If it's a bright, clear day outside, you may instinctively reach for your sunglasses when you head for the door. And you probably do it without much thought about them. But you probably do think about sunglasses when you go to buy a new pair -- whether you walk into the discount store or the Sunglass Hut at the mall, you are immediately struck by the bewildering array of choices before you! For instance, there are differences between tinted, reflective, photochromic and polarizing sunglasses. The style of the frame and size of the lenses also make a difference. Is that $200 pair of Serengeti sunglasses really any better than a $10 pair from the flea market?

In this article, we'll take the mystery out of sungl­asses and help you understand what to look for when you buy a pair. We'll analyze the different styles and look at the technology behind the different lens compositions. You will also learn how light works and see why light, in certain situations, can make sunglasses absolutely essential. You will be amazed at how complex and sophisticated a simple pair of dark glasses can be.

­