In October 2025, the New England Journal of Medicine published results from the PRIMAvera trial—an international study across 17 sites in five European countries involving 38 patients with advanced dry age-related macular degeneration, all legally blind in their central visual field. The patients received a photovoltaic retinal implant about half the thickness of a human hair, placed beneath the retina, paired with augmented-reality glasses that project near-infrared light onto the chip. At 12 months, participants improved by an average of five lines on an eye chart. Some could read large print. Some could recognize objects. Some could cook, play cards, navigate rooms they hadn’t been able to see clearly in years.
The lead developer, Daniel Palanker at Stanford’s Byers Eye Institute, described the PRIMA system as “the only way to restore sight in AMD patients” who have already lost their photoreceptors. By June 2025, Science Corporation—the bioelectronics startup founded by Neuralink co-founder Max Hodak, which acquired Pixium Vision’s assets in April 2024—submitted a CE mark application for European approval. The restored vision is in shades of gray, not color. It’s crude by any standard of normal sight. And for people who couldn’t see the faces of their grandchildren or read a word on a page, it’s transformative.
Age-related macular degeneration affects roughly 200 million people globally. It’s one of the most common causes of blindness in people over 50, and until PRIMA, there was no treatment that could restore vision once the photoreceptors were gone. Drugs can slow progression. Nothing reversed the damage. The PRIMA trial is the first clinical evidence that an electronic implant can meaningfully restore central vision in this population—and it published in the NEJM, which is about as close to a stamp of legitimacy as medical science gets.
How a retinal implant actually works
The retina is essentially a biological sensor array at the back of the eye. Photoreceptor cells—rods and cones—detect light and convert it into electrical signals that travel through the optic nerve to the visual cortex of the brain. In diseases like macular degeneration and retinitis pigmentosa, the photoreceptors die, but the rest of the neural circuitry—the bipolar cells, ganglion cells, and the optic nerve itself—often remains largely intact. A retinal implant replaces the dead photoreceptors with an electronic substitute.
The PRIMA system works through a three-component chain. A camera mounted on augmented-reality glasses captures the visual scene. A pocket-sized processor converts the image into patterns of near-infrared light. The glasses project those infrared patterns onto the photovoltaic chip implanted beneath the retina. The chip’s pixels convert the infrared light into electrical current, which stimulates the surviving bipolar cells, which relay the signal through the remaining visual pathway to the brain. The photovoltaic pixels replace the dead photoreceptors. The brain—remarkably—learns to interpret the artificial signal and merges the prosthetic vision with whatever natural peripheral vision remains, creating what patients describe as a single continuous image.
The elegance of the photovoltaic approach is that the implant is entirely wireless. No battery. No external power source threading through the eye. The infrared light from the glasses simultaneously carries the visual information and powers the chip. Earlier devices, like Second Sight’s Argus II, required wired connections between external hardware and the implant, which created durability and surgical complications that ultimately contributed to the device’s commercial failure.
The Argus II cautionary tale
Any discussion of bionic eyes in 2026 has to reckon with the Argus II, because it’s the field’s most instructive failure. Second Sight Medical Products received FDA approval for the Argus II in 2013—making it the first retinal prosthesis approved in the United States—and implanted the device in roughly 350 patients with retinitis pigmentosa worldwide. The device had 60 electrodes (compared to PRIMA’s much higher pixel density) and restored crude vision: flashes of light, edges, shapes, movement. Not reading. Not face recognition. Basic spatial orientation.
Then Second Sight went bankrupt in 2020 and ceased operations in 2022. Patients were left with implants in their eyes and no company to maintain them, update the software, or replace failing components. The external hardware—glasses and processor—became orphaned technology with no manufacturer support. The IEEE Spectrum description was blunt: the Argus II was “a pure bridge to nowhere.” Lloyd Diamond, Pixium Vision’s outgoing CEO, said it directly when Science Corporation acquired the PRIMA assets: “It’s very important to us to avoid another debacle like Argus II.”
The Argus II failure wasn’t primarily a technology failure. The device worked, within its limitations. It was a business model failure—a medical device company that couldn’t sustain operations long enough to support implanted patients for the lifetime of the implant. This is the shadow that hangs over every bionic eye company in 2026: the device has to work, and the company has to survive. Patients are making a decades-long commitment to hardware inside their body; the manufacturer needs to make the same commitment to them.
Where the field stands across all approaches
Retinal implants are the most clinically advanced category but not the only one. The landscape in 2026 includes three distinct approaches to electronic vision restoration, each targeting different anatomical locations and different patient populations.
