Dark mode and eye health. What the experts say

Dark mode (dark mode) is a feature that changes the appearance of a device’s interface – instead of a light background with dark text, the user sees a dark background with light elements. The idea is not new, because at the beginning of the computer era CRT monitors displayed green letters on a black background. Over time, however, light themes became the standard, as they were meant to imitate the look of paper and were more natural for editing documents. Only with the development of smartphones and OLED technology did the dark mode trend return, and within a few years it became one of the most popular system features.

On which devices is dark mode available?

Dark mode is now available on most of the devices we use every day. On Android and iOS smartphones, you can enable it globally and set a schedule for automatic switching, which is especially appreciated by owners of OLED and AMOLED screens, where real energy savings are visible. Similarly, computers with Windows, macOS and Linux offer a dark theme that covers the entire interface and more and more apps, which increases comfort when working in the evening and in dark rooms. It has become equally common in mobile and web apps such as YouTube, Messenger, WhatsApp or the Chrome and Firefox browsers, which allow you to adjust the appearance independently of system settings. Dark interfaces also appear in Smart TV televisions, especially those based on Android TV and Google TV, where they improve aesthetics and viewing comfort in the evening. It is also present in tablets and e-readers – in the latter, such as Kindle, it works by inverting colours, which makes night-time reading easier and reduces eye strain. Thanks to this, dark mode has become almost a standard and it is hard to imagine a device without this function today.

We can now find dark mode almost everywhere:

• Smartphones – both Android and iOS allow you to set a global dark theme and an automatic activation schedule.

• Computers – Windows, macOS and Linux have a dark mode that covers the system and compatible apps.

• Mobile and web apps – YouTube, Messenger, Instagram, Facebook, WhatsApp, Twitter/X, as well as the Chrome, Firefox and Edge browsers offer their own dark mode settings.

• Smart TV televisions – some models, especially those based on Android TV and Google TV, also allow you to set a dark interface.

• Tablets and e-readers – on tablets it works similarly to smartphones, while on e-readers (e.g. Kindle) dark mode is based on colour inversion, which is very important when reading at night.

How does dark mode work on different screens?

The effects of dark mode depend on the type of screen. On OLED and AMOLED displays each pixel works independently, so black means it is turned off, which actually reduces power consumption and extends battery life. On LCD and LED screens the backlight is on all the time, so the savings are minimal, although the dark theme still improves comfort at night. In e-book readers with e-ink screens, dark mode is based on colour inversion, which for many people makes night-time reading easier, although not everyone finds it comfortable.

• OLED/AMOLED – each pixel lights independently, so displaying black means the pixel is actually turned off. Thanks to this, dark mode really saves battery, sometimes even by several percent.

• LCD/LED – the backlight is on all the time and the colours are filtered through the matrix. Dark mode does not significantly affect energy consumption, but it changes visual comfort.

• E-ink (readers) – dark mode is based on colour inversion, which for some users is more comfortable for night-time reading.

Advantages of dark mode

1. Battery savings
Most noticeable on smartphones with OLED and AMOLED screens. Studies have shown that when displaying dark content, power consumption drops, extending the device’s operating time without charging.

2. Less eye strain at night
In low light, a dark interface is less dazzling. This is especially important when using a smartphone before bed or in a dark room.

3. Reduced blue light emission
Although dark mode does not replace blue light filters, it does lower its level, which can have a positive effect on sleep hygiene.

4. Aesthetics and modern look
For many people, the dark theme simply looks better. It is associated with elegance, minimalism and professionalism.

5. More privacy
On a dark background, it is harder to read screen content from a distance, which for some is an additional advantage.

Disadvantages of dark mode

1. Worse readability in bright environments
In full daylight, the dark theme can be less readable and the contrast of text on a black background may make it harder to concentrate.

2. Eye strain during long reading
Paradoxically, white text on a black background can cause more eye strain when reading long blocks of text. This is due to the effect of letters “blurring” at high contrast.

3. Inconsistency between apps
Not all apps support dark mode. Sometimes it happens that you are working in a dark interface and when opening another app a bright background suddenly appears.

4. No real energy savings on LCD
Users of devices with LCD screens may not notice any difference in battery consumption, which can be disappointing.

Myths and facts about dark mode

Many myths and misunderstandings have grown around dark mode. It is often said that it always saves battery, but in reality this mainly applies to OLED and AMOLED screens, where black pixels actually turn off. In the case of LCD this effect practically does not occur. It is also a common belief that dark mode protects the eyes from fatigue – and indeed at night it can be less tiring, but in bright surroundings it can be the opposite, making reading more difficult. The same goes for sleep: less blue light can support sleep hygiene, but limiting screen time is far more important. Some people also believe that the dark theme is just a passing trend, whereas the benefits are real – although not in every situation and not for every user.

Practical tips – when is it worth using dark mode?

1. At night or in low light to reduce eye discomfort.

2. On smartphones with OLED/AMOLED screens to save battery.

3. When using devices in multimedia mode – video, photos and games often look better on a dark background.

4. If you value aesthetics and minimalism – the dark interface is more modern.

When is it better to stick with standard settings?

Although dark mode has many advantages, there are situations where it is better to stick with the light theme. The most obvious is using devices during the day, especially in brightly lit places, where the dark background reduces readability and tires the eyes faster. The light mode is also better for office work with a lot of text, because black letters on a white background are more natural and easier to read for long periods. Finally, if the device has an LCD screen, enabling dark mode does not bring any practical energy benefits, so using it becomes purely a matter of aesthetics.

Is it worth using dark mode?

Dark mode is more than just a passing trend. On suitable devices it can actually save battery, and at night it clearly improves comfort. However, it is not a universal solution – during the day it can be less practical, and when reading long texts it may strain the eyes. The best compromise is to use automatic theme switching depending on the time of day. This way we gain comfort, aesthetics and better hygiene when working with screens.