There has been a great deal of evolution as well as diversification in the colored contacts available on the market today. This is the reason why what started from a very basic set of features has now risen to a point where a lot of different types of the same can be seen.
One of the very first and the highly asked for type of contacts today is the opaque lenses. These lenses are given the name opaque owing to the way they function. They are comprised of a colored ring in them, which is of the almost exact size as the iris of the human eye, and a whole inside it. The light can only pass through this whole into the retina and out of the eye and this is how by reflecting all other components of the eyes except the color of the ring, the desired color effect could be seen on the eyes. Most of the colored contacts found in the market today are opaque.
Another very important type of colored contacts is the enhancer tints. These contacts are perfectly translucent and are best known to induce any color effects in the eyes, but rather to enhance the natural color of the eyes of a person(as by the name). However there is a limitation to the working of such colored contacts. They do not work very well for dark-colored eyes and for such eyes, opaque contacts are probably the best option.
Yet another type of enhancing these contacts is known as visibility tints. These are even less effective in changing the color of the eye and rather fortify and reflect the original eye color. They carry a simple tint so as to make it easy for the person to handle, apply, and remove the lens.
More information is available on turtlecontacts. They offer information on colored contacts, including finding the right color contacts that fits your prescription.