Have you seen mirrored glasses on display windows? These are sunglasses which have polarized lenses. Much like mirrors, these lenses have a silver layer which blocks the light from passing through the lens, so only the wearer of the sunglasses can see the other side. No translucent silhouette of the wearer’s eyes can be seen by people who are looking at the wearer.
If you’re looking for a really efficient pair of sunglasses which you can use for driving and hanging out at the beach, then you might want to consider mirrored sunglasses. These are available in a variety of styles and lens shapes and are more than just aesthetic accessories. The mirrored or silver tint reflects sunlight, so it’s slightly better at shielding your eyes from the rays of the sun compared to regular sunglasses.