Is blue light from all our devices really harmful to us?

Since screens dominate so much of our daily lives, people want to know if they have any influence on us – not only based on the content we watch, but also on the light of the screen itself. Some people are particularly concerned about the effects of blue light, and as a result we are offered all kinds of accessories to combat its supposed effects. But does blue light really affect our health?

What is blue light?

Blue light is a color in the light spectrum visible to the human eye, occurring at wavelengths of 380 to 500 nanometers and making up about one third of the light we see.

Although many people have heard of this in the context of digital devices, the reality is that the vast majority of our exposure to blue sunlight comes from the Sun – compared to screens like computers and phones, we get very little.

Blue light is thought to be potentially harmful in two main ways: it damages your eyes and prevents you from getting a good night’s sleep. How much truth is there in these statements?

How can blue light affect our eyes?

“Blue light causes blindness”

One major study making headlines is a 2018 paper by researchers at the University of Toledo. “Blue light from phone screens accelerates blindness” is the headline of a Guardian article about the study, one of many — but the study didn’t show that at all.

In this study, the team looked at how the retina, a light-absorbing compound in the eye, responds to exposure to blue light and found that cell membranes were damaged in the cells they tested.

Although the retina is present in the human eye, the study results cannot be applied to our case. That’s because it didn’t mimic the conditions in a real, live human eye; all but one of the cell lines tested were from other parts of the body that are not exposed to blue light. The retina also does not touch the cell membrane of the cells found in human eyes.

Another study tested cells that If present in the retina – the part of the eye that senses light and converts it into electrical signals interpreted by the brain. The researchers found that two hours after exposure to blue light, these cells suffered severe DNA damage, causing them to die.

However, there is a catch – the study was conducted on rat cells. This means not only that the results may not necessarily translate to humans, but also to what research is conducted in vitro means you can’t even say much about how live rats will react.

“Blue light causes eye strain”

If you’ve ever come across an advertisement for blue light-filtering glasses to wear when using devices, you’ve probably noticed claims that they can help reduce eye strain – meaning that eye strain is caused by blue light. However, there is no solid evidence to suggest this is the case.

For example, a 2023 Cochrane review examined 17 clinical trials that compared the eye effects of blue light-filtering lenses with non-blue light-filtering lenses and concluded that the former “may not improve symptoms of eye strain when using a computer for long periods of time.” . short observation period compared to lenses that do not filter blue light.”

According to the American Academy of Ophthalmology, what appears to be the main cause of eye strain after using digital devices is insufficient blinking when using them.

How can blue light affect our sleep?

Conversations about blue light also often cover its impact on our sleep, often with a warning that we should not use devices right before bed because of this. But how true are such claims?

This is a bit vague, mainly because this area requires much more research. A review of 36 studies found that half of them found that exposure to blue light reduced fatigue and sleep efficiency decreased, but the time it took to fall asleep and the quality and duration of sleep decreased. NO seem to have an influence.

A study published late last year exposed people to different types of light – dim blue, yellow and white – and found that there was no clear evidence of differences between them in their effects on sleepiness, actual sleep or the body’s circadian rhythm (our sleep cycle and standby).

That being said, the study conditions weren’t exactly like those in real life.

“In this study, we specifically designed light exposure… to avoid activating light-sensitive cells in our eye that are known to be responsible for resetting our circadian rhythm that does not correspond to actual lighting,” Dr. Alexander Solomon, neuro-ophthalmic surgeon, who was not involved in the study, told Healthline.

“This cell is sensitive to blue light, so to say that blue light doesn’t play that big of a role is untrue. This simply means that bright yellow light can affect things just as much as dim blue light.

The most important thing

There is currently no evidence that blue light is harmful to us, especially when it comes to causing eye damage. Its effects on our sleep may be a bit more controversial, but it’s still not enough to justify the need to spend a lot of money on blue light glasses.

If you feel like your devices are keeping you awake, there are some much cheaper solutions – switch them to night mode (which can be found on many devices these days) or simply try to use them less often before bed (easier said than done when it’s TikTok drama, we know).

All “explanatory” articles are confirmed by fact checkers believed to be correct at the time of publication. Text, images and links may be edited, removed or added at a later date to keep the information up to date.

The content in this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. If you have any questions about a medical condition, always seek the advice of a qualified healthcare professional.