With a tiny eye implant and special glasses, some legally blind patients can read again

People suffering from a leading cause of blindness were able to read again thanks to a tiny wireless chip implanted in the back of the eye and specialized augmented glasses, according to the results of a study published Monday in the New England Journal of Medicine.

The trial involved 38 European patients, all with advanced dry age-related macular degeneration (AMD), known as geographic atrophy.

There is no cure for AMD, which is caused by changes in a part of the retina called the macula caused by inflammation and a buildup of waste. Photoreceptor cells in the macula are responsible for producing sharp, detailed, and colorful vision. When the disease reaches the stage of geographic atrophy, these cells deteriorate and die, and people lose their central vision, meaning an object straight ahead may appear blurry or covered with a dark spot.

In the United States, about 22 million people have AMD and about 1 million have geographic atrophy, according to the American Macular Degeneration Foundation.

In the study, participants, with an average age of 79, were fitted with the “PRIMA device”, a system intended to reproduce vision. Patients wear augmented reality glasses integrated with a camera that captures their visual field. What the camera “sees” is transmitted to the chip implanted in the eye in the form of infrared light. The chip converts light into electrical current, which realistically stimulates the remaining healthy cells of the macula, allowing the brain to interpret the signals sent by these cells as vision.

An image processor, which the user must carry with them, allows patients to zoom and enlarge the images they see, which appear in black and white.

Thanks to the PRIMA device, 80% of the 32 patients who returned for re-evaluation one year after chip implantation achieved clinically significant visual improvements. Patients experienced side effects, mostly related to the surgery: The study reported that 26 serious adverse events occurred in 19 of the patients, ranging from high blood pressure in the eye to accumulation of blood around the retina. The majority of adverse events resolved within two months of implantation.

“This is the first ever treatment approach that has led to improvement in visual function in this group of patients,” said Dr. Frank Holz, principal investigator of the trial and director of the Department of Ophthalmology at University Hospital Bonn in Germany. “Advanced age-related macular degeneration is a dismal disease. Patients are no longer able to read, drive a car, watch television or even recognize faces. Thus, [these results] are a game-changer in my mind.

One patient, Sheila Irvine, 70, who was fitted with the PRIMA device at Moorfields Eye Hospital in London, said in a statement provided by the hospital that her life before receiving the implant was like “having two black discs in your eye, with the outside distorted”. Irvine, who described herself as an “avid bookworm” before losing her sight, said she was now able to do crosswords and read prescriptions.

Dr. Sunir Garg, professor of ophthalmology in the retina service at Wills Eye Hospital in Philadelphia, who was not involved in the study, said the findings represent a major advance for patients with geographic atrophy. All doctors have been able to offer, he says, are visual aids, like magnifying glasses, and emotional support.

“Even with new medical treatments, the best we can do is slow it down,” said Garg, who works with several drugmakers involved in AMD treatments, including Apellis Pharmaceuticals, the maker of pegcetacoplan. This medication, which slows the progression of geographic atrophy, was recently approved in the United States and must be injected into the eye every 1 to 2 months. “We can’t stop it, and we can’t do anything to bring back the lost vision.”

Dr. Demetrios Vavvas, director of the retina service at Mass Eye and Ear in Boston, who was also not involved in the study, said the PRIMA system is not without limitations.

Vavvas noted that the surgery required to implant the chip in the eye requires a high level of surgical skill and is not without risk. “You have to lift the retina from its normal position to implant this device, which increases atrophy,” said Vavvas, a consultant at Sumitomo Pharmaceuticals, a company working on stem cell therapies for patients with other forms of vision loss.

Vavvas said it was important to note that the device did not restore normal vision, as patients could only see in black and white rather than color, and trial participants had to undergo significant training in order to learn to see with the PRIMA device. He also said it was unclear whether improvements in visual ability had significantly improved patients’ quality of life.

But at the same time, Vavvas was also optimistic about its future potential, describing the current iteration of PRIMA as a key stepping stone in the field of visual restoration.

“Think of this device as an early version of the iPhone,” he said. “The limits are clear. We should not exaggerate that quality of life has actually improved. But there were some [visual] tasks at which the patients were significantly better. So this shows us that there is potential in this approach. It is still, in some ways, a prototype. They are working on iterations of this device that will be better.

Further upgrades to the PRIMA device could arrive in the coming years.

The PRIMA system was invented by Daniel Palanker, professor of ophthalmology at Stanford University, and is being developed by California-based neural engineering company Science Corporation.

Palanker said technical improvements were being made to increase the number of pixels in the chip from 400 to 10,000. The new chips have already been tested on rats and the improved chips are being manufactured for future human trials. Using the camera’s zoom feature, Palanker said it could theoretically allow patients to achieve 20/20 visual resolution.

“We are also working on next-generation software that will allow patients to perceive not only black and white text, but also natural grayscale images, such as faces,” Palanker said.

Palanker suggested the technology could be tested in other retinal diseases that cause blindness, such as Stargardt disease, which has symptoms similar to age-related macular degeneration but is genetic and typically affects younger people.

Garg and Vavvas look forward to seeing larger trials providing more details on how the device improves patients’ ability to function in daily life. Vavvas suggested that future trials should include a control arm to understand to what extent the device produces concrete benefits, for example compared to existing electronic magnifying glasses.

“Is this something that’s enough for patients to say, ‘Well, I’ve got my independence back because I can now write my own credit card bills, stamp and address my envelopes myself and look at grocery store labels?'” Garg said. “Those kinds of practical things I’d like to know more about.” »

“This is a chronic disease that you will have for life, so we need more than a year of follow-up to see other risks, other problems,” Vavvas said. “Does this signal of effectiveness that we observe at 12 months persist two years later?

Although Vavvas said he wouldn’t call the device a complete panacea for blindness, the study showed that brain-computer interfaces can represent an important approach to combating different types of severe vision impairment. “As iterations of this device improve, it could become a real solution for a cohort of patients,” he said.