Diseases like macular degeneration and retinitis pigmentosa destroy the retina and lead to blindness. But a broad coalition has formed to create an artificial retina and combat the darkness. This implant would replace damaged rods and cones, acting as a light receptor and optical signal converter.
A tiny camera and RF transmitter on the patient's glasses captures images. A microcomputer worn on the belt processes the images. From there, they're transmitted to the microchip. Next, the chip transmit the images as electrical pulses to the retina via an array of implanted electrodes. That information is then processed and sent to the brain, creating the effect of sight. For this to work, a number of issues must be addressed. That's why the coalition is so broad, as each organization adds its specific expertise.
Oak Ridge National Laboratory and the University of Southern California Doheny Eye Institute are developing better electrodes and fabrication techniques, as well as studying the device's long-term stability. The institute also will conduct the clinical testing. Argonne National Laboratory is using its patented ultrananocrystalline diamond technology to make the implant biocompatible with the surrounding ocular tissue. Lawrence Livermore National Lab is coming up with a thin, flexible implant that will conform to the retina's curved shape.
The goal for Los Alamos National Lab is to develop advanced optical imaging techniques and map the interaction between the brain and the retina. Sandia National Labs will contribute advanced electrodes based on microelectromechanical systems. North Carolina State University researchers are examining how much energy can be used to stimulate the remaining non-diseased cells through electrical and thermal modeling. Wireless technology from the University of California, Santa Cruz, will provide the link between the camera and the implant. Second Sight Medical Products will integrate all of this technology into product designs destined for clinical trials.
The Department of Energy has pumped $8 million into the project, so far yielding a 16-electrode prototype. With 16-pixel resolution, this device lets patients detect the presence or absence of light and recognize large objects. In fact, the first patient to receive a prototype could see large letters and differentiate between a cup, plate, and knife after being blind for more than 50 years. Another prototype with 50 to 100 electrodes is in preclinical trials.
The DoE's Office of Science will continue to fund the Retinal Prosthesis Project with $20 million over the next three years. The project's next goal is a 1000-electrode implant that could provide black-and-white images with higher resolution. Researchers also hope to miniaturize the system for complete implantation without the need for glasses or an external microprocessor.
For details, go to www.energy.gov.
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