Summary: A landmark European clinical trial demonstrates that an electronic retinal implant used with augmented-reality (AR) glasses can restore reading vision in people who lost central sight from geographic atrophy (GA) caused by dry age-related macular degeneration (AMD). The PRIMA System enabled 84% of participants to read letters, numbers and words using prosthetic vision through an eye that had previously been blind.
The implant is an ultra-thin, wireless subretinal microchip that functions like a tiny photovoltaic panel. Paired with bespoke AR glasses and a pocket computer, it converts visual scenes into near-infrared stimulation that the chip transforms into electrical signals the brain interprets as central vision. This achievement marks a major advance in artificial vision and offers practical, everyday benefits for people with untreatable GA from dry AMD.
Key Facts:
- Restored reading ability: 84% of trial participants regained the capacity to read letters, numbers and words using the implant and glasses.
- Compact technology: The PRIMA System uses a 2 mm microchip implanted under the retina combined with AR glasses that project near-infrared light to the device.
- Improved daily life: Participants reported being able to read books, do crosswords and read small print again, helping independence and emotional well‑being.
Source: UCL
Overview
A multicenter European trial led by University College London (UCL) and Moorfields Eye Hospital shows that the PRIMA implant can restore meaningful central vision in people with geographic atrophy from dry AMD. The study, published in The New England Journal of Medicine, involved 38 patients at 17 hospital sites across five countries; Moorfields was the UK site. All participants had complete loss of central vision in the treated eye before implantation.
On average, treated patients could read five lines of a vision chart after activation of the device; several participants could not see the chart before surgery. No significant loss of peripheral vision was observed after implantation.
Dry AMD is a progressive degeneration of the macula in which light-sensitive retinal cells die, and geographic atrophy represents an advanced stage where the central retina is lost. There is currently no licensed therapy that restores vision for GA, which affects millions worldwide; the PRIMA System is the first subretinal implant to produce readable central vision in this condition.
Mr Mahi Muqit, associate professor at the UCL Institute of Ophthalmology and senior vitreoretinal consultant at Moorfields Eye Hospital, who led the UK arm of the trial, described the results as opening a new era in artificial vision. He highlighted the practical impact of restored reading ability on mood, confidence and independence, and noted that the implantation procedure can be performed safely by trained vitreoretinal surgeons in under two hours.
The surgical technique involves a vitrectomy to remove the vitreous gel, followed by placement of the ultra-thin photovoltaic microchip — roughly the size of a SIM card at 2 mm by 2 mm — into a small subretinal pocket under the central retina. After a recovery period of around a month, the implant is activated.
Patients wear AR glasses containing a video camera. The camera sends the scene to a small computer worn at the waist that uses algorithms to process and convert the image into near-infrared light patterns. These patterns fall on the implant, which converts them into electrical stimulation that travels through surviving retinal circuitry and the optic nerve to be perceived as central visual input. A zoom function on the system allows magnification of text, and patients undergo several months of rehabilitation to learn to interpret the new visual signals and relearn reading.
Participants were encouraged to use the device for practical tasks. One trial participant returned to puzzles and crosswords; another used the system to assist with navigation. Such everyday gains illustrate the device’s real-world value beyond chart-based tests.
The global trial was led by Dr Frank Holz at the University of Bonn and included sites in the UK, France, Italy and the Netherlands. The PRIMA System is under development by Science Corporation, a company working in neural engineering and brain-computer interfaces.
More about the device:
The PRIMA implant is a wireless subretinal photovoltaic microarray paired with specialised AR glasses that project near-infrared light. The implant is approximately 30 micrometres thick — about half the width of a human hair — and sits beneath the layer of retinal cells that have been lost. The system remains inactive until the glasses and pocket computer are switched on.
Rehabilitation is a critical component of successful outcomes. Patients follow tailored training programs to practice recognizing letters, focusing with the glasses, and using the zoom feature to read smaller print. The trial showed that consistent practice improves reading performance over time.
Sheila Irvine, a Moorfields participant, described regaining the ability to read as life-changing. She reported no operative pain, gradual progress in recognizing letters, and growing confidence as she practiced reading labels and crosswords.
These results support regulatory steps toward approval and wider clinical availability of the technology for people with geographic atrophy from dry AMD.
Key Questions Answered:
A: PRIMA is a subretinal photovoltaic implant that receives near-infrared patterns from AR glasses. The implant converts those patterns into electrical pulses that stimulate remaining retinal pathways, producing a form of central prosthetic vision.
A: The device is intended for people with dry AMD and geographic atrophy who have lost central vision but still retain peripheral sight in the implanted eye.
A: In the trial, many patients who were blind in one eye could read up to five lines on a vision chart after implantation — a substantial and previously unattained improvement for prosthetic vision in GA.
About this visual neuroscience and neurotech research news
Author: Chris Lane
Source: UCL
Contact: Chris Lane – UCL
Image: The image is credited to Neuroscience News
Original Research: Closed access. “Vision Restoration with a Neurostimulation System in Geographic Atrophy Due to AMD” by Mahi Muqit et al., The New England Journal of Medicine. (Clinical trial PRIMAvera, NCT04676854.)
Abstract
Vision Restoration with a Neurostimulation System in Geographic Atrophy Due to AMD
Background
Geographic atrophy from age-related macular degeneration is a leading cause of irreversible central blindness worldwide and affects millions. No treatments currently restore central vision in these patients. The PRIMA System pairs a subretinal photovoltaic implant with AR glasses that project near-infrared light to the implant to restore sight to areas of central retinal atrophy.
Methods
This open-label, multicenter, prospective study evaluated participants with geographic atrophy and poor baseline central acuity. Vision was assessed with and without the PRIMA glasses at six and 12 months after implantation. The primary endpoints included a clinically meaningful improvement in visual acuity at 12 months and the safety profile through 12 months.
Results
Thirty-eight participants received the implant; 32 completed 12‑month assessment. Among those 32, 81% achieved a clinically meaningful improvement in visual acuity at 12 months. Accounting for missing data, the estimated rate of meaningful improvement was about 80%. Twenty-six serious adverse events were reported in 19 participants, most occurring within two months of surgery and the majority resolved. Peripheral visual acuity after implantation was similar to baseline.
Conclusions
In this cohort of patients with geographic atrophy due to AMD, the PRIMA System restored central vision for many participants and produced a statistically significant improvement in visual acuity at 12 months. These findings support further regulatory review and wider evaluation of the technology for treating central vision loss from dry AMD.