Category of sun lens protection: How to choose?

WHAT DO SUNGLASSES PROTECT OUR EYES FROM?

When we are exposed to the sun, the pupils of our eyes dilate to filter the sunlight until it reaches our retina. In some situations, this natural filter is not sufficient. Sunglasses should protect you from:

INVISIBLE LIGHT

Ultraviolet rays, which are highly harmful to the eye. While UVA rays are mildly dangerous, UVB rays can cause burns and numerous vision-related symptoms.

Infrared rays, which can be dangerous to the eyes in extreme conditions (high mountains, deserts) by causing dryness and raising the temperature.

Protection of your eyes with lenses that block 100% of UV rays is therefore crucial.

VISIBLE LIGHT

The dangers of visible light include glare, fatigue, discomfort, and possible temporary vision impairment. This light does not always have the same intensity depending on the location, climate, terrain, etc. Therefore, there are different filtration indices or categories of protection to protect your eyes from these hazards.

FILTRATION INDEX AND/OR PROTECTION CATEGORY

There are five categories classified on a scale ranging from 0 to 4, based on the increasing percentage of light filtered; according to the European standard NF EN ISO 12312-1:2013 concerning sunglasses for general use, published by the AFNOR group.

The filtration index or the category of sun protection is essentially the same thing; both are determined by the amount of visible light they allow to pass through the lens. The lower the transmission rate, the darker the lens, and it is this lens tint that affects glare but not UV rays.

If you're unsure, we recommend category 3: it's the most versatile and suitable for all sunlight conditions. There are also photochromic lenses that cover multiple categories of sun protection as they darken or lighten according to UV exposure. This type of lens is ideal for frequent changes in sunlight and brightness. To learn more about this, we invite you to discover our REACTIV photochromic technology. But above all, the choice of a lens should correspond to your usage, and our article "Which Sunglasses for Which Sport?" can provide you with some insights.

Beyond the category, it's also important to consider the lens color, which affects your vision comfort, and the material for their optical quality.

/!\ Category 4 lenses are not permitted for driving as they filter too much light.

KEY TAKEAWAYS

To conclude, beware of misconceptions: just because your lens is dark doesn't mean you'll be protected from UV rays! The tint only affects visible light. So before making any purchase, make sure that the CE UV 400 standard is present on the sunglasses; it imposes construction and performance requirements on manufacturers to offer sunglasses that block all light rays with a wavelength of 400 nanometers, covering all UVA and UV rays.

At Julbo, all our lenses belong to optical class 1 and guarantee 100% protection against UVA, UVB, and UVC. Be very careful about this, especially with fancy sunglasses for your children. You can continue reading with the article: "Don't Play with Your Children's Eyes".