Forget those days of wearing any heavily clad spectacles in your eyes. Now contact lens has come to solve the problem for you. Modern contact lenses are made from synthetic polymers. Contact lenses can be used for correction of visual imparity or simply for cosmetic purposes.
Throughout the world, an approximated population of 125 million is wearing contact lenses. More than 40% of those come from either US or Japan. Doctors prescribe contact lenses for correction of near vision (hypermetropia), distant vision or farsightedness (Myopia) and if there is any aberration in the contour of the cornea (astigmatism). These are simply effortless to wear when you know the correct technique. However, for the first time users, it may take a day or two to become well acquainted with the method of wearing the contact lens. Wearing a contact lens is pure pleasure. It does not cause any heaviness in front of your eyes unlike spectacles. You don’t have to go for the costly corrective eye surgery either, which can be detrimental if not done properly.
At the very beginning, before the invention of corneal lens in 1949, contact lenses were made from glass. It caused real problem for the person who was wearing it. This is mainly due to the characteristics of the glass. Our eyes need oxygen for various reasons; nutrition is being the most important cause. This oxygen is primarily supplied by air. When a glass was covering the cornea, there was no point coming in contact with the atmosphere. Therefore, it had become a troublesome experience to wear the contact lens for a longer time. This crisis was countered with the invention of various gas permeable polymers. Contact lenses made from these polymers are collectively called Rigid Gas Permeable lenses (RGP lens). After that some soft polymers were also developed to produce the contact lenses.
Therefore, contact lenses have two main categories – rigid lens and soft lens. Rigid lenses are again classified into older gas-tight and recent gas-permeable lenses. Soft lenses are also sub-divided into low moisture content (less than 50%) and high moisture content (more than 50%). Rigid lenses are for prolonged use. You can use the lens for up to five years without changing it. Only thing you have to do is to put off them during night time and clear it with disinfectant solutions. On the contrary, soft lenses need regular changes. Presently they are coming in disposable form. These lenses you have to discard permanently once you remove them from your eyes.
There are various contact lenses for cosmetic reasons also. Lenses come in different colors, patterns. Nowadays, they can be studded with tiny bright objects to suit your needs.
Contact lenses can be spherical, multifocal or toric. Spherical lenses are prescribed to counteract long or shortsightedness, multifocal lens is used for the treatment of presbiopia (when eyes cannot quickly accommodate itself in changing intensity of light) and the toric lenses are meant for the astigmatic eye.
Wearing contact lens is better when it comes to comparison with spectacles. Contact lens gives you more ‘field of vision’, there is less chance of change in the power of your eyes and lastly the cosmetic value. Only drawback of a contact lens is maintenance. You have to clear and disinfect the lenses regularly with proper fluid.
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