National Labs Collaborate on MEMS Device to Treat Blindness

Originally Published MDDI October 2002

R&D DIGEST

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.

In cases such as macular degeneration, the eye's rods and cones that normally convert light to electrical impulses are damaged. However, even when input from the rods and cones ceases, 70 to 90% of the nerve structures that receive those inputs are still intact. The research is focusing on developing a method that can bypass the rods and cones.

According to Sandia project leader Kurt Wessendorf, "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 household chores." He adds, however, that "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 a little slowly and appear yellow. But people who are blind will see."

The plan is to use a tiny camera and radio-frequency transmitter integrated into the frame of a patient's glasses to transmit information and power to modules placed within the eyeball. The modules will be linked to retinal nerves that will then send electrical impulses to the brain for processing.

The current project is an extension of research conducted by Mark Humayun, MD, at Johns Hopkins University (Bethesda, MD). He later began the Intraocular Retinal Prosthesis Group at Doheny Retina Institute at the University of Southern California (USC) in Los Angeles, and his research moved with him. Working with Eli Greenbaum, PhD, at Oak Ridge National Laboratory, he visited several of the national labs and ultimately arranged to have each lab work on a different aspect of the electrode array/retina interface.

According to Neal Singer of Sandia, "It seemed like a worthy use of in-place equipment. Scientists are always hungry, like everyone else, to do something for humanity. And when DOE provided funds, all the elements were in place."

Says Dean Cole, a biomedical engineer who directs the project at DOE's Office of Biological and Environmental Research (Washington, DC), "We felt that blindness is a devastating problem and that the modern conjunction of materials science with micro- and nanotechnologies in our multidisciplinary national labs offers possibilities for advances where before people had hit brick walls."

The role of Sandia is to produce the MEMS components using its LIGA techniques as well as its methods for making surface-micromachined silicon devices. The processes are similar to those used by the computer industry to manufacture silicon chips. The MEMS chips will be attached to the retina within the vitreous humor of the eyeball. The goal is to directly stimulate some of the nerve endings within the retina to produce images that are sufficient for reading large print or distinguishing between objects in a room.

According to Singer, a miniature of the devices to be used was inserted in human subjects in April at USC. The researchers hope to increase from 10-by-10 electrode arrays for fiscal year 2002 to 33-by-33 electrode arrays for 2004.

In addition to Sandia's role, Oak Ridge National Laboratory, the lead lab, will manage the multilaboratory effort and test various components; Argonne National Laboratory will investigate the viability of diamond-based electrode arrays and biocompatible coatings; Lawrence Livermore National Laboratory will experiment with rubberized electrode arrays; and Los Alamos National Laboratory will model and simulate neural paths between the retina and the brain. USC personnel will implant the devices and test their medical effectiveness. North Carolina State University in Raleigh leads the development of the in situ electronics, and Second Sight (Santa Clarita, CA), will commercialize the finished products.

Copyright ©2002 Medical Device & Diagnostic Industry