UV rays everywhere, we see this term all over the media, on our sunscreen bottles and even on our clothes… but who are they really, and most importantly, what are their dangers?

What is a UV ray?

First of all, we’re going to start with a little scientific explanation (I promise it won’t last long!). Alright, let’s go back to our high school Physics lessons and pay attention! ????

As a reminder, it was our dear Newton who discovered the light spectrum (Well, he didn’t just get hit by an apple for nothing!). The analysis of light consists of creating its spectrum through the phenomenon of dispersion, which allows us to observe the different radiations that make it up.

Each light radiation is associated with a wavelength (λ). Those between 400 nm and 800 nm are visible to the human eye.

As you can see, ultraviolet rays are part of the invisible spectrum, just like infrared rays and many others.

But why are UV rays not visible to our eyes?

In fact, they have a wavelength that is too short to be visible to the human eye. But a shorter wavelength means much higher energy, making them even more harmful to the human body, especially to our eyesight.

However, rays with a longer wavelength are generally more numerous and can be more penetrating.

Warning, they are not visible but our eyes can still be affected by them!

The different types of UV rays and their dangers for our eyes

Ultraviolet rays are classified into 3 categories depending on their wavelength, which can range between 100 nm and 400 nm. They are divided into UVA, UVB and UVC rays. Thanks to the absorption of UV rays by the ozone layer, almost 95% of the rays that reach the Earth’s surface belong to category A.

You should not confuse the feeling of heat caused by the Sun with UV rays — this is mainly caused by infrared rays. Even when the weather is cold and cloudy, ultraviolet rays still pass through the atmosphere.

Good to know:

• UV rays are stronger at higher altitudes because the wavelength decreases with altitude (especially between 12 PM and 4 PM when the sun is at its highest). Skiers should be extra careful!
• They are reflected by water, sand, grass and especially snow.
  
  

UVA rays (315-400 nm)

UVA rays are the closest to visible light. As mentioned above, they represent 95% of the UV radiation that reaches the Earth’s surface. With their long wavelength, they are not extremely energetic but are highly penetrating. They can pass through glass and penetrate the skin down to the dermis, so imagine what they can do to your eyes!

UVA rays pass through the upper layers of your eyes and reach the lens. The cornea can still block 99% of these ultraviolet rays (Nature really does things well!), but the retina remains exposed to 1%, which can have serious long-term consequences for your eyes. Excessive absorption could cause keratitis or even cataracts.

Good to know:

• They contribute to immediate tanning
• These rays accelerate skin ageing and the appearance of wrinkles
• They are believed to be responsible for skin cancers.

UVB rays (280-315 nm)

UVB rays have a medium wavelength and only penetrate the surface layers of the skin. Yes, they are the ones responsible for your sunburns! (Yes, we have all fallen asleep on our towel between two swims ????).

If you do not wear sunglasses, UVB rays reach the cornea, which can filter them but becomes damaged little by little. Excessive exposure to UVB rays can cause inflammation of the cornea.

UVC rays (100-280 nm)

This type of ultraviolet ray is the most harmful, but fortunately the ozone layer still manages to filter them all. However, they can still be found on Earth through specific lamps used in biological laboratories.

Which sunglasses should you choose to stay properly protected?

As you can see, it is really important to be careful when choosing your sunglasses. Here are a few rules to follow:

1. You should make sure they comply with the CE standard, which guarantees 100% protection against UVA and UVB rays. This standard may be indicated as follows: 100% UV400.
2. You should not confuse lens categories with UV protection. If sunglasses comply with the CE standard, regardless of the lens category you choose, you will always be 100% protected. Categories indicate the ability of a lens to absorb natural sunlight. For everyday use, we recommend choosing category 3 sunglasses.
3. You can choose polarized lenses, which do not affect UV protection but improve visual comfort. This technology helps you reduce glare effects, especially from car surfaces.
   
   

There you go, we hope we have helped you better understand these famous UV rays that everyone talks about. And don’t hesitate to ask us any questions in the comments!