LONDON: People with a leading cause of blindness were able to read again thanks to a tiny wireless chip implanted in the back of the eye and specialised augmented glasses, according to study results published Monday in the New England Journal of Medicine.
The trial involved 38 European patients, all of whom had an advanced stage of dry age-related macular degeneration (AMD) known as geographic atrophy. There is no cure for AMD, which is driven by changes in a part of the retina called the macula and caused by inflammation and a build-up of waste. The photoreceptor cells in the macula are responsible for producing sharp, detailed and colored vision. When the disease has progressed to the geographic atrophy stage, these cells deteriorate and die, and people lose their central vision — meaning that an object straight ahead may appear blurry or covered up with a dark blotch.
Roughly 22 million people in the US have AMD, and about 1 million have geographic atrophy, according to the American Macular Degeneration Foundation. In the study, the participants, who had an average age of 79, were fitted with the “PRIMA device,” a system meant 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 the light into an electrical current, which stimulates the remaining healthy cells in the macula in a realistic way, enabling signals these cells send to be interpreted by the brain as vision.
An image processor, which the user must carry, lets patients zoom in and magnify the images they see, which appear in black and white. With the help of the PRIMA device, 80 percent of the 32 patients who returned for a reassessment one year after the chip implantation had achieved clinically meaningful visual improvements. Patients did experience side effects, predominantly related to the surgical procedure: The study reported that 26 serious adverse events occurred in 19 of the patients, ranging from elevated blood pressure in the eye to an accumulation of blood around the retina. The majority of the adverse events resolved within two months of the implantation.
“It’s the first ever therapeutic approach that has led to an improvement in visual function in this group of patients,” said Dr Frank Holz, the trial’s lead investigator and chair of the department of ophthalmology at the University Hospital of Bonn in Germany. “Late-stage age-related macular degeneration is a dismal disease. Patients are no longer capable of reading, driving a car, watching TV or even recognising faces. So [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 akin to “having two black discs in my eyes, with the outside distorted.” A self-described “avid bookworm” before losing her vision, Irvine said she was now able to do crosswords and read prescriptions.
Dr Sunir Garg, professor of ophthalmology at the retina service of Wills Eye Hospital in Philadelphia, who was not involved in the study, said the results represent a breakthrough for patients with geographic atrophy. All doctors have been able to offer, he said, are visual aids, like magnifiers, and emotional support.
“Even with new medical therapies, the best that we can do is slow it down,” said Garg, who works with several drugmakers involved in treatments for AMD, including Apellis Pharmaceuticals, the maker of pegcetacoplan. That drug, which slows the progression of geographic atrophy, was recently approved in the US 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 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 that the PRIMA system is not without limitations. Vavvas was also optimistic about its future potential, describing the current iteration of PRIMA as a key stepping stone in the field of vision restoration.
“Think of this device as the pre-release iPhone,” he 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. They’re working on iterations of this device that will be better.” New upgrades to the PRIMA device could be coming in the next couple of years.
