A new research suggests that contact lenses packed with vitamin E could help save the sight of millions of people afflicted with glaucoma, which happens to be one of the leading causes of vision loss and blindness. Glaucoma affects almost 67 million people worldwide, including more than half a million in the UK.

Glaucoma is usually treated using only eye drops. Some patients need to put the drops in several times a day as the medicine is usually washed out of the eye within minutes, reducing its effectiveness.

The new lenses, which slowly release the drugs and hold them in place, could vastly improve treatment, an American Chemical Society conference has heard:

Dr Chauhan, of the University of Florida, said: 'These vitamin structures are like "nano-bricks".  The drug molecules can't go through the vitamin E, they must go round it.

'Because the nanobricks are so much bigger than the drug molecules - we believe a few hundred times bigger - the molecules get diverted and must travel a longer path.

'This increases the duration of drug release from the lenses.'

The lenses, which are due to be tested on people within the next two years, have the added benefit of protecting the eye from sun damage.

Dr Chauhan said: 'Vitamin E in contact lenses blocks UV radiation, leading to increased protection against UV light.;'

The lenses, which are no more difficult to see through than normal contacts and can be worn for a month at a time, could also be loaded with drugs for cataracts and other eye conditions.