What will the clinical trial involve?
Ten patients will undergo surgery to tackle Retinitis Pigmentosa (RP), an inherited disease that causes blindness. The procedures will take place at Moorfields Eye Hospital and Manchester Eye Hospital (MREH) from 2017.
Who has funded this clinical trial?
NHS England will fund this through its Commissioning through Evaluation (CtE) scheme, designed to gather vital evidence for treatments that show significant promise for the future. NHS England will assess how the ‘Bionic Eye’ helps patients function with everyday tasks.
Has this been done before?
Yes, surgeons at Moorfields and Manchester Eye Hospital made history by delivering the world’s first trial of the Argus II ‘Bionic Eye’ implants in RP in 2008. Specialists at both hospitals initially supported early studies, which demonstrated that the Argus II restores a degree of visual function to patients who have suffered complete blindness due to the condition.
How does the surgery work?
Patients using the system, developed by American company, Second Sight®, are given an implant into their retina and a camera mounted on a pair of glasses sends wireless signals direct to the nerves which control sight. The signals are then ‘decoded’ by the brain as flashes of light.
What is Retinitis Pigmentosa?
The trial involves patients with an eye condition called Retinitis Pigmentosa. Retinitis pigmentosa (RP) is the name given to a group of inherited conditions of the retina that all lead to a gradual progressive reduction in vision.
Is this treatment available now?
At the moment the implant is only available as part of a clinical trial. Therefore, it is not available to patients outside of the trial. The clinical trial participants will need to be followed up to assess the long term effect of the treatment, and the overall results may not be available for some months.
Can I take part in the clinical trial?
If you are interested in joining the clinical research trial please email firstname.lastname@example.org, call 0207 253 3411 (extension 2036), or speak to your Moorfields consultant to find out if you fit the criteria.
What do the researchers hope to achieve?
In this form of retinal degeneration the photoreceptor cells are completely lost. The aim is provide this lost function. To do so the picture is captured with a camera and this signal is transmitted to a device implanted in the eye. The device stimulates the remaining nerves by way of an electrode panel in the eye. The signal is then passed up the optic nerve to the brain.
Are there plans for future trials for other forms of retinal conditions?
It would be possible to use this device in other conditions where the photoreceptors are lost and there is good function of the optic nerve. However, this first trial is for severe Retinitis Pigmentosa only.
How does the Argus II device work?
The device consists of a tiny camera and transmitter mounted in sunglasses, an implanted receiver, and an electrode-studded array that is tacked to the retina. A video processor and battery pack worn on the belt powers the entire device. The camera on the glasses captures an image and sends the information to the video processor, which converts the image to an electronic signal and sends it to the transmitter on the sunglasses. The implanted receiver wirelessly receives this data and sends the signals through a tiny cable to the electrode array, stimulating it to emit electrical pulses. The pulses induce responses in the retina that travel through the optic nerve to the brain, which perceives patterns of light and dark spots corresponding to the electrodes stimulated.
How long will it work for?
We cannot yet conclusively state what the expected lifetime of the implant is. Second Sight® has undertaken extensive verification testing that indicates that the device should last many years, but the final determination on expected lifetime has yet to be made.
How big is the implant?
There is a portion of the implant that sits on the outside of the eye, underneath the conjunctiva (the white-pink tissue around your cornea). Because it is covered by the tissue this portion of the device is not visible, although the bump that it creates under the tissue may be visible in some patients. There is another small part of the device that goes into the eye and gets attached to the retina with a micro-tack. None of this portion would be visible to someone looking at the patient, although a physician will certainly be able to see this part of the device inside the eye when performing a routine eye exam.
What else does the subject wear and what does it look like?
There are several external pieces that the subject has to wear. The most noticeable are the glasses which house the small camera and transmitting antenna. These glasses are dark and stylish. There is a cable that runs from these glasses to a processing unit. The cable can run under clothing if desired and the processing unit can be held in the hand, attached to a belt or contained in a case or purse.
Is it easy to operate?
The implanted patients to date have found the system relatively easy to operate. The system and implant is set up in the clinic so that the patient need only control a few aspects such as on/off, and simple image controls such as brightness. Additionally the subject is trained on how to change the rechargeable battery.
Where has the technology come from?
The technology was developed by Second Sight® with the goal of creating a retinal prosthesis to provide sight to patients blinded from outer retinal degenerations, such as Retinitis Pigmentosa. Second Sight®’s mission is to develop, manufacture and market implantable visual prosthetics to enable individuals with sight loss to achieve greater independence.
Where can I get more information about Retinitis Pigmentosa?
Visit the website of RP Fighting Blindness for further information.