A new study shows that large amounts of vitamins and minerals can slow the loss of sight linked to aging. The condition is called age-related macular degeneration or A-M-D. The disease is a major cause of blindness among old people. Doctors don't know what causes it.

The disease destroys the central part of the retina (视网膜), the cells at the back of the eye that gather light. The first sign of A-M-D usually is a loss of visual clearness. People with the disease have trouble reading, driving and recognizing faces. They can't see clearly through the center of their eyes. They must look at things from the sides of their eyes. Over time, A-M-D can cause blindness.

The National Eye Institute carried out the six-year study. Almost 5,000 people in 11 areas of the USA took part. They were between the ages of 55 and 80. Some of the people had more severe forms of the disease than others.

The researchers tested a combination of large amounts of vitamins and minerals. Some people in the study were given the mineral zinc. Others took the vitamins C and E. A third group received both the zinc and vitamins. The remaining people took inactive substances called placebos (安慰剂).

The people in the study were in three groups. Based on the severity of their disease, the researchers compared the vision abilities and other conditions of the patients after 5 years of treatment. Their findings were published in the Archives of Ophthalmology (眼科学).

The scientists say the combination of vitamins and zinc had no effect on patients with the least severe form of A-M-D.

However, they say the vitamins and zinc helped people with more serious A-M-D.

The treatment cut the risk of developing the most severe form of A-M-D by about 25%. The vitamins and zinc also prevented some vision loss for those patients already suffering severe A-M-D. The patients tak-ing zinc and vitamins separately also were helped but not as much as those taking both. Earlier studies had shown that people who eat large amounts of fruits and vegetables containing important vitamins are at lower risk of developing the eye disease.

5. The disease of A-M-D can lead to ________.

A. blindness B. visual clearnessC. visual loss D. cataract

6. According to what they take, the scientists carried out a study and divided those people into________.

A. two groups B. three groupsC. four groups D. five groups

7. As a healthy person, we should eat more ________to prevent the disease A-M-D.

A. mineral and zinc B. vitamins C. vitamin and zincD. fresh fruits and vegetables