The U.S. Department of Energy has awarded major
responsibility for the development of a third-generation retina prosthesis to
Lawrence Livermore National Laboratory (LLNL, Livermore,
Calif.). The third-generation artificial
retina will enable previously blind people to read, recognize people's faces
and restore mobility so that people can navigate about the world again using
their sight.
Artificial retina team
member Terri Delima holds a thin-film artificial retina array fabricated at the
Lawrence Livermore National Laboratory.
The retinal implant is designed for the millions of patients
worldwide suffering from retinitis pigmentosa and age-related macular
degeneration, since it implants an electrode array atop the old damaged retina
to stimulate the undamaged nerve ganglia lying underneath, with image
information wirelessly transmitted to it from a video camera mounted on a pair
of eyeglasses.
The first-generation implants were successfully tested on
six patients, but only held 16 electrodes (4-by-4-pixel array), which enabled
the crude perception of lighted areas versus darkness after about 15 seconds.
The second-generation implant upped the electrode array to 60 electrodes, which
enabled 34 test patients to recognize doorways and windows as well as the edges
that assist in navigation, such as walls and low-lying branches, after about 3
seconds.
The goal of the third generation of the implant will be to
increase the electrode array to more than 200 electrodes, which will enable the
near instantaneous recognition of text for reading, pictures and all the edge cues
needed to navigate the world unaided. Ultimately, the artificial retinal will
contain over 1,000 electrodes, which should restore instantaneous recognition
of faces and other fine details that should fully integrate patients back into
everyday society.
The artificial retinas are being fabricated on silicon
wafers by LLNL with the assistance of four other national laboratories, four
universities and a private company, Second Sight Medical Products (Sylmar,
Calif.), the latter of which will be responsible for commercializing the
third-generation device, including performing all the field trials necessary to
obtain full Food and Drug Administration (FDA) approval.
Also instrumental in the third-generation device will be the
Doheny Eye Institute, at the University of Southern California (Los Angeles),
which will provide the clinical testing of the electrode array implants, and
Argonne National Laboratory (Illinois), which will use its ultrananocrystalline
diamond film technology to hermetically seal the package for the prosthetic
device to protect it from the salty environment inside the eyeball.
The third-generation retinal implants are fabricated 12 at a
time on silicon wafers using LLNL's polymer-based micro-fabrication techniques.
The entire retinal implant assembly is composed of a thin-film electrode array
that contains the neural electrodes and a biocompatible package that contains
the electronics for stimulating the retina, as well as a wireless receiver for
powering the device and receiving the image data from the camera. LLNL is also
developing a companion ocular surgical tool that will enable the easy insertion
and attachment of the thin-film electrode array inside the eye.
Other project contributors include Los Alamos National
Laboratory, Oak Ridge National Laboratory, Sandia National Laboratory,
California Institute of Technology, North Carolina State University and the
University of California at Santa Cruz.
