Blind World

Artificial retina brings light to the blind.

January 21, 2005.

If the vision-restoring visor worn by the Star Trek: The Next Generation character Geordi La Forge is an indication of things to come, then researchers in Germany have taken a big step toward making such a device a reality.

IIP Technologies, a start-up company based in Bonn, has announced promising early results from tests of an artificial replacement for the retina, the light-sensing membrane inside the eye.

It's a small electrode array that is surgically placed against the front of the retina, says John Wyatt, a professor of electrical engineering at the Massachusetts Institute of Technology who worked as a consultant for IIP on the project.

The implants are "very flat and thin. They pass current through each electrode and it stimulates some of the retinal nerves that lie beneath it, producing the perception of a localized spot of light, at a position such as it would land at the same place in your retina."

According to IIP's Web site, the implant is just part of a vision system that also includes special glasses containing a camera chip that takes pictures of the environment.

Signals from the camera will be sent to a neuro-computer chip that "transforms the camera's signals into pulse sequences," the website states.

The pulses are then sent through a wireless system to the implanted component, which in turn sends small electrical impulses to cells on the retina. Stimulated vision nerves then transmit signals to the brain.

Twenty people from four centres in Germany and Austria were enrolled in a test of the artificial retina. They all suffered from retinitis pigmentosa, a progressive degeneration of the retina that causes severe vision loss.

Nineteen of the participants reported they saw some light when small amounts of electrical current were sent through the device. "It was safe ... but they only saw, generally, single spots of what seemed to be light," Wyatt says.

He adds the study was more of a proof-of-principle trial to confirm that people would see something from the stimulus, and to determine how much current was safe.

The next step is to take the complete device and test it in animals for long-term use. Once it passes those tests, the device can be tested in blind human volunteers.

Wyatt is working with researchers in Boston on a similar system that also includes an implantable retina stimulator, special glasses and a battery pack.

End of article.

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