Kali Knickerbocker
Many people actually take sunglasses for granted. Believe it or not sunglasses are an essential when it comes to those summers spent on the lake and for those snow days in upstate New York. The sun can do an incredible amount of damage to your eyes and many people do not realize it. People do not realize that UV damage can build up over time. UV rays are an invisible form of radiation, and pelts our retinas at 186,000 miles per second causing various different problems (“Thermonuclear”). There are various ways in which manufacturers help to protect peoples eyes.
Sunglasses provide various different benefits from protecting your eyes from UV rays to being an added accessory. Good sunglasses protect your cornea and retina from ultraviolet light, which can cause various problems (“How”). Some of the most common problems caused by UV light include cataracts, photokeratitis and pterygium. Cataracts may begin as just making people nearsighted and eventually not able to see blue colors. Unfortunately it can also cause people to lose some vision and possibly even becoming blind (“Cataracts”). Photokeratitis can also be called snow blindness, it is a burning of the cornea. This usually happens at high altitudes and with snow (“Definition”). Pterygium is most common among people living in the tropical climates or those who spend a lot of time in the sun. This can also lead to blindness and is not pretty to look at (“Pterygium”). The sunglasses also protect our eyes from intense light. For example when an eye receives too much light it naturally closes the iris. When the iris closes as much as possible people then squint. Too much light coming into the retina causes damage to the retina. Sunglasses can also protect our eyes from glare. Surfaces such as water and snow reflect a great amount of light. As long as sunglasses are polarized they will protect from harmful glares(“How”).
~Cataract~
~Photokeratitis~
~Pterygium~Polarized lenses main function is to reduce the glare and protect your retinas. Polarized lenses incorporate a vertical polarized filter, which then absorbs the horizontal light. This then eliminates the glare. A person is then left with a clear vision, increased contrast and depth perception (“Why”). One way to test and see if your sunglasses are polarized is to: look at a horizontal reflective surface, and then slowly tilt your head to the right or the left. You should notice that the glare off the surface brightens as you adjust the angle in which you are viewing the surface from. Buyers must be careful when purchasing sunglasses because many say they are polarized when in reality they may not be (“How”). There are various techniques that sunglass manufactures use to help sell products as well as protect buyers eyes.
((http://science.howstuffworks.com/sunglass2.htm) -Page 4 has a nice demonstration of this.)
Tinting is another part of sunglasses that help to protect eyes. The color of the tint determines which parts of the light spectrum are absorbed. For example, a gray tint reduces the overall amount of brightness. A gray tint also has the least amount of color distortion and have pretty good protection against glare. A yellow or gold tint reduces the amount of blue light, which allows a larger amount of other frequencies through. This tint can make everything brighter and sharper, and distorts color perception. The amber and brown tints are good for general use sunglasses. They definitely reduce the glare and absorb higher frequency colors, such as blue. The Green tints filter out some blue lights and also reduce glare. The green tine offers the best contrast and the best visual acuity; sunglasses with this tint are very popular. Purple and rose tints offer a very good contrast of objects against a green or blue background, which makes them good for hunting or water skiing (“How”). Various tints provide different benefits, be sure to explore your options before purchasing new sunglasses.
Another option dealing with sunglasses are the Photochromic Sunglasses. These sunglasses are often prescription glasses and darken when exposed to the sun. These lenses have millions of molecules of substance such as silver chloride or silver halide. Then the glasses are exposed to UV rays in the sunlight the molecules go through a chemical process which causes them to change shape. This new structure absorbs portions of the visible light, which causes the lenses to darken. These glasses to eventually switch back because when there is an absence of UV radiation the molecules snap back to the original shape. There are numerous different ways in which sunglasses can protect your eyes (“How”). Next time you go to purchase sunglasses take into account a couple things. It is understandable that you may want something to follow a trend in the fashion place but your eyes are more important. Every person is only given one set of eyes, which need to last his or her entire life. Your eyes need to stay protected from harmful situations. There are many manufactures today that combine the fashion and the needed amount of protection. Before purchasing a pair of expensive sunglasses make sure they provide the needed protection.
((http://science.howstuffworks.com/sunglass2.htm) -Page 4 has a nice demonstration of this.)
Tinting is another part of sunglasses that help to protect eyes. The color of the tint determines which parts of the light spectrum are absorbed. For example, a gray tint reduces the overall amount of brightness. A gray tint also has the least amount of color distortion and have pretty good protection against glare. A yellow or gold tint reduces the amount of blue light, which allows a larger amount of other frequencies through. This tint can make everything brighter and sharper, and distorts color perception. The amber and brown tints are good for general use sunglasses. They definitely reduce the glare and absorb higher frequency colors, such as blue. The Green tints filter out some blue lights and also reduce glare. The green tine offers the best contrast and the best visual acuity; sunglasses with this tint are very popular. Purple and rose tints offer a very good contrast of objects against a green or blue background, which makes them good for hunting or water skiing (“How”). Various tints provide different benefits, be sure to explore your options before purchasing new sunglasses.
Another option dealing with sunglasses are the Photochromic Sunglasses. These sunglasses are often prescription glasses and darken when exposed to the sun. These lenses have millions of molecules of substance such as silver chloride or silver halide. Then the glasses are exposed to UV rays in the sunlight the molecules go through a chemical process which causes them to change shape. This new structure absorbs portions of the visible light, which causes the lenses to darken. These glasses to eventually switch back because when there is an absence of UV radiation the molecules snap back to the original shape. There are numerous different ways in which sunglasses can protect your eyes (“How”). Next time you go to purchase sunglasses take into account a couple things. It is understandable that you may want something to follow a trend in the fashion place but your eyes are more important. Every person is only given one set of eyes, which need to last his or her entire life. Your eyes need to stay protected from harmful situations. There are many manufactures today that combine the fashion and the needed amount of protection. Before purchasing a pair of expensive sunglasses make sure they provide the needed protection.
(Typical layering used to create a pair of high-grade sunglasses.)
Sources:
“How Sunglasses Work.” http://science.howstuffworks.com/sunglass.htm. February 25, 2008.
“Why are Polarized Lenses Important.” http://www.dentalplans.com. February 25, 2008.
“Thermonuclear Protection.” http://www.oakley.com. February 25, 2008.
“Pterygium.” http://www.stlukeseye.com/Conditions/Pterygium.asp. February 25, 2008.
“Definition of Photokeratitis.” http://www.medterms.com/script/main/art.asp?articlekey= 19394. February 25, 2008.
“Cataracts.” http://en.wikipedia.org/wiki/Cataract. February 25, 2008.
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