Take a look around. I bet, in any given moments you can spot at least a few screens. Be it a TV, laptop, iPad or your mobile phone. We live in the world, where we are surrounded by screens emitting blue light from every corner of your home or workplace.

There have been claims that blue light is actually harmful. People often view it in the category of light pollution, implying that it can disturb your sleep and impact other functions of your body. Is any of it true? What do researchers say about it? Should we be scared?

Blue light – what is it?

Blue light is a type of light visible on the light spectrum. Blue refers to the color (obviously). It has a short wavelength (between 400−500 nm), which means it is a type of high energy visible light.

Just to put it into perspective the sunlight contains all kinds of different color rays, just like a rainbow. Some of them are visible to us, some not (like UV light for example). All of those rays together form a light as we know it – the ‘white light’ or simply sunlight.

The Light Spectrum

Different color rays have different energy levels. Blue light is a high energy light that is still visible to human eyes.

Blue light does not come only from the screens. You can see it everywhere, even in nature. In fact, our daylight contains blue light too. Whenever we see lots of light, we know it’s daytime. Our attention is higher, the mood is better and reaction time is faster. Our bodies get the signal to stay awake. That’s pretty much everything you’d expect to happen during the daytime, right?

When the evening comes, our bodies usually slow down, attention is dropping, we get sleepy. Now, if we overstimulate ourselves and expose our bodies to too much light during this time, the body gets confused and natural rhythms of sleep and awake times get disrupted.

Any type of light could have this same effect, however, it seems that blue light is particularly strong.

Screens vs. your eyes.

The issue of screens affecting the eyesight is quite well researched. Sadly, it seems conclusive, that blue light has a negative impact on our eyes and health. The study published in the International Journal of Ophthalmology called ‘Research progress about the effect and prevention of blue light on eyes’ claimed the following:

‘…blue light passes through the cornea and lens to the retina causing diseases such as dry eye, cataract, age-related macular degeneration, even stimulating the brain, inhibiting melatonin secretion, and enhancing adrenocortical hormone production, which will destroy the hormonal balance and directly affect sleep quality.’

It seems to be true, that staring at a computer or mobile screen for too long could damage your eyesight and damage your health.

Sleepless nights

Do you have trouble falling asleep? The blue light of your mobile phone might be to blame. 1

If you have trouble falling asleep, getting restful nights and are sluggish in the morning try observing your nighttime routine. One study found that simply reading on your iPad in the evening could really mess up your head. Blue light emitted during that time delays the production of melatonin (the sleep hormone), which in turn causes a disruption in your circadian rhythm. In this study, it affected people so much so that they felt sleepy an hour and a half later than usual. Moreover, those using iPads before bed had worse quality of sleep and felt more tired in the morning. Participants who read a traditional book before bed, those effects were not observed.

There is a good reason to believe that you shouldn’t, in fact, be staring at your iPad or mobile phone right before bedtime, as it might affect the quality of your sleep.

Could the new inventions help you to sleep better?

Since the theories of blue light from screens have been popularised, many tech companies started to invent the cure. They didn’t want people to stop using their products (of course!).

The night shift mode

Night mode on your iPhone is a good example. Apple came forward to meet the needs of their consumer when designing this additional feature. You can easily switch it on in your settings, or even schedule it, so it’s automatically on and off at your desired times. Sounds great, right? Now you can scroll through your Instagram or Facebook long hours into the evening, guiltfree!

Do you have trouble falling asleep? The blue light of your mobile phone might be to blame. 2

Well, not exactly. The Lighting Research Center has actually conducted a study to investigate if the night shift on the iPhone is actually effective. They found that switching to night mode in the evening times indeed had an impact on melatonin levels but that’s not enough to gain the health benefits.

As written in their press release: ‘For a two-hour exposure to the iPad, the LRC measured: 

  • 23% melatonin suppression on regular settings (not using Night Shift; from previous Wood et al. study)
  • 19% melatonin suppression while using Night Shift High CCT 
  • 12% melatonin suppression while using Night Shift Low CCT’

If 20% is enough for you, that’s great. Be aware, that your sleep quality will be still affected. According to LRC what matters, even more, is adjusting the brightness of the screen. However, if you really care about the quality of your sleep, it’s best to simply avoid any screens one to two hours before sleep.

Blue light blocking glasses

Image result for blue light blocking glasses

This is quite a new invention. In theory, such glasses contain filters in their lenses, which supposed to block the blue light. Those types of products are quite new. There are still no regulations and really almost no research to prove that they work.

Singular research done so far, like the one by the University of Houston from 2017 seems to confirm that ‘the use of short wavelength‐blocking glasses at night increased subjectively measured sleep quality and objectively measured melatonin levels and sleep duration...’.

The hype is just starting. According to Market Study Report ‘the global market size will reach US$ 27 million by 2024, from US$ 18 million in 2019. Maybe it’s worth the try?

The dark mode

Do you have trouble falling asleep? The blue light of your mobile phone might be to blame.

Switching your devices to the dark mode can prolong your battery life indeed. Whether it does anything for your health, it’s questionable. There is no conclusive evidence that it actually helps at all. It probably won’t kill you, but don’t expect the miracles. You simply won’t have excellent sleep quality and healthy eyes, if you constantly staring at the screens, dark mode or not.

Surely, tech companies and software developers will try to convince you otherwise. They don’t want you to stop using their products, not at night, not ever! Either way, feel free to join the dark side, if you wish and see if it makes a difference.


Good quality sleep is important for our health. If you have trouble falling asleep, or you are always tired in the morning it is worth checking your nighttime routine. Certainly, you can bring on the heavy guns, switch your phone on the night shift mode, implement the dark mode on all of your devices and wear the blue light blocking glasses, but if you still scrolling Facebook long hours into the night, I’m afraid this won’t help you.

Surely, it would be best to find a way to train yourself to sleep less and still be rested. However, a much simpler solution is probably just taking a break and turning off your devices before bedtime. It costs nothing, gives you guaranteed results and it’s good for your mental health.

Do you have trouble falling asleep? The blue light of your mobile phone might be to blame. 3