The PRIMA implant is just
2
milimeteres wide and thinner than a human hair.
In the clinical trial
84%
of patients reported the ability to read letters, numbers, and words
Geographic atrophy causes
20%
of legal blindness cases in Europe
The PRIMA system is designed to replace the function of light-sensitive cells in the eye that have been lost due to degenerative retinal diseases, including dry age-related macular degeneration (AMD).
In degenerative retinal diseases, the light-sensitive first layer of cells (rods and cones) fail, leading to blindness.
PRIMA works by bypassing the lost rods and cones and stimulating the next layer of cells (bipolar cells) directly to restore visual input to the brain.
Developed by Science Corporation, the PRIMA implant is the first and only treatment shown in clinical trials to restore functional central vision to patients with geographic atrophy (GA) caused by age-related macular degeneration (AMD).
This is the story of the PRIMA implant and the people who made the it happen.
Credit: Science Corporation
video transcript
My mother has AMD. My grandmother was blind. My grandfather, he was an aerospace engineer. He was also a photographer. And so I remember going from like being taught to develop film in a dark room to him losing his sight.
Macular degeneration is the most common condition that people suffer from. Um probably from the age of 55, 60 onwards.
Everyone knows someone who has macular degeneration. We call it AMD. the cells just gradually melt away and they lose their central vision.
Like if you put your hands in 10 cms in a distance in front of your eye, you can see the periphery. So I can see that there’s a person there. But if I want to have some details, it's impossible. It means they can't recognize faces. They cannot read anymore. They can't drive a car. It interferes with every aspect of life.
Previous attempts only achieved slowing of the disease progression. No improvement. What's that though?
Visual prosthesis to restore vision to the blind have been a big like prize for like many I mean arguably centuries.
There have been many companies that have built uh implants. There have been many companies that have pursued gene therapies, drugs. All had very serious trade-offs. None have really lived up to the potential.
Telling them there's nothing available is is heartbreaking. That's what it has been in the past. Yeah. Yeah.
The general perception around 30 years ago is that this was never going to work.
We rely on vision more than anything else. About 40% of the brain power is used for processing visual information.
It also a window into the brain. He is a frontier of science. Now I work on retinal prosthesis since 2004.
This project is actually my longest and most challenging and most rewarding. I found this project about vision restoration and I dedicated my life to it.
I started my research with my PhD. The professor told me, "Yeah, Mr. Hornik for this project you need to have 10 years and 10 million Deutsche mark. How long have you been working on it?
About 29 years now.
It was a hard work to come from light perception to reading. This took decades. The beginning we thought it's easy. You stimulate at a certain region on the on the retina and then the patient sees some patterns. Among the key question we found were what level of resolution what is the accuracy of the image you need to propose so that the brain would be able to use this information. We came to solutions in terms of electrodes in terms of stimulation strategy that created this pattern recognition where we are right now.
Evolving technologies made it possible to come up with Daniel Palanka's lab in a 2x2 mm small chip that has many pixels on it that convert light into electrical simuli.
One of the things that makes Prima special is the the fact that it's powered by light. The implant itself is essentially an array of tiny solar panels. The eye is still there. The optic nerve is intact. The brain knows how to see, but the eye is no longer light sensitive. The device replaces a function of photo receptors that are lost in retinal degeneration. Our patients see form vision and not just light.
About 10 years ago, they were saying they have this device and it's now being tested. That's the perfect safety.
As we started our clinical trials, we thought it's will be impossible to find volunteers to do research there. It was the opposite. Many people who said yes.
The trial was run across many European countries. We implanted 38 patients, 20 hospitals.
Prima needed to have a procedure that was something you could easily do in your standard practice. The aim was to try and partially restore vision. 4 weeks later after the implantation, the devices have been switched on. We adjust the parameters of the device mechanically and electrically. And then the patient learn how to use the device and learn how to see.
When you're running drug trials and things, we have to demonstrate that there's a certain improvement in the numbers and levels of vision to offer patients meaningful benefit that will then lead to a meaningful improvement in quality of life. That's what's been running for the last number of years.
Patients are very excited, was very proud about this.