Subretinal implants, like PRIMA, sit beneath the retina and stimulate bipolar cells. They’re the furthest along clinically and are best suited for conditions where photoreceptors are damaged but the rest of the visual pathway is intact—primarily AMD and potentially retinitis pigmentosa, though results for RP with PRIMA are expected to be more limited because the retinal damage is more widespread.
Suprachoroidal implants, developed by the Bionics Institute in Australia, sit in the space between the retina and the outer wall of the eye. Their second-generation device demonstrated substantial improvements in functional vision, navigation, and quality of life over 2.7 years in a phase I/II trial, with 97 percent of electrodes remaining functional and no serious adverse events. The device has received FDA breakthrough device designation, and larger multi-center trials are planned. The suprachoroidal position is surgically less invasive than subretinal placement, which could matter for broader adoption.
Cortical visual prostheses bypass the eye entirely. An electrode array implanted directly on the visual cortex at the back of the brain stimulates the neurons that process vision, creating artificial sight even in people with severely damaged or missing eyes. This approach can theoretically help patients whose optic nerves are damaged—a population that no retinal implant can serve. Neuralink’s Blindsight system, which uses 36 flexible threads with roughly 3,000 electrodes sewn into the visual cortex by a surgical robot, has shown success in monkey tests. Neuralink received preliminary regulatory approval for early human studies in the U.S., Canada, the U.K., and the EU, and reported plans to implant the first human volunteers by 2026. The Orion Visual Cortical Prosthesis, originally developed by Second Sight (before its collapse) and now continued by Cortigent, has published five-year data from its early feasibility study.
A fourth approach—the Science Eye, being developed by Max Hodak’s Science Corporation—combines a retinal implant with optogenetic therapy: a genetically engineered virus delivers a gene that makes specific retinal cells light-sensitive at a particular wavelength, and a tiny implanted display with resolution sharper than an iPhone screen provides precise control over those sensitized cells. This hybrid biological-electronic approach is the most ambitious and the least clinically proven.
The resolution problem
The fundamental limitation of every bionic eye in 2026 is resolution. The human retina has roughly 120 million rods and 6 million cones. The PRIMA implant has 378 pixels per square millimeter across a 2-by-2-millimeter chip. The Argus II had 60 electrodes. Even the most optimistic next-generation devices are operating with electrode counts measured in thousands, not millions. The gap between what the implant provides and what a healthy retina delivers is roughly four to five orders of magnitude.
This is why the restored vision is grayscale, crude, and limited to central-field perception. It’s enough to read large print, recognize shapes, navigate rooms, and regain a measure of independence. It is not—and won’t be for the foreseeable future—enough to drive a car, recognize a face across a room, or see the world the way a sighted person does. The next-generation PRIMA device under development uses smaller pixels for higher density, and software improvements including electronic zoom and image stabilization are being tested. But the trajectory is incremental improvement within a fundamentally low-resolution paradigm, not a leap to natural vision.
Daniel Palanker draws the comparison to cochlear implants—devices that restore hearing by stimulating the auditory nerve. Early cochlear implants provided crude sound perception. Today, after decades of refinement, they enable many deaf patients to understand speech and enjoy music. Retinal implants may follow a similar arc: the first generation establishes the principle, each subsequent generation improves the resolution, and the technology becomes standard clinical practice over a timeline measured in decades.
The honest prognosis
PRIMA works. The NEJM data shows it. Patients are seeing things they couldn’t see before the implant, and the benefits are durable over years. The Australian suprachoroidal device works. The cortical approaches show promise. The field in 2026 is further along than it has ever been, with more clinical data, more companies, more approaches, and better-funded organizations than at any point in the history of vision restoration.
The caveats are significant. The PRIMAvera trial was not placebo-controlled—an anonymous retinal-degeneration researcher told Nature that the intensive training and motivation from receiving an exciting new device might have inflated the results. The resolution remains orders of magnitude below natural vision. The commercial viability question—whether any company can sell enough devices at a price patients can afford while sustaining operations for the multi-decade life of the implant—is unanswered. The Argus II proved that a technically successful implant and a commercially sustainable business are not the same thing.
But for 200 million people with macular degeneration, and for the broader population with retinitis pigmentosa, glaucoma, and other causes of irreversible blindness, the PRIMA trial represents something that didn’t exist before October 2025: evidence, published in the world’s most prestigious medical journal, that an electronic implant can restore meaningful central vision in humans. That’s not a cure. It’s not normal sight. It’s the beginning of a technology that may, over decades of refinement, make blindness from photoreceptor loss a treatable condition rather than a permanent one.
We cover retinal implants alongside brain-computer interfaces, neural stimulation for depression, and the full landscape of neuroprosthetic technology across our Neuroprosthetics course—including why the most important medical device of the 2020s is a chip the size of a pencil eraser that lets people read again.