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Thirty million to 40 million people around the world suffer from retinitis pigmentosa or macular degeneration, two diseases in which the retina--a thin sheet of cells in the back of the eye--slowly loses its ability to convert light into the electrochemical signals that are transmitted to the visual centers of the brain. As the diseases progress, sufferers gradually lose more and more of their sight. First the peripheral vision goes, then light sensitivity narrows until one day their window on the world snaps completely shut. Once surgically placed in the eye, Chow's Artificial Silicon Retina (ASR)--a computer chip about the size of a pinhead--takes on the job of the retina's damaged photoreceptors. The ASR restores only functional--not total--vision and works just on patients with retinitis pigmentosa or macular degeneration, so it's not a cure for blindness. Nevertheless, Chow says, the 10 trial patients all have shown "moderate to substantial" improvement, and "one patient who had been able to see only shadows for years could make out the faces of his family." Chow, who co-founded his company six years ago with his brother Vincent, believes he's still five to 10 years away from making his bionic eye procedure generally available. First he has to win full regulatory approval from the U.S. Food and Drug Administration. He also has to bring costs well below their current level, nearly $2 million per operation.
An equally breathtaking effort to use technology to supplement the body comes from MnemoScience of Aachen, Germany. The company is developing a thin strip of plastic that, once delivered into the body, can wrap and twist itself into just the right shape to help mend bones, open blood vessels and close wounds. Mnemo's technology is a new riff on shape-memory alloys, materials that can shrink or expand themselves and return to their original shape when stimulated by heat or electricity. Most shape-memory materials are metals, but Mnemo's plastic strips have a distinct medical advantage: they are biodegradable. A strip of Mnemo plastic threaded loosely around a hard-to-reach internal wound, for example, could shrink itself into a tight suture. In another application it could expand into scaffolding over which new tissue would grow in a bone cavity. Or it could expand into a stent, a device surgeons use to open blood vessels. And Mnemo co--managing director Dietmar Hellenbroich says surgeons could even tailor the material to degrade after two weeks or two years, depending on a patient's needs. While Mnemo, founded in 1998 by M.I.T. professor Robert Langer and scientist Andreas Lendlein, has not worked its product into the market yet, Hellenbroich is confident that Mnemo shape-memory plastics will be used inside people by 2005.