Tuesday, October 4, 2011

Amazing facts-Vision Chip helps blind people see again

German scientists have invented an implant that they say has allowed three blind people to see well enough to make out shapes, raising hopes for the thousands of patients with degenerative eye disease.
The implant was tested on three patients with retinitis pigmentosa, an inherited degenerative eye disease in which the eye’s light receptor cells gradually stop functioning and die off.
Researchers developed a tiny, three-by-three millimetre microchip that contains 1,500 pixels designed to pick up light. The idea is that when an image hits the chip, it is converted into electrical pulses that stimulate healthy cells in the retina. These cells send signals to the brain, where the image is reconstructed.

The researchers implanted the device underneath the retina to directly replace the patients’ damaged retinal light receptors. They then had each patient wear a battery on a necklace to power the chip.
Seven to nine days after the surgery, the researchers then tested the patients’ vision.
Among the three patients in the study, two were able to make out shapes and objects. The third patient, who had been blind for several years, responded so well, he could identify objects placed on a table in front of him, such as a knife and fork, and walk around a room without the use of a white cane.

He could even read large letters as complete words and differentiate between seven shades of grey, the researchers report in the Proceedings of the Royal Society B.
A spokesperson for Retinal Implant AG, the company that is developing the device, said the trial results were a “proof of concept.” The company now plans further trials to test the device in as many as 50 patients.
Those studies should be completed in two to three years. If all goes well, the device could be on the market in about five years’ time.
Researchers at Oxford University in England, including Dr. Robert McLaren, will be joining the upcoming studies.
“In the field of ophthalmology, making a blind person see again is pretty much as good as it gets,” McLaren said.
The implant is being developed for retinitis pigmentosa, which is diagnosed in 3,000 Canadians every year. But the technique could be suitable for a range of conditions that affect rod and cone cells, the cells that detect light and convert it into electrical signals through the optic nerve.
Those conditions include age-related macular degeneration, the leading cause of blindness in older people, which affects about a million Canadians.
Jonathan Abro of the Fighting Blindness Society in England is among the 25,000 Britons who are losing their eyesight to retinitis pigmentosa.
“People who’ve lost all or most of their vision are able to distinguish shapes and are learning to see something again,” Abro said. “That’s very exciting.”
The implant wouldn’t work, though, for other eye diseases that affect other parts of the eye, such as the optic nerve, for example.


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