Oxford professor invents self-focusing glasses

An Oxford physics professor is selling 10 million pairs of revolutionary new spectacles to Africa which enable the users to wear them for a lifetime without ever going to an optician.

The glasses could help the billion people around the world who are deprived of spectacles but suffer from long or near sight. Joshua Silver's simple invention could in theory help to eradicate adult illiteracy in developing countries.

Professor Silver's "adaptive glasses" look like ordinary ones except for the two knobs on either side of the frame that can adjust the curvature of the lens. It means that in countries where opticians are scarce, wearers can simply alter the focus as their eyesight deteriorates over time.

Uncorrected poor vision is considered among the most serious problems in the developing world, holding back economies by forcing educated classes to retire early with failing eyesight. The World Health Organisation (WHO) estimates one billion people worldwide need but do not have access to spectacles.

The lenses are filled with silicon oil, controlled via a small pump on the frame. This alters the curvature of the lens, allowing the wearer to see clearly with the simple turn of a knob. Through a deal with the WHO and the World Bank, Prof Silver plans to sell up to 400,000 adaptive glasses in Ghana with another deal for 9.3 million pairs in South Africa also in the pipeline. The glasses are sold at about £6 through his company Adaptive Eyecare, based in Oxford, but cost less than that to make. With just 50 opticians in Ghana out of a population of almost 20 million, glasses that last a lifetime will prove a boon.

"It would take on average about 200 years to be seen by an optometrist in Ghana," explained Prof Silver. "But adaptive glasses obviate the need for a trip at all."

The professor began work on his invention 17 years ago although the technique of using liquid in lenses dates back to the 18th century. "When I first started working with variable power lenses, it was simply to see if they could be made," he said. "Then I realised that if I could build something with the potential to help millions of people, I ought to just go out and give it a go."

The lack of optometry has undermined Ghana's £19m World Bank-funded adult literacy programme. A recent study found that 74 per cent of those on the programme needed glasses. Dr Kweku Ghartey, one of Ghana's leading eye surgeons, is backing the invention. "People can't be taught unless they can see what is put before them," he said.

Trials which have been under way in Ghana since 1996 have already proved successful. "There was one girl who didn't know trees have leaves," said Dr Ghartey. "You should have seen the smile on her face when she understood that the leaves she found on the ground came from the trees."