More than one in six people over 40 get a cataract, where the eye's normally clear lens fogs up. Surgery to replace the lens is the only fix, and ageing is the biggest risk factor. But there are other risks:

—Smoking

—Prolonged sun exposure.

—Obesity.

—Alcoholism.

—A family history of cataracts.

—Use of certain steroid medications.

—Diabetes.

—Eye injuries.

Eye specialists recommend a cataract exam for people with those risks and say everyone 65 and older should get one as part of a comprehensive eye exam every year or two.