An atomic physicist who has spent more than 20 years developing innovative water-filled spectacles wants to put them on the faces of a billion people in the developing world.

Oxford University professor Joshua Silver, from Cumnor, first came up with the idea for glasses to which the user could add or drain water to correct their vision in 1985.

More than 23 years later, following dozens of different prototypes and trials in 15 countries, Mr Silver is ready to launch the specs.

Mr Silver, 62, said: “I met a man in 1994 from the World Health Organisation and asked him how many people in the world needed corrective eyewear and he said it was about a billion.

“I said ‘I can solve that problem’, which was very cheeky of me, and he said ‘if you can, you should do’.”

Initial trials were carried out in Ghana, South Africa, Malawi and Nepal, then the World Bank bought 11,000 pairs as part of an adult literacy project in Ghana.

A further 20,000 have been sent to 15 countries, mostly in Africa, as part of a United States Department of Defence humanitarian aid project.

Now Mr Silver, director of Oxford University’s Centre for Vision in the Developing World, is looking for funding to distribute a million pairs in India in the next year — with the ultimate goal being to produce and distribute a billion pairs of the glasses by 2020.

He said: “What is more important than bringing corrective eyewear to half the world?

“This is not about making money, which would be neither ethical nor practical in the developing world. My main motivation is to solve this problem.

“I’m determined, so far as it is in my power, to see the technology applied in all the developing world.”

The glasses have two circular sacks filled with fluid inside the lenses, which can be topped up by detachable syringes attached to either side of the glasses, altering the focus for the wearer.

He said what made the glasses so important was the fact the person who wears them can change them to their own prescription without needing an optician’s assistance.

It means a trip to the optician is not neccessary.

Mr Silver, who is short-sighted, has seen for himself the reaction of people when they first try on the glasses.

He said: “As they get to clear focus they will smile.

“One of the first guys who wore a pair had lost his job in a factory because he could not see well enough.

“So such a simple thing as correcting his vision meant he could then work and remain economically productive for longer — and there are hundreds of millions of people in that condition globally.”

The glasses currently cost $19 but for them to be distributed on the scale Mr Silver hopes the costs needs to come down to about one or two US dollars — a goal he believed was achievable.

fbardsley@oxfordmail.co.uk