By implanting a small eye and special glasses, some blind patients can read again

People with one of the leading causes of blindness were able to read again thanks to a small wireless chip implanted in the back of the eye and custom glasses, according to study results published Monday in the journal New England Journal of Medicine.

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

There is no cure for age-related macular degeneration, which is caused by changes in a part of the retina called the macula and results from inflammation and the buildup of waste products. Photoreceptor cells in the macula are responsible for producing sharp, detailed, and colorful vision. When the disease progresses to geographic atrophy, these cells degenerate and die, and people lose their central vision, meaning the object directly in front of them may appear blurry or covered in a dark spot.

Nearly 22 million people in the United States have AMD, and about 1 million people have geographic atrophy, according to Macular Degeneration Foundation of America.

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

The image processor, which the user must hold, allows patients to zoom in and out of the images they see, which appear in black and white.

With the help of the PRIMA device, 80% of the 32 patients who returned for re-evaluation one year after chip implantation achieved clinically meaningful visual improvements. Patients did experience side effects, mostly related to the surgical procedure: The study reported that 26 serious adverse events occurred in 19 patients, ranging from ocular hypertension to blood accumulation around the retina. The majority of adverse events resolve within 2 months of transplantation.

“It is the first-ever therapeutic approach that has improved visual function in this group of patients,” said Dr. Frank Holz, the trial’s principal investigator and head of the Department of Ophthalmology at Bonn University Hospital in Germany. “Late-stage age-related macular degeneration is a depressing disease. Patients can no longer read, drive a car, watch TV, or even recognize faces. So [these results] They were game changers in my mind.

One patient, Sheila Irvine, 70, who had the Prima device installed at Moorfields Eye Hospital in London, said in a statement provided by the hospital that her life before the transplant was like “having two black discs in my eyes, with a deformity on the outside.” Irvine, who described herself as a “voracious bookworm” before losing her sight, said she was now able to solve crossword puzzles and read prescriptions.

The findings represent a breakthrough for patients with geographic atrophy, said Dr. Sunir Garg, a professor of ophthalmology in the Retina Service at Wills Eye Hospital in Philadelphia, who was not involved in the study. He said that all the doctors were able to provide were visual aids, such as magnifying glasses, and emotional support.

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

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

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

Vavas said it is important to note that the device does not restore normal vision, as patients were only able to see in black and white instead of color, and trial participants had to undergo a significant amount of training in order to learn how to see with the PRIMA device. He also said it was not clear whether improvements in visual ability significantly improved patients’ quality of life.

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

“Think of this device as a pre-release iPhone,” he said. “The limitations are clear. It should not be an exaggeration to say that the quality of life has actually improved. But there was certainty [visual] Tasks that patients were clearly better at. So it shows us that there is potential in this approach. In some ways it is still a prototype. They are working on an iteration of this device that will be even better.

It is possible that new upgrades to the PRIMA device will be released in the next couple of years.

The Prima system was invented by Stanford University professor of ophthalmology Daniel Palanker and is being developed by California-based neuroengineering firm Science Corporation.

Palanker said technical improvements are being made to increase the number of pixels in the chip from 400 to 10,000. The new chips have already been tested on mice, and upgraded chips are being manufactured for future human trials. With the help of the camera’s zoom function, Palanker said this could theoretically enable patients to achieve 20/20 visual accuracy.

“We are also working on the next generation of 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 that this technology could be tried in other retinal diseases that cause blindness, such as Stargardt’s disease, which has symptoms similar to age-related macular degeneration but is hereditary and usually affects younger people.

Garg and Favas look forward to seeing larger trials that provide more details about how the device improves patients’ ability to function on a daily basis. Vavas suggested that future experiments could include a joystick to understand the extent to which the device achieves real-world benefits, for example, compared to existing electronic amplifiers.

“Is it something good enough for patients to say, ‘Okay, I’ve regained my independence because now I can pay my credit card bills myself, stamp and address my own envelopes, 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 find out other risks and other problems,” Vavas said. “Is the efficacy signal that we see after 12 months still there after two years?”

While Vavas said he would not call the device a complete panacea for blindness, the study showed that brain-computer interfaces could represent an important approach to treating different types of severe visual impairment. “As iterations of this device get better and better, it may become a real solution for a group of patients,” he said.