A new artificial retina, an array of electrodes implanted on the back of the eye, has been found to restore partial vision to totally blind people. In a study focused on 15 blind participants who had the implant for at least 3 months, 10 of the patients subsequently tested were able to identify the direction of moving objects.
“These results give new hope to the many people with degenerative retinal diseases,” said Jessy Dorn, PhD, of Second Sight Medical Products, Inc., lead author of the study. More than 2 million Americans suffer from eye diseases such as retinitis pigmentosa and age-related macular degeneration, slowly losing their vision as the nerve cells that detect light are destroyed, due to either age or illness. There is no known cure.
In this case, the researchers worked around the destroyed cells. Each participant was given a pair of glasses with a small video camera mounted on it, and a belt with a tiny computer attached. The computer processed video images from the camera and transmitted the data to the implanted electrodes on the retina. When the users “looked” at a monitor with a white bar sweeping across a black screen, the electrodes that corresponded with the moving bar stimulated cells in the eye, creating spots of light in their fields of vision.
“We found that most of the study participants were better able to determine the direction of the bar when using the prosthesis system than without it, or with a scrambled video input,” Dorn said. “In other words, this new system gave most blind people the ability to identify an object’s direction of motion — something they could not do without it.”
An international clinical trial is now testing the prosthesis system. To date, 32 blind people have received the implant.
“Basic neuroscience research has formed the basis for significant progress in treating eye disease,” said press conference moderator Rachel O. L. Wong, PhD, of the University of Washington, an expert on visual system development. “These studies would not be possible without technological advances and basic science research that continues to explain the normal function and development of the visual system,” Wong said.
Retinitis pigmentosa and age-related macular degeneration destroy the light-sensitive nerve cells in the retina, leading to blindness. In all, vision loss and eye disease affect 3.6 million Americans and cost the United States $68 billion each year.
Illustration: Microsoft clipart.
Society for Neuroscience Press Release (10/20/09)
Science Daily (10/21/09)
Scientific Computing (10/21/09)
Medical Device Guru (10/21/09)
Abstract (Presented at Neuroscience 2009, the annual meeting of the Society for Neuroscience. Scientific Presentation: Sunday, Oct. 18, 2:15–2:30 p.m., Room N228)