Bionic eye could stimulate sight in blind - The Stanford Daily Online

Bionic eye could stimulate sight in blind - The Stanford Daily Online


A group of Stanford researchers this February unveiled a new technology that could someday simulate vision for the blind.
Collaborating in an interdisciplinary effort to present this innovation — a highly sensitive retinal prosthesis called the bionic eye — a team of researchers and faculty members from the Departments of Ophthalmology, Cell Biology, Physics and Neurobiology, as well as from the Hansen Experimental Physics Laboratory, published an extensive article in the Journal of Neural Engineering.
Harvey Fishman, director of Stanford’s Opththalmic Tissue Engineering Laboratory, spearheaded the research, which was funded by the Air Force Office of Scientific Research.
The bionic eye system described in the article is said to be dramatically restorative, unlike corrective laser surgery, and it could potentially benefit people suffering from degenerative retinal diseases, particularly muscular deterioration that occurs with age.
Patients whose photoreceptor cells degenerate become increasingly blind. On his Web site, article co-author Daniel Palanker, an assistant professor of ophthalmology, wrote that although photoreceptors can be destroyed, “many of the retinal neurons that transmit signals from the photoreceptors are preserved for a prolonged period of time.”
The bionic eye theoretically restores lost sight by sidestepping defunct photoreceptors and stimulating these neurons on the inner retina.
The group of researchers began working on the concept four years ago and is currently developing the actual practical machinery, Palanker said in an interview.
According to the article, the key component of the system is a light-sensitive chip, which would be implanted into a patient’s eye. The chip picks up light signals and transmits them to neurons in the retina, where the remaining healthy portion of the eye will naturally process the impulses.
Palanker said that information is exchanged between the chip and other elements of the bionic eye, including a tiny camera, a compact portable computer and infrared video goggles.

Because the material costs of the invention are insignificant, Palanker said he anticipates that “the prosthesis itself will not be much more expensive than a cochlear implant [a device that enhances hearing], which is covered by medical insurances.”
The idea for the retinal implant was pioneered in 1988 by John Wyatt, professor of electrical engineering and computer science at the Massachusetts Institute of Technology, and Joseph Rizzo, associate professor of ophthalmology at Stanford.
Currently, there are several other groups in the United States, Germany and Japan conducting similar research. In fact, the Stanford team collaborates regularly with researchers at Harvard, the University of Southern California and Rizzo’s project at MIT, said Mark Blumenkranz, chair of Stanford’s Ophthalmology Department.
The Stanford bionic eye research is distinguished because of the group’s progress with alternative pathways to neurons in the retina, and also because its goal is to create a very sensitive and accurate prosthesis.
“Our goal is to develop what we consider a high resolution product that would allow the patient to read,” Blumenkranz said.
Because the number of electrodes included on the device is directly correlated to the resolution, Stanford researchers knew they needed to find a way to place as many electrodes near to the neurons as possible without damaging the retina, and they did.
Stacey Bent, associate professor chemical engineering and a member of the project, said Stanford’s research is different also in its use of a chemical chip that uses neurotransmitters to stimulate neurons.
“There are only a couple of groups to my knowledge taking this chemical approach,” she said. “Most others are working on an electrical chip using electrical current to stimulate the neurons.”
However, development of this chemical chip is still in the preliminary stages, Blumenkranz said, adding that “this approach is more sophisticated by closer to a physiological process.”
The public, he said, is more likely to see the electronic version of a bionic eye sooner, a prototype of which will be tested on animals later this year. Human testing will likely commence within another two years, and the first device suitable for clinical use could be available within five to 10 years.