The Two Purposes of Contact Lenses
The very first usable contact lens was produced in Germany in 1887, and since then, billions of people worldwide have used them. Contact lenses are generally used for two purposes: one is to correct vision and the other is for cosmetic reasons.
There are also two specific eye problems which contact lenses are better at correcting than spectacles, which are aniseikonia and keratoconus.
On is the hard or rigid version, which has been on the market for a very long time. The other is the soft lens, which is a newer and more widely accepted version. Initially, hard contact lenses were not gas permeable, which caused many users to suffer from infections and discomfort. Now, hard lenses are called gas permeable, as they let oxygen through to the surface of the eye, thus reducing the risk of infection and making them far more acceptable.
Whereas hard contact lenses fit only over the iris, which is the colored part of the eye and are virtually invisible, soft lenses have a larger circumference and extend on to the sclera, the white portion of the eye.
Thus soft lenses can often be seen on the eye, with hard lenses being harder to spot. One of the greatest attributes of hard contact lenses is that they can be used to change the color of the eye, to give the wearer a completely different look. For example, green or purple coloured non-prescription hard contact lenses placed over brown or hazel colored eyes will give them a deep and unusual colour which many users want. Hard lenses can also have lines or dots printed on them, to intensify the natural characteristics of hazel eyes.
Reducing the Risk of Infection
In order to reduce the occurrence of eye infections, many contact lens users often suffer from disposable version. These lenses are thus thrown away after being used only once, thus the whole cleaning and sterilizing is done away with and the risk of infection is also greatly reduced.