What is a cataract?

A cataract forms when the lens of the eye, which is living tissue that helps to focus light on the retina, becomes cloudy. This probably occurs because of changes in the proteins that are packed into the lens. Cataracts are extremely common; more than half of Americans age 65 and older have a cataract (often in both eyes), and it is thought that nearly everyone will develop one if they live long enough. Cataracts take a long time to develop to the point that they are a serious problem for your vision. There are several types of cataract; the most common is called nuclear cataract because it affects the inside of the lens. In the form called cortical cataract, the outside of the lens becomes cloudy.

In developed countries, cataracts are routinely removed by a simple operation. However, cataract continues to be the leading cause of blindness worldwide.

Who is at risk for cataract?

The older you get, the greater your chance of having cataracts, and of their progressing enough to interfere with your vision. Sometimes babies are born with cataracts (congenital cataract). Prolonged use of steroids can cause cataracts. And some young adults who have systemic illnesses, like diabetics, develop cataracts because of their disease (secondary cataract). However, the vast majority of noticeable cataracts form in people over age 60. Therefore, cataract is usually considered an age-related disease.

Women live, on average, several years longer than men. For this reason, many more women than men live long enough to develop cataracts. Furthermore, for unknown reasons, women are intrinsically at somewhat higher risk than men of getting the cortical form of cataract.

What are the symptoms of cataract?

The main symptoms of a cataract are blurred, cloudy, or dulled vision in the affected eye that cannot be corrected by wearing stronger glasses or contact lenses. Colors may seem faded. In addition, a brighter light may be needed for reading. Increased sensitivity to glare can also be a sign of cataract; a halo may be seen around bright lights at night, and this can cause a problem in driving. If you notice any of these symptoms, you should visit an eye care professional.

Can anything be done to prevent cataract?

Smoking greatly increases the chance of getting nuclear cataracts, the most common type in the United States. Therefore, the most effective way to lower your risk of cataract is not to smoke. People with diabetes, even young ones, often develop cataracts. Formation of diabetic cataracts can be slowed by keeping blood sugar under tight control.

The scientific evidence for other preventive measures is weak, but suggestive. Sunlight exposure may have an effect on hastening the formation of cortical cataract. Antioxidants (especially vitamin C) and carotenoids in the diet may slow down the progression of some types of cataract, but the evidence is conflicting. The prudent thing to do is to eat several portions a day of fruits and vegetables, and to wear sunglasses and brimmed hats in bright sunlight. Even if it doesn’t reduce your risk of cataract, this behavior will help protect you against heart disease, skin cancer, and probably AMD.

Although we don’t yet know much about how to protect them against cataract, people over the age of 60 are at increased risk for many vision problems besides cataract. If you are age 60 or older, you should have an eye examination through dilated pupils at least every two years. This kind of exam allows your eye care professional (optometrist or ophthalmologist) to check for signs of age-related macular degeneration and glaucoma, as well as cataracts. Prompt treatment of AMD, and especially glaucoma, can usually prevent unnecessary blindness.

What is the treatment for cataract?

Cataract is a curable eye disease. In the early stages, stronger lighting and eyeglasses may lessen vision problems caused by cataracts. At a certain point, however, surgery will be needed to improve vision. Cataract surgery is the most common operation performed today in the United States. The procedure is rapid, safe and nearly always completely successful. A cataract needs to be removed only if it interferes with your vision enough to prevent you from driving, reading, or other essential activities. A “ripe” cataract can easily be extracted by an eye surgeon. If you have cataracts in both eyes (which is often the case), the surgeon will remove only one of them at first; you will have to return at a later date for the second eye to be operated on.

Cataracts are usually removed these days by a procedure called phacoemulsification, or phaco. Your doctor makes a small incision on the side of the cornea (the clear, dome shaped surface that covers the front of the eye). The doctor then inserts a tiny probe into the eye. This device emits ultrasound waves that soften and break up the cloudy center of the lens so it can be removed by suction. 

Usually a clear, artificial lens (called an intraocular lens or IOL) is implanted in the eye during surgery to replace the removed lens, so that people no longer need to wear glasses. The IOL requires no care.

Current research is aimed at learning the molecular pathways involved in cataract formation, and how to interfere with them.


Women’s Eye Health