How long have you spent looking at a screen today? If you’re close to the average person, it’s likely more than eleven hours. But if you’re here, you’re probably aware of your screen time. Now you want to know if there is a reason to be concerned.
In this article, you’re going to learn about blue light and myopia (also known as nearsightedness). Are these two things connected in any way? Here’s what you need to know:
What Is Blue Light?
Let’s start by understanding what exactly is blue light.
Blue light is one of the many colors in the visible light spectrum. These are the colors your eyes can see and include red, orange, yellow, blue, green, purple, and all the possible combinations between them. When you see a rainbow, you are seeing the visual light spectrum.
Light is made up of particles that travel in waves. Each color has a different wavelength and energy level:
Blue Light Wavelength
Wavelength is the distance between corresponding points of two consecutive waves. To measure it, we use a very small unit called a nanometer (nm). One nanometer equals one-billionth of a meter.
Blue light wavelength is shorter than other colors. As the name suggests, this type of light is perceived as blue in color. However, blue light may be present when you look at something that appears white or another color. For example, sunlight is made up of red, orange, yellow, green, blue, indigo, and violet light. When combined, it becomes the white light we see.
Blue light is considered high-energy visible (HEV) light. It contains the most energy of all visible light. More energy means the light is more intense and has more capacity to do work and interact with what’s receiving light.
As illustrated in the picture above, rays on the red end have longer wavelengths and less energy. On the other end, blue and purple rays have shorter wavelengths and more energy.
Further down the light spectrum is ultraviolet (UV) light. UV light is invisible to our eyes and has the most energy (more than blue light), making it not only capable of producing changes in your skin like suntans and sunburns, but also damage to the surface of your eyes. This is why you should never look directly at the sun.
Different animals are sensitive to different ranges of wavelengths. For example, snakes can detect infrared waves, and the visible range of many insects goes beyond ultraviolet.
Sources of Blue Light
All light we see is a combination of different wavelengths. Sunlight is the main source of blue light and being outdoors gives you the most exposure to blue light. In addition, smartphones, laptops, TVs, and tablets are manmade sources of blue light. The blue light exposure you receive from digital screens is minimal compared to the amount that comes from the sun.
Blue light exposure in the average human increased a lot in the past few decades. The sun used to be our only source of blue light. Now, many of our offices, homes, and shops are full of blue light.
We know high-energy light from the sun — like ultraviolet rays and blue light — is harmful to your eyes. The question is whether or not blue light from digital screens is also harmful. You might be wondering:
Does Blue Light Worsen Eyesight?
There is currently no scientific evidence saying that blue light damages your eyesight, but studies are ongoing.
However, doing tasks that involve looking at something close for long periods of time is bad for your eyes. Unfortunately, this is exactly what most of us are doing in our day-to-day life. We spend enormous amounts of time looking at mobile devices and computers, and this increases eye strain. Here’s the deal:
Blue light can be associated with worse eyesight because we spend so much time looking at screens, but it’s not the cause for it. When looking at close objects for long periods of time, you’re training your eyes to be in close-up mode all the time without giving them a chance to relax.
Also, when we look at screens we tend to blink less. This can contribute to eye strain and dry eyes.
We’re getting more and more exposed to blue light because of our transition to a digital lifestyle. However, digital reading is not something humans were designed to do.
Do Blue Light Glasses Help With Myopia?
No. It is unlikely that blue light blocking lenses can help with myopia or reduce eye strain. Blue light and myopia are not directly connected.
Myopia is increasing worldwide and our increased screen time definitely is among the causes for this, but blue light is not the direct problem. Our eyes need breaks from close-up focus. Outdoor activity is one of the most important factors for controlling myopia, especially in children.
With that said, blue light glasses can help with sleep. Let’s see how:
Blue Light Effect on Sleep
Blue light stimulates your internal biological clock (circadian rhythm). Staring at your computer screen or smartphone at night is like staring at the sun early in the morning — it tells your brain to wake up and stay alert. This makes you are more likely to have poor sleep.
Exposing your eye decreases your melatonin because your brain thinks it’s still daytime. Melatonin is a hormone that helps control your night and day cycles, so it plays an extremely important role in helping you get quality sleep.
To fix this, you can simply reduce your screen time before bed, or turn on night mode on your devices. But if that isn’t convenient, you can try glasses with a blue light filter. Now:
Blue light is not the devil! Good health requires blue light exposure from the sun. It boosts alertness, memory, cognitive function and can elevate your mood. The blue light effect in the daytime is good and helps regulate your circadian rhythm.
The Bottom Line
Blue light is a visible type of light with high energy. It’s mostly present in the light rays that come from the sun. However, blue light is also in screens such as TVs, smartphones, and computers.
Myopia and blue light have an indirect connection. It is not the cause for myopia, but spending a lot of time looking at screens up close (instead of being outside) increases the probability of having myopia.
Blue light plays an important role in your circadian rhythm. Many of us use electronics long after the sun has set and this can cause poor sleep quality. A blue light filter will help. On the other hand, exposure to sunlight throughout the day helps synchronize your body’s internal clock.
We need more research, as the types of screens we use nowadays are something very recent in human history.
If you have any questions, leave them below in the comment section! We will get back to you as soon as possible.
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