People must pay attention to the lens, color, and uv index while selecting sunglasses. The card of the sunglasses is the ID card of it which indicates its production place and other useful information. 

It is best to choose light grey, light green and Russian blue to protect from ultraviolet radiation, because the color of nature won't be changed with these soft colored glasses. UV index is an important standard in filter ultraviolet radiation out. They are usually between 96-98%, and dear-color is better than light color.