Believe it or not, sunglasses come with many different lenses, which will offer you different kinds of protection. Your local eye doctor can help you pick out a lens that would be best for you to protect your eyes from different harmful elements such as the suns UV rays.
One of the lens options is called a Blue-Blocker. These lenses do just as they say. They block any sort of blue light. Usually Blue Blocker sunglasses will come in an amber colored lens. It is not sure whether blue light is harmful or not, so these sunglasses are not imperative to your eye safety, but they are always great to have around!
There are other lenses called Mirror-coated lenses. This kind of lens will limit the amount of light that goes into your eyes. This is a lens that is designed more so for comfort.
If you get sunglasses with a Gradient Lens, you will find yourself with a pair of sunglasses that are tinted all the way from the top to the bottom. The top of the lens is the darkest, and the middle has a clear look to it, while going back to the darkest shade at the bottom of the lens again. It would be wise so that you did not drive while wearing a Gradient lens.
All sunglasses are required by the FDA to have impact-resistant lenses. There are other lens options out there, such as color coded, styles, and everything is all a personal preference when it comes to getting your self a pair of sunglasses! If you talk with your eye doctor they can help you find a lens that meet all of your needs for personal eye care, whether it is to protect your eyes against UV rays, or to get a good looking pair of sunglasses.