London, England (CNN) -- Second phase trials have started across Europe into pioneering eye surgery that allows some blind people to see.
The technology is the result of 15 years' work by researchers at the University of Tuebingen in Germany led by professor Eberhart Zrenner.
"I think we are like the Brothers Wright when they had the first airplane. ... They proved that flying is possible. We have found that the electronic transmission of images is possible," Zrenner told CNN.
The procedure is unique in that it involves implanting a chip underneath the retina that transforms images into electrical impulses, which then are sent to the brain. Other research under way elsewhere involves the use of cameras and processing units outside the body.
The results of the first human clinical trials were published Wednesday in the Proceedings of the Royal Society B, and involved patients suffering from retinitis pigmentosa, a hereditary condition that slowly destroys the retina.
Of 11 patients who underwent surgery, five were able to to recognize and localize sources of light or large, whitish objects. The final patient was able to distinguish objects, read letters and tell the time on a large clock. They had all been blind for at least two years.
"One of the patients just last week from the Netherlands told me that he had seen his girlfriend for the first time. He's been blind for 15 years," Zrenner said.
"He looked at her and saw her smiling because of her white teeth between her lips. So of course it's not vision as we see faces, but he says he sees the shadow of her nose and the shadow of her eyes, [though] not the eyes themselves," he said.
Professor Robert MacLaren of the University of Oxford describes the success of the first clinical trial as a "significant advance" in the technology. He is due to take part in the second phase of the trial in the UK.
"One previously blind patient was able to read his own name with the implant switched on. Up until now, this concept would have been considered only in the realms of science fiction," he said in a statement.
Retinitis pigmentosa is believed to affect 10 percent of the blind population, or around 1 in 4,000 of the global population.
In Europe, that amounts to between 100,000 and 150,000 patients whom Zrenner has invited to apply for free surgery as part of the second phase trial.
Surgeons are being trained in Germany to perform the "relatively complex" procedure in the United Kingdom, Hungary and Italy next year.
During the trial, between 25 and 50 patients will receive an updated version of the implant, which will be permanently embedded under the skin for two years.
In the first clinical trial, the device was powered through a cable outside the body and was in place for four months.
Zrenner said not every sufferer of retinitis pigmentosa will be a suitable candidate for surgery, particularly people who have been blind for an extended period of time.
And he said people who had been blind from birth were not likely to benefit.
"We have not tried it, but it would probably not work very well because people need to have learned seeing. The brain has to be trained to interpret what light and objects mean," he said.
MacLaren said while the early results were promising, more needed to be known about how long the chip would last and how the images seen could be improved.