Implant Prima: restoring sight in the face of AMD

Age-related macular degeneration ( AMD ) is the leading cause of vision loss in industrialized countries. It affects more than 8% of the French population and up to a third of those over 75. 

Until now, the most common form of the disease, the atrophic (or dry) form , had no treatment. But recent international research conducted by the Vision Institute (Inserm/CNRS/Sorbonne University) , in collaboration with the Adolphe de Rothschild Foundation, the Quinze-Vingts National Hospital, Stanford University, and Science Corporation, has just reached a historic milestone. Thanks to the Prima implant , a neurostimulation retinal implant, patients with the atrophic form have regained partial vision. This breakthrough gives hope to the millions of people affected by this still incurable disease.

AMD: Understanding a disease with many faces

AMD is a chronic and progressive disease that manifests after age 50. It is characterized by the progressive degeneration of the photoreceptor cells of the macula — these specialized cells that capture light and allow the perception of details and colors.

Two main forms can be distinguished:

• Exudative (or wet) AMD : due to the abnormal proliferation of blood vessels under the retina, it progresses rapidly but can be slowed down by intraocular injections of anti-VEGF.
• Atrophic (or dry) AMD : this accounts for approximately 80% of cases. Its progression is slow but irreversible, causing permanent loss of central vision, with no treatment currently available.

The main risk factors are well identified: age, tobacco use, genetic predisposition, unbalanced diet, and prolonged exposure to blue light . With the aging population, age-related macular degeneration (AMD) could affect more than 5 million people worldwide by 2050.

The Prima retinal implant: a revolution in visual neurostimulation

Developed by researcher Daniel Palanker at Stanford University, the Prima system ( supported by the French company Pixium Vision) is based on a simple but bold idea: replacing destroyed photoreceptor cells with an electronic chip capable of transforming light into an electrical signal.

The device comprises two elements:

• a photovoltaic microchip implanted under the retina, measuring only 2 mm on each side and 30 microns thick , composed of 378 electrodes ;
• a pair of augmented reality glasses , equipped with a miniature camera and connected to a mini laptop.

Its operation is ingenious. The camera captures images of the environment, processes them via an algorithm that adjusts the contrast, brightness, and magnification (up to 12x), before converting them into infrared beams . These beams are projected in real time onto the implant, which transforms the light into electrical impulses, directly stimulating the still-functional retinal neurons.

The system works without wires or an external battery , with power supplied by the infrared beam itself — a technological feat that avoids any cables coming out of the eye.

Spectacular and promising clinical results

The results of the clinical trial, published in the New England Journal of Medicine in October 2025, are described as "exceptional" by the researchers.

Conducted in 17 European centers (including Bordeaux, Lyon, Marseille, Nantes and Paris for France), the study included 38 patients with severe atrophic AMD, aged on average 79 years.

After implantation of the Prima implant and several months of visual rehabilitation, the results are unprecedented:

• 81% of participants improved their visual acuity by at least 0.2 logMAR , meaning they could read 10 more letters on a standard chart.
• 78% achieved an improvement of 0.3 logMAR , reading 15 letters or more .
• The best score showed a gain of 59 letters , corresponding to a dramatic improvement.
• Finally, more than 84% of patients reported being able to read letters, numbers and even words again in their daily lives.

These advances fulfill a promise long considered utopian: to allow blind patients at the center to regain functional vision while preserving their natural peripheral vision .

As Professor José-Alain Sahel , co-author of the study, points out:

"This is the first time a system has allowed patients who have lost their central vision to read words, or even sentences, while preserving their peripheral vision."

The observed side effects (ocular hypertension, localized retinal hemorrhages or detachments) were controlled and resolved in 95% of cases, confirming good clinical tolerance .

Towards a new era of artificial vision

The Prima implant is only the first generation of a technology destined to evolve rapidly. The next versions currently under development promise:

• improved visual resolution , with pixels reduced to 20 microns (compared to 100 currently) and up to 10,000 electrodes per chip;
• the introduction of grey level (today, patients perceive shapes in black and white);
• Thinner and more ergonomic glasses, combined with artificial intelligence algorithms to optimize reading and facial recognition.

These prospects suggest applications beyond AMD, particularly in retinitis pigmentosa or Stargardt disease , other degenerative pathologies affecting photoreceptors.

According to Serge Picaud, research director at the Vision Institute :

"This positive message regarding atrophic AMD will undoubtedly help bring these patients back into the care pathway and broaden the scope of retinal therapies to other, still orphan, diseases."

A concrete hope for millions of patients

By restoring the ability to read, orient oneself and recognize everyday shapes, the Prima system marks a major turning point in the history of modern ophthalmology.

The result of more than twenty years of research, this innovation combines neuroscience, photonics and artificial intelligence to compensate for the loss of photoreceptors — a feat once reserved for science fiction.

Although the device still needs to be subject to long-term monitoring and regulatory validation, its commercialization could take place within two years , paving the way for a real revolution in the management of dry AMD .

Science has not yet found a way to rejuvenate the retina, but it has just proven that it can reinvent vision …