A system named as the PRIMA device is helping older partially blind adults regain some vision in a small European study published in the New England Journal of Medicine.
The patients had geographic atrophy, a type of late-stage dry age-related macular degeneration (AMD). A disease that causes a progressive loss of cells in the macula—the part of the retina responsible for sharp, central vision. Eventually, people’s vision becomes fuzzy or has patches of darkness in the center.
“Late-stage age-related macular degeneration is a dismal disease,” trial leader Dr. Frank Holz said. “Patients are no longer capable of reading, driving a car, watching TV or even recognizing faces. So [these results] are a game changer in my mind.” He added. This tiny chip was invented by Stanford professor Daniel Palanker and is being developed by a neural engineering company in California
How the PRIMA device works
The study had 38 patients, with an average age of 79 years old. They all had a tiny wireless chip placed under the retina of one eye. After that, they put on augmented reality glasses that were connected to a portable image processor.
The camera in the glasses captures whatever the person wearing them is looking at. The image is projected onto the chip inside the eye after being converted to infrared light. The chip turns light into electrical signals that activate the macula’s remaining healthy cells. These signals are interpreted by the brain as vision. Patients can also zoom and magnify images, although they only see in black and white for now.
32 patients came back for testing a year after surgery. About 80% of them showed a significant improvement in vision in the treated eye when the PRIMA system was activated. Sheila Irvine, a 70-year-old patient, compared her life before to the implant to “having two black discs in my eyes, with the outside distorted.” Now, she described herself as a former “avid bookworm” that can againg read her prescriptions and solve crossword puzzles.
However, to implant the chip, surgeons must lift the delicate tissue of the retina. Some patients experienced serious side effects, like bleeding or increased intraocular pressure. Even though most problems were fixed in two months, experts warn that not everyone is a suitable candidate for this difficult process.
Hope, but not a cure
Other eye specialists describe the results as exciting, but they also point out the limitations. For Dr. Sunir Garg, a retina surgeon, “even with new medical therapies, the best that we can do is slow it down. We can’t stop it, and we can’t do anything to bring back lost vision.”
With PRIMA, patients still have poor vision overall, see in black and white, and need instruction to operate the device. Dr. Demetrios Vavvas, another specialist said: “The limitations are clear. We shouldn’t oversell that the quality of life really improved. But there were certain [visual] tasks at which the patients were clearly better. So it shows to us that there is potential in this approach. It is still, in some ways, a prototype.”
Garg and Vavvas both share a desire for improvement. “Is it something that is good enough for patients to say, ‘Well, I’ve regained my independence because I can now do my credit card bills myself, stamp and address my envelopes myself, and look at grocery store labels’?” Vavvas continued, adding that AMD is an incurable disease, an that “we need more than one year of follow-up to see other risks, other problems. Does that signal of efficacy that we see at 12 months remain two years later?”
Improving, though within limits
According to Palanker, his team is already developing a more sophisticated chip that will have a resolution of 10,000 pixels instead of 400: “We are also working on next-generation software that will allow patients to perceive not just black-and-white text, but also gray-scale natural images, such as faces.”