How Do Contact Lenses Work?
Do you wear contact lenses and would you like to know a little more about them, such as how do contact lenses work? Contact lenses are defined as a corrective (or sometimes cosmetic) lens that is placed in the center of your eye. Contact lenses are primarily worn to improve your vision, and sometimes worn simply to alter the color of your eyes. Yet, what is the history behind this invention, and exactly how do contact lenses work?
Leonardo da Vinci is considered the first individual to describe the idea behind contact lenses. He sketched a proposal in one of his journals in 1508. This journal was called Codex of the eye, Manual D. However, Leonardo da Vinci’s idea behind the lenses was not for corrective vision. Rather, the lenses were going to be used to expose how the eye can make accommodations.
After Leonardo da Vinci, Rene Descartes is next credited with suggesting an idea for contact lenses. In 1636, he suggested that a glass tube filled with liquid could be used to correct vision by placing the glass tube so that it touched the cornea. However, the idea was not feasible because it did not allow individuals to blink.
After Descartes, Thomas Young and Sir John Herschel both suggested ideas for contact lenses. However, Thomas Young’s idea was also unfeasible, and Sir John Herschel never tested to see if his ideas would work. Later companies were able to use some of Herschel’s ideas to improve contacts.
The First Contact Lenses
In 1887, F.E. Muller created the first type of eye covering that didn’t irritate the wearers, and also allowed them to see through the covering. In the same year, Adolf Gaston Eugen Fick was able to construct what is considered the first contact lenses, and he fit them on an individual. Fick was a German ophthalmologist.
The first contact lenses created by Fick were composed of heavy blown glass. They were approximately eighteen to twenty one millimeters in diameter. These contact lenses did not rest directly on the cornea. Rather, they rested on the outside area that surrounds the cornea.
These initial lenses had a number of problems. They were quite large, and they were difficult to put in the eye. Further, if they were worn for longer than a couple of hours, they caused significant irritation in one’s eyes. However, they were an important step in the development of modern day contacts.
How Do Contact Lenses Stay in Place?
Contact lenses stay in place because of the moisture in your eye. The contacts stick to your eye, and then your eyelids actually keep the lenses from falling out. The eyelids keep the lenses from falling out. This is because each time you blink, tears are produced. The tears help your eyes remain moist, and thus help the contact lenses to stay in place.
How Do Contact Lenses Work?
Now that you know a little more about the history behind contact lenses, you may want to know how do contact lenses work? Today, contact lenses are made from plastic, and most contact lenses are flexible and are disposable. You place the lenses directly over the iris of your eye.
Contact lenses are effective because they refract light in certain directions. Individuals with both nearsightedness and farsightedness have difficulty getting the proper light refraction to enter their retina. For example, if you are nearsighted this means that the light does not enter all the way into your retina. If you are farsighted, this means that the light is too focused at the back of your retina.
Contact lenses are curved to influence the light to enter the retina properly, and thus to allow you to see properly. The way that the contact lenses are curved depends on your prescription, and thus contact lenses for nearsightedness are different than contact lenses for far sightedness.