Many people who wear sunglasses believe that the darker the colour of the lenses, the safer it may be for the eyes. But beware, 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 without glasses. For this reason, when buying sunglasses, one should always pay great attention to the so-called filter categories, which indicate the intensity of the tinting.The EU categories, which are usually indicated in five digits, Roman (I to V) or Arabic (0 to 4), are helpful here:
|Filter category||Glass shade||Utilisation|
|0||3 – 20%||Offers the least protection.|
|1||20 – 57%||For partly cloudy days.|
|2||57 – 82%||Suitable for normal summer days in Central Europe|
|3||82 – 92%||Offers intensive protection. Recommended for holidays by the sea, in Southern Europe and for mountain walks.|
|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.|
UV rays damage the retina
If you get too close to the sun, you will get a sunburn. The ultraviolet
rays – the so-called UV rays – increase the risk of skin cancer.
Furthermore, frequent sunbathing can accelerate skin aging. But it's not only
the skin that can be damaged, the eyes can be impaired too. If unprotected eyes
are exposed to the sun, a long and intensive irradiation can lead to
inflammations 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 sunglasses with guaranteed UV protection!
UV-C rays are basically absorbed by the earth's atmosphere, but UV-B and UV-A rays penetrate unhindered to the earth's surface. The designation UV400 with guaranteed UV protection protects against harmful UV-B and UV-A radiation. Furthermore, the sunglasses reduce visible light, which makes seeing in the sunshine more pleasant.
In short, the term UV400 means that the glasses absorb UV-A, B and C rays, up to a wavelength of 400 nanometers.
Other quality features of sunglasses
- CE mark: The CE mark has been existing 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.
- Polarization filters: The polarized 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 polarizing lenses are particularly suitable for car drivers.