Cell Phones and Computers – Does Blue Light Really Harm Our Eyes?


You shouldn’t look at your cell phone before going to bed and blue light damages our retina – this has been heard a lot in recent years. New studies provide clarity.

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Various studies have looked at the effects of blue light on our eyes.


For a long time it was said that the blue light from screens harms our retina.

For a long time it was said that the blue light from screens harms our retina.


But that's not true, confirms the German Ophthalmological Society.

But that’s not true, confirms the German Ophthalmological Society.


  • For a long time it was said that blue light was harmful to our eyes.

  • The light from screens is also said to have a strong influence on sleep.

  • Current studies are now providing new insights.

  • It turns out that blue light filters have no effect on how tired our eyes get after working on screens.

  • And according to experts, the light from screens cannot harm our eyes.

No cell phone before going to bed, computer screens ruin your eyes and blue light filters are useful antidotes – there are countless opinions and advice on the subject of screens and their blue light. How harmful blue light and screens actually are for our eyes is controversial. In order to answer these questions once and for all, various scientists have carried out several studies.

To find out how blue light actually affects our eyes and our brain, researchers from Australia divided 120 study participants into two groups. Half received special glasses that filter out blue light from screens, the other half received placebo glasses with normal glass lenses. They were then instructed to work on a computer for two hours.

Blue light filter glasses

Afterwards, the scientists were unable to detect any differences in the degree of eye fatigue of the participants, as the results published in the American Journal of Ophthalmology showed. From this it can be concluded that the glasses with the blue light filter actually have no influence on the eye fatigue caused by computer or cell phone screens.

It was also shown that no differences in the critical flicker sequence could be measured. This is a frequency in which light has to flicker so that the human eye perceives it as continuous light and not as flickering. Here, too, the glasses with the blue light filter had no effect.

Do screens cause retinal damage?

Does this mean that blue light is harmful to the eye, regardless of whether blue light filter glasses are worn or not? No, concludes the German Ophthalmological Society. Prof. Dr. Michael Bach from the University Clinic Freiburg tested how the illuminance levels of screens differ from the light conditions in the open air, as describes. “The light intensity of electronic devices is far too low to cause retinal damage to the eyes,” reports the professor.

Specifically, the exposure level on a cloudy day in winter is around 5000 lux. However, screens that are set very brightly only reach 500 lux when the eyes are 50 centimeters away from them. This result is also confirmed by Dr. Christoph Schierz from the Technical University of Ilmenau. According to the expert, screens fall below the critical light limit values ​​around 290 times. So there is no damage due to the light irradiation of the eyes through screens.

And the night mode of cell phones?

In addition, a study by Brigham Young University has found that the night mode of cell phones, which is supposed to reduce the blue light on the screen, has no effect on falling asleep. For example, the use of the filter did not lead to easier falling asleep or better sleep quality in the participants of a study compared to those who did not use the night mode.

However, this does not mean that you should now safely watch videos on your mobile phone for hours in the dark before going to bed. The study clearly showed that not using smartphones at all before going to bed definitely has an impact on sleep quality. If you value a high quality of sleep, it is better to pick up a good book than your mobile phone before going to bed.

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