If you smoke and carry on smoking you are four times more likely to develop age-related macular degeneration when you are old - this makes you go blind.

A new study was carried out at Manchester University (UK). The researchers say that cigarette warnings that appear on packets should include something about this risk.

Age-related macular degeneration (AMD) is the main cause of blindness. In the UK it affects about 500,000 people.

People over the age of sixty with AMD lose their central vision, the condition is irreversible eventually.

Simon Kelly, Ophthalmic Surgeon, says that about 54,000 people have AMD in Great Britain because of tobacco. 17,800 of them are totally blind.

Kelly and his team say there should be a public health campaign to make people aware of this. Nobody knows they could go blind as a result of smoking. All smokers know about is the cancer and heart risks.

The researchers say that 25% of AMD cases with blindness or visual impairment are attributable to present or past smoking.

If you give up smoking now your risk goes down, they say. Your long-term response to laser therapy and other treatments also improves if you give up smoking (or if you never smoked).

The Royal National Institute for the Blind (RNIB), UK, says that people fear losing their eyesight more than anything else. Knowing that smoking could make you go blind could encourage lots of people to give up. The RNIB says that the public needs to know this risk.