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| History of Contact Lenses |
In “1508 Codex of eye” Leonardo da Vinci is subjected as introducer of contact lenses. He gave a methods saying that the corneal power of eye can be altered by submerging it in a bowl full of water. But the contrasting fact is he never focused his idea towards correction of the vision defect. He concentrated upon the system of adjustment of the eye.
In 1636 René Descartes came with an idea. He said liquid filled glass tube can correct the vision defect when positioned in direct contact with the cornea. But blinking of the eye made this idea impractical.
Again in 1801 Scientist Thomas young gave a discovery with liquid filled “eyecup”, his discovery worked perfectly, but it failed in correcting the refraction fault.
In 1845 Sir John Herschel gave an idea of animal jelly filled glass capsule. Which he mentioned in Encyclopedia Metropolitana. Later Dr. Dallos used Sir Jon Herschel idea and invented a method, by which he enable the manufacturing of corneal shaped lenses.
Adolf Eugen flick created and fixed foremost eye lens and tested the lens on rabbits, then on him. He used afocal scleral contact shell which can used easily to cover the cornea with and rest on less sensitive part of eye.
Later on in Germany Muller invented a lens which is made up of sclera log glass blown. This was far more convenient to wear on eye. In 1930s PMMA or Perspex was used to make plastic lenses. The credit of introducing plastic lenses goes to the name of Optometrist William Feinbloom, the lenses he made were more unproblematic and even lighter.
In 1960 PMMA lenses became the major manufacturing lenses in history of contact lenses. These lenses could be used as long as for sixteen hours a day. This feature made theses lenses most popular in people in history of contact lenses. There was a major drawback with PMMA lenses, oxygen cannot pass through the material resulting in deficiency of oxygen on cornea. Adverse clinical effects are seen as oxygen was not getting in contact with cornea. In late 1990, polymers are used to make a new kind of contact lens which is gas permeable.
RGP or rigid gas permeable lenses allow oxygen to pass through them; this fact helped them to over gain to popularity over PMMA lenses. But later on in 1959 soft lenses came. These lenses were the effort of the Czech Chemist Otto Wichterle and Drahoslav Lim. The material used for making these lenses was hydrogel. Hydrogel also allows oxygen supply through the lens.
In 1971 Food and Drug Administration approved these soft lenses and from then they preferred more than RGP lenses, as they require less time to adopt the cornea shape. As they are more comfortable and can be used for long periods now people prefer hydrogel lenses.
In advancement to these lenses silicone hydrogels lenses are introduced, these new lenses permit more oxygen to pass through them. They are more comfortable than the traditional hydrogel made lenses. One major advantage of these lenses is they can be used overnight also. Till now three generation of these lenses has been launched. Latest generation has more water and oxygen content than the older one. Now they are much more comfortable ans can be wore for as long as 15 days without a break.
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