To be considered UV sunglasses, the lenses are required to block 75% to 90% of visible light and must offer UVA and UVB protection to block 99% of ultraviolet radiation. Ideally, you want sunglasses that offer UV 400 protection since they offer virtually 100% protection from UV rays. Womens Sunglasses UV400 Mirrored Lens, Fit for Outdoor, Vacation, Driving.bought in past month.