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Retinal prosthesis a potential boon for the blind

Thursday, Aug 16, 2012 - 03:11

Aug. 16 - Researchers at Stanford University in California are developing a retinal prosthesis system they hope will one day give millions of blind people the ability to see again. The system has proved successful with rats but is designed ultimately for sufferers of degenerative retinal diseases like Retinitis Pigmentosa. Ben Gruber reports.

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For the past five years Jim Loudin has been designing a tiny photovoltaic chip. It's one third the width of a single human hair, but he says that one day, its impact on people with degenerative blindness will be enormous. The chip is part of retinal prosthesis system being developed at Stanford University. (SOUNDBITE) (English) JIM LOUDIN, RESEARCHER, STANFORD UNIVERSITY, SAYING: "A retinal prosthesis goes in and actually tries to restore the light-sensing ability to the areas of the retina that no longer have that." Daniel Palanker, an Associate Professor of Ophthalmology, helped design the chip. He says it's the principle component of a system that uses goggles to captures video and convert it into infrared laser light that is transmitted to the tiny chips implanted in the retina. (SOUNDBITE) (English) DANIEL PALANKER, ASSOCIATE PROFESSOR OF OPHTHALMOLOGY, STANFORD UNIVERSITY, SAYING: "So it's like a remote control in a TV. You don't see that there is light coming out but a TV set does. That's the same idea. The eye does not see this light but chip can still absorb these photons and convert them into an electrical current." (SOUNDBITE) (English) JIM LOUDIN, RESEARCHER, STANFORD UNIVERSITY, SAYING: "And then that infrared light is picked up by this implant which is a bunch of solar cells underneath the retina. That light is then converted to electrical current and that electricity stimulates the retina and restores some visual sensation to an otherwise blind patient." Georges Goetz, another member of the research team, says that during trials on blind rats, the team has proven that those electrical currents are picked up by neurons in the eye and passed on the brain to form an image. (SOUNDBITE) (English) GEORGES GOETZ, RESEARCHER, STANFORD UNIVERSITY, SAYING: "The most difficult question at the moment is what kind of resolution we can get out of the devices." To move the research forward, the scientists need to answer a difficult question. How can you tell if a rat's vision is improving? Daniel Palanker says the answer is in its brainwaves. (SOUNDBITE) (English) DANIEL PALANKER, ASSOCIATE PROFESSOR OF OPHTHALMOLOGY, STANFORD UNIVERSITY, SAYING: "So the way we plan to do it is exactly the way it is done with small children that don't tell you what they see. It turns out that the brain strongly responds to motion." (SOUNDBITE) (English) JIM LOUDIN, RESEARCHER, STANFORD UNIVERSITY, SAYING: "If you project a checkerboard on a rats' eye and that move that around. If the rat can perceive that as a checkerboard than that tells you that he has that kind of resolution. If that is below is perceptual resolution it will just look gray to the rat and you will see no brainwaves. So by taking these checkerboards of different sizes and reading the brainwaves you can actually you can actually tell the resolution of what the rat is seeing." The team is now in the process of gauging just how well their retinal prosthesis works. Their goal is to prove that the system can restore vision to a level which would justify human clinical trials. (SOUNDBITE) (English) JIM LOUDIN, RESEARCHER, STANFORD UNIVERSITY, SAYING: "Now if we are able to prove a really high resolution than suddenly the amount of patients that we can treat would go way up. So more than anything else we have to prove that we are able to restore a high resolution which is something that we have been working on." Millions of people around the world suffer from degenerative blindness. Palanker says that if prosthetic limbs can allow people to move again - there is no reason why retinal prosthetics can't allow people to see again as well.

Retinal prosthesis a potential boon for the blind

Thursday, Aug 16, 2012 - 03:11

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