Spectacles is advisable to have glass. Latest plastics of course are not so bad, but on them quickly appeared scratches. The glass can be easily distinguished from the plastic by weight: it is much more difficult.
Separately, the glass must have 100% UV protection. According to internetdict, sunglasses from polymers such as CR- 39 and C-13 used most professional athletes who spend a long time in the sun. Mirror lenses are spectacular, but still do not provide 100% protection. The degree of protection, which is usually indicated on the handle, label or the passport of the glasses does not depend on the color of the glass. Look for sign UV 400! It means that the chemical composition of glass entering supplements that provide precisely 100% protection.
The “CE” means that they comply with the European quality standards, and the inscription “glare protection” evidence of additional features – these glasses can repay glare from reflective surfaces.
It is proved that yellow, pink and orange glasses are harmful.
Yellow instance stimulates the retina, causing optical stress.
Green sunscreen filters have a healing effect because lower eye pressure. For the retina of the human eye is most suitable neutral greyscale. Such filters do not change the natural color vision, but only slightly muffle it. The two color glasses, darker on top and lighter at the bottom, suitable for drivers.
A so-called. Glasses-chameleon is not the best option for the summer season – they are not able to protect you from the harmful rays.