MedicineNet.com
About Us | Privacy Policy | Site Map
December 2, 2008
  MedicineNet home Picture Slideshows Diseases and conditions Symptoms and signs Procedures and tests Medications Health and Living Health news and views MedTerms medical dictionary  
Font Size
A
A
A


Cataracts

What is a cataract?

A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.

A cataract can occur in either or both eyes. It cannot spread from one eye to the other.

What is the lens?

The lens is a clear part of the eye that helps to focus light, or an image, on the retina. The retina is the light-sensitive tissue at the back of the eye.

In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain.

The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred.

Are there other types of cataract?

Yes. Although most cataracts are related to aging, there are other types of cataracts:

  • Secondary cataract. Cataracts can form after surgery for other eye problems, such as glaucoma. Cataracts also can develop in people who have other health problems, such as diabetes. Cataracts are sometimes linked to steroid use.


  • Traumatic cataract. Cataracts can develop after an eye injury, sometimes years later.


  • Congenital cataract. Some babies are born with cataracts or develop them in childhood, often in both eyes. These cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed.


  • Radiation cataract. Cataracts can develop after exposure to some types of radiation.


Eyeball Illustration - Cataracts


Next: What are the causes and risk factors for cataracts? »

Printer-Friendly Format  |  Email to a Friend


space Related health and medical articles From the Doctors at MedicineNet.com MedicineNet Doctors recommend space
space
MedicineNet Doctors Recommend
  • Cataract Surgery - Get information about cataract surgery. Learn how it's performed, what to expect before and after surgery, risks, complications and the causes and diagnosis of cataracts. Source:MedicineNet
  • Radiation Therapy - Source:MedicineNet
  • Tonometry - Get the facts on tonometry, a method for measuring intraocular pressure (IOP) and detecting glaucoma. Learn how tonometry is performed and the equipment that's used during the procedure. Source:MedicineNet
  • Read 93 more Cataracts related articles ...
Latest Medical News
space

WebMD Daily

Get breaking medical news.




Topics Related to Cataracts


Cataracts
RSS FeedSpecialty RSS       Add to My Yahoo! What is this?

Glaucoma Laser Treatment Glaucoma Laser Treatment
Glaucoma is a sight-stealing condition caused by pressure in the eye. Now patients are finding results through glaucoma laser treatment. See more WebMD Videos »












Health categories:

Slideshows | Diseases & Conditions | Symptoms & Signs | Procedures & Tests | Medications | Health & Living | News & Views | Medical Dictionary

Popular health centers:

Allergies | Arthritis | Cancer | Diabetes | Digestion | Healthy Kids | Heart | Men's Health | Mental Health | Women's Health | More...

Publications:

ePublications (PDFs) | XML News via RSS | Audio Podcasts | Email Newsletters

MedicineNet.com:

About Us | Privacy Policy | Search Help | Site Map | WebMD® | Medscape® | eMedicine® | eMedicineHealth® | RxList®

HON Code We comply with the HONcode standard for health trust worthy information:
verify here.

©1996-2008 MedicineNet, Inc. All rights reserved. Notices and Legal Disclaimer.
MedicineNet does not provide medical advice, diagnosis or treatment. See additional information.