About Us    Contact Us    Careers    Site Map    Search

Health Care Services    Hospitals & Facilities    Health Information    Find a Doctor    Why Choose Baptist
 
Home Health Information Health Topic Library Eyes and Vision
Types of Contact Lenses
 
Hard lenses, made of a plastic called polymethylmethacrylate (PMMA), were among the first contact lenses available. Although they are not often prescribed now, they had several advantages. They were easy to put in and take out and easy to care for. They did not cost very much and lasted a long time. For many people, they provided very good vision.

However, hard lenses were often uncomfortable during the first week or two of wear. Also, they did not allow much oxygen to reach the cornea. (The cornea is the clear dome in the front of the eyeball.) Not getting enough oxygen can damage the cornea. Gas permeable lenses are much more common today.

Gas permeable contact lenses
Gas permeable lenses are made of a type of plastic that allows oxygen to reach the cornea. They are easier to care for than soft contacts. They are also easier to insert and remove. Gas permeable contacts can correct most vision problems. At first, most people need a few days to get used to them. Some of the newest gas permeable lenses are approved for extended wear. Most contacts should not be worn during sleep. Follow your eye doctor's recommendations about how long you can leave in extended wear lenses.

Soft contact lenses
Soft contacts are lenses made of flexible plastic that absorbs liquids. Unlike gas permeable or hard lenses, they usually do not cause discomfort when you first wear them. They can correct many vision problems. Also, soft lenses can be tinted to make your eyes look a different color. They are often worn for sports and other activities where gas permeable or hard contacts might come out.

Putting soft contacts in and taking them out may take a little practice. Also, soft contacts must be cleaned and sterilized very carefully. Daily-wear soft lenses are sterilized nightly. Extended-wear soft lenses are sterilized each time you remove them.

Soft lenses cost more than gas permeable lenses. They may wear out and need to be replaced more often. People who wear soft lenses may have more problems with allergies. Also, they may develop eye infections more often, especially if they sleep in their contact lenses. An eye infection called a corneal ulcer can be serious. People with dry eyes may not be able to wear soft contacts.

Regular soft lenses do not correct astigmatism (vision problems caused by an uneven cornea) as well as gas permeable lenses do. However, special soft lenses called toric lenses are available for people with astigmatism.

Disposable contact lenses
Disposable contact lenses are soft contact lenses that are replaced frequently. Some extended wear disposable contacts are worn for 1 week and then thrown away. Some are sterilized after 1 week of wear, worn for a second week, and then thrown away. Daily wear disposable lenses are removed and sterilized nightly for 2 weeks and then thrown out.

The disposable contact lenses are convenient and they provide the clear vision and comfort often associated with new lenses. They may help people who are allergic to contact lens solutions or protein deposits on their lenses. The disadvantages of disposable contacts are that they cost more than other contact lenses.

Bifocal contact lenses
Bifocal contact lenses have both your distance prescription and your reading prescription in each lens. They are available as gas permeable or soft lenses, and as daily wear or extended wear types. However, not everybody likes bifocal contacts so a trial period is usually recommended.Reviewed and approved by the Wilmer Eye Institute of The Johns Hopkins Medical Institutions, Baltimore, MD. Web site: http://www.wilmer.jhu.edu




Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File eye4223.HTM Release 9.0/2006. Copyright © 2006 McKesson Corporation and/or one of its subdiaries. All Rights Reserved.


Top of Page

Baptist Online
Read the latest articles about a variety of health subjects, with many practical tips to help you take control of your health.
More

See Information Related to This Topic
Home | Health Care Services | Hospitals & Facilities | Health Information | Find a Doctor | Why Choose Baptist
©2010 Baptist Memorial Health Care Corporation. All Rights Reserved. Disclaimer. Notice of Privacy Practices.
Baptist Memorial Hospital In keeping with the three-fold ministry of Christ — healing, preaching and teaching — Baptist Memorial Health Care Corporation is committed to providing quality health care.