Contacts Lenses
Just as eyeglasses or LASIK procedures can correct such problems as astigmatism, farsightedness or nearsightedness, contacts lenses can be used for those problems and enable one to see quite clearly. At last count, Americans who wear contact lenses to correct their vision was approximately 20%.
Contacts lenses have been around for a very long time; in fact Leonardo da Vinci actually came up with the idea of contact lenses in 1508. No one followed up on the idea until an English astronomer by the name of Sir John Herschel made a mold of the patient's eyes so that contact lenses could be made and actually conform to the patient's eye.
Then in 1887, a man named F.A. Muller who was a German glassblower, created the first glass contact lens. Later, a Parisian optician worked with a Swiss physician to fit the very first glass contact lenses, which took care of both nearsightedness and farsightedness.
Eventually, the contact lenses were made of both plastic and glass, and much later they were made entirely of plastic. Even through the 1960's lenses were made of hard plastic that were both uncomfortable and could even pop out of the eye, and that's when many TV shows made fun of people who were always losing their contact lenses and had to crawl around on all fours until they were found!
In 1961, finally the world heard about soft contact lenses that could actually absorb water, and Bausch & Lomb introduced the first commercially made ones in 1971. Interestingly, people who wear contact lenses even today, wear the soft plastic ones.
Since then the majority of most lenses were made from hydrogel, meaning that they are water soluble, plastics. Then silicone hydrogel contact lenses came out. These allow more oxygen through the lens and thus to the eye itself, therefore they are much less prone to dehydrate.
There are even different designs that are worn for specific eye problems. Spherical lenses can correct either nearsightedness or farsightedness. Bifocal lenses correct both nearsightedness as well as farsightedness, which afflicts many older people. The condition is called presbyopia. Orthokeratology lenses are worn during sleep enabling the person to go without any lenses during the day as they reshape the cornea while the person sleeps. Toric contact lenses are used to correct astigmatism.
You may want to check out my other guide on wavefront lasik and contacts lenses
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