Girl looking at harmful sun light with UV400 protection

What makes UV-radiation so harmful?

The sun emits harmful UV radiation and that is why it is important with high-quality sunglasses. But what exactly is UV radiation and what is sufficient UV protection? In this article, we will explain to you how to protect yourself from this harmful radiation.

Briefly about UV-radiation

The sun emits light in the form of waves of different wavelengths. The visible light is slow enough for our eyes to perceive it, but UV rays have faster wavelengths. This is called the UV index.



The UV radiation is divided into three sub-groups. The UVC has the most energy, but is absorbed by the ozone layer in the atmosphere. This is therefore harmless to us. But both UVB and UVA rays have wavelengths that break through the ozone layer and therefore reach us.

UVA radiation is closest to the visible light and is the UV radiation with the least energy. It is the UVA that gives makes us tan. The majority of UV radiation from the sun that reaches the Earth is within the UVA part of the spectrum. .

UVB radiation has higher energy than UVA. It’s UVB that primarily causes us to get sunburned when we are careless in the sun. The ozone layer actually prevents 70-90 % of the UVB radiation from the sun from reaching the Earth’s surface.

Both UVB and UVA radiation that hits our skin initiates much-needed production of vitamin D. But you don’t need more than 10 minutes of sun without sunscreen to replenish vitamin D stocks. More UV radiation, on the other hand, will hurt us. The eyes are especially exposed!

Eyes are exposed to UV-radiation

Fortunately, the skin has some protection against harmful UV radiation. The eyes have none. That’s why the cornea is very sensitive to radiation. The cornea can therefore become sunburned.

Just like your skin gets sunburnt, so can the eye. It can even flake. That’s what we call snow blindness!

The risk of cataracts and other damages to the retina increases over time. The World Health Organization estimates that about 20% of all cataract cases in Norway are caused by UV rays.

That’s why it is important to stop the UV rays! We do this by protecting ourselves with a material strong enough to block it out. Sunglasses are strong enough to block out UV rays, but weak enough to let through visible light.

Glasses without color actually stop over 97 of the UV rays, so the dark color is for even better comfort when it’s extremely bright outside. Did you know that?

But still, sunglasses are designed to be more accurate on what kind of light is being released through its lens. The difference between the harmful and the harmless rays is small. The sunglasses allow more of the visible light to reach the eyes which provides increased visual comfort.

In the EU, it is actually legally required that all sunglasses should be CE marked. That is a minimum requirement where the sunglasses must stop all harmful and dangerous UV radiation. So if you buy sunglasses from a safe place in Europe, then there’s no difference in how good your glasses are at blocking out UV rays. The quality difference lies on other properties such as BlueBlock, scratch resistant coating, anti-dew and so on.

Why choose Mokki sunglasses?


All sunglasses legally sold in Europe are CE marked. This indicates that the sunglasses have adequate protection. Sunglasses that do not meet these requirements can be dangerous to use!


Buy directly from a trusted brand like Mokki, so you don't end up with a copy or a false CE-mark.


Different activities require different glasses. It is important that the glasses fits your face well, especially by the sea, on the mountain or in areas with reflective light. The reflections send UV-rays into your eyes from other angles than normal. E.g. the side, from above or from below. For increased comfort, we recommend polarized sunglasses, which better block out reflections.


Children’s eyes let in more radiation than adults, and they also spend more time outdoor. That’s why they need extra-good sunglasses that provide extra protection. More tips for children and sunglasses can be found here.


UV rays are also found when cloudy. Especially important in the south or near the equator where there is more UV radiation.

Do you need help finding a pair of sunglasses that suit you? Read more in our eyewear guide!

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