A patient from Moorfields Eye Hospital has been able to detect signals in her blind left eye thanks to a revolutionary new implant. She is the first UK patient to receive this new device, as part of a Europe-wide clinical trial. It offers the hope of partially restored vision for people with geographic atrophy (GA), the most common form of dry age-related macular degeneration (AMD).
The procedure involves inserting a 2mm wide microchip under the centre of a patient's retina, by surgically creating a trapdoor into which the chip is posted. The patient uses special glasses, containing a video camera that is connected to a small computer attached to their waistband.
The chip captures the visual scene projected by the glasses and transmits this to the computer. Artificial intelligence (AI) algorithms process this information and instruct the glasses to focus on what they perceive to be the main object in the image. The glasses project this image as an infra-red beam through the eye to the chip, which converts this into an electrical signal. This signal passes through the retinal cells and optical cells into the brain, where it is interpreted as if it were natural vision.
Four to six weeks after being inserted, this implant is tested by switching the chip on, and at this stage the patient should be able to see a signal. They then go through a rehabilitation programme to learn how to use the vision they have been given. After this, patients are potentially able to recognise words when they couldn't before. It is being trialled with patients who have lost their vision in an eye because of GA. This condition is progressive and currently has no treatment. 12% of those over 80 will be affected by dry AMD, while GA affects 6.7% of over 80s.
video transcript
A Moorfields patient has become the first person in the UK to receive a bionic eye implant, to help restore part of her sight. Here the 88 year old grandmother from London talks about her experience of the procedure, her happiness at being able to enjoy some of her hobbies again, and getting the nickname the 'bionic nana'.
“They tested me for this microchip that they put in my eye at the beginning of December and I've had tests done, and then they tried the camera today. I could see a small light, and then it went off, and then after that then, I was trying to describe what it looked like, and that it was like a V upside down. I could still see a little bit even before, but when I was writing, I was writing scribbles and that’s all.
“Well I'm happy now that it's working, and that it'll help other people. Because I've had this dry macular for a good many years. I found out after, when my husband died, my grandson died, my sister-in-law died, my mum, and my sister died, all within four years, and I couldn't cry. And when I went to the opticians and I explained it to them, so he put something on the eye and held it down, and that's when I found out it was dry macular. And then obviously went to the doctor, and then went to the hospital.
“Well I'll be able to do painting, and do watercolours. Just before the pandemic had started, I was doing colouring by colouring book, and I couldn't even see half of them. It'll be good to be able to get back to it.
“Now just when they found out that I was going to have the glasses and the microchip that's when they started saying the 'Bionic Nana'”.
This research is supported by the NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS foundation trust and UCL Institute of Ophthalmology.
An 88-year-old woman with seven children and eight grandchildren was the first UK patient to benefit from this implant. Losing the sight in my left eye through dry AMD has stopped me from doing the things I love, like gardening, playing indoor bowls and painting with watercolours. I am thrilled to be the first to have this implant, excited at the prospect of enjoying my hobbies again and I truly hope that many others will benefit from this too.
This groundbreaking device offers the hope of restoration of sight to people suffering vision loss due to dry AMD. The success of this operation, and the evidence gathered through this clinical study, will provide the evidence to determine the true potential of this treatment.
This research is supported by the NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology.
The Prima System device used in this operation was developed by Pixium Vision in France.
Prima system
The Prima System is intended to partially replace the normal physiological function of the eye’s photoreceptor cells by electrically stimulating the nerve cells of the inner retina, which then transmit the visual information to the brain via the optic nerve.
Prima System features
- Configured to be minimally invasive with its miniaturised design
The PRIMA implant used in the feasibility clinical study is of 2x2mm size and 30 microns thick (third the size of a human hair). It is a miniaturized passive and totally wireless sub-retinal implant that acts like a tiny solar panel that is powered by pulsed near infrared light through a miniaturized digital projector integrated in the pair of glasses worn by the implanted subject. PRIMA implant’s small size and wireless design enables minimally invasive surgery, which could be performed under local or general anaesthetic.
- Aiming to improve the perceptual resolution and designed for a physiological signal processing
In addition to minimally invasive surgery, the aim of the Prima System design was also to potentially improve the resolution of the prosthetic artificial visual perception by implanting directly at the level of the degenerated photoreceptors. the sub-retinal implantation leverages a physiological network that is still functioning: the internal retinal layers. The PRIMA wireless photovoltaic subretina implant also comprises 378 electrodes with each pixel having its own local electrical return path aiming to provide more targeted electrical stimulations.
The Prima System aims to elicit functional artificial, or bionic, vision in the form of light perception replacing partially the natural central vision loss. The Prima System is composed of three main elements: Wireless retinal implant, pair of glasses with a camera and digital projector, and a pocket processor.
The Prima System operating principle
A mini camera mounted on the glasses captures visual scenes in the environment. The visual scene is processed and simplified by the pocket computer equipped with breakthrough algorithms from artificial intelligence in order to extract useful information from the images.
The simplified images are then sent back to the glasses where a miniaturized digital projector then projects the processed images via pulses of near infrared light on the PRIMA wireless photovoltaic subretina implant, through the pupil, at the back of the eye under the retina.
The photovoltaic cells of the PRIMA implant convert this optical information into electrical stimulation to excite the bipolar nerve cells of the inner retina and subsequently induce visual perception in the brain.
January 2022