The contact lens also known as a corrective lens is a thin device worn right over the eye to improve the vision. A contact lens is worn directly over the cornea and it floats on a layer of tears. Contact lenses are meant to worn during the day and they are removed at night. They usually serve the same corrective aim as conventional spectacles. In fact people who use contact lenses have always indicated their preference over the spectacles. As it gained popularity the demand for spectacles came down steadily and still is dwindling.
They are lightweight and almost invisible. To make them visible in the storage and cleansing solution many manufacturers have given it a slight blue tint. Many people also wear specially colored lenses just to alter the color of the eyes. Moreover, they are preferred over spectacles to increase the appeal of the face. Active sportsmen prefer contact lenses as it allows them to see in all the dimensions.
The history of contact lens can not be fixed to one period and one person. It may be surprising to note that the Italian artist Leonardo Da Vinci of the Monalisa fame has been credited with depicting and drawing the first sketches of contact lenses in the year 1508. It was in reality designed and worn over the eye after 300 years. It was only in the year 1887 that the German physiologist Adolf Eugen Fick fabricated and fitted the first successful contact lens. He made it from heavy brown glass. In 1936 an optometrist, William Feinbloom innovated plastic lenses. They were much more light and easy to use. Since then the manufacturers kept experimenting and designing better variants of contact lenses.
There are fundamentally three types of lenses soft, hard, and gas-permeable. The soft contact lenses are the most convenient form of contact lenses, but on the other side they break and tear very easily. Hard contact lenses have a tendency of not staying in their place, they sometimes pop out. The demand for something which balanced the good points of hard and soft lenses came into being. Thus, to fill this demand gas-permeable lenses were designed. They compromised between the hard and the soft lenses and have become the most popular form of lenses today. They are comfortable and do not pop out, and are sturdy enough, such that they do not break and tear easily.
More recently, in the year 1999 disposable contact lenses were introduced in the markets. These contacts lens are worn for one day or more and disposed off, obviating the bother of cleansing them every time they are taken off.