UV protection and filter categories for sunglasses and glasses (UV 400 Filter)

Many people who wear glasses or sunglasses believe that the darker the colour of the lenses, the safer it may be for the eyes.

Here's the truth:

The colour of the lenses does not necessarily correspond to their protective qualities. Dark colours increase the dilation of the pupil, which leads to more harmful UV rays coming into the eye than if you weren't wearing glasses.

For this reason, when buying glasses and sunglasses, you should always pay close attention to the so-called filter categories, which indicate the intensity of the tinting.

Better protection thanks to filter categories

We wear glasses or sunglasses to see more clearly and protect our eyes from sunlight.

The levels of protection are divided into filter categories.

The EU categories, which are usually indicated by Roman (I to V) or Arabic (0 to 4) numerals, are as follows:

Filter category	Weather conditions	Glass shade	Utilisation
0		3 – 20%	Offers the least protection. Colourless or very light filter. Typically sport or protective glasses designed to protect against wind, dust or debris, but not against sun.
1		20 – 57%	For partly cloudy days. Very lightly coloured lenses, usually yellow or orange, suitable for weaker sun radiation or as wind or dust protection.
2		57 – 82%	Suitable for normal summer days. Medium dark filter suitable for medium sun radiation and for casual wear. The tint is slightly lighter than usual. Can be used for spring and autumn walks on sunny days. They also come in handy while driving and frequently shifting between shade and sun.
3		82 – 92%	Offers intensive protection. Recommended for holidays by the sea, in Southern Europe and for mountain walks. Dark filter suitable for intensive sun radiation on the beach or in the city. This category is typical for most types of glasses and sunglasses. It is perfect for summer because it provides a higher degree of protection against sun radiation than the previous category.
4		92 – 97%	Particularly strong protection, which is suitable for high mountains and glaciers. Category 4 sunglasses are forbidden in road traffic. These are marked with the symbol of a crossed-out car.* Very dark filter for very intense sun radiation. Sunglasses for mountains or deserts and everywhere where the sunshine is not just extremely strong, but also reflects a lot.

*Note: Due to the light conditions in the car, filter category 2 lenses, which transmit between 18% and 43% of light, are suitable for driving during the day. Filter category 4 lenses only transmit between 3% and 8% of light of light and should therefore not be used while driving at any time.

As good as the quality of the lenses is, up to 60% of the UV rays can penetrate from above or through the sides.

Therefore, large lenses and wide temples ('arms' of glasses) can contribute to optimal protection. In addition, wearing a hat or cap can be helpful.

What does UV 400 mean?

UV 400 is the category which blocks all light rays with wavelengths up to 400 nanometers. This covers both UVA and UVB rays. Please refer to the above table.

Do UV rays damage the retina?

After prolonged exposure to the sun, you get sunburnt. The ultraviolet rays – the so-called UV rays – increase the risk of skin cancer. What's more, frequent sunbathing can accelerate skin ageing.

But it's not only the skin that can be damaged; the eyes can also be impaired.

If unprotected eyes are exposed to the sun, prolonged or intense radiation can lead to inflammation of the conjunctiva and cornea.

In the worst case, the visual organ may be damaged in the long term and the lens may become cloudy (cataract).

Therefore always wear glasses and sunglasses with guaranteed UV protection!

UVC rays are absorbed by the Earth's atmosphere, but UVA and UVB rays travel unhindered to the Earth's surface. UV 400 lenses with guaranteed UV protection protect against harmful UVA and UVB radiation.

Sunglasses also reduce visible light, making your eyes more comfortable on a sunny day.

Other quality features of glasses and sunglasses

• CE mark: The CE mark has existed since 1 July 1995, and indicates that there is UV protection up to at least 380 nanometres. It is located on the inside of the temples, and indicates that the model complies with current EU standards.
• Spectacle frame: As already mentioned in the article, sunlight can also infiltrate from above and laterally. Therefore, in order to ensure optimum protection, slightly larger lenses and wider temples can be used.
• Polarisation filters: The polarised lenses have a special coating that increases visibility through filtering during exposure to intense light rays. These lenses are designed to reduce the glare of surfaces such as water, snow or glass. Sunglasses with polarising lenses are particularly suitable for car drivers.