The regional programme, launched in Beijing on Monday, will tackle the major causes of sight loss - vitamin A deficiency in children, accidents in adolescence and cataracts and the disease trachoma in adults.

China has the largest number of blind people in the world, and the western Pacific area is home to one in five of the world's blind.

An estimated 450,000 people become blind in China every year - 400,000 because of cataracts. In total, it is estimated that four in five cases of sight loss are avoidable.

Vietnam plagued by cataracts

This represents just under 0.2% of the population. In Vietnam, more than 0.8% of the population suffer from cataracts.

Dr Bjorn Thylefors, Director the WHO's Geneva-based Disability Prevention Programme, said: "Against the background of a huge population of some 1,267m people, these figures do not look impressive.

"However, in absolute terms, the number of blind people in China has already surpassed the population in such countries as Denmark, Finland or Norway."

However, China currently does not have the resources to deal with its people's cataract problems.

Of 22,000 eye doctors currently practising in the China, less than half practice eye surgery. This means there is one cataract surgeon per 150,000-200,000 people.

The WHO campaign involves a joint effort between 12 charities and other non-governmental organisations, who spend between them about $80m on blindness prevention and treatment per year.

Blindness on the rise

The "Vision 2020" campaign was globally launched in February this year.