03 BUYING NOTES
Compare how much light sunglasses let through
Visible light transmission, often listed as VLT, tells you how much visible light passes through a lens. A lower percentage means less light gets through. A higher percentage can suit overcast conditions.
Ask for the VLT of the exact tint you want if the listing offers several colors. Compare that figure with the lighting where you expect to use the glasses.
Smith Optics examples of lens tints and VLT