Know your lenses better before you wear

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<h1>Know your lenses better before you wear</h1><strong> Author: <a href='http://www.articleseen.com/profile_Marie Chrismer.aspx'>Marie Chrismer</a></strong><br /><p>If you have interest in contacts, you are at the right place. We shall shoot light at the contact lens matters from a broad spectrum. During this discourse you will know various issues regarding its origin and modern modifications. At first let us take a step into the history of its origin. Leonardo da Vinci is credited with the illustration of the first concepts of contact lenses in 1508. After 300 years, Sir John Herschel, a British Astronomer designs practical lens. Finally modern soft contact lenses were fabricated by Czech chemist Otto Wichterle. In 1887, contact lenses were made from glass and were larger in size than modern lenses because it covered the entire eye. In 1939, attempt to make lenses from plastic was made for the first time. Later, diversity in contacts came into being and in 1981 it got an approval from FDA. Glasses have been serving to correct our vision problems since a long time but in modern days, lenses are replacing glasses for several reasons. If we assess a difference between the utilities of the two, the explicit facts come to the fore. First of all, glasses have a poor side vision and the distance between it and eyes tends to create distortion sometimes; on the other hand lenses fit on to the cornea and gives perfect focus and thus giving more natural central and side vision. During glass wear, you have to be aware of the frame and lens and as well as the reflections on the backside, but with contacts, the problem is hardly seen. There is an impact of temperature on glasses; it can fog up but contacts don’t. Glasses become an obstruction during sports; at the same time, contacts are safe because you need not give extra effort holding these. These are the structural differences. The most important fact is the corrective quotient of lenses is greater than the glasses when one is suffering from nearsightedness or farsightedness or astigmatism. If we classify the lenses on material basis, there are usually three types. Hard lenses are known as PMMA or Plexiglas or Lucite. It is among the first generation of contacts and is barely used these days because of being virtually obsolete. The soft and rigid gas permeable types are widely practiced. Whereas the former is made of water absorbing soft, gel like plastics, the latter is made of rigid waterless plastics which allow oxygen to pass through the cornea. There are four types of lenses in design. Spherical one is conventional and generally used to correct myopia and hyperopia. The bifocal one is combined with two specs at a time and its use includes presbyopia. Ortho-k types are specially designed to give the cornea a desired shape during sleep. The last type is toric lens which give more perfect vision comparatively and correct astigmatism. There are colored lenses available which can be slightly tinted with light colors or may come in hard colors which are widely used for dramatic reason. Now, UV blocking contact lenses have also been launched to protect eyes from the Ultra Violet rays.</p><strong>About the Author:</strong><br />Get the best place to <a rel="nofollow" href="http://www.contactlensescompared.com">buy contact lenses</a> is Contact Lense Compared where you can find the best quality <a rel="nofollow" href="http://www.contactlensescompared.com">contact lenses</a> at a reasonable range.<p> Article Source: <a href='http://www.articleseen.com/Article_Know-your-lenses-better-before-you-wear_10743.aspx'> http://www.articleseen.com/Article_Know your lenses better before you wear_10743.aspx</a></p>

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