The U.S. Department of Energy has awarded major responsibility for the
development of a third-generation retina prosthesis to Lawrence
Livermore National Laboratory, California. 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.
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.
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