Contact lenses or contacts are lenses placed on the eye that are worn to correct problematic vision. They are also used to temporarily change the colour of our eyes.
They act the same way as normal spectacles do. The advantage is that they are invisible, they can be discarded regularly, and they are very light.
Leonardo da Vinci is believed to have introduced the idea of contact lenses in 1508 and in 1801, Thomas Young made a very basic pair based on the model of Rene Descartes in 1636.
A.E. Fick developed the first true wearable contact lens in 1888, a Zurich based physiologist.
The first contact lenses to enter the markets were hard plastics, but could not be worn for more than about 4 hours as they began to irritate the eyes.
With increased technological advancements, plastic contact lenses were designed to fit the exact shape of the iris of the eye.
Furthermore, saline solutions to keep the contact lens moisturized (like tears keep our eyes moist) were not needed in these new ones. So they could be worn all day long.
Soft water absorbing plastic contact lenses was developed in the 1960s and this made contact lenses popular for both medical and cosmetic purposes.
Over a period of years, as optometrists (eye doctors) began experimenting and understanding different conditions of the eye, contact lenses were designed to correct them.
Today contact lenses come as multipurpose packages, ones that can be discarded every day, tinted ones, and disposable ultra violet absorbs (that act like dark glasses).
As technology improves, wavelength lasers are being used to make contact lenses to the exact measurement of the person wearing them.