The scheme, called Vision 2020, is being co-ordinated by international charities and has been endorsed by the World Health Organisation.

Sight Savers International, one of the charities involved, called the project "an unprecedented example of global collaboration".

Ms Short will sign a declaration of support for Vision 2020 on Thursday.

Dr Gro Harlem Brundtland, director general of the WHO, will officially launch the scheme at the same time.

Avoidable blindness

David Coe is executive director of ORBIS, another of the charities involved.

He said: "People are 10 times more likely to go blind in developing countries than here in the UK. Yet 80% of that blindness could be prevented or cured."

His organisation uses a flying eye hospital to visit developing countries to offer checks and surgery.

The plane will form a central part of the coalition's strategy.

This week it will be in Santo Domingo, in the Dominican Republic, offering treatment exclusively to children.

Simple but effective approach

The project will also follow techniques used by the WHO in its successful bid to eradicate smallpox worldwide.

Richard Porter, executive director of Sight Savers, outlined the approach.