Overview
Stanford researchers implanted a chip smaller than a Tic Tac under the retinas of 38 blind patients. A year later, 27 could read again. Some read entire books. The PRIMA device, published October 20, 2025 in the New England Journal of Medicine, is the first prosthetic to restore functional vision to people with macular degeneration—the leading cause of irreversible blindness.
Three competing approaches are racing to cure blindness: retinal implants that replace dead photoreceptors, optogenetic gene therapies that reprogram surviving neurons, and cortical brain chips that bypass the eye entirely. The stakes are massive—over 5 million people worldwide have geographic atrophy from macular degeneration, and the broader market for vision restoration could hit $7 billion by 2032. But the field is littered with failures. The pioneering Argus II implant went obsolete in 2020, stranding 350 patients with unsupported devices embedded in their eyes.
Key Indicators
People Involved
Organizations Involved
Four-year-old neurotechnology company that acquired Stanford's PRIMA technology and raised $260 million to commercialize it.
Stanford's Department of Ophthalmology developed the photovoltaic retinal prosthesis technology underlying PRIMA.
Brain-computer interface company developing Blindsight, a cortical implant that bypasses the eye to restore vision.
Developed the first FDA-approved retinal prosthesis but ceased support, stranding 350 implanted patients.
Developing optogenetic gene therapy that reprograms surviving retinal neurons to become light-sensitive.
Timeline
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PRIMA Restores Reading Vision in Blind Patients
ResearchNew England Journal of Medicine publishes landmark PRIMA trial: 27 of 32 patients regained reading ability after one year with implant.
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Neuralink's Blindsight Gets FDA Fast-Track
RegulatoryFDA grants breakthrough device designation to Neuralink's Blindsight cortical visual prosthesis, accelerating development timeline.
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GenSight Reports Optogenetics Trial Data
ResearchGenSight Biologics announces 1-year safety and efficacy signals from PIONEER trial of GS030 optogenetic therapy for retinitis pigmentosa.
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Hodak Leaves Neuralink, Founds Science Corp
MarketNeuralink co-founder and president Max Hodak departs to launch Science Corporation, targeting vision restoration with retinal implants.
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First Optogenetic Vision Restoration
ResearchSahel's team achieves first partial vision restoration in blind patient using optogenetic gene therapy with ChrimsonR protein.
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PRIMA Early Safety Data Published
ResearchPalanker and Sahel publish preliminary PRIMA safety data in Nature Communications, showing feasibility of photovoltaic subretinal prosthesis.
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Argus II Support Ends, Devices Go Obsolete
MarketSecond Sight ceases technical support for Argus II and Orion implants, stranding patients with obsolete devices still embedded in eyes.
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Second Sight Halts Argus II Manufacturing
MarketRevenue shortfalls force Second Sight to stop manufacturing Argus II despite 350 patients worldwide with implanted devices.
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FDA Approves First Retinal Implant
RegulatoryArgus II receives FDA approval under humanitarian device exemption, becoming first approved visual prosthesis in the United States.
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Palanker Conceives Photovoltaic Retinal Prosthesis
ResearchDaniel Palanker at Stanford realizes the eye's transparency enables wireless information delivery via infrared light, conceiving PRIMA.
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First Human Retinal Prosthetic Implant
MilestoneSecond Sight's Argus I device implanted in first six patients with retinitis pigmentosa, launching the modern era of visual prosthetics.
Scenarios
PRIMA Reaches Market, Restores Vision to Thousands
Discussed by: Science Corporation management, medical device analysts, Stanford and Pittsburgh researchers
Science Corp wins regulatory approval in Europe and the U.S. by late 2026, commercializing PRIMA for geographic atrophy patients. The device's demonstrated safety profile and functional reading outcomes convince payers to cover the procedure. With 5 million potential patients worldwide and growing surgical adoption, PRIMA captures significant market share. Competitors struggle to match PRIMA's clinical results. The success validates retinal implants as the fastest path to vision restoration and establishes Science Corp as the market leader. Improved versions with higher resolution and larger visual fields follow within 3-5 years.
