How to choose suitable outdoor sunglasses when traveling

The first is to have the function of UV400. Sunglasses without UV400 can't effectively filter the ultraviolet rays in UVA, UVB and UVC, but it is harmful to the eyes (Baidu's popular science knowledge about UV400 sunglasses). . . Secondly, the function, UV400 sunglasses are divided into: photochromic type, which belongs to omnipotence, and also suitable for dark light at night (but the lenses are transparent gray, and the standard sunglasses without color coating are cool), standard type (commonly known as "sunglasses", and the lenses are plated with black or metallic color), and polarized type (when there is a large area of glass reflecting water, tall buildings and windows, the reflection can be filtered out, and it is clear that the water or glass is behind it. Some imported polarized sunglasses of more than 1,000 yuan also have the function of filtering blue light; Polarization type is relatively expensive, and it has the best eye protection effect in strong light, but it is not suitable in dark light. . . Finally, the appearance, eye protection is the first, the damage of ultraviolet rays to the eyeball is irreversible, some people can't feel it when they are young, but their eyesight will drop rapidly in middle age; At the same time, the appearance of mainstream big-name sunglasses is also good. . . Choose the above according to your own needs.