The sun is our friend, but it can also be a deadly enemy. Getting excessive and constant exposure to sunlight without adequate protective gear can wreak havoc on the skin and the eyes. That's why it's important to apply sunscreen on the skin and to wear sun glasses before venturing outdoors. Most people realize that the sun's ultraviolet radiation can cause skin cancer, but not as many people realize that the same ultraviolet rays can cause a raft of eye diseases, such as photokeratitis, cataracts, and macular degeneration. Wearing sun glasses can go a long way toward preventing these disorders ? and they look good, too!

The history of using eyewear for protection is not so new. In fact, there is archaeological evidence that the prehistoric Inuit who lived in the Arctic fashioned eye shields with slits out of pieces of bone or wood to avoid snow blindness. And in the ?Earth's Children? historical novels of Jean Auel, the main characters Ayla and Jondalar pretty much used the same kind of protective eye shields to safeguard their vision from glare coming from ice and snow as they made their way across a gigantic glacier during the Ice Age. Auel's novels are based on extensive archaeological research and evidence, so it's not farfetched to think that our primitive ancestors used devices to protect their eyes from the elements, as we do now.

Tinted lenses, however, seem to have emerged in China during the medieval period. And they weren't used to protect the eyes from the sun. Instead, judges used tinted spectacles that contained smoked quartz to hide their reactions from other people during a trial. In the 18th century, an English maker of scientific tools, James Ayscough, came up with the idea of tinting the lenses in his spectacles because he thought that white light was not conducive to good vision. The fact that he was an apprentice to an optician named James Mann greatly aided his efforts to create eyewear with tinted lenses that could correct vision disorders.

It was near the middle of the 20th century that sun glasses came into vogue. An American by the name of Sam Foster sold a pair in 1929 in Atlantic City, New Jersey and they started increasing in popularity from 1930 onwards.

The American military saw the potential of the eyewear to reduce glare that plagued pilots in the air and manufacturers rushed to supply the army's needs: Bausch & Lomb created glare-reducing shades for the Army Air Force while Ray Ban released its signature aviator-style shades, which used polarized lens and an innovative frame, also to shield the eyes of aviators from solar glare. To this day, Ray Ban's aviator style glasses remain bestsellers and they are regarded as a classic piece of eyewear.

Today, sunglasses are worn by virtually every person from virtually all walks of life. In addition to using them to protect the eyes from the rays of the sun, they have become a vital fashion accessory ? so much so, that they are worn even at night! They come in all shapes, colors, and sizes and are available in a wide range of prices. The less-expensive pieces can be had for next to nothing ? just don't expect to be getting value for money. On the other hand, some models run into the hundreds or thousands of dollars. This may be because of the cachet that comes with certain brand names. Or it may be because of the materials used to create the eyewear. Some designer creations are made with expensive materials like platinum, gold, and silver. Some are even encrusted with precious gemstones! This is all well and good if you can afford it, just don't neglect the basic qualities of good sun glasses.

First of all, not only must they flatter your face, they must also be comfortable. The materials used can influence comfort greatly. Glass is usually the best material for lenses since they don't scratch easily. But they're heavy and can break when hit, so some individuals opt for other materials such as polycarbonate plastic, acrylic plastic, and CR-39. Frames also come in a variety of materials, such as metal, nylon, and plastic and can help create the look that one wants. Want to look strict, or elegant, or fun, or whimsical? So many frames and lenses can contribute to getting that look and more.

Sun glasses sure have come a long way, and it looks like they are here to stay. They're great just to have personally, or to give and receive as gifts, knowing that they contribute significantly to a person's eye health and wardrobe.