In summer, it is usually when we take the initiative to buy ourselves a good sundial, in addition to the aesthetic criteria of each one, we find ourselves faced with a diverse range of types of lenses, UV protection, different categories of solar filter, polarized lenses etc.
In this post I will try to explain all these aspects:
PROTECTION UV400 (CE Marking)
Although the eye has protection mechanisms against the threats of solar radiation, such as the contraction of the pupil and eyelids, they are not always sufficient. The best way to avoid creating potential problems is to use sunglasses, always purchased in health facilities and under the supervision of a health professional. In addition, it is essential to ensure that they protect against ultraviolet rays (especially UV-400 radiation) and that they comply with European Union safety standards, in which case they will bear the CE marking.
This image can help to detect whether the EC symbol is original or an unapproved copy.
CATEGORIES OF LIGHT ABSORPTION IN %.
Sunglasses are designed to protect the wearer against the dangerous action of the sun’s Rays. The European standard EN1836 classifies solar filters into 5 categories that are distinguished by the percentage of light absorbed by the lens, this % of light absorbed, is different from UV protection, since all must have a UV protection, the idea of these 5 categories is to choose the best type of filter according to the tasks to be performed.
The filtration of the UV radiation is performed on the lens material, is independent of the degree of stain since even the lenses white lenses have filter protection UV400.
COLORATION OF THE LENS
Another option when choosing our sundial is the choice of the color of the lens, in the following image you can see which colors and for which activity are the most recommended.
POLARIZED OR NON-POLARIZED
As the last aspect of choice, it is the polarization of the lens.
Sunlight vibrates in all directions, but when it bounces off a smooth surface (asphalt, snow, water,…) it produces quite uncomfortable reflexes, especially in driving situations and Nautic and/or mountain sports. The polarized lenses contain a special filter that blocks the reflected light and only allows useful light to pass through, allowing a vision without reflexes much more comfortable.