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What is a cataract?

A cataract is a cloudy area in the lens of the eye. The lens is located inside the eye behind the iris (the colored part of the eye). The lens gets cloudier over time and causes vision problems.

How does it occur?

Most cataracts happen naturally as people get older. What causes cataracts is not known, but many things may make cataracts more likely to form, such as:

  • aging
  • smoking
  • eye injury or previous eye surgery
  • diabetes or other diseases
  • exposure to radiation, especially X-rays
  • long-term use of steroid medicine
  • exposure to medicines such as gout medicines, cholesterol lowering drugs, antibiotics, and diuretics
  • inflammation in the front of the eye (iritis)
  • prolonged exposure to sunlight

Cataracts don't spread from one eye to the other, but many people have cataracts in both eyes. The cataract can be worse in one eye compared to the other.

What are the symptoms?

The symptoms of a cataract include:

  • blurred vision
  • a need for frequent changes in your eyeglasses or contacts
  • glare from lights, especially at night
  • being sensitive to bright light
  • change in color vision (yellow, orange, and red appear brighter and blue appears dull)

Cataracts do not usually cause complete blindness. However, it is possible to lose enough vision to make it hard to recognize objects.

How is it diagnosed?

The symptoms of a cataract develop slowly and are painless. The condition may go unnoticed and undiagnosed for a long time. It is often found during a routine eye exam.

An eye care provider will do a thorough exam. He or she will evaluate symptoms and determine the best course of treatment.

How is it treated?

If a cataract is not interfering with your lifestyle or work, your provider may suggest changing your glasses or using brighter lights to help you read.

If the cataract is seriously affecting vision and cannot be helped with glasses or contact lenses, a surgeon may need to remove the lens. The surgeon may first use sound waves (ultrasound) to break up the lens so the pieces can then be removed through a narrow hollow suction tube. This part of the procedure is called phacoemulsification. In some cases, the lens is removed in one piece through a larger incision (nuclear expression). After the lens is removed the surgeon will put a new plastic lens in the eye.

Lasers are not used to remove cataracts. However, they may be used to open a cloudy membrane that may develop after cataract surgery.

How long will the effects last?

With glasses, contact lenses, or surgery, you can regain vision if the rest of your eye is normal. Surgery to remove cataracts is usually more than 95% successful in restoring vision. Although a cataract cannot grow back, you may develop a cloudy membrane months to years later. This membrane can be removed using a laser.

How can I take care of myself?

  • Be sure to follow your provider's instructions.
  • Call your eye care provider if your vision gets worse.
  • Be careful when you drive at night. A cataract can make lights such as oncoming headlights seem very bright, causing a glare that makes it hard to see.

What can be done to help prevent cataracts?

You may reduce the risk of damaging your eyes and in turn reduce the risk of developing cataracts by wearing goggles or safety glasses at work or during activities where your eyes could be injured. Wearing glasses with a UV coating that protects your eyes from sunlight might prevent or delay some types of cataracts, but this is not proven.

Good blood sugar control can slow the progression of cataracts related to diabetes.

If you smoke, quit.

Dietary supplements and vitamins have not been proven to prevent cataracts.

If you are a woman and plan to have a baby, make sure you have had a German measles (rubella) shot at least 1 month before you try to become pregnant. If you have German measles while you are pregnant, your baby's eyes should be checked by an eye care professional soon after birth. A baby can develop cataracts if you had German measles or other kinds of infections while you were pregnant.

Reviewed for medical accuracy by faculty at the Wilmer Eye Institute at Johns Hopkins. Web site:
Developed by RelayHealth.
Published by RelayHealth.
Last modified: 2011-07-20
Last reviewed: 2010-09-07
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2011 RelayHealth and/or its affiliates. All rights reserved.
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