"Gradient lenses" refer to sunglasses lenses that are tinted in a way where the top part is darker and gradually becomes lighter towards the bottom. Full definition
The sharp square frame and color gradient lenses complete this one - of - a-kind style. (sunglass.la)
New Vintage Christian Dior D01 Oversized frame sporting a pair of flawless gradient lenses. (1stdibs.com)
Silver - tone metal Burberry aviator sunglasses with gradient lenses, House check details at temples and blue acetate trim throughout. (therealreal.com)