Help for those blinded by retinitis pigmentosa?
Chris James and Robin Millar of the United Kingdom both lost their vision after birth because of a genetic condition known as retinitis pigmentosa, in which light-sensitive cells in the eye stop working. Now, surgeons have partially restored vision to both men with tiny electronic chips that promise to help the blind see the same way cochlear implants have helped the deaf hear. Teams of doctors at the Oxford Eye Hospital and King’s College Hospital in London embedded the small square chips—0.12 by 0.12 inches—in a thin sheet of tissue at the backs of the men’s eyes. As soon as they were switched on, the chips began performing the duties of defunct photoreceptors—also called rods and cones—converting light into electrical impulses that travel to the brain. A thin cable threaded beneath the skin connects the chip to a battery pack, which also sits under the skin near the ear.
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Retina Implant AG, a medical technology company in Germany, designed the chips that James and Millar received; surgeons have implanted similar chips in at least 10 other patients so far as part of clinical trials. Eberhart Zrenner of the University of Tubingen, who helped found Retina Implant AG, has been improving the chips over the past decade, making them safer and more portable. In a special report on “Tomorrow’s Medicine” in the May issue of Scientific American, I wrote about Zrenner’s research and a Finnish man named Miikka Terho who also went blind because of retinitis pigmentosa. In 2008, Terho received an earlier version of Zrenner’s chip:
“Miikka Terho knows the difference between an apple and a banana. He can tell you that one is round and sweet and crunches when you bite it and that the other is long and curved and turns to mush if you let it ripen too long. But if you ask him to tell one fruit from the other without touching, smelling or tasting them, he is at a loss. Terho is completely blind. For three months in 2008, however, he recovered the ability to distinguish an apple and banana by sight thanks to a tiny electronic chip that researchers implanted in his left eye. Though brief, the new technology’s initial success has permanently changed the prospects for Terho and many others like him.”
http://www.huffingtonpost.com/2012/05/03/bionic-eye-microchip-implant-vision-blind_n_1475960.html
