Contact Lenses And Why We Wear Them

by E-NewsCast Team
September 3rd, 2010

We wear contact lenses mainly because we are vain.But, they come in handy for any kind of sports, people even wearthem while swimming although you have to watch they don’t floatout.The Inventor of the contact lens concept was Leonardo da Vinciin 1508,who sketched and described several forms of contactlenses.Hard contact lensesHard contact lenses are manufactured from a rigid material,PolyMethylMethacrylate (PMMA). This substance is also combinedwith other plastics to increase the oxygen permeability. Visualacuity is perfect.In 1632 Rene Descartes of France suggests the first hard contactlens, which idea was actually developed in 1801 by Thomas Young;resulting in a quarter-inch-long, water-filled glass tube, theouter end having a microscopic lens,and he is the first user.In 1887 a German Glassblower, F.E. Muller ofWiesbaden,fabricates the first piece of glass acting as acontact lens which could be seen through seen through andtolerated.Soft daily wear lenses have the main advantage that they allowthe eyes to be oxygenated through the lens.They’re also easy to adapt to and difficult to lose. You can getthem in all kinds of colours. Fantastic for wearing in sportactivities.Not a panacea for all vision problems and they have to bethoroughly cleaned. Maximum lifespan 1 year.In 1936 William Feinbloom, a New York optometrist, manufacturesthe first American- made plastic contact lenses. These werestill hard lenses.The first soft, water-absorbing plastic lenses were developed in1960 by Otto Wichterle and Drahoslav Lim .Disposable lenses1.Extended-wear disposableSoft lenses that you are able to wear for an extended period oftime, up to six nights, and then you can throw them away. Theyhardly require any cleaning and have virtually no chance ofcausing eye infection if user instructions are followed…You can get them tinted and as bifocals. Your Vision may not beas sharp as with other lenses and they do not correct all visionproblems. More difficult to handle.2. Planned soft daily replacement lensesSoft daily wear lenses that you replace on a planned schedule,either every two weeks, monthly or quarterly. Require thoroughcleaning and disinfection. all vision problems. Not easy tohandle.Colored lensesThere are 4 types of colored contact lenses:visible tints, tints to enhance, color opaque tints and tintsthat filter light Most of these colored contact lenses areavailable in plano form (without visual correction), as well asfor astigmatism, who need bifocal correction, or who want adisposable or frequent replacement lens.Astigmatic lenses (toric) were first introduced in 1978 andapproved for distribution in the United States.These lenses contain both a spherical and cylinder component tocorrect prescriptions which have astigmatism. Lenses may bethicker in one meridian or have modified thickness profiles toenable the lens to maintain the correct orientation on the eye.Bifocal contacts became available in 1982 for commercialdistribution.There are a variety of designs in bifocals, essentially alltrying to provide a transition or reading zone for use at neardistances. The different designs include; + aspheric multifocal- + simultaneous vision concentric – has either a central nearor distance zone with surrounding zone of opposite type tocentre (eg, centre near,distance surround) +diffraction/holographic – based on diffraction gratingprinciples.Eye exercises There seems to be a natural alternative toeyeglasses, contacts, intacs, and even Lasik surgery, which is aseries of eye muscle exercises over a period of 30 days thatsupposedly corrects your vision to quite an extent.The validity of this method of vision correction has not beenfully proven.

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