About Contact Lenses

Modern contact lenses fall into two categories: soft lenses that are made from water-containing plastics, and GP or "oxygen permeable" rigid contact lenses.
Contact lenses may also be classified by wearing schedule. Daily wear lenses must be removed, cleaned and stored each night, while extended wear contact lenses are made from materials which are safe to be worn during sleep. You may also have heard of "continuous wear" contact lenses, a type of extended wear that can be worn for up to 30 days.
Various lens designs are available for different vision problems. Spherical contact lenses correct nearsightedness or farsightedness and are indicated by a minus or plus in your prescription, respectively. Bifocal contact lenses are similar to multifocal eyeglasses in that they use different optical zones to correct presbyopia (the decreased ability see at both near and far distances). Toric contact lenses correct astigmatism, which can accompany either nearsightedness or farsightedness.
All of the contact lenses mentioned above can be custom fabricated for unusual prescriptions, and many other contact lens designs are available as well, including designs for conditions like keratoconus.
Many lens designs come in colors that can enhance or change your natural eye color. Special-effect contact lenses are also available for novelty use and are used extensively in theatrical and filmed productions. Prosthetic lenses are colored contact lenses that can cosmetically mask eye disfigurement. Many contact lenses also come with an embedded UV inhibitor.
Which is the right contact lens for you? First and foremost, your contact lenses must correct your vision problem. Second, each lens must properly fit your cornea, so contact lenses come in tens of thousands of parameters, meaning the combination of size, shape and power.
Your eye care practitioner will evaluate your eyes to determine which lens is right for you, and will take into account your special needs such as dry eyes, a desire for color change or the need for overnight wear.