Generally, most sunwear lenses will absorb UV lenses to some degree. Lenses that are marked CR-39R plastic, absorb about 88 percent of UV light. If sunglasses contain polycarbonate lenses, UV absorption will be 100 percent.
I believe once you put on a pair of polarized sunglasses you will understand and appreciate the difference. the clarity , and the difference in color is amazing. It is also one of the best way to protect you eyes from the harmful ultraviolet rays of the sun. A "regular" pair of sunglasses is better than nothing ( along with wearing a hat) in protecting your eyes from the sun, but there is no comparison to polarized sunglasses