The trial has essentially demonstrated that over 3/4 of patients have reached that improvement which is quite remarkable.
Some of our patients are able to fill in cross word puzzles. This is a very complex task.
When I saw a patient pick up a regular book and they were able to read the text quite fluently, it's jaw-dropping.
Perm vision means that when you glance at something without any scanning, you see a form. You see a shape of a letter, face and so on. As opposed to source of light that you have to scan over time and that was characteristic to many other implants in the past. In our case, it's instantaneous form vision, which is key for fast perception. And we see that our patients indeed can read and write.
People had never gotten these types of clinical trial results before in humans.
People had never gotten a form vision image in the mind's eye of a blind patient before who was unable to recognize faces. And that that blew us away. That was a major advance.
This publication in the New England Journal of Medicine is a huge confirmation of all the work that we have done in the last 20 years.
Now that the trial has demonstrated these results, next step is trying to get it to our patients.
It’s so beautiful to see that you give vision back to people.
The impact is enormous for these patients.
The more important is the level of energy it gives you to continue because the most important is that this is not the end of the story. I remember one patient telling me, I thought my eyes were dead and now they are still alive.
My eyes are still alive. one of her very first patients. I remember after she was switched on, she was a bit teary and she says that you Mr. Muqit, I know you um didn't want to promise me too much, but what you've given me uh from my age, in my time in life, I'll be ever grateful for that, you know. And she's like a grandmother, had a huge family. She said, "I can see again." I thought, you know, I'm a bit emotional now cause she was, you know, uh one of our patients.
How does PRIMA work?
During the procedure, the surgeon places a tiny electronic chip underneath the centre of the retina, the light-sensitive tissue at the back of the eye. The chip is extremely small, measuring just 2mm by 2mm, and is thinner than a human hair.
After surgery, the patient wears special augmented reality glasses fitted with a camera. The camera sends images to a small computer worn on a belt or waistband. Advanced artificial intelligence (AI) software processes the images and converts them into electrical signals.
These signals are sent to the retinal cells and then along the optic nerve to the brain, where they are interpreted as visual information. Using the glasses, patients can focus on and scan objects, while a zoom function can enlarge text and other details.
Following the procedure, patients take part in a personalised rehabilitation programme over several months. This helps them learn how to interpret the new visual signals and make the most of their restored sight, including developing the ability to read again.
video transcript
Prima targets the retina which has three major layers. Here's how the prima implant is placed in the eye.
First, a light is inserted to aid the surgeon and the vitrius fluid is removed from the inner chamber. Then, a space is formed beneath the retina where the implant will be placed.
A delivery tool primes the implant for precise insertion. The delivery tool is inserted and the
implant is placed in the space below the retina.
Fluid is injected to push the retina back down. And finally, the implant is adjusted to best target the central visual field. The implant rests under the bipolar cells in the place of atrophied photo receptors.
It's difficult to read without central vision. So, a pair of glasses with an embedded camera captures visual information from the environment which is transmitted into the eye via near infrared light. The implant accepts this light and stimulates the retina in the
same pattern.
PRIMA glasses
The PRIMA glasses include a camera and infrared projector. A built-in near-infrared light projector wirelessly sends power and visual information to the implant.
Who is suitable for the PRIMA implant?
Who is eligible for PRIMA?
PRIMA is suitable for patients who:
Have geographic atropy - a term for late stage dry age-related macular degeneration, where there are dark patches in the central retina. The nerve cells of the retina must still be in tact for the PRIMA implant to work.
Are able to commit to the full rehabilitation programme. Once implanted, patients need to train their brain to intepret the new signals coming from the implant. This can take between two to six months of regular rehabilitation and training.
Are otherwise in good heath. As the rehabilitation programme requires up to two to four months of training and follow up appointments, patients should be in general good health. At your initial appointment, your consultant will assess your suitability, including a broader physical assessment.
Are able to pay for the treatment. The PRIMA implant is not currently available on the NHS and is only available privately. Patients need to commit to the full cost of the programme.
Who will PRIMA not work for?
