In ITOOTI sunglasses we used green polycarbonate lenses that let in 15% of light. They are commonly called "G15" and were invented in the 1930s for the needs of fighter pilots in America. Over time, they have become widely available to civilians and are still used by leading sunglasses manufacturers as a flagship product.
All sunglasses, regardless of where they are sold, must meet the standards in force in the country they are sold.