[tabi] Fw: A Chip For The Eye: Artificial Vision Enhancers Being Put To The Test
- From: "Dan Orange" <dorange@xxxxxxxxxxxxx>
- To: <tabi@xxxxxxxxxxxxx>
- Date: Mon, 21 Sep 2009 09:22:32 -0400
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From: Lappland
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Sent: Monday, September 21, 2009 6:59 AM
Subject: A Chip For The Eye: Artificial Vision Enhancers Being Put To The Test
A Chip For The Eye: Artificial Vision Enhancers Being Put To The Test
Article Date: 19 Sep 2009 - 1:00 PDT
Visually impaired or blind patients with degenerative retina conditions
would be
very happy if they were able to regain mobility, find their way around, be
able to
lead an independent life and to recognize faces and read again. These wishes
were
documented by a survey conducted by a research team ten years ago to find
out what
patients' expectations of electronic retina prostheses (retina implants)
were.
Today these wishes look set to become reality, as the presentations to be
given at
the international symposium "Artificial Vision" on 19 September 2009 at the
Wissenschaftszentrum
Bonn demonstrate. The symposium is being staged by the Retina Implant
Foundation
and the Pro Retina Stiftung zur Verhütung von Blindheit (Pro Retina
Foundation for
the Prevention of Blindness), a foundation of the patients' organization Pro
Retina
Deutschland e.V.
Scientists have been working on developing retina prostheses for more than
twenty
years now. Research has been conducted particularly intensively in Germany,
where
scientists and patients have worked in tandem and have succeeded in
obtaining government
funding. "Back then we didn't want high-tech just for space and defence
programs
but finally high-tech for people as well," Professor Rolf Eckmiller, a
neuro-informatics
specialist at the University of Bonn and a pioneer in the field, recalls.
This investment is now bearing fruit. The German research consortiums lead
the field
in this area of research. Three of the four research teams presenting their
findings
in Bonn are from Germany.
As the presentations show, all the electronic retina prostheses convey
visual impressions,
so-called phosphenes. Patients participating in a US study were able to
distinguish
light and dark and to register movement and the presence of larger objects.
In addition,
early reports from a project being conducted by a German research group led
by Profesor
Eberhart Zrenner at the University of Tübingen indicate that restoring
visually impaired
patients' ability to read is not just wishful thinking. Some patients are
able to
read letters if these are eight centimetres high.
"We're in the final run-up," explains Professor Peter Walter from the
University
Eye Clinic in Aachen. Walter is scientific director of the symposium
"Artificial
Vision." "The final studies prior to market launch have begun or are set to
begin,"
he says in his latest progress report. These studies are designed to test
the long-term
tolerability of the retina implants and their benefits in everyday life. The
manufacturers
expect the implants to be approved in 2011.
Naturally, there is a lot of interest among patients in the new products.
"Compared
with the study we conducted ten years ago, patients now have a much clearer
idea
[of what they expect from retina prostheses]," says Helma Gusseck,
chairperson of
the Stiftung Retina-Implantat (Retina Implant Foundation). Gusseck, who also
chairs
the Pro Retina Stiftung, suffers herself from Retinitis pigmentosa, a
degenerative
retina condition and can now only distinguish between light and dark. For
her the
research findings are a relief: "You can, so to speak, go blind without
worrying
about it, because you know that the systems will soon be ready and we
therefore have
an option."
Nevertheless, this is really only the beginning. "What we're seeing is
different
systems racing to compete," says Peter Walter. In one of the systems the
sub-retinal
implant the chip is implanted under a layer of nerve cells in the retina.
There,
like the photoreceptors in the retina, it receives light impulses, converts
these
into electrical signals and transmits them to the nerve cells of the retina.
The
retina prosthesis developed by Professor Zrenner's team in Tübingen and that
developed
by a US team led by Joe Rizzo and Shawn Kelly at the Boston Implant Project
in Cambridge,
Massachusetts, work according to the same principle.
In the case of the so-called epiretinal implant the chip is fixed to the
upper-most
layer of nerve cells. There it receives data from a small camera installed
in glasses
worn by the patient and likewise converts these into impulses for the nerve
cells.
This is the principle employed by the retina prostheses developed by the two
other
German research teams. One of the systems IRIS was developed by the Bonn
company
IMI, the other (EPIRET3) by a research consortium that includes scientists
from the
RWTH Aachen and the Fraunhofer Institut für Mikroelektronische Schaltungen
und Systeme
(Institute for Microelectronic Circuits and Systems) and doctors at the
University
Eye Clinic Aachen led by Peter Walter.
Alongside these various systems, which also differ from one another in a
number of
other details, the next generation of retina prostheses is already in the
pipeline
in laboratories around the world. Engineers, computer science specialists,
biologists
and doctors are pooling their knowledge to evolve new strategies for linking
electronic
devices and nervous systems.
Teams of researchers in Switzerland and Japan, for example, are developing
systems
in which the chip is no longer implanted in the eye but outside it on the
dermis
that protects the eyeball in the socket. Only the electrodes that stimulate
the nerve
cells in the retina are inserted inside the eye through a small incision.
Chinese
researchers are developing retina prostheses that, instead of stimulating
the nerve
cells of the retina, stimulate the optic nerve directly. And an American
team is
trying to activate the visual cortex in the brain directly. At this point it
is not
clear when, if ever, any of these systems will be ready for patient trials
currently
they are still at the experimentation stage.
Much interest has also been shown in projects to use other communication
signals
between nerve cells. Australian and American scientists are working on
retina prostheses
that produce biochemical impulses instead of electrical ones. The idea is
for the
retina prostheses to release neurotransmitters according to spatially and
temporally
controlled patterns and thus stimulate the nerve cells.
The question remains whether retina prostheses will eventually be able to
register
shapes, as Rolf Eckmiller hopes they will. "To do this will require a retina
prosthesis
capable of learning and that is able to produce a kind of melody of impulses
that
can be recognized by the brain and classified as a particular shape, like a
cup."
Eckmiller is convinced that the complex central vision system which occupies
a third
of the cerebral cortex can only register a shape if the right "melody" is
transmitted
via a sufficiently large number of cells.
Source: ProScience Communications GmbH
www.accessible-devices.com
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