You must select a tint option for your sunglasses.
Polycarbonate lenses are more impact resistant then standard plastic or glass lenses,
They provide 100% protection from UV radiation, and are light weight giving added comfort.
Originally developed for cockpits of fighter planes.
High Index 1.67 will improve the cosmetic look of high prescription lenses because there
is less curvature required to obtain the same RX compared to standard plastic. (thinner lenses)