Overview
of the
Artificial Retina Project
The DOE Artificial
Retina Project is a multi-institutional collaborative effort to
develop and implant a device containing an array of microelectrodes
into the eyes of people blinded by retinal disease. The ultimate
goal is to design a device with hundreds to a thousand microelectrodes.
This resolution will help restore limited vision that enables
reading, unaided mobility, and facial recognition.
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A retinal prosthesis contains a small implantable chip with
electrodes. These electrodes stimulate the retina and help
people regain limited vision. The artificial retina devices
developed in this study offer hope to people suffering from
diseases that cause blindness but leave the cones and rods
(cells that detect light) intact. |
The device is intended
to bypass the damaged eye structure of those with retinitis pigmentosa
and macular degeneration. These diseases destroy the light-sensing
cells (photoreceptors, or rods and cones) in the retina, a multilayered
membrane located at the back of the eye.
A first implantable
device
The DOE project builds
on the foundational work of its leader, Mark Humayun at the Doheny
Eye Institute of the University of Southern California. In a breakthrough
operation performed in 2002, a team led by Humayun successfully
implanted the first device of its kind—an array containing
16 microelectrodes—into the eye of a patient who had been
blind for more than 50 years. Since then, 5 additional volunteers
have had devices implanted, all with encouraging results. This
device now enables patients to distinguish light from dark and
localize large objects.
For more information,
see
Integrating
revolutionary DOE technologies for useful vision
Achieving the quantum
improvements in resolution needed for useful vision requires the
integration of revolutionary technologies such as those developed
at DOE national laboratories. In 1999, the Doheny group began
collaborating with researchers at DOE’s Oak Ridge National
Laboratory, who were also working on approaches for restoring
sight to the blind. Shortly thereafter they began to evaluate
technologies at several other national
laboratories as well.
To speed the design
and development of better models, in 2004 Doheny and DOE (including
six of its national laboratories), two other universities, and
Second Sight Medical Products Inc. (a private-sector company)
signed a Cooperative Research and Development
Agreement. Under the agreement, the institutions will jointly
share intellectual property rights and royalties from their research.
This will spur progress by freeing the researchers to share details
of their work with collaborators.
Three models
in testing and development
Three models are now
in development or testing. Model 1, with 16 electrodes, was implanted
in six patients. In addition to providing
rudimentary sight for the patients, this apparatus is beginning
to answer important fundamental biological questions that will
enable researchers to go much further in developing this concept.
Clinical trials for a second, more compact device with
60 electrodes are under way with U.S. Food and Drug Administration
approval. A third, far less invasive and higher-resolution model
is under development.
DOE role and funding
DOE supports the design, construction, and some preclinical (nonhuman)
testing of the devices. Funding is for research in the following
areas:
- Neuroscience imaging
studies on Model 1
- Some preclinical
animal studies of Model 2
- Design and fabrication
studies of Model 3
Over the past several
years, the DOE Office of Science project has grown from a pilot
funded at $500,000 (FY 1999) to a full-scale effort with current
support of $6.8 million (FY 2007).
Synergies with
others
Doheny also receives
other federal funding to support and extend the work on the retinal
and other neural prostheses. The National Eye Institute of the
National Institutes of Health, for example, supports fundamental
and applied research related to the prosthesis.
Additionally, the National
Science Foundation provides funding for the longer-term goals
of further enhancing the retinal prosthesis and adapting the technologies
to treat a wide range of other neurological disorders. For example,
researchers are studying how the foundational concepts used to
create the retinal prosthetic can be used to reanimate paralyzed
limbs and even restore short- and long-term memory for stroke
and dementia (as in Alzheimer’s disease). For more details,
see Biomimetic MicroElectronic
Systems.
Worldwide projects
Other retinal prostheses
projects are under way in the United States and world-wide, including
Germany, Japan, Ireland, Australia, Korea, China, and Belgium.
These programs pursue many different designs and surgical approaches.
Some show great promise for the future, but have yet to demonstrate
practicality in terms of adapting to and lasting long-term in
a human eye. Thus far the projects that have progressed to clinical
(human) trials are the collaborative DOE effort, a project at
Optobionics (Chicago), and two efforts in Germany at Intelligent
Medical Implants AG and Retinal Implant AG. [For more information
on worldwide projects, see Science 312,
1124-26 (2006).]
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