National Labs Collaborate on MEMS Device to Treat Blindness
From: Medical Device and Diagnostic Industry - October 2002

A coalition of researchers is hoping to adapt MEMS technology to treat eye
disease. Funded by a $9 million, three-year grant from the Department of
Energy's Office of Biological and Environmental Research, the team includes
Sandia National Laboratories (Albequerque), four other national labs, a
private company, and two universities. Their goal is to position 1000 MEMS
electrodes on the retinas of those blinded by age-related macular
degeneration, retinitis pigmentosa, and similar diseases. 

Read the full story at:
http://www.devicelink.com/mddi/archive/02/10/014.html

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MEMS-based Imaging System Will Restore Sight to the Blind
From: Electronic Design - November 11, 2002 - page 36
By: Richard Gawel

Researchers at five national labs, two universities, and a private company
have joined forces in an effort to enable the blind to see. They hope to use
MEMS technology to combat disorders like age-related macular degeneration and
retinitis pigmentosa, which affect hundreds of thousands of people in the
U.S. each year. 

These disorders blind their victims by damaging the lightgathering cells in
the eye. The researchers hope to implant MEMS chips with thousands of
electrodes directly on the retina, essentially replacing the damaged cells.
The implant would receive signals broadcast by a tiny camera and RF
transmitter on the patient’s glasses and stimulate the nerve endings in the
retina accordingly to produce the effect of sight (see the figure). 

"Compared to the elegance of the original biological design, what we're doing
is extremely crude," says project leader Kurt Wessendorf of Sandia National
Laboratories. Rods and cones - the light-gathering cells in the retina - and
their nerve connections are in the micron range. At this point, the
researchers lack the technology for one-to-one replacement of electrodes to
cells. But they are getting closer. 

"We’ll use a crude, shotgun approach that fires groups of nerves," explains
Sandia manager Mike Daily. "In the long run, of course, we'd like to
stimulate each individual nerve." The project is aiming for 10-by-10
electrode arrays by the end of the year, with 33-by-33 arrays expected by
2004. With these sizes, patients will see the equivalent of 1000 points of
light. 

"The aim is to bring a blind person to the point where he or she can read,
move around objects in the house, and do basic chores," Wessendorf says.
"They won't be able to drive cars, at least in the near future, because
instead of millions of pixels, they'll see approximately a thousand. The
images will come slowly and appear yellow, but people who are blind will see."  

The MEMS package is key. It must ensure high-reliability operation in a
saline environment for decades, Daily notes. The chip is made of LIGA (a
German acronym for lithography, electroplating, and molding) and
surface-micromachined silicon parts. Argonne National Laboratory is
investigating the viability of diamond-based electrode arrays and
biocompatible coatings. Lawrence Livermore National Laboratory is
experimenting with rubberized electrode arrays. 

The retina must be protected as well, as it can't handle much pressure.
Sandia's researchers are counting on spring-loaded electrodes that ensure
good contact with minimal force. Also, protein fouling can disturb interfaces
intended to transmit electrical impulses. Biocompatibility, or whether or not
the body will accept alien matter, is another issue. 

Over the next five years, the researchers will begin with goggles and move
toward corneal implants. If all goes well, five patients could be prepared
for the procedure before the project is completed. The project began at Johns
Hopkins University under Mark Humayun, who then founded the Intraocular
Retinal Prosthesis Group at Doheny Retina Institute at the University of
Southern California. It is now funded by a $9 million, three-year grant from
the Department of Energy's Office of Biological Research. 

Oak Ridge National Laboratory is managing the multilab effort and testing the
components that the other labs develop. Los Alamos National Laboratory is
modeling and simulating the neural paths of and from the retina to the brain.
Second Sight of Santa Clara, Calif., will commercially produce the finished
system. For more information, go to http://www.sandia.gov. 


Caption:
An RF system in Sandia National Laboratories' vision implant will transmit
signals to modules within the eyeball. The electrode module will be connected
to retinal nerves, where electrical stimulation will be processed by the
brain.


http://www.sandia.gov/news-center/news-releases/2002/mat-chem/blindsee.html