exposure.
By appropriately managing the amount of exposure you’re getting or using a blue light filter, you can prevent any damage that would otherwise occur.
2. Limit your computer and TV time
Unless you’re cranking away at a computer for 10 hours a day every day, your biggest concerns will be when you expose yourself to blue light and for how long.
Our bodies are naturally conditioned and programmed to fall asleep when it gets dark and wake up when we’re exposed to light. A study performed by Harvard Medical School found that blue light suppresses melatonin for about twice as long as green light and shifts circadian rhythms by twice as much .
The same study also found that green light may be damaging and strenuous on the eyes as well. The typical wavelength of blue light falls between 450 and 490 nanometers. The wavelength for green light is 520 to 560 nanometers, with cyan falling in between.
Because the two lights are so similar in terms of strength, and there are few remedies for green light exposure, it’s important to limit and monitor the amount of screen time you’re getting from computers and devices each day - even if you use a blue light filter.
Of course, this is much easier said than done given how much we all depend on our devices and computers. If you’re up late watching TV or working on your PC, your body may have difficulty adjusting and falling asleep so be sure to use some form of blue light filtration.
3. Get your eyes checked regularly
It’s not just blue light that can affect your vision. As we age, the lens inside our eye can lose flexibility, resulting in the inability to change focus from far to near. Getting regular comprehensive eye exams are an important component to maintaining eye health, no matter how much time you spend in front of screens.
If you already have prescription glasses, you can move to multi-focal lenses. If not, then “readers” from the drug store may be enough - at least for a while. You can also have your optometrist add a blue light filter on your glasses or find reading glasses that include one.
4. Blink, rest, and restore
Dry eyes are irritated eyes. Your body’s natural defense is to blink. This lubricates and cleans our eyes, and in normal situations the average person blinks 10 to 20 times per minute. Unfortunately, studies have shown that when we concentrate, our blink rate drops. We only blink 3 to 8 times per minute when reading, watching TV, or looking at a computer screen .
Take time to rest your eyes every 20 minutes or so. Look away from the computer and focus on something distant - like a poster on the wall across the room or out a window. Close your eyes gently, then squeeze and hold them shut for a moment, then open and relax them. Try to remember to blink more often in between, too, and when you are thinking, instead of squinting at the screen, turn away and blink a few times. Your eyes will thank you.
What is a blue light filter?
A blue light filter can either be a physical barrier that repels and blocks out blue light or an application that changes the light emitted by your device or computer display.
Filter software programs
Built-in nighttime settings on devices often leave an orange tint on the screen that can distort images and diminish the quality of your viewing experience if you’re watching a video or surfing the web. However, they are effective at reducing your exposure and protecting your eyesight.
One of the most popular blue light filter applications is F.lux®. Like most blue light filter applications, F.lux reduces the blue light coming from your screen and boosts the warmer colors like red, yellow, and orange. One of the unique features that makes F.lux stand out from the other applications is the ability to adjust your settings to the time of day. Rather than setting timers and remembering to activate the filter on your PC or device, F.lux will automatically change in accordance to the ambient light throughout the day.
Another great application is Iris®. Iris is one of the most intuitive and user-friendly blue light filter applications. With Iris, you can choose from a variety of modes and types within the settings menu. Select from options like automatic, manual, and paused mode for your convenience and preference.
Within the type settings, you can select health, reading, programming, biohacker, sunglasses, dark, movie, and overlay. Each of these options gives the user a slightly different experience and changes the display setting to accommodate specific tasks or activities.
Video and movie displays are often the most affected and distorted by application-based blue light filters. Fortunately, the video setting on this blue light filter is one of the best. You won’t get an ugly orange glare from your screen when you’re watching movies late at night on your laptop or PC.
Unlike F.lux, Iris is not free. It’ll cost you $15 to install on your computer. If you don’t want to pay without giving this software a thorough test drive, Iris offers a seven-day free trial for new users and a one-month free trial for every friend who installs the software after your initial free trial.
With over twenty different features, Iris is a worthwhile expense to protect your eyesight.
Physical blue light filters
Physical blue light filters work by blocking short, high-frequency waves and allowing long, low-frequency waves through.
If you were to do a side-by-side comparison of blue light filter applications and physical blue light blockers like glasses, it would quickly become apparent that the physical barrier diminishes the quality of the picture and color far less than its application-based counterpart.
Filtering screen covers
Physical blue light filters are the easiest and best way to reduce your blue light exposure. Some blue light filters for PCs are just a clear piece of plastic material that covers your monitor, while other filters come in the form of blue light blocking glasses.
Blue light filtering glasses
Blue light filter glasses have become increasingly popular due to the recent studies revealing the potential damage and health concerns surrounding blue light.
If you have to work late at night on a PC or cell phone, wearing blue light filtering glasses for 3 to 4 hours before bedtime is the easiest way to keep your melatonin levels in check  and your retinas protected. While some of the flashier glasses may cost upwards of $80, you can get inexpensive pairs for $10 to $20 online.
The downside of physical blue light filters is that they are rarely made of durable material and you may end up having to replace them from time to time. Additionally, many prescription and over-the-counter reading glasses come with blue light filters in the lenses, so it may be a waste of time and money to invest in a blue light filter if you regularly wear prescription glasses.
How to set up blue light filters in your settings
Don’t want to deal with the hassle of purchasing a physical blue light filter or downloading an application? Windows 10 comes with a built-in feature in your settings called Night Light.
With Night Light you can set a timer that controls the lighting on your computer screen for a section of time; for example, sunset to sunrise. What’s great about Night Light is the ability to control how much your screen’s blue light decreases.
Here’s a step-by-step guide on how to use the Windows 10 Night Light:
- Open up your start menu
- Select the gear icon to open up your settings menu
- Go to system settings (display, notifications, and power)
- Select display
- Turn the Night Light switch on
- Go to Night Light setting
From here, you can adjust the levels of blue light reduction and the timeframe you would like to restrict and control them. You may also choose to automatically adjust the brightness when the lighting changes.
While this is the simplest blue light filter for your PC because you won’t have to download or purchase any additions, you should still consider investing in a physical form of protection.
Give one of these tried and true solutions a go to save yourself the discomfort and strain caused by blue light.
 Harvard Heath Publishing; Blue Light Has a Dark Side
 Vision Source; Are you blinking enough?
 NY Magazine; Do Blue-Light-Blocking Glasses Actually Do Anything?