font size

Contact Lenses: Colored, Soft, Hard, Toric & Bifoc (cont.)

Rigid Gas Permeable Hard Contact Lenses

Rigid gas permeable lenses, or hard contact lenses, are more rigid than soft contact lenses and therefore more durable. Unlike older versions of hard contact lenses, rigid gas permeable lenses are made with silicone polymers, allowing oxygen to circulate to the cornea of the eye. Compared to soft contact lenses, hard contacts maintain their shape better and offer clearer vision for some types of corrections. They are also easy to take care of and are extremely durable. However, if you are considering this type of hard contact lens, you should know that:

  • There is a 10-15 times greater risk of developing corneal ulcers, a serious infection, which may damage your vision if not treated.
  • Sleeping in extended wear contacts may decrease flow of oxygen to the cornea.
  • Undesirable reshaping of the cornea may occur.
  • The amount of time needed to adjust to hard contact lenses is often repeated after not wearing them for as little as a day. Therefore, in order to achieve maximum comfort you have to wear the contact lenses everyday.

Bifocal Contact Lenses

Bifocal contact lenses are designed to give good vision to people who have a presbyopia . These contact lenses work much like bifocal eyeglasses, having two powers on one lens one to correct distant vision and another to correct near vision. Bifocal contact lenses come as both soft and rigid gas permeable lenses.

Toric Contact Lenses

Toric contact lenses are special lenses for people with astigmatism. Toric contact lenses are made from the same material as other contact lenses and come in soft or rigid gas permeable forms. Like bifocal lenses, toric lenses have two powers, one for the astigmatism and another for nearsightedness or farsightedness if either of these conditions is also present.

© 2005-2014 WebMD, LLC. All rights reserved.
Source article on WebMD


Source: MedicineNet.com
http://www.medicinenet.com/contact_lenses_colored_soft_hard_toric_and_bifoc/article.htm

Women's Health

Find out what women really need.

advertisement
advertisement
Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations