Patient Education

Confused about the different types of contacts lenses? What is the difference between "hard" and "soft" lenses? What are "disposable" lenses? Can contacts correct astigmatism? Are there contacts designed to be worn overnight? To sort out the confusion, let’s discuss the basic types of contact lenses.

Rigid gas permeable lenses (RGPs) are generally the healthiest for your eye. RGPs allow for good tear exchange under the lens and a good supply of oxygen to the eye. These lenses provide excellent vision, and can even correct astigmatism. RGPs are relatively comfortable to wear, easy to put on and take off, simple to care for, relatively inexpensive and have a long life. Adaptation may take longer than other types of contacts. Consistent wear to maintain adaptation is a requirement. Wearing lenses on an occasional basis may be difficult. Replacing a lost RGP takes a few days, as all RGPs are custom made.

Daily-wear soft lenses, on the other hand, require a much shorter adaptation period and can be worn on an occasional basis. They are more difficult to dislodge than RGPs and debris does not get under the lens as easily. These lenses are relatively inexpensive and can be tinted to change the color of your eyes. Vision with daily wear soft lenses may not be as sharp as with RGPs. Handling of these lenses may not be as easy. These lenses should be replaced every year at least once a year.

Disposable / Planned Replacement soft lenses are very similar to the daily-wear soft lenses. However, disposable contacts are disposed of and replaced according to a wearing schedule, which may consist of throwing a pair of lenses away after 3 months, 1 month, 2 weeks or 1 day. Protein deposits, which often build up with time and cause eye problems, are less of an issue compared to daily wear lenses since lenses are discarded more frequently. A more simplified cleaning and disinfecting process may be used. Tearing or losing a lens is no big deal. Spare lenses are readily available. The main disadvantage is disposable lenses are more expensive than the daily wear.

Another sub-type of daily-wear and disposable/planned replacement soft lens is the toric soft lens, which corrects for astigmatism. The pros and cons are similar to daily wear and disposable soft lenses. The main difference is the fitting of these lenses is more difficult and requires more office visits. Also the astigmatism may not be corrected as well compared to astigmatism correction with a RGP.

Extended-wear lenses are RGP or soft lenses that can be worn overnight. Protein deposits and bacteria can build up on the lens, thus, increasing the risk for complications, such as eye infections. More frequent office visits are required for follow-up care. In general, extended wear contact lenses are not recommended.

This is just a brief overview of the basic types of lenses out there. Determining if contacts are right for you and which ones can help you depends on many factors, such as your prescription, the health of your eye, and lifestyle. A consultation with an eye care professional can help you make that decision.