Because the natural color of the eye isn't uniform, some color contacts have tiny dots and lines of color rather than a uniform tint. These patterns of color on the contact are intended to mimic the appearance of a real eye and make the final eye color look more natural.
Color contacts can be used to enhance the natural color of the eye or to change the color of the eye completely. Contacts intended to enhance the color are usually translucent and are worn by individuals with naturally light-colored eyes. Contacts intended to change the color of the eye are opaque. Some individuals choose functional colors, such as a green tint, to enhance vision on the tennis court.