Canadians cannot tell how much UV protection a pair of sunglasses will provide by their price, colour, or by the darkness of the lenses. Consumers should look for labels that list the type and amount of protection. General purpose sunglasses block from 60 to 92 percent of visible light and UVA rays, and between 95 and 99 percent of UVB rays. These sunglasses are good for driving, and are recommended whenever sunlight is harsh enough to cause squinting. Other types of sunglasses, including cosmetic tint and special purpose, are not recommended for driving.