Seeing Is Believing

Science World, March 6, 2000 by Maia Weinstock

After 36 years of darkness, a blind man can see again. Thanks to a new "eye opening" technology, a patient identified only as "Jerry"--a 63-year-old man who went blind in 1964--can once again view the world around him. He's one of the first people to receive an experimental seeing device that restores sight by artificially stimulating the brain.

Dr. William Dobelle, chairman of the Dobelle Institute in New York, created the seeing device after 30 years of research in vision correction for the blind. The invention includes a mini-camera connected to a pair of sunglasses and a dictionary-size computer that a patient carries on a belt pack (see diagram, far left).

But getting the device to work was no easy task. First, Jerry had to undergo brain surgery. Surgeons implanted a 7-cm (2.75-in.) piece of platinum foil between Jerry's brain and dura, a membrane that surrounds the brain. The foil is covered with electrodes (tiny metal pieces that conduct electric pulses), which connect directly to brain cells that control sight. The electrodes are then attached to a wire that protrudes from Jerry's skull through a small hole and hooks up to his computer.

For Jerry to see an image, the camera on his sunglasses first snaps a picture. This image then travels through a wire to his portable computer, which translates the data into a series of electrical pulses. The pulses race through the wire connected to Jerry's brain. Finally, the electrodes stimulate his brain cells into thinking they're seeing. "Each electrode produces dots of light in the patient's visual field, like stars in the sky," says Dobelle. "It makes the world look like a photo negative." (See diagram, near left.)

Although the device can't fully restore sight, patients can discern the shape of close objects. The procedure is designed to work not only for those who lose their vision, but also those who were born blind, Dobelle says. However, at a hefty $50,000, it may be a number of years before the device becomes affordable to all those in need of second sight.

1 A camera snaps images and sends them to a computer on the patient's belt.

2 The images are processed and sent to electrodes implanted in the brain.

3 The electrodes stimulate the brain cells that control sight. The patient is tricked into "seeing" images as a pattern of bright spots forms the outline of nearby objects.