Contact lenses may be identified by the type of refractive error they are designed to correct.
•Spherical contact lenses for nearsightedness and farsightedness
•Toric contact lenses for astigmatism;
•Bifocal lenses for presbyopia, the loss of ability to focus on reading or close-up activities.
As an alternative to special bifocal contact lenses, many practitioners use a system called monovision where one eye is fitted with a distance lens and the other with a reading lens. Approximately two-thirds of patients adapt to this type of contact lens wear.
By Type of Tint
Contact lenses may be described as clear or tinted. Tints are used to make lenses more visible during handling, or for therapeutic or cosmetic reasons. Tints can enhance eye color, or change it altogether.
Three categories of tinted contact lenses are available.
•Cosmetic enhancement tints are translucent and are designed to enhance your natural eye color. They are best for light-colored eyes (blues, greens, light hazel or grays). When wearing these tints, the color of your eye is a blend of the lens tint and your natural eye color and iris pattern.
•Opaque or "cosmetic" tints change the color of your eyes whether they are dark or light. The pattern on the lens, which is colored, overlies the colored part of your eye, resulting in a color with a natural look.
•Visibility tints are very pale, colored just enough to make the contact lens visible while you are handling it. They usually have no effect on eye color.