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The default setting on most devices is to display black text on a white background. Setting your device to dark mode means that it will display white text on a dark background.

Dark mode is intended to reduce blue light exposure and help with eye strain that comes with prolonged screen time.

There’s no definitive evidence to suggest that dark mode does this, but let’s take a look at what we know and don’t know about dark mode.

To understand whether dark mode has any health benefit, we first have to consider the way the blue light affects our eyes.

Blue light waves are emitted from our screen devices. But blue light comes primarily from the sun, scatters into our atmosphere, and colors our sky blue.

These waves have more energy than other colors of light and send our brains the signal that it’s daytime.

While we’re only now starting to understand the side effects of excessive blue light exposure from screens, you can imagine why it would start to confuse your eyes.

People who promote dark mode sometimes claim that using it in the hours before bedtime helps them to fall asleep more quickly and stay asleep for longer periods of time.

In theory, this is because default screen settings expose you to more blue light after dark, disrupting your circadian rhythm and suppressing melatonin, the hormone that signals your body that it’s bedtime.

Dark mode may also be easier to read, especially when you’re in a room with the lights off. The reduction in blue light may reduce any squinting or strain associated with high amounts of brightness.

These anecdotes about blue light and eyes aren’t necessarily backed by research or supported by expert opinion, though.

The American Academy of Ophthalmology (AAO) states that digital eye strain is caused by the way we use our digital devices, not necessarily the blue light that comes from them.

Studies on whether dark mode and other blue light filtering solutions work to mitigate blue light exposure are inconclusive. However, it seems dark mode is more likely to affect sleep rhythm than eye strain.

Some research has been done specifically on the impact of dark mode on people’s ability to fall asleep.

A 2019 study of Apple’s dark mode settings didn’t demonstrate any notable difference in melatonin production between people who used Night Shift on their iPad before bed and people who didn’t.

The study’s authors further suggested that Night Shift alone wouldn’t be enough to restore circadian rhythm. Turning down the device’s brightness settings appeared to be equally (or perhaps more) important.

This finding seems to line up with official recommendations from experts. The AAO officially recommends reducing glare and brightness by changing the settings on your screen as well as setting devices to dark or night mode.

Some research has suggested that there may be some connection between blue light and how quickly you fall asleep.

A small study published in 2017 showed that playing games on a smartphone right before bed caused people to take longer to fall sleep as compared to those who used a blue light filtering software on their device.

The research into dark mode’s effects is far from conclusive. But anecdotally, some people claim that using dark mode does benefit them.

Dark mode may reduce eye strain

Fans of dark mode claim that it can increase the amount of contrast between the text that you’re reading and the background.

This would, in theory, make it easier to read on your device. Since reading for long spans of time on a screen can lead to eye strain and dry eye, it seems like it might be worth giving it a try to give your eyes a break.

Dark mode may cut down on blue light exposure

Blue light exposure does have demonstrated side effects, such as difficulty sleeping and eye strain.

Dark mode may cut down on your exposure to blue light, but you may also achieve these results by turning down the brightness of your screen after dark, especially when the space around you is dark.

Dark mode may increase the battery life on your device

This isn’t exactly a health benefit.

But if you’re looking at screens a lot, it can’t hurt to add an hour or two between charges of your device.

Dark mode may help with eye symptoms

Some symptoms can indicate it’s time to start using dark mode to help protect your eyes and decrease blue light exposure, such as:

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Seek out professional medical help if you’re starting to have certain symptoms and at-home treatment or prevention strategies aren’t working.

See an eye doctor if you begin to notice any of the following:

  • significant eye strain or pain
  • chronic dry eye
  • frequent headaches or migraine attacks that don’t respond to over-the-counter medication
  • obstructions in your vision
  • signs of an eye infection

Conditions including dry eye, eye strain, and insomnia can be triggered by overexposure to blue light.

Treatment for these symptoms include:

How to prevent eye strain and reduce blue light exposure

  • Stay hydrated during the day. This helps your whole body, including your eyes, stay well-lubricated.
  • Take breaks from the screen. The AAO recommends a minimum 20-second break, every 20 minutes of screen time.
  • Keep your phone out of your bedroom overnight. Also, scale back screen time in the 2 hours before you turn in for the night.
  • Lubricate your eyes with over-the-counter eye drops. This is helpful when you’re using the computer for long periods of time.
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Dark mode may work to decrease eye strain and dry eye for some people who spend a lot of time staring at screens.

However, there’s no conclusive date that proves dark mode works for anything besides extending the battery life of your device.

It doesn’t cost anything and won’t hurt your eyes to give dark mode a try. But if you continue to have symptoms of eye strain and dry eye, you should pay a visit to your eye doctor to discuss other treatment strategies.