PRIMA’s technological core consists of a minuscule, 2-by-2-millimeter wireless chip implanted in the retina’s macular region, where photoreceptors have been irreversibly damaged by geographic atrophy, a form of advanced AMD. Unlike conventional photoreceptors, which respond to visible light, this implant is uniquely sensitive to near-infrared light. Real-time imaging is facilitated by an external camera mounted on a pair of innovative glasses worn by the patient. The glasses capture the scene, convert it into infrared signals, and project these onto the retinal chip, which then converts the light into electrical stimulation. This process substitutes for the missing photoreceptors, enabling the retinal neurons to relay form-based visual information to the brain.

The development of this cutting-edge device is the culmination of over two decades of intense research, experimentation, and clinical trials. Daniel Palanker, PhD, the visionary behind PRIMA, first conceptualized a light-based wireless mechanism at Stanford, exploiting the eye’s natural transparency to deliver visual data directly to the retinal neurons. The system’s photovoltaic properties eliminate the need for cumbersome external wired power supplies, previously a major limitation for retinal prostheses, granting patients more practical and less invasive treatment options.

The clinical trial encompassed 38 participants over 60 years old suffering from geographic atrophy with severely impaired vision—worse than 20/320 in at least one eye. Following implantation and recovery, patients utilized the augmented glasses, which featured adjustable magnification, brightness, and contrast settings, enabling personalized enhancement of the visual scenes. Where prior devices offered only rudimentary light detection, PRIMA restored the ability to perceive shapes, letters, and patterns, ushering a new era in prosthetic vision therapy.

After one year of continuous use and guided visual training, the results were undeniably promising. Of the 32 participants who completed the trial, 27 regained the capacity to read printed text, some achieving visual acuity approximating 20/42—remarkably close to normal functional vision for daily activities. Equally important, patients integrated their prosthetic central vision with their remaining peripheral natural vision, enabling improved spatial awareness and navigation. This hybrid visual input represents a significant advantage, as it prevents the patient’s vision from being restricted solely to the artificial implant’s field.

Technically, PRIMA’s infrared projection system was expertly designed to be invisible to remaining functional photoreceptors outside the implant area, ensuring that patients’ natural peripheral vision remains uncontaminated by the device’s stimulation. The implant uses an array of 378 pixels, each about 100 microns wide, calibrated to generate finely localized electrical pulses that activate retinal neurons, effectively simulating the intricate responses of healthy photoreceptor cells. This precise mimicking is what distinguishes PRIMA from previous prosthetic attempts that produced only generalized light sensitivity rather than clear form vision.

While the trial reported some manageable side effects, including occasional ocular hypertension, peripheral retinal tears, and localized hemorrhages, none of these adverse events posed long-term risks, with most resolving within two months. This safety profile is particularly encouraging considering the advanced age and compromised retinal integrity of the participants. Moreover, two-thirds of patients expressed moderate to high satisfaction with the device’s performance in their day-to-day lives, using it to read books, food labels, and public signage—activities that profoundly enhance independence and quality of life.

Looking ahead, the researchers are vigorously pursuing multiple avenues to augment PRIMA’s capabilities. One key ambition is to introduce grayscale vision, addressing a major patient demand for enhanced perception that supports facial recognition and nuanced environmental interpretation. Achieving grayscale vision will represent a quantum leap beyond the current black-and-white image display, facilitating richer and more naturalistic visual experiences essential for social interactions.

In addition, technological refinements aim to dramatically increase pixel density by shrinking pixel size from 100 microns to as little as 20 microns in forthcoming generations of the implant. This advancement, already successfully tested in preclinical animal models, would expand the pixel count from 378 to approximately 10,000. Such a boost in resolution could theoretically provide prosthetic vision approaching 20/80 acuity, which, coupled with adjustable electronic zoom in the glasses, holds the potential for near-normal 20/20 visual capabilities.

Furthermore, the modular design of PRIMA invites application beyond AMD, potentially addressing other degenerative diseases involving photoreceptor loss. As the implant technology matures, it could provide a versatile platform adaptable to various types of retinal degeneration, broadening its impact across ophthalmology. Concurrent efforts to streamline the glasses into a more ergonomic form factor promise to enhance user comfort and social acceptance, key factors for widespread adoption.

This groundbreaking research epitomizes the power of interdisciplinary collaboration, bringing together expertise from institutions across Europe and the United States, including the University of Bonn, University of Pittsburgh, University College London, and several eminent medical centers. Supported by funding from Science Corp., the National Institute for Health and Care Research, and Moorfields Eye Hospital NHS Foundation Trust, the study represents a triumph of biomedical engineering integrated with clinical ophthalmology.

In sum, PRIMA heralds a transformative era in vision restoration, no longer content with rudimentary light detection but enabling practical, functional sight in patients previously consigned to despair. Although early in its lifecycle, this device encapsulates a future where technology and biology seamlessly converge to repair sensory loss, restoring not just vision but autonomy, dignity, and human connection.

