Study links smoking to blindness
Smoking leads to blindness, according to a New Zealand study.
A survey of more than 1,300 blind people revealed smoking as a leading cause.
The study calls for warnings on cigarette packets about the risks of smoking impairing vision.
The study, in the New Zealand Medical Journal, found that 1335 people registered as blind in New Zealand have age-related macular degeneration caused by present and past smoking.
That figure represents more than a quarter of the cases of registered blindness due to the condition.
The macula is a small spot near the centre of the retina of the eye where vision is especially sharp.
The research also estimated that smoking caused 400 (13%) of cataract operations each year, reports The Dominion newspaper.
Smoking was thought to cause cataract formation through oxidative damage and heavy metal accumulation in the lens, according to the study.
Dr Nick Wilson the study's co-author, says many smokers might be unaware that cigarettes contained toxic heavy metals. Studies show that quitting smoking reduced the risks of developing cataracts.
The research was based on studies carried out in Australia, but Dr Wilson says the New Zealand findings probably under-estimated the true impact of smoking on eye disease.