I'll tell you a story about how the blind can see...

Virtual reality headset designed to process data from satellites makes reading possible again

A registered blind man is reading books again, thanks to a piece of equipment designed by the United States space agency to process satellite images.

Dr Tom Thompson, 42, suffers from macular degeneration, an eye disease that leaves sufferers walking around in a fog. But now a virtual-reality headset for less than pounds 4,000, developed by Nasa with specialists at Johns Hopkins University in Baltimore, has rejuvenated his sight.

Macular degeneration is common in the elderly, but does not usually start to affect people's vision until they are past retirement age. The macula is the most sensitive part of the retina, onto which the eye focuses the central part of any scene. The degeneration causes loss of detail in the central area, making reading or driving difficult or impossible. Peripheral vision remains, but it is not detailed enough for many tasks.

Dr Thompson's condition was first detected three years ago, and he had been unable to read for more than a year. But while in the US, visiting friends in Baltimore, he met an optician who told him about a piece of equipment called the Low Vision Enhancement System - or LVES, pronounced "Elvis" by its users.

"I had a go on the equipment and it was amazing. I could actually read a book. I talked it over with my wife and we decided it would be worth using our savings so I could read again," Dr Thompson, a former GP of Hutton Buscel, North Yorkshire, said.

The LVES system, which is available for sale or hire in the US, costs $5,600 (pounds 3,600). A number of companies in the US sell it, including Sight Systems of Olympia Fields, Illinois. There are fewer than 200 users of LVES in the US, and Dr Thompson is believed to be the only one in Britain.

LVES weighs about two pounds, and consists of three cameras - one for each eye and a zoom lens - in a head-mounted system which covers the eyes, with two tiny screens in front of the eyes onto which pictures from the cameras are projected. The cameras can focus on objects at any dis- tance down to two inches, and they can magnify by up to 25 times.

The LVES magnifies the centre of a scene and enhances its contrast, to compensate for the reduced effectiveness of the macula.

The processing required is carried out by a hand-held box, the technology of which was originally developed by Nasa to cope with data relayed from satellites.

But the scientists at Johns Hopkins decided that the same system, allied to a virtual reality set-up, could compensate for all sorts of visual defects, including extreme nearsightedness.

Another benefit of the system for Dr Thompson is that his children love seeing him using it. "Naomi and Joe think it's great fun because I look like something out of Star Trek when I'm wearing it," he said.