BEALER Sport Wrap BL6608 Two-Pack Z01, Matte Black / Grey, twice

What the rating on the lens means

UV400 on a lens means the lens is rated to stop ultraviolet light up to a wavelength of 400 nanometres, which covers UVA and UVB, the two bands that reach the ground. That rating is the whole of what a sunglass lens does about the sun; polarization is a separate property that cuts reflected glare and, in the words of the American Academy of Ophthalmology, provides no UV protection on its own. The academy also says a darker lens is not a safer lens and that the sun's rays pass through haze and cloud, so the number to read on any pair, ours included, is the UV rating rather than the tint. A pair of sunglasses is not treatment for any eye condition, and light sensitivity that arrived suddenly is a question for an optometrist or ophthalmologist, not for a lens.

Every sentence in this note about the eye comes from a named public source. All of them, with the date we read them, are on our updates page.