Multiple Technologies Coexist, Target Different Patients
Discussed by: Vision restoration researchers, neuroethics scholars, ophthalmology professional societies
Retinal implants, optogenetics, and cortical BCIs each carve out distinct patient populations based on disease stage and anatomy. PRIMA dominates macular degeneration with intact retinal structure. GenSight's optogenetics serves early-stage retinitis pigmentosa patients. Neuralink's Blindsight targets those with completely destroyed retinas or optic nerves. The market fragments across approaches, with no single winner. Insurance coverage and pricing become key battlegrounds. Patients face difficult choices about invasiveness, performance, and long-term support. Regulatory frameworks evolve to ensure companies maintain support for implanted devices throughout patient lifetimes.
Safety Concerns or Support Failures Stall the Field
Discussed by: FDA officials, bioethicists, patient advocacy groups, IEEE Spectrum investigation
Long-term complications emerge with PRIMA or competing devices—infections, retinal damage, or device failures requiring risky removal surgeries. Or Science Corp faces financial pressures and reduces patient support, echoing Second Sight's 2020 abandonment of Argus II patients. Regulators respond with stricter requirements for device longevity and mandatory company reserves for lifetime patient support. The setbacks slow adoption and spook investors, delaying the vision restoration revolution by 5-10 years. The Argus II debacle becomes a cautionary tale cited in every regulatory review.
Cortical BCIs Leapfrog Retinal Implants
Discussed by: Neuralink, brain-computer interface researchers, futurist technology analysts
Neuralink's Blindsight or competing cortical implants demonstrate superior visual acuity within 2-3 years, rendering retinal approaches obsolete. Direct brain stimulation enables higher resolution, larger visual fields, and eventually augmented vision beyond natural human capability. Retinal implants prove to be a transitional technology, useful for the first generation but superseded by brain-direct approaches. Elon Musk's bold claims about exceeding normal vision prove prescient. The market tilts heavily toward cortical BCIs despite their invasiveness, driven by dramatically better performance.
Historical Context
Cochlear Implants Transform Hearing Restoration
1984-presentWhat Happened
The FDA approved the first cochlear implant in 1984 to replace the sense of hearing in profoundly deaf adults. Early devices provided limited speech recognition, and many in the deaf community opposed them. But successive generations improved dramatically. Today over 1 million people worldwide have cochlear implants, with many users achieving near-normal hearing and speech comprehension.
Outcome
Short term: Initial skepticism and modest results gave way to steady technological refinement and expanding FDA indications through the 1990s-2000s.
Long term: Cochlear implants became standard of care for profound deafness, proving that prosthetic sensory restoration was medically and commercially viable at scale.
Why It's Relevant
Cochlear implants provide the template for visual prosthetics: early modest results, iterative improvement, eventual mainstream acceptance, and a sustainable market supporting long-term device improvements.
Argus II Goes Obsolete, Stranding Implanted Patients
2013-2020What Happened
Second Sight's Argus II became the first FDA-approved retinal prosthesis in 2013. More than 350 blind patients worldwide paid $150,000 each for the implant. But the company generated only $32 million in revenue against $300 million invested. Financial pressures from COVID-19 forced Second Sight to cease manufacturing in 2019 and stop technical support in 2020, leaving patients with obsolete devices still embedded in their eyes. A 2023 merger promised renewed support but highlighted devastating ethical failures.
Outcome
Short term: Patients lost the ability to use their implants as external hardware failed and software support vanished, some describing it as 'going blind twice.'
Long term: The Argus II collapse became a cautionary tale driving regulatory focus on device longevity and company obligations to support implanted patients throughout their lifetimes.
Why It's Relevant
The Argus II failure hangs over every new visual prosthetic, raising critical questions about whether companies like Science Corp can sustain long-term patient support if commercial success proves elusive.
Human Genome Project Accelerates Medical Technology
1990-2003What Happened
The Human Genome Project sequenced all human DNA, taking 13 years and costing $2.7 billion. The achievement seemed like a moonshot with unclear applications. But it catalyzed an explosion in genomics, gene therapy, and precision medicine. Tools that once took years and millions became routine in labs worldwide within a decade. Gene therapies for previously untreatable conditions began reaching patients in the 2010s-2020s.
Outcome
Short term: The completed genome initially underwhelmed—no immediate cures emerged, and many questioned the investment's value through the early 2000s.
Long term: The genome project's tools and knowledge enabled an entire generation of therapies including CAR-T cancer treatments, gene therapies for blindness, and mRNA vaccine platforms.
Why It's Relevant
Vision restoration technologies like optogenetics and retinal prosthetics directly descend from genomics and neuroscience breakthroughs the Human Genome Project accelerated, showing how foundational research enables seemingly impossible medical achievements.