Many people turn to contact lenses when they grow tired of wearing glasses day after day. Contacts fall into two basic groups: soft and rigid gas permeable. The contacts that used to be called "hard" are very rarely prescribed anymore. There are also a few popular specialized styles of contact lenses.
Soft contacts are made of a soft flexible plastic that is up to 80 percent water. They are usually the most comfortable lenses. Their softness can be a disadvantage, though, when it comes to collecting grime with wear. There are a couple of types of soft contacts. Extended wear contacts can be worn overnight. Disposable contacts are thrown away after a set number of days, giving the wearer a regular supply of fresh, clean contacts.
Rigid gas permeable (RGP) contacts are made of a slightly flexible plastic that may cause discomfort when they are first worn, but the eye quickly adapts. They create sharper vision than soft contacts in some cases. RGP contacts are also much more durable than soft variants, and thus more expensive per lens. Extended wear contacts are also available in rigid gas permeable form, thereby allowing for overnight wear.
Toric lenses for astigmatism can be either soft or RGP; the name refers to the lens design. They are created with special curvatures and will stay in place once in the eye for steady vision. Other lenses can be used to correct astigmatism with careful fitting, but torics work best in the most severe cases.
Bifocal lenses are available as both soft and RGP contacts. They are designed much like bifocal glasses with one area of the contact for near vision and the other for seeing distances. It requires an adjustment period, but the eye adapts to looking through the proper area. If this style of lens doesn't work out, it is also possible to put a different lens in each eye to simulate the bifocal effect.
Special effects or novelty contact lenses are used for non-prescription purposes and can also come in either soft or rigid gas permeable styles. Whether you want to try a new eye color or look like a cat, it's possible with these types of lenses.
