How Do Contact Lenses Come About

Contact lens, which seems to be a modern invention

, is actually an innovation with a long history which can be dated back to 1508 when Leonardo da Vinci firstly illustrated the concept of contact lenses. He proposed to put a lens directly on the eye to aid in vision, so did Rene Descartes bear the similar concept of corneal contact lens, but they all failed, either for impracticability or for inapplicability. In 1801, Thomas Young developed a devise, which was thought to be the predecessor of contact lens, on the basis of Descartes' idea that was a quarter-inch-long, water-filled glass tube, the outer end containing a microscopic lens, but it was not for eyesight correction. What's more An English astronomer Sir John Herschel also suggested make a mold of the cornea that can conform exactly to the eye's surface.

Although so many conceptions concerning contact lens emerged in the greats' minds, it was not until 1887 that Glassblower F. E. Muller of Wiesbaden, Germany produced the first eye covering designed to be seen through and tolerated, which marked the milestone of contact lens production. But who was the first one to wear contact lenses? You must be surprised with the answer, which were the rabbits. In 1888, Adolf Eugen Fick made such an experiment of trying contact lens on the eyeball of a rabbit, and he tried himself later. Due to the undeveloped technology, the lens could not be worn long for its large size, 18-21 mm in diameter, and heavy weight; moreover lens at that time could not directly contact to the cornea, but with a dextrose solution between the eye and lens.

The great improvement of contact lens was achieved by Hungarian Dr. Dallos in 1929, who perfected methods of taking molds from living eyes so that lenses could be made to conform more closely to individual eyes. And in 1939, lenses were firstly made from plastic, which were designed to cover only the eye's cornea in 1948, plus one was able to wear these lenses all day long. From that time on, plastic lenses took the place of glass lenses. During this time, polymethyl methacrylate (PMMA) was the rage, but it came to its end in the 1970s, because PMMA does not allow the exchange of oxygen, resulting in some side effects, including dry eyes and some infections. Soft lenses are what we mainly used today, but it has been introduced in the 1960s when Otto Wichterle and Drahoslav Lim experimented with contact lenses made of a soft, water-absorbing plastic they developed, and in 1971 soft lens became approved "Soflens" materials admitted by the Food and Drug Administration (FDA) and were available for commercial distribution in the United States.

In modern society, materials for contact lenses vary. Since 1999 when silicone hydrogels were applied in contact lens manufacture, more contact lenses of organic materials, which are both highly permeable to oxygen and good to eye health, are explored, making the wearers feel more comfortable and safer.

If you want to know more about contact lenses knowledge, then feel free to visit http://vision.firmoo.com/contact-lenses

by: homas Carter

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