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Overview of the DOE
Artificial Retina Project:
The DOE Artificial Retina Project
is a coordinated multi-institutional effort
to develop an implantable micro-electronic medical
device (a retinal prosthesis) that will restore
useful vision to blind patients. The team, lead
by Dr. Mark Humayun, consists of researchers
at Doheny Eye Institute at University of Southern
California, 6 Department of Energy laboratories
(ORNL, BNL, ANL, SNL, LANL, LLNL), a company
whose sole mission is developing and marketing
a retinal prosthesis (Second Sight), and other
university partners, including UC Santa Cruz
and NC State University. The project made medical
history when the first device of its kind was
successfully implanted in the eye of a patient
who has been blind for more than 50 years. Since
then, 5 additional patients have had devices
implanted, all with encouraging results. The
first implant, made by Second Sight, is a 16
channel or pixel implant and allows the otherwise
blind patients to see images transmitted from
a tiny camera mounted on a pair of glasses.
The goal of the project is to enhance the resolution
(increase the pixels) and decrease the surgical
complexity of the procedure so that the device
will provide the patient with unaided mobility,
as well as enable patients to recognize faces
and read.
Current Status
The DOE Artificial Retina research
team is aggressively working on three major
research areas. The DOE component of these studies
is the design, construction and pre-clinical
testing of the devices. The NIH supports the
clinical studies. The DOE research focus areas
are the:
- Neuroscience imaging studies
of patients implanted with Model 1 retinal
prosthesis.
- FDA pre-clinical animal studies
of the Model 2 retinal prosthesis (60 microelectrode
array).
- Design and fabrication studies
of the Model 3 retinal prosthesis (256+ microelectrode
array).
Model 1 Retinal Prosthesis
The current Model 1 retinal prosthesis,
which has been implanted in 6 patients, consists
of a 16 channel microelectronic device in a
one inch package that allows the implanted electronics
to wirelessly communicate with a camera mounted
on a pair of glasses. The system is powered
by a battery pack worn on a belt. The 16 electrode
device allows patients previously without light
perception to distinguish objects within a forced
choice test environment. These patients are
now able to locate a chair, differentiate between
a cup, plate, and knife, and trace out large
1.5 foot letters that are two feet away. In
order to evaluate the long-term effects of the
retinal implant, two patients have been approved
by FDA to use the activated device (device turned
on) for up to 8 hours each day in a home environment.
Model 2 Retinal Prosthesis
A smaller, more compact Model
2 retinal prosthesis has been developed and
is currently undergoing FDA pre-clinical studies
in animals. The Model 2 implant, which will
be the first commercial device, will be about
a fifth of the size of the Model 1 device and
consists of 60 microelectrodes instead of 16
microelectrodes. In addition, the image/data
receiving coil which was located behind the
ear in the model 1 device has been moved to
a position next to the eye. Subject to FDA approval,
plans are to implant the Model 2 device into
the first patient during 2006. The surgical
time to implant Model 2 device is expected to
be about 90 minutes compared to the six hours
required to implant the Model 1 device.
Model 3 Retinal Prosthesis
The Model 3 device which will
have 256 or more microelectrodes is undergoing
design and fabrication studies at the DOE National
Labs. This device will use more advanced materials
than the silicone/platinum materials used in
the first two devices. A special on-chip coating,
only a few microns thick, is being developed
at ANL to replace the bulky sealed package used
in the previous models. In addition, the model
3 device will be constructed of flexible substrate
materials that will conform to the shape of
the inner eye. Since the model 3 device will
be many times smaller than previous devices,
it will be able to be placed entirely inside
or around the eye. It is anticipated that the
256+ electrode device will be the first device
that will allow blind patients to read and recognize
faces.
January 2006
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