PRIMA is not suitable for patients who:
Have wet AMD in both eyes or vision loss due to causes other than geographic atrophy such as glaucoma, damage to the optic nerve or cornea, or retinal detachment. The nerve cells in the retina must be in tact in order for the implant to be able to send signals to the brain.
Have dementia, due to the cognitive requirements of the rehabilitation programme, patients with dementia are often unsuitable for the PRIMA implant.
What is geographic atropy?
Geographic atrophy is damage to the retinal cells which leads to loss of central vision. People with geographic atrophy tend to see dark patches in the middle of their vision with the side vision, known as peripheral vision, remaining in tact.
To be suitable for PRIMA, your vision will have a large central blind spot that inhibits your ability to read, recognise faces, and see fine detail in your central vision.
In the history of artificial vision, this represents a new era. Blind patients are actually able to have meaningful central vision restoration, which has never been done before.
Frequently asked questions about the PRIMA implant
Is the PRIMA implant available on the NHS?
No, the PRIMA implant is curently only available privately.
Is there financial assistance available?
Financial assistance is not available through Moorfields or Moorfields Private. Patients would need to self-fund the full cost of their treatment.
How long does surgery take?
The surgical procedure itself takes approximately 2 hours.
What are the risks with the implant?
Any surgery comes with some risk.
The clinical trials found that most negative side effects were related to the implantation surgery procedure rather than the PRIMA device itself.
The most common serious adverse events were ocular hypertension, peripheral retinal breaks, and minor hemorrhages, which were mostly manageable and resolved within two months.
Can the implant be removed or upgraded as technology improves?
Although the implants are designed to be permanent and no devices have been removed from patients thus far, their wireless design allows for potential replacement with next-generation wearables as the technology advances, enabling even higher vision resolution or a larger area of restoration.
How big is the PRIMA implant?
The PRIMA implant is 2 × 2 mm wide and 30 μm (microns) thick, which is half the thickness of a human hair or about the same thickness as a sheet of plastic wrap.
This ultra-thin design allows it to fit seamlessly under the retina without causing discomfort or interfering with the eye's natural function.
How long does the rehabilitation programme take?
The post-operative rehabilitation programme supports the patient to learn how to use the technology and train the brain to intepret the signals from the PRIMA implant.
The programme can take two to six months of regular sessions.
Is PRIMA a cure for dry AMD?
PRIMA vision is a different form of vision, and it takes practice to learn. PRIMA does not cure dry AMD or restore full natural vision, but it can help you see details that were previously lost. It may also be used alongside other assistive devices.
What results will I get from PRIMA?
In the clinical trials, 94% of patients demonstrated central visual perception and 84% reported reading letters, numbers, and words at home. 69% reported medium-to-high satisfaction with the system.
The average (mean) improvement was 5 lines on an eye chart. The best improvement was 11 lines.
Individual results may vary. The PRIMA glasses include adjustable digital zoom and contrast. Patients who follow the full rehbilitation programme are more likely to achieve the best possible outcome with these features.
Meet your surgeon: Associate Professor Mahi Muqit
Associate Professor Mahi Muqit is a leading consultant ophthalmic surgeon at Moorfields Eye Hospital, specialising in cataract, medical retina and vitreoretinal surgery. With thousands of successful procedures and over 80 peer-reviewed publications, he is recognised for his expertise in treating macular holes, diabetic eye disease, and retinal detachment. He is also an Associate Professor at UCL and actively involved in global eye health initiatives and clinic research trials.
Associate Professor Muqit led the UK trial for the PRIMA device. The clinical trial involved 32 patients and of these, 27 were able to read again using their central vision.
Sheila's story
Sheila was one of Moorfields’ patients on the PRIMA clinical trial, which concluded in 2025.
Sheila says:
“At first, I noticed I couldn’t judge things when I was driving - I kept hitting the pavement. I was told I had age-related macular degeneration. I cried all day long when I sent my driving licence back over 15 years ago, but then I said to myself, ‘Move on and get on with things.’
“I can't see TV very well, but I still have it on in the background. I don't let anything stop me. I’ve got lots of friends, we catch up down the pub, I live by myself and want to stay independent.
