Not only do sunglasses enhance how we look, they also shield our eyes from the sun's harsh rays so we don't have to keep squinting or cover our eyes when under the sun's glare. But this fashion item plays another role. Sunglasses also shield our eyes from that same sun's UV ray. Prolonged exposure of our eyes to UV could result in developing some diseases.

Sunglasses can block both kinds of ultraviolet radiation -- both UVA (ultraviolet alpha rays) and UVB (ultraviolet beta rays) . UVA is the type of ultraviolet rays that gets through the planet's ozone layer, and when we are exposed to it too much, it can make our skin age faster. UVB is the type of ultraviolet rays that the ozone absorbs in larger amounts, but could also give us skin cancer or cataracts when we are exposed to these rays for prolonged periods.

To prevent these problems from developing, it's important to wear sunglasses that not only curb the bright light's glare (so they must be dark enough), but also provide enough visibility to see objects clearly, without distorting colors and limiting what we see. When tinted right, these sunglasses will shield our eyes. The shielding effect is important, not so much the over-dark look of your shades.

UV400 is the regular UV protection level. This level shields our eyes from nearly 100 percent of UV rays. Comparative studies reveal that the cheap shades (around $5) provide the same UV protection as more expensive one. So you don't have to cash out much to get UV shields for your eyes. Also, the prescription glasses UV protection level is the same as those bought from stores.

Sunglasses enthusiasts will be happy to note that manufacturers are required to follow FDA regulations when it comes to making sunglasses. For one, sunglasses must comply with the FDA's impact requirements, which means they should be relatively shatterproof or able to withstand moderate impact. Manufacturers or sunglasses are also required to comply with labelling regulations. If you've bought a pair of sunglasses before, you've probably noticed a sticker on one of the lenses that you have to peel off first.

When you buy sunglasses, you buy protection for your eyes. But that doesn't mean buying the expensive stuff gets you more eye protection. The cheap ones protect you from UV rays just as well.