Jan 03, 2023 20:00:00

What does 'dark mode' mean?

``Dark mode'', which has a black-based layout, is thought to make the screen easier to see, prevent eye strain, and help save the battery of the terminal, so OS, browsers, applications, etc. Various software supports dark mode. However, Kev Quirk, a developer who stopped using dark mode as a result of various investigations, explained why he came to that conclusion.

Is Dark Mode Good For Your Eyes? | Kev Quirk

https://kevquirk.com/is-dark-mode-such-a-good-idea/

◆: readability
According to a survey comparing visibility between dark mode and light mode, light mode performed better for people with normal vision.

Humans have evolved to hunt during the day, which means they have adapted to seeing dark objects on a bright background. As Mr. Quirk's experience when he was in the military, he said that there is a rule of camouflage strategy that 'do not expose yourself to a place where your silhouette is easy to see, such as on a hill.' This is because dark blobs in front of a bright background are much more noticeable to the human eye than vice versa.

◆: Eye strain
The aforementioned research also casts doubt on the indication that dark mode can prevent eye strain. The reason for this lies in the way the human pupil works. The pupil contracts when more light enters the eye, and conversely expands to let in more light when it is dark.

At this time, if the pupil is small, it is less susceptible to

spherical aberration , which is a phenomenon in which the image is out of focus and the image is blurred, and the depth of field is deep, so there is no need to try to focus on the letters. It is said that it becomes difficult to get tired. Conversely, when the screen is dark and a lot of light has to be collected, the pupil dilates and the eyes get tired easily.

Then, what on earth causes eye strain other than light mode? Blue light is the biggest factor. Eye strain can also be caused by fonts that are too small, astigmatism that is not properly corrected, and dry eyes caused by not blinking for long periods of time.

Mr. Quirk says that as a countermeasure against blue light, the night mode of the OS is enabled to reduce the blue light emitted from the screen. It's also important to take regular breaks and consciously blink.

If you still experience eye strain or headaches, it might be a good idea to visit an optician. In fact, when Mr. Quirk consulted an optician while struggling with this problem, it turned out that he was actually farsighted and needed reading glasses. Since then, Mr. Quirk has suffered almost no headaches or eye strain.

◆: Battery consumption
According to Mr. Quirk, few sites and apps have a real black background in dark mode, and in most cases it is dark gray or dark blue. In that case, light mode and power consumption will be almost the same.

If it's true black, the power consumption depends on the display. First, in the case of liquid crystal displays, even black color consumes power. On the other hand, for organic EL displays (OLED), black pixels consume no power.

Below are the results of a survey conducted by the news site Android Authority on

active matrix organic EL (AMOLED) displays. As a result, it was found that using dark mode on AMOLED can cut battery consumption by about 41%.

From this point of view, Mr. Quirk said, ``Dark mode is neither easy to read nor prevents eye fatigue.In addition, unless it is an organic EL, it does not extend battery life.Depending on your constitution, dark mode may be necessary. So my site will continue to support dark mode, but if you use dark mode for no reason like I used to, problems will occur eventually and it may hurt your eyes. I summed it up.