Vision restoration nearing reality with new system in development
Carnegie Mellon senior systems scientist Shawn Kelly is developing a retinal prosthesis capable of restoring vision to those with degenerative eye diseases. He was recently awarded a four-year, $1.1 million grant from the U.S. Department of Veterans Affairs to continue his research.
According to the Centers for Disease Control and Prevention (CDC), 21 million Americans suffer from functional vision problems or eye diseases that may lead to loss of vision.
The CDC also reported that Americans are more likely to experience vision loss due to age-related eye diseases, such as glaucoma, cataracts, and age-related macular degeneration (AMD), the breakdown of the macula tissue near the retina that allows a person to see fine details clearly. Left untreated, AMD can lead to permanent blindness.
Kelly’s device is designed specifically to combat AMD; his team works to help victims of the disease see again.
“My tools are designed to help individuals struggling with blindness, and to ultimately help injured veterans with head and eye wounds recover some peripheral vision,” said Kelly, who worked at Boston Veterans Hospital before coming to Carnegie Mellon last year.
“A device like this will not easily work on someone who has been blind since birth and hasn’t created the visual connections in the brain,” Kelly warned. But he did affirm that “it will work on someone whose degenerative disease has left them completely blind later in life.”
The 15 micrometer-thick prosthesis is surgically inserted through a small incision near the back of the eye, and is held in place by the retina. Its communication coil — which allows the chip to “talk” to external devices — is attached to the sclera, or the white of the eye.
“We don’t expect significant discomfort,” Kelly said of the seemingly intrusive implant. “Other ophthalmic devices sit in this area, including scleral buckles to repair retinal detachments, and some glaucoma pressure valves.”
After surgery, a patient would wear a pair of eyeglasses with a camera fitted into its frame. The camera connects to a portable image processor, which wirelessly transfers a compressed version of the captured image data to the implanted device. The prosthesis then sends stimulating signals to the appropriate retinal nerves, creating a pixelated form of the original image.
The entire process comes together to form a version of the macula cells responsible for high-resolution vision that are destroyed by AMD.
Kelly recalled his success in the early phases of his research where blind volunteers tested a prototype of the device.
“We delivered stimulating currents to the retina and asked what the volunteer saw,” Kelly said. “They reported seeing spots and lines, which was the proof of concept that we needed to begin developing a chronically implantable device.”
Many technical challenges stood in the way of that development, including the device’s low power draw and the logistics of wireless data and power transfer. But the most difficult part of the project for Kelly and his team has been the chip’s packaging.
“Creating an airtight package that is small enough to fit on the side of the eye but has enough connections to create an image with a few hundred pixels is pushing the edge of existing technology,” he said.
Kelly, who began this project as a graduate student at the Massachusetts Institute of Technology, has developed four different prototypes of the device in his 16 years of research. He and his colleagues are working on a fifth and final prototype of the prosthesis, with clinical trials expected to begin in about two years.
“We expect the device to be available for sale on the market in about five years,” he said.