A cataract is a cloudy area in the lens of your eye. Cataracts can make your vision blurry, hazy, or less colorful.  

Most cataracts are caused by natural changes in your eyes as you get older. The good news is that surgery can get rid of cataracts.

How does a cataract form?

Cataracts form when the proteins in the lens of your eye clump together, making your lens cloudy.  

The lens of your eye is normally clear, allowing light to pass through. The lens helps focus the light on your retina (the light-sensitive layer of tissue in the back of your eye) so you can see things clearly, whether they’re up close or far away.

Your lens is mostly made of water and proteins. Normally, the proteins line up in a special way so that your lens is completely clear and light can pass through easily. If the proteins in your lens clump together, the lens gets cloudy. 

Cataracts keep you from seeing clearly because light can’t pass through the clumps of proteins in your lens very easily. Over time, the clumps of proteins get bigger and thicker, making it harder for you to see. The lens may also develop a yellow or brown tint, which can change how you see colors.

What causes a cataract?

After age 40, the proteins in the lens of your eye naturally start to break down. Most cataracts happen because of these natural changes. 

Doctors and researchers don’t know exactly what makes some people get cataracts, but they do know that there are things that can make cataracts form faster, including: 

  • Smoking 
  • Drinking too much alcohol 
  • Spending too much time in the sun without sunglasses 

Some health problems and treatments can also make cataracts more likely, including: 

  • Diabetes 
  • A serious eye injury 
  • Eye surgery to treat glaucoma or another eye condition 
  • Taking steroids — medicines used to treat a variety of health problems, like arthritis or allergies — for a long time 
  • Getting radiation treatment for cancer or other diseases 
Last updated: May 29, 2019