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- WASHINGTON (Reuters) - A
New York researcher said on Monday he had helped a blind man see again
using electrodes implanted into his brain and connected to a tiny television
camera mounted on a pair of glasses.
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- Although he does not ``see'' in the conventional sense,
he can make out the outlines of objects, large letters and numbers on a
contrasting background, and can use the direct digital input to operate
a computer.
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- ``If he is he walking down a hall, the doorway appears
as a white frame on a dark background,'' William Dobelle, of the Dobelle
Institute and Columbia-Presbyterian Medical Center in New York, said in
a telephone interview.
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- His ``Dobelle Eye,'' described in detail at www.artificialvision.com,
consists of a tiny television camera and an ultrasonic distance sensor
mounted on a pair of eyeglasses. A cable runs to a dictionary-sized computer,
worn in a belt pack.
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- After processing the information from the camera, the
computer sends a signal to the user's brain via 68 platinum electrodes.
``Each electrode on the surface of the brain produces dots of light when
stimulated that resemble stars in the sky,'' Dobelle told Reuters Television
in an interview. These dots are known as phosphenes.
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- He demonstrated with Jerry, a 62-year-old patient who
lost his vision at the age of 36 after a blow to the head.
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- ``On a black background, he gets white phosphenes. With
small numbers of phosphenes you have (the equivalent of) a time and temperature
sign at a bank,'' Dobelle said. ``As you get larger and larger numbers
of phosphenes, you go up to having a sports stadium scoreboard.''
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- Jerry, who does not want his last name used, demonstrated
by walking across a room to pull a woolly hat off a wall where it had been
taped, took a few steps to a mannequin and correctly put the hat on its
head.
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- A reproduction of what Jerry sees showed crosses on a
video screen that changed from black to white when the edge of an object
passed behind them on the screen.
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- ``When an object passes by the television camera ...
I see dots of light. Or when I pass by it,'' Jerry said.
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- The system works by detecting the edges of objects or
letters. Jerry, currently the only user of the latest system, must move
his head slightly to scan what he is looking at.
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- Writing in the ASAIO Journal (the journal of the American
Society of Artificial Internal Organs), Dobelle said Jerry has the equivalent
of 20/400 vision -- about the same as a severely nearsighted person --
in a narrow field.
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- ``Although the relatively small electrode array produces
tunnel vision, the patient is also able to navigate in unfamiliar environments
including the New York City subway system,'' Dobelle said in a statement.
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- Jerry can read two-inch tall letters at a distance of
five feet. And he can use a computer, thanks, Dobelle said, to some input
from his 8-year-old son Marty.
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- ``He was with us this summer and he said, 'you guys are
out of date. Why don't you take digital signals straight from the TV or
computer?''' It worked. Jerry must scan these images, using a joystick
for a computer game, but he is learning to use a computer and is eager
to try some on-line stock trading. ``He's hot for that,'' Dobelle said.
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- Dobelle said he thought being able to use a computer
would ultimately prove more important for blind users of the system than
the mobility it offers them.
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- Jerry and one other patient have had the electrodes implanted
in their brains since 1978, said Dobelle, who specializes in various neural-stimulating
implants.
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- He said only recently was he able to get the computer
small enough to be portable. ``The original electronics package was 10
feet long, 5 feet high and 3 feet wide,'' (3 m long, 1.6 m high and 1 m
wide) he said.
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- ``It weighed 2,000 pounds (800 kg). The present system
weighs 10 pounds (5 kg) and is 500 times faster. The semiconductor technology
that we needed to implement active stimulation has changed dramatically
and that was the last technology piece. The chips became available less
than a year ago.''
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- One other patient who has tried the new system cannot
''see'' anything with it. Dobelle said the man was blinded at the age of
5, 60 years ago, and his brain may have ``forgotten'' how to use its visual
cortex.
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- He added that he does not know whether the system will
work for people who were born blind.
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