Thursday, November 4, 2010

Retinal implant allows blind man in Finland to see again

From Canoe in Canada:

A 46-year-old blind man from Finland can now read letters, discern patterns and identify items thanks to an electronic chip implanted into his eye.

He's one of three people involved in a pilot project at the University of Tübingen in Germany, the results of which were published Nov. 3 in the journal Proceedings of the Royal Society B.

Within three years of getting the chip, all three blind participants could make out shapes and identify bright objects on a dark table.

One participant, Miikka Terho, showed remarkable progress, learning to "correctly describe and name objects like a fork or knife on a table, geometric patterns, different kinds of fruit and discern shades of grey with only 15% contrast," the study says.

"Without a training period, the regained visual functions enabled him to localize and approach persons in a room freely and to read large letters as complete words after several years of blindness."

Terho suffers from retinitis pigmentosa, a hereditary disease that kills light-sensitive cells in the eye. He's been slowly losing his vision since his teens. In an interview with the Guardian, Terho describes the process of regaining sight.

"When the chip was first turned on, I just saw flashes and flickering. It didn't make any sense. But in a matter of hours, everything started to get clearer and clearer," Terho told the U.K. newspaper. "When I looked at people for the first time, they looked like ghosts. I knew it was a person, but they were hazy. Then things got sharper.

"It was such a good feeling to be able to focus on something, to see something right there, and maybe even reach out and grab it. I wasn't able to identify what was in front of me on the street, but I knew when something was there, so I didn't walk into it."

The 3 mm-by-3 mm chip is installed under a part of the retina called the macula and wired to a thin battery worn on a necklace. It contains 1,500 light-sensitive elements that replace the retina's defunct cells.

The researchers are excited about the project's success, and will start fitting U.K. patients with the device for the next stage of trials next year.

However, they caution the chip doesn't work for all forms of blindness, just conditions that affect rod and cone cells, which detect light and convert it into electrical signals that are relayed to the brain.

Retinitis pigmentosa, choroideraemia and age-related macular degeneration would all be treatable with this technology, but diseases in which the optic nerve is damaged would not.