AMD is a chronic disease that affects the central part of the retina of the eye, resulting in blurred central vision or a blind spot in the center of one's visual field.

Although macular degeneration does not affect a person's peripheral vision, the loss of clear central vision can destroy the ability to read, drive and recognize people's faces without causing total blindness.

It is one of the leading causes of severe vision loss in old age and the researchers from the University of Sydney say their study provides strong evidence of the link between cigarette smoking and this particular loss of vision.

For the study the research team led by Jennifer Tan followed 2,454 Australians who were at least age 49 at the start of the study for a 10 year period.

Of the participants, more than 50% were lifelong nonsmokers, 35.5% were former smokers and the remaining 13% were current smokers.

The researchers from the Centre for Vision Research and Westmead Hospital's ophthalmology department, found that smokers were around four times more likely to develop the disease than people who never smoked, and they also developed the condition an average of five years earlier.

The study also found that previous smokers were three times as likely to have an advanced form of the disease than people who never smoked.

The researchers say the risk from smoking seemed to persist above that of 'never smokers' for a considerable time after quitting smoking.

The study participants were questioned about past and current smoking and their diet; retinal photos were taken and weight and blood-pressure measurements were also recorded.

Even when the data was adjusted on the basis of participants' age, sex, and other AMD risk factors, current smokers were still four times more likely than nonsmokers to develop late AMD.

On average, smokers developed late AMD when they were nearly 69 years old, five years earlier than nonsmokers.

The findings appear in the Archives of Ophthalmology.

During the study period of on average 9.4 years, 1,450 women had one or more cardiovascular events, including 274 heart attacks, 298 strokes, 889 coronary revascularization procedures (bypass surgery or angioplasty) and 395 cardiovascular deaths (out of a total 995 deaths).

The research revealed that only a combination of vitamins C and E conferred a slightly lower risk of stroke compared to placebos.

But the study also found that taking the supplements did not harm the women, as some recent research has suggested.

Heart disease is the leading cause of death in the industrialized world and experts say supplements cannot be expected to reverse 30 years of heart disease.

Some studies have shown that supplements with modest amounts of antioxidants do confer some benefits over a long period of time.

The study is published in the Archives of Internal Medicine.