Sunglasses Options are Plentiful

Protecting your eyes from the sun's harmful rays is very important if you are spending any time outdoors. Even days that are hazy or dull require protection for our eyes. Here are a few considerations.

Sunglasses come in a bewildering array of choices; never have there been so many options to select from. With all the variety you'll want to know ahead of time what the differences are between tinted, reflective, photochromic and polarizing lenses. Of course the style of frame and size of lenses will be obvious differences when shopping for sunglasses. It will also be important to know exactly what purpose you'll be using your sunglasses.

Sunglasses allow for us to see easier in the bright light. Some glasses protect against ultraviolet (UV) rays while reducing glare and giving protection from physical damage that may be caused to the eyes. Everyone is at risk for sun related eye problems. People who spend long hours in the sun during work or outdoor activity are at higher risk, than someone who is working indoors all day long. Other people may be at higher risk of eye damage if they are on certain medications such as; tetracycline, birth control pills, diuretics and sulfa drugs.

Ultraviolet light can damage both the cornea and retina, so with a good pair of sunglasses the UV can be eliminated from entering the eye completely. Whatever sunglasses you select they should provide the most possible UV protection possible. It's good to find a pair of glasses that block the sun from all angles, best achieved with a large framed pair that wrap around the face. Purchase sunglasses that block both the UVA and UVB rays, your lenses should indicate this when buying them, if they don't specify what protection is offered it is best not to buy them. On top of wearing sunglasses it is a good idea to wear a wide brimmed hat.

Manufacturers use different colors of tints to produce specific results for a variety of sunglasses needs. The color of the tint will determine the parts of the light spectrum that will be completely absorbed by the sunglasses. Yellow or gold tints reduce there opposite color, which is blue while allowing other lights to pass through. Blue lights tend to create a glare otherwise known as blue haze. Gray tints are generally used as an all- purpose tints reducing the overall brightness with the least amount of color distortion. The gray lenses are a good lens for general use and driving. Brownish and amber tints are another example of good all-purpose glasses. They reduce glare, absorbing blue and UV rays. Blue and violet have been shown to contribute to cataract formation. Purple and rose tints are great choices for water sports or golfing as they offer contrast of objects against a blue or green background. Green tints are another popular option as they absorb some blue light while reducing glare.

To recognize a pair of reflective sunglasses they will be the pair with the mirrored look. Reflective sunglasses use a reflective coating called a half-silvered surface as it is applied in a very sparse, thin layer. The reason the process is called half-silvered is because the reflective molecules applied over the glass is distributed evenly but only half the glass is covered because of the speckled process. Thus the surface will reflect only about half the light striking the surface, letting the other half go through the glasses. Many styles of mirrored glasses come in gradient forms that have additional protection on the top part of the glasses with less protection at the bottom of the lenses. Mirrored sunglasses are unfortunately easily scratched so extra caution must be used to keep them protected.

Both sunglasses and prescription eyeglasses that darken when exposed to the sun are known as photochromic (or photochromatic) sunglasses. The special lenses work by using a chemical reaction with the UV radiation. The lenses have millions of molecules of substances such as silver halide or silver chloride. When the lenses are exposed to UV rays from the sunlight, the molecules embedded in the lenses undergo a chemical reaction causing them to absorb light thus darkening.

Without the UV light, the lenses go back to their original state, it should be noted that the lenses would not darken in the car as the windshield block out most of the ultraviolet light. Most of the photochromic lenses do however have a bit of tint included in them, so they will still work while driving.

It helps to know a bit about polarization to understand why polarized sunglasses work. Polarization happens when radiation, especially light through being transmitted, scattered, refracted or reflected is restricted to vibrate in only one part