“I wanted to take part in research to help future generations, and my optician suggested I get in touch with Moorfields. Before receiving the implant, it was like having two black discs in my eyes, with the outside distorted.
“I was an avid bookworm, and I wanted that back. I was nervous, excited, all those things. There was no pain during the operation, but you’re still aware of what’s happening. It’s a new way of looking through your eyes, and it was dead exciting when I began seeing a letter. It’s not simple, learning to read again, but the more hours I put in, the more I manage to pick up.
“The team at Moorfields has given me challenges, like ‘Look at your prescription’, which is always tiny. I like stretching myself, trying to look at the little writing on tins, doing crosswords.
“It’s made a big difference. Reading takes you into another world, I’m definitely more optimistic now.”
Credit: BBC News
video transcript
Now for some good news. For the first time, blind patients have been able to read again thanks to a microchip implanted at the back of the eye. A surgeon at Moorfields Eye Hospital in London who led the pioneering treatment says the results are "astounding".
Our medical editor, Fergus Walsh, has been to meet Sheila, who says the treatment has changed her life.
Sheila Irwin began losing her sight more than 30 years ago and is registered blind. This is what her world looks like due to a condition called dry age-related macular degeneration (AMD).
"Is it left now?"
"Yeah, it says 'No Entry'. That's it, yeah."
But everything changes when Sheila, who is 70, puts on these special glasses.
"They docked at Bourne."
She can read again for the first time in years.
So how is this possible?
This tiny microchip, as thin as a human hair, was implanted under Sheila's retina. Here you can see it in position at the back of her eye. A camera in the glasses sends a video feed via an infrared beam to the chip, which is enhanced by computer processing.
The images on the left are the camera output. Those on the right are what Sheila sees.
"It's out of this world. Amazing."
"One happy bunny."
"I could have cried when I looked because I haven't seen letters for so long. Then I lit up a word and it was overwhelming."
"It's really made a tangible difference to your life?"
"A big difference entirely, because I read the post, read books, do crosswords."
"Did you ever imagine that you'd be able to read a book again?"
"Never. Never on your Nelly."
"See, I'm just checking the macula. The chip's in an excellent position."
Moorfields Eye Hospital in London played a key role in the international trial.
Of 32 blind patients given the implant, 27 were able to read again using their central vision.
"So this is the first treatment that's been demonstrated to effectively give patients meaningful vision that they can use in their daily life, such as reading and writing. I think this is a major advance. This is pioneering and I think what you'll find with patients is that it is life-changing."
"There we go, Sheila."
"Thank you."
The technology is not yet licensed or available on the NHS, but it offers hope to thousands of patients with Sheila's form of dry AMD.
"I'm going to turn off the lights now."
"Thank you."
It takes concentration, but she is now able to read every letter on an eye chart.
Sheila's delight at the new technology is plain to see.
"Very impressive. Very good. Very good."
Fergus Walsh, BBC News.
How much does the PRIMA implant cost?
Initial consultation
Consultant fee: £300 (confirm with Mahi)
This fee is payable to the consultant.
Hospital fees: £668
These fees are payable to the hospital for the pre-implant imaging and testing. These include:
OCT
Multi colour fundus and autoflourescence
Mircoperimetry
If further outpatient tests and investigations are required, they will be charged at an additional rate. Your consultant will discuss this with you at your consultation.
Pre-operative assessment
£200
A pre-operative appointment with a psychologist is required before you can proceed to surgery.
Surgery and rehabilitation
From £220,000
This includes:
Surgical fees
Anaesthetist fee
Surgeon's fee
Drugs and dressings
Overnight stay
PRIMA implant and glasses
Rehabilitation programme.
Follow up appointments
Approximately £XXX - £XXX
The follow up schedule will be determined by your consultant after surgery, depending on how well you are recovering. The cost shown here is indicative of X to Y appointments, and includes both consultant fees and the regular tests required to monitor your progress.
Some patients require fewer follow up appointments, some patients may require more.
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For more information
The PRIMA implant is developed by Science Corporation. PRIMA is approved for commercial use in the EU/EEA.
