“ Yes, we will succeed in restoring sight“ , declared in 2016 Science and Future Professor José Sahel, former director of the Vision Institute (Paris), Regarding the expected outcomes in ophthalmology. Eight years later, the scientist continued his pioneering work begun in retinitis pigmentosa and this autumn co-authored with an international team an important study published on October 20, 2025 in the journal New England Journal of Medicine.
The promise has therefore materialized with the first successes of a retinal implant tested for the first time in atrophic age-related macular degeneration (AMD), the most common type and still without treatment to date, the trial having been carried out on patients all suffering from severe forms with very impaired vision.
“ These initial results are exceptional.
“ These initial results are exceptional. specifies Science and Future Serge Picaud, research director and now head of the Vision Institute. Who continues: " On the one hand, this is the first time that an implant of this type has been used not in retinitis pigmentosa. but in atrophic AMD, and on the other hand, this neurostimulation device has the particularity of operating without any wires or cables coming out of the eye patients, explains the researcher who is not not in the list of signatories of the study, but who has participated for several years in the numerous preclinical stages of this work.
As a reminder, in age-related macular degeneration (AMD), the macula, the central part of the retina responsible for sharp and detailed vision, is progressively destroyed. This is what allows us to read and recognize faces, while peripheral vision remains intact.
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There are classically two forms of AMD, the so-called atrophic (or dry) form, the most frequent (80% of patients) without treatment to date, and the so-called wet (or exudative) form, less frequent (20%) but benefiting from a medical approach, repeated injections allowing to delay the destruction of the macula and the formation of neovascularization.
In both cases, the photoreceptor cells, those that capture light and transmit images to the brain, gradually disappear, causing irreversible loss of central vision.
42 patients have already benefited from this implant
This recent work, carried out by an international team associating the Vision Institute (Inserm/CNRS/Sorbonne University), the Adolphe de Rothschild Foundation, the National Hospital of the Quinze-Vingts, Stanford University and Science Corporation, recruited 38 patients aged on average 78.9 years in 17 centers spread across five European countries, including several French sites (Bordeaux, Créteil, Lyon, Marseille, Nantes). This follows an initial study which had already included four initial patients, thus bringing to 42 the total number of patients implanted to date with this Prima implant.
Designed by researcher Daniel Palanker at Stanford University (USA) and then developed by the company Science CorporationIt is a silicon photovoltaic microchip, a small square 2 mm on each side, 30 microns thick, which has 378 electrodes. For the patient who is about to receive the implant, everything begins in the operating room with a small incision made in the retina to allow the implant to be inserted underneath.Serge Picaud explains.
A simple procedure performed in one to two hours maximum. Upon waking and then continuously, the patient will wear a pair of augmented reality glasses equipped with a miniature camera, the unique feature of which is that it is wirelessly connected to the implant, which “ "This avoids the problem of having to position an external cable coming out of the eye." the researcher explains.
It is this camera which will film the patient's surrounding images and transmit them, in the form of a video stream, to a small computer located in a pocket. An algorithm will enhance the images, enlarging them up to 12 times, increasing their contrast and brightness, and it is this video stream, once converted into infrared beams, that will be projected in real time onto the retinal implant.
Finally, the The role of the silicon chip is to short-circuit dead photoreceptor cells by transforming, at the level of the residual retina, light into electrical signals communicated to the brain, and it is the energy provided by the infrared beam that activates each of the 378 electrodes arranged in the implant.
Diagram of the Prima subretinal implant's operation. Credits: Frank G. Holz et al., NEJM 2025
Reading letters, numbers and words
Equipped with their implant, glasses, and computer, the thirty or so patients were able to regain partial sight within a year, allowing them to read letters, numbers, and words.
Their vision was of course assessed before and after the procedure by reading the lines of letters that can be found at any ophthalmologist's office. The main criterion for effectiveness used by the researchers was to achieve a reading of at least 10 additional letters and, good news, " 81% of patients reached this improvement threshold without any change in their peripheral vision.Serge Picaud explains. For 78% of them, the gain was even 15 letters, with a peak of 59 additional letters being reached for one patient.
“ The device now comprises 378 electrodesSerge Picaud explains, m"This could perhaps be further improved in the future by slightly increasing the size of the implant."
While awaiting its commercialization, which could be effective within one to two years, Serge Picaud hopes that the Prima implant will also be tested on patients suffering from retinitis pigmentosa or carriers of genetic diseases such as Stargardt disease. Furthermore, this positive message regarding atrophic AMD will undoubtedly help to bring these patients back into the care pathways.", the researcher hopes.
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