How harmful is blue light really for your eyes?

Blue light from screens has been controversial for years. Many people swear by special glasses that filter the blue light and supposedly protect against eye strain. But do they really work? Or are these glasses just an expensive marketing ploy?

What the science says

A large analysis of 17 randomized, controlled studies has investigated precisely this: do blue light filter glasses really protect the eyes? The result is sobering: there is no clear evidence that these glasses reduce eye strain or improve eye health.

The lead scientist of the study put it clearly: "There is little evidence that blue light filter glasses help against eye strain."

The reason: the blue light emitted by smartphones, tablets and monitors is far too weak to damage the retina. Rather, the problem lies elsewhere.

The real problem: not blinking enough

If you stare at a screen for a long time, you blink less. This causes your eyes to become dry, irritated and feel tired. It is not the blue light that is the culprit, but the lack of moisture in the eye.

Ophthalmologists therefore recommend the 20-20-20 rule:

• Every 20 minutes

• For 20 seconds

• Look at a distance of 20 feet (about 6 meters).

This relaxes the eyes, increases the blinking rate and ensures better hydration.

Blue light and sleep - there is an effect here

But there is one situation in which it makes sense to reduce blue light: in the evening. Blue light inhibits the production of the sleep hormone melatonin, which can make it difficult to fall asleep.

Blue light filter glasses or software solutions such as "Night Shift" (iPhone) or "Reduce Blue Light" (Android) can be helpful here. Even better: switch off digital devices 1-2 hours before going to bed.

Conclusion: Do you need blue light filter glasses?

To protect your eyes? No. For better sleep? Maybe. If you notice that less blue light helps you in the evening, then targeted use can make sense. But don't wear these glasses all day - it can mess up your internal clock.

Sources:

• Lawrenson, J. G., et al. (2023). "Blue-light filtering lenses for digital eye strain: a systematic review and meta-analysis."

• American Academy of Ophthalmology (2022). "Does blue light from screens really harm your eyes?"