Not really a “tint”, but a clear chemical coating used to filter out ultraviolet light. More than a dozen studies have shown that chonic exposure to sunlight without proper protection can increase the chances of developing age-related eye diseases like cataracts and macular degeneration. We routinely recommend UV treatment of ALL glasses. It is inexpensive and offers protections against UV-A and UV-B. Also, people mistakenly believe that sunglasses automatically block out UV light by the color and darkness of the lenses. Therfore, it is important that sunglasses have UV protection as well. Usually the manufacturers’ label will indicate UV protection. Make sure the sunglasses offer complete absorption. Some labels may say “UV absorption up to 400 nm.” This is the same thing as 100% abosrption.