Subject of Research: People
Article Title: Vision Restoration with the PRIMA System in Geographic Atrophy due to AMD
News Publication Date: 20-Oct-2025
Web References: DOI: 10.1056/NEJMoa2501396
Image Credits: Palanker Lab/Stanford Medicine
Keywords: Macular degeneration, Prosthetics

Age-related macular degeneration, particularly its advanced atrophic form known as geographic atrophy (GA), stands as the foremost cause of irreversible blindness among older populations worldwide. The degeneration involves the destruction of photoreceptors in the macula, the small but critical region of the retina responsible for sharp, central vision. This leads to the progressive worsening of visual acuity, severely impacting daily activities such as reading and recognizing faces for over five million individuals globally. Until now, no treatment could reverse this loss or restore central vision.

The international, multi-center PRIMAvera clinical trial, co-led by distinguished ophthalmologists José-Alain Sahel, Daniel Palanker, and Frank Holz, examined the efficacy of the PRIMA implant in 38 participants aged 60 and older across 17 sites in Europe. Sahel, based at the UPMC Vision Institute, Palanker from Stanford University, and Holz from the University of Bonn, pooled their expertise to analyze outcomes following one year of device usage, highlighting a paradigm shift in the management of AMD.

Remarkably, among the 32 participants who completed a full 12-month follow-up, an overwhelming 81% demonstrated clinically meaningful improvements in visual acuity, while 84% reported using prosthetic vision for functional tasks such as reading numbers and words in their everyday environments. Quantitatively, the average improvement amounted to 25 letters on the standard eye chart, which translates to an approximate five-line gain in vision, underscoring the implant’s profound functional impact.

The PRIMA system is a marvel of biomedical engineering designed to replace the lost photoreceptor function through a compact, wireless 2×2 mm subretinal implant. Developed initially by Dr. Palanker, the implant converts projected near-infrared light into precisely calibrated electrical stimuli that activate the residual retinal neurons. The process begins with a miniature camera mounted on specially crafted glasses, capturing real-time images and transmitting them wirelessly to the implant beneath the retina where the bioelectronic conversion occurs.

Unlike conventional vision restoration approaches, the PRIMA device bypasses the damaged photoreceptors and directly stimulates the inner retinal circuitry. This bioelectronic retina replacement leverages the remaining retinal structure to transmit visual information to the optic nerve and subsequently to the brain’s visual cortex, reestablishing a functional visual pathway. Moreover, patients can customize zoom and contrast settings, optimizing the quality of prosthetic vision to meet their individual needs and visual preferences.

Across the trial cohort, post-surgical recovery was exemplary, with all procedure-related adverse effects resolving within the first year. The visual gains were substantial and consistent, with the most dramatic case achieving an extraordinary 59-letter improvement, equivalent to twelve lines on the eye chart—a transformative functional restoration that exceeds the expectations of previous experimental interventions.

While achieving full 20/20 vision restoration remains beyond the current capabilities of the PRIMA system, researchers at UPMC and collaborators actively pursue enhancements through combined technological and biomedical advancements. These efforts aim to surpass legal blindness criteria, dramatically elevating patients’ independence and quality of life beyond current thresholds, signaling a future of renewed hope for those afflicted with vision loss from AMD.

This early success has galvanized regulatory pathways, prompting Science Corporation, the device manufacturer, to seek clinical authorization for widespread use in Europe and the United States. Notably, UPMC has been at the forefront, implanting the PRIMA system in the United States as early as 2020 within an initial trial led by associate professor Joseph Martel, evidencing the accelerating translation from research breakthroughs to clinical implementation.

In addition to the leading institutions involved, the study’s collaborative authorship spans notable eye centers including the Adolphe de Rothschild Foundation Hospital in Paris, Moorfields Eye Hospital in London, and the University of Rome Tor Vergata, reflecting a robust multinational effort in addressing one of ophthalmology’s greatest challenges.

Funded primarily by Science Corporation alongside support from the National Institute for Health and Care Research Biomedical Research Centre and UCL Institute of Ophthalmology, the study exemplifies a model of synergistic public-private research endeavors driving innovative solutions in medical science.

The clinical implications of this technological triumph extend beyond AMD, potentially heralding a new era in neuroprosthetics and vision science. The PRIMA system’s design embodies the convergence of bioengineering, ophthalmology, and neuroscience, opening avenues for future applications in other retinal diseases and sensory impairments, thereby expanding the horizon of restorative medicine.

As the global population ages, the burden of vision loss is expected to rise, amplifying the necessity for scalable, effective treatments. This breakthrough positions the PRIMA implant as a cornerstone technology with the capacity to transform the landscape of treatment options for degenerative retinal diseases, offering patients not just incremental improvements, but the restoration of meaningful vision and autonomy.

Subject of Research: People
Article Title: Vision Restoration with the PRIMA System in Geographic Atrophy Due to AMD
News Publication Date: 20-Oct-2025
Web References: https://www.nejm.org/doi/full/10.1056/NEJMoa2501396
References: Disclosure forms by the authors are available with the full text at NEJM.org
Image Credits: UPMC

Keywords: Macular degeneration, Vision disorders, Prosthetics, Retina, Ophthalmology, Blindness