Around 4 days ago I overused my computer. I simply used it so much that I ended up with a horrible migraine. My headache actually lasted for around 4 hours and it was surely due to blue light. Now I do use f.lux to not have this problem anymore. I can tell you that the difference is huge. I can use the computer for a lot longer, although breaks are still needed.

Leaving the personal story aside, light is something most people do not actually understand. It is simply so much more complex than we think.

We are naturally exposed to different visible and invisible light rays. This happens as you go outside, turn on the light in your room, look at your smartphone and so on.

The good news is that most people know that sunlight includes invisible UV rays and visible light rays. They know that UV rays can burn or tan the skin. What is not known is that there are many different colors in that light that is emitted by the sun, each with different energies.

Let’s Understand Blue Light

In sunlight we have blue, green, yellow, orange and red light rays, together with other shades of the colors. All is based on individual ray wavelength and energy. When these colored lights are combined, we have what we refer to as sunlight or “white light”.

We cannot get into physics too much, mainly because my personal knowledge is quite limited. There is a lot of research on the topic if you want to find it. What has to be pointed out is that blue light rays are on the opposite visible light spectrum end and have the highest energy and shortest wavelengths. They are also often called violet light or blue-violet light. Practically, these are really close in category to UV radiation, which is just beyond what we refer to as a visible light spectrum.

Basically, when referring to blue light we are really close to UV rays, which have high energy and can produce changes in our skin, creating those suntans.

Blue light is usually defined as the visible light that ranges between 380 and 500 nm. Around one third of the visible light is blue light with high energy.

Blue light is similar to UV rays in the sense that it has both dangers and benefits. This is why we should all know the following.

You Cannot Avoid Blue Light

The main blue light source is sunlight. You are mostly exposed to blue light when you are outside. However, numerous indoor blue light sources exist, like LED lighting, flat-screen TV sets and fluorescent lighting.

What has to be remembered is that display screens of electronic notebooks, computers, smartphones and most digital devices emit a lot of blue light. This is just a small part of what the sun emits but the big problem is that you are really close to the devices and you use them for a long time. That’s why many eye doctors now warn people about blue light long-term effects.

Your Eyes Do Not Really Block Blue Light

The human eye does a great job of blocking UV rays. This is why we normally talk about skin problems when sun exposure is high. Just 1% of the UV radiation actually reaches your retina when you do not wear your sunglasses.

Unfortunately, close to all the visible blue light you see will reach your retina. This practically means that the retina can be damaged when there is too much blue light exposure. In extreme cases, even permanent vision loss can appear.

We still do not know how much man-made and natural blue light is way too much for our eyes.

Digital Eye Strain

Blue light has short wavelength and high energy so it scatters with ease. The eye cannot focus it as easy as other light colors. As you look at your PC screen, you have visual “noise”. The eye cannot easily focus on the blue light so digital eye strain is made worse.

Computer glasses that have yellow-tinted lenses can increase comfort when you use the computer too much. In fact, when you use an app like the f.lux I mentioned, your display starts to look more yellowish. This increases your comfort if you use the screen for a long time as the contrast is increased.

Blue Light Is Not Always Bad

Just like most things in life, blue light is not fully bad for you. Getting blue light exposure is actually good for your health. This can boost alertness, elevates mood and helps both cognitive function and memory. Simply put, when you reduce blue light, you end up feeling sleepier and your focus goes down. You automatically feel this when you use an app that removes blue light or you start to use protective gadgets/eyewear that reduces blue light.

Blue light is also really important in regards to your circadian rhythm, which is the body’s sleep cycle and natural wakefulness. Blue light exposure that happens during the daytime will help you have a healthy circadian rhythm. However, if too much blue light happens during the night, like when you read a book on your Kindle before you go to sleep, the cycle is disrupted. You can potentially end up with daytime fatigue and sleepless nights.

Simply put, blue light helps you to stay away during the day and negatively affects you when it is time to sleep.

Protecting Yourself From Blue Light At Night

As soon as I learned about blue light and I started to pay attention to it, things changed. I now sleep better and am more alert during the day. The most important thing is to reduce how much blue light you are exposed to during the night, especially when it is close to sleep time.

Some protection options to consider are:

  • Blue Light Filters – They are available for computer screens, tablets and smartphones and will prevent a lot of the blue light to reach your eyes, all while display visibility is not affected. It just looks a little weird but you get used to it quite quickly.
  • Computer Glasses – They are helpful and you can buy them without a prescription.
  • Apps – Add them to your smartphone if you use it before you go to sleep. For Windows users, f.lux is free and really good. I am not aware of the best apps for Mac users.

Final Thoughts

Please do not take this lightly. Even if you do not have a problem right now, if you do use your computer or smartphone a lot during the night, you have to learn all that you can about blue light and the circadian rhythm. I did not do this and it was pretty bad for me. The migraine I mentioned is not the first one. It is just the longest one yet.

Neglecting the circadian rhythm for years and not even thinking about blue light led to a situation in which I was much more tired than I should be. I thought this was simply because of doing a lot of work. Now I sleep better and feel better.


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