Medical Specialties: Family practice, Ophthalmology

Clinical Definition

Normally, the lens in the eyes are clear or transparent. However, a cataract is an abnormal clouding or opacity of the eye’s crystalline lens. The opacity can lead to a decrease in vision and possibly blindness.


Cataracts are thought to develop as a result of age-related degenerative alterations to the proteins in the lens. Smoking, diabetes and steroid use may also be contributing factors to the development of cataracts. 

In Our Own Words

Cataracts are a common eye condition, and most cases develop over time due to aging. The lens of the eye is made up of water and proteins. As people grow older, changes to the proteins may take place. These changes involve the proteins sticking together, which leads to cataract formation. The lens of the eye then becomes clouded, and vision decreases.


Additional factors that may cause cataracts include diabetes, smoking and steroid use. Other forms of cataracts may also occur, including congenital cataracts and traumatic cataracts. Treatment may involve surgery, depending on how badly the cataracts impair a person’s vision or impact activities.

Relevant Conditions
  • Age-related visual changes
Common Types
  • Age-related cataracts
  • Congenital cataracts
  • Traumatic cataracts
Side Effects
  • Blurred, foggy or filmy vision
  • Poor night vision
  • Problems with glare or oncoming headlights
  • Sudden nearsightedness
Share this article
  • American Optometric Association. “Cataract.” Accessed November 2013.
  • Emory Eye Center. “Cataracts.” Accessed November 2013.
  • The Ohio State University Wexner Medical Center. “Cataracts.” Accessed November 2013.
  • Cleveland Clinic. “Cataracts.” Accessed November 2013.
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