Recent Advances in Wireless Retinal Prostheses: Visual Outcomes and Safety Insights

In a world-first, researchers have restored meaningful vision to patients with advanced macular degeneration using a wireless retinal implant and high-tech glasses — a breakthrough that could transform the treatment of irreversible blindness. The clinical trial, led by Stanford Medicine and involving global collaborators, demonstrated that the device enabled most participants to read text, recognize patterns, and navigate the world with renewed visual ability.

The study, published October 20 in The New England Journal of Medicine, evaluated the PRIMA system, the first retinal prosthesis to restore functional central vision—also known as form vision—rather than mere light perception. Of the 32 participants who completed one year of follow-up, 27 regained the ability to read, some achieving visual acuity close to 20/40.

At the heart of PRIMA is a 2-by-2-millimeter wireless chip, implanted in the retina's central region where photoreceptors have been lost due to geographic atrophy, an advanced form of age-related macular degeneration (AMD). Affecting more than 5 million people worldwide, AMD is the leading cause of irreversible blindness in older adults.

Macular degeneration progressively destroys the retina’s photoreceptor cells, which convert light into electrical signals that the brain interprets as vision. However, retinal neurons responsible for relaying signals remain intact, creating an opportunity for intervention. PRIMA taps into this residual neural circuitry.

The system includes two parts: a tiny photovoltaic chip that converts infrared light into electrical signals and a pair of augmented reality glasses with an embedded camera. The camera captures visual scenes in real time, processes the images, and projects them into the eye using invisible infrared light. The chip responds to this light by stimulating nearby retinal cells, effectively replacing the function of lost photoreceptors. Importantly, the device preserves patients’ natural peripheral vision, as only the central retinal area is implanted. The use of infrared light ensures no interference with the remaining healthy photoreceptors.

The clinical trial enrolled 38 participants aged 60 and older with geographic atrophy and severely impaired vision—worse than 20/320 in at least one eye. Four to five weeks after receiving the implant, patients began using the glasses. With ongoing training, most saw significant improvement.

Visual acuity improved by an average of five lines on a standard eye chart, with one patient gaining 12 lines. Twenty-seven could read standard printed text, food labels, and subway signs. Participants also used the glasses’ digital features—such as brightness control, contrast enhancement, and up to 12x magnification—to improve clarity.

The PRIMA chip’s photovoltaic design eliminates the need for external power sources or tethering cables, a limitation that hindered previous retinal prostheses. Side effects—including elevated eye pressure and subretinal bleeding—were mostly mild and transient, resolving within two months. Importantly, no life-threatening complications occurred, and the device was well tolerated over a full year.

Participants reported high satisfaction, with two-thirds rating the experience as medium to high in usability and impact.

Still, the current version only provides black-and-white vision, and resolution is limited by pixel size. But Palanker’s team is already engineering the next generation of implants—with grayscale capabilities and 20-micron pixel resolution, potentially delivering 20/80 vision or better.

The upgraded chip, already tested in animal models, could include up to 10,000 pixels, dramatically improving image detail. When combined with the system’s zoom capabilities, some patients could approach 20/20 vision.

Beyond macular degeneration, PRIMA’s architecture may be adaptable for other photoreceptor-degenerative diseases, such as retinitis pigmentosa, expanding its therapeutic reach. The system’s modular design, light-based communication, and compatibility with preserved retinal circuits make it a promising platform for diverse forms of vision loss.

The study reflects a broad international collaboration, with contributors from leading institutions across Europe and the U.S., including the University of Pittsburgh School of Medicine, Moorfields Eye Hospital, University College London, and the Sorbonne. Funding was provided by Science Corp., the UK’s National Institute for Health and Care Research, and multiple clinical partners.

With these results, the field of bionic vision may have just entered a new era—one where reading, recognizing faces, and navigating independently are within reach for patients once resigned to irreversible blindness.