Posts tagged retinal implant
Articles and news from the latest research reports.
Researcher advances retinal implant that could restore sight for the blind
People who went blind as a result of certain diseases or injuries may have renewed hope of seeing again thanks to a retinal implant developed with the help of Florida International University’s W. Kinzy Jones, a professor and researcher in the College of Engineering and Computing.
A tiny video camera mounted on special glasses captures the scene in the patient’s environment, and a pocket controller relays the captured video signal to the implant. Inspired by cochlear implants that can restore hearing to some deaf people, the retinal implant works by electrically stimulating nerve cells that normally carry visual input from the retina to the brain, and bypassing the lost retinal cells.
The Boston Retinal Implant Project, a highly-specialized, academically-based team of 30 researchers including Jones, was responsible for bringing the implant to light. The group is comprised of biologists and engineers from Harvard, Cornell, Massachusetts Institute of Technology (MIT) and others who are developing new technologies for the blind.
“Jones’ work was one the most important technological developments needed to make the device possible,” said Douglas Shire, engineering manager for the Boston Retinal Implant Project. “As a result, users of the retinal implant will be able to adjust the implant according to their needs.”
Jones has been working for years to advance the airtight sealed titanium housing and feed-through component that transfers the signals from the implanted microchip to the electrodes. His improvements in the density of that feed-through will greatly improve the quality of the image the person wearing the device will see.
The retinal implant was designed for people who lost vision due to injury to the eyes; progressive vision loss caused by eye disorders (also known as retinitis pigmentosa); or age-related macular degeneration, when the center of the retina that is responsible for central vision deteriorates. According to the National Institutes of Health, age-related macular degeneration is a leading cause of vision loss in Americans 60 years old and older.
“The impact of this technology, which increases the available pixels that can be stimulated, will bring enhanced visual acuity to people with debilitating eye loss,” Jones said. “My mother had macular degeneration and I saw the quality of her life degrade as the disease progressed. Hopefully, when these devices are available for FDA approved use, total loss of eye sight from macular degeneration or retinitis pigmentosa will be a thing of the past within 10 to 15 years.”
Recently, a similar device that features 60 electrodes was approved for use in patients and has proven successful in allowing people who were blind to read words on a screen.
Shire explained that the device that the Boston Group is building with Jones’ help has more than 256 electrodes and therefore allows for images with a larger number of pixels, which is expected to give patients a meaningful visual experience.
What It’s Like to See Again with an Artificial Retina
Elias Konstantopoulos gets spotty glimpses of the world each day for about four hours, or for however long he leaves his Argus II retina prosthesis turned on. The 74-year-old Maryland resident lost his sight from a progressive retinal disease over 30 years ago, but is able to perceive some things when he turns on the bionic vision system.
“I can see if you are in front of me, and if you try to go away,” he says. “Or, if I look at a big tree with the system on I can maybe see some darkness and if it’s bright outside and I move my head to the left or right I can see different shadows that tell me there is something there. There’s no way to tell what it is,” says Konstantopoulos.
A spectacle-mounted camera captures image data for Konstantopoulos; that data is then processed by a mini-computer carried on a strap and sent to a 60-pixel neuron-stimulating chip that was implanted in one of his retinas in 2009.
Nearly 70 people around the world have undergone the three-hour surgery for the retinal implant, which was developed by California’s Second Sight and approved for use in Europe in 2011 and in the U.S. earlier this year (see “Bionic Eye Implant Approved for U.S. Patients”). It is the first vision-restoring implant sold to patients.
Currently, the system is only approved for patients with retinitis pigmentosa, a degenerative eye condition that strikes around one in 5,000 people worldwide, but it’s possible the Argus II and other artificial retinas in development could work for those with age-related macular degeneration, which affects one in 2,000 people in developed countries. In these conditions, the photoreceptor cells of the eye (commonly called rods and cones) are lost, but the rest of the neuronal pathway that communicates visual information to the brain is often still viable. Artificial retinas depend on this remaining circuitry, so cannot work for all forms of blindness.
Farsighted engineer invents bionic eye to help the blind
For UCLA bioengineering professor Wentai Liu, more than two decades of visionary research burst into the headlines last month when the FDA approved what it called “the first bionic eye for the blind.”
The Argus II Retinal Prosthesis System — developed by a team of physicians and engineers from around the country — aids adults who have lost their eyesight due to retinitis pigmentosa (RP), age-related macular degeneration or other eye diseases that destroy the retina’s light-sensitive photoreceptors.
At the heart of the device is a tiny yet powerful computer chip developed by Liu that, when implanted in the retina, effectively sidesteps the damaged photoreceptors to “trick” the eye into seeing. The Argus II operates with a miniature video camera mounted on a pair of eyeglasses that sends information about images it detects to a microprocessor worn on the user’s waistband. The microprocessor wirelessly transmits electronic signals to the computer chip, a fingernail-size grid made up of 60 circuits. These chips stimulate the retina’s nerve cells with electronic impulses which head up the optic nerve to the brain’s visual cortex. There, the brain assembles them into a composite image.
Recipients of the retinal implant can read oversized letters of the alphabet, discern objects and movement, and even see the outlines and some details of faces. And while the picture is far from perfect — the healthy human eye sees at a much higher resolution — it’s a breakthrough for people like the first patient, a man in his 70s who was blinded at age 20 by RP, to receive the implant in clinical trials. “It was the first time he’d seen light in a half-century,” said Liu, adding that “it feels good as the engineer” to have helped make this possible.
Liu joined the Artificial Retina Project in 1988 as a professor of computer and electrical engineering at North Carolina State University. The multidisciplinary research project was funded by the U.S. Department of Energy’s Office of Science because it envisioned a potential pandemic of eyesight loss in America’s aging population. Leading the project was Duke University ophthalmologist and neurosurgeon Dr. Mark Humayun, now on faculty at USC. He tapped Liu to engineer the artificial retina.
“I thought it was a great idea,” Liu said. “But I asked, ‘What can I do?’ because I didn’t know much about biology.” Humayun handed him a six-inch-thick medical manual on the retina. “The learning curve was very steep,” Liu recalled with a laugh.
However, Liu’s fellow engineers questioned his sanity. “I was working on integrated chip design and had just gotten tenure when I signed on to this project. They said, ‘You’re crazy!’ But I’m glad I made that choice, getting into this new field.”