2007年12月24日星期一

What To Look For When Purchasing Sunglasses

There are many different types of sunglasses available on the market today along with confusing information from manufacturers. Make sure you have a basic knowledge of the lenses and the technology associated with them before purchasing sunglasses.

Always buy sunglasses with lenses capable of blocking 99% of ultraviolet rays. It is recommended that you purchase sunglasses that are able to absorb the UV rays because of added improved chemicals inside the lens instead of an applied special coating to the surface of the lens. A lens with an applied special coating can potentially become scratched and therefore loose its effectiveness. A quality polarized lens with added UV protection is what you need to block the harmful rays of the sun.

Beware of low quality polarized lenses that impair your vision and cause glare when around light-reflective surfaces such as water and snow. For this
reason alone it is wise to buy from a reputable manufacturer that has proven quality products over time.

Make sure the lens is capable of blocking 90% of infrared rays. Beware that some sunglasses manufacturers use health claims to promote their products due to the infrared protection, but research has not shown a connection with infrared rays and eye disease.

Look for wraparound glasses to prevent the harmful UV rays from entering around ordinary eyeglass frames. Studies have shown harmful rays enter through the side of the frames reducing the effect and benefit of the lens. Look for large-framed wraparound sunglasses to fully protect yourself from the suns rays.

Photochromic lenses is capable of automatically darkening in bright light and becoming lighter in low light. The earlier photochromics were glass lenses, but now you can choose from plastic and polycarbonate lenses. Keep in mind the photochromic lens is only capable of changing when exposed to ultraviolet light.

Sunglasses with yellow lenses work best when driving at night. They will cut the glare from street lights and on coming traffic, and also can be worn indoors to help cut the glare from a computer screen. Yellow lens sunglasses typically offer minimum protection from UV rays.

All sunglasses must be impact resistant and must meet the impact standards set by the Federal Food and Drug Administration. One important note is plastic lenses are less likely to shatter then glass lenses.

Make sure you choose a lens that is best for you depending on when you will use them most. A medium darkness lens will work for most situations, however, if you are often going to be exposed to highly reflective surfaces such as water or snow then choose a darker lens.