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See Inside December 2006

Sight Savers

Technology that could help the blind see is now in the laboratory

Conventional wisdom specifies that the central nervous system—the brain, spinal cord and eye nerves—cannot heal in adults. This thinking no longer holds. Larry I. Benowitz of Children's Hospital Boston and his colleagues found a molecule that triggers better nerve regeneration than any other studied. The scientists discovered that a protein, oncomodulin, is secreted in damaged eyes by immune cells known as macrophages. They found that oncomodulin, when given with compounds that enhance its activity, can increase nerve regeneration fivefold to sevenfold in rats with injured optic nerves (right). Benowitz believes oncomodulin could someday help reverse optic nerve damage caused by glaucoma, tumors or trauma and plans to investigate whether the treatment could work to help treat stroke and spinal cord injury.

Another invention affords hope that some blind people may be able to view images and video. Visually challenged artist and poet Elizabeth Goldring, a senior fellow at the Massachusetts Institute of Technology's Center for Advanced Visual Studies, developed just such a “seeing machine.” It projects images directly onto the retina using light-emitting diodes, similar to much more costly scanning laser ophthalmoscopes used by medical institutions. In a pilot clinical trial of the seeing machine with 10 volunteers, most of whom were legally blind because of retinopathy and other causes, six correctly interpreted all 10 examples from a specially crafted visual language that combines words and pictures.

Prosthetics of another kind may in the future enable an amputee to use electrical signals from remaining muscles so that he or she can move an artificial arm more naturally. Protagoras Cutchis of Johns Hopkins University developed an electrode array implanted around the sheath of a peripheral nerve that does not penetrate into the nerve itself, unlike previous technologies. The electrode can process signals from electrical impulses from the brain that might eventually direct an arm to perform up to 22 distinct motions, far superior to previous prostheses that could move in only three directions. Machines are thus proving ever more able to take up the slack when the human body falters.

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