| Overview
of the
Artificial Retina Project
The DOE Artificial
Retina Project was 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 was to design a device to help restore limited vision
that enables reading, unaided mobility, and facial recognition.
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.
For
more information, see How
the Artificial Retina Works.
History
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, more than 30 additional volunteers around the world have
had first- or second-generation (60-electrode) devices implanted.
These devices enable patients to distinguish light from dark and
localize large objects. For more information, read patient
stories.
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 also were 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 additional universities,
and Second Sight™
Medical Products, Inc. (a private-sector company), signed a Cooperative
Research and Development Agreement. Under the agreement, the
institutions jointly share intellectual property rights and royalties
from their research. This spurs progress—freeing the researchers
to share details of their work within the collaboration.
|
| Argus™
I is pictured above. A
retinal prosthesis contains a small implantable chip with
electrodes. These electrodes stimulate the retina and help
people regain limited vision. |
Three models
in testing and development
Model 1 (Argus™
I)
The Model 1 device
[developed by Second Sight™ Medical Products, Inc. (SSMP)]
was implanted in six blind patients between 2002 and 2004, whose
ages ranged from 56 to 77 at time of implant and all of whom have
retinitis pigmentosa. The device consists of a 16-electrode array
in a one-inch package that allows the implanted electronics to
wirelessly communicate with a camera mounted on a pair of glasses.
It is powered by a battery pack worn on a belt. This implant enables
patients to detect when lights are on or off, describe an object’s
motion, count individual items, and locate objects in their environment.
To evaluate the long-term effects of the retinal implant, five
devices have been approved for home use.
Model
2 (Argus™ II)
The smaller, more compact Model 2 retinal prosthesis (developed
by SSMP with DOE contributions) is currently undergoing clinical
trials to evaluate its safety and utility. This model is much
smaller, contains 60 electrodes, and surgical implant time has
been reduced from the 6 hours required for Model 1 to 2 hours.
Model 3
The Model 3 device, which will have more than 200 electrodes,
has undergone extensive design and fabrication studies at the
DOE national laboratories and is ready for preclinical testing.
The new design uses more advanced materials than the two previous
models and has a highly compact array. This array is four times
more densely packed with metal contact electrodes and required
wiring connecting to a microelectronic stimulator. Simulations
and calculations indicated that the 200+ electrode device should
provide improved vision for patients.
DOE role and
funding
DOE
supported the design, construction, and some preclinical (nonhuman)
testing of the devices. Funding was 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
During the funding period, the DOE Office of Science project grew from a pilot
funded at $500,000 (FY 1999) to a full-scale effort with
support of roughly $7 million per year. DOE funding for the project ended in FY 2011.
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 the now-defunct 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).]
|
Overview
