Endless scrolling through the vastness of the internet on a smartphone screen tires the eyes. This is because the light it emits is very similar to daylight. It is believed that blue light makes us chronically sleepy. Following this theory, blue light filters appeared in smartphones. How do they work, and do we even need them?
How does a blue light filter work?
Although we haven't personally tested this, we've heard rumors that overdosing on certain famous blue pills makes you see the world in that color. This is certainly an interesting case for doctors, but it's probably not worth trying yourself, because in this situation, a blue light filter definitely won't help. Why? It's a function to control the color of the light emitted by the smartphone display. It doesn't apply to this medical case.
The principle of its operation is quite simple – the filter reduces the intensity of the blue channel of the RGB signal based on information received from sensors built into the monitor. The idea is for the screen to react to the color of the natural or artificial lighting in the room.
What does a blue light filter do?
Blue light has a stimulating effect on the body. Its cool color causes the brain to receive a signal that it's midday, even at night. The blue light filter causes the screen to automatically raise the color temperature of the displayed images, reducing the blue light component. This way, the brain is not fooled, and the difference between the light from the screen and the intensity of external light is safely minimized.
We can confidently state that using a smartphone with a blue light filter in the evenings makes your eyes less tired. On the other hand, if you don't put your smartphone away in time, you won't sleep well even with an active blue light filter. Remember, even in the times of Vikings, people liked to get a good night's sleep, so it's better not to overdo smartphone use late into the night. After all, a well-rested Viking is a happy Viking.
Blue light filters in smartphones are implemented through operating systems, but they also have their hardware equivalent. Special films or screen protectors are also available for purchase, which work similarly to software filters. People who wear glasses and work in front of a monitor can also opt for lenses with a polarizing filter. Eyeglass lenses with filters are a convenient solution. Especially if you wear glasses all the time, they will save you from wondering whether the devices you use adjust to the time of day and lighting intensity.
Does a blue light filter work?
Researchers have differing opinions on blue light filters. However, the connection between melatonin secretion and the lighting conditions we function in is still being studied, as are the mechanisms that are activated in the body during sleep. There is still no definitive answer to the question of whether the blue light filter in the monitors of various devices is effective.
However, we do know which light will cause stimulation and which will make you feel sleepy. Warm light (with a temperature up to 3000 K) has a relaxing effect. The cool color of blue light (with a temperature above 5000 K) is stimulating. Yellow light imitates natural lighting at sunset. Therefore, it's completely normal that it causes sleepiness. We can be sure of one thing (though certainty can sometimes be deceiving, see below) – to ensure healthy and peaceful sleep, it's best to put away your smartphone or tablet an hour before falling asleep.
Different opinions on blue light filters
Interestingly, Dr. Tim Brown, a scientist from the University of Manchester, conducted a study that was supposed to prove the opposite. The conclusions he published could suggest that exposure to blue light does not affect sleep quality. The British scientist conducted his study on mice, not human volunteers, so there is no 100% certainty about the accuracy of his findings.1
In light of this latest research, a blue light filter is not essential – simply manually reducing the screen brightness is enough to solve the problem. On the other hand, we are so accustomed to automatic functions in our smartphones that there's probably no need to give up convenience, right?
How to turn on the blue light filter?
It couldn't be simpler! Smartphones currently on the market have a blue light filter as standard. Both Android and iOS operating systems offer this feature without requiring additional installation. Moreover, it's fully automatic and doesn't need to be manually controlled. It activates on its own and adjusts screen colors based on sensor information. On Android phones, you'll find it under an icon named Eye protection. Convenient, isn't it?
On iPhones, this feature is called Night Shift. You'll find it in the control center under the Brightness icon. To activate it, simply tap the sun icon. Another way is to go to Settings, then Display & Brightness – after opening it, find the Night Shift icon. Apple's blue light filter offers manual control or setting a schedule for the function, so the screen changes color automatically.
Is it worth using such solutions? Definitely yes, especially since smartphones accompany us everywhere these days, and we spend a lot of time staring at their screens. And although we sell internet for your devices on a daily basis, we also believe that it's not filters, but common sense (surprised? We're surprised too, but yes, we follow the principle of sense and madness in a 50/50 ratio) that should guide us when using electronics. When you feel your eyes are tired, simply put down your phone and go conquer the world of sleepy dreams about battles, conquering other peoples, expeditions, and looted treasures.
PS. Reach for it in the morning, fully energized after your adventures.
1 https://www.bbc.com/news/health-50807011
