A British woman has spoken of her joy of being able to see for the first time in 16 years after receiving the world’s most advanced ‘bionic eye’.
Rhian Lewis, 49, underwent an eight-hour surgery at John Radcliffe Hospital in Oxford, UK, whereby a 3 x 3mm chip was inserted into her right eye behind her retina. This chip contains 1,600 light sensors that send electrical signals to nerve cells; the information is then processed by a tiny computer that sits underneath the skin behind her ear.
Lewis was diagnosed with retinitis pigmentosa – a disorder that destroys photoreceptors in the retina – when she was five. She is completely blind in her right eye and has virtually no vision in her left eye as a result of the condition, for which there is no cure.
However, behind the destroyed photoreceptors she still had an intact optic nerve and all the brain wiring needed for vision, making it possible to restore vision if only a way could be found to substitute the function of the photoreceptors.
The chip was developed by German engineering firm Retina Implant and captures the light entering the eye to stimulate the nerve cells of the inner retina to deliver signals to the brain through the optic nerve.
The device is connected to a small computer that sits underneath the skin behind the ear. This is powered by a magnetic coil, which is applied to the skin from the outside and looks similar to a hearing aid. The device is then switched on once everything has healed after the surgery.
When the device is first switched on patients will often see flashes of light, but over a few weeks the brain converts those flashes into meaningful shapes and objects to build up an image.
One test involved Lewis looking closely at a large cardboard clock to see if she could tell the time correctly. She has not been able to tell the time with her right eye in 16 years and for about six years with her left eye.
'Now, when I locate something, especially like a spoon or a fork on the table, it's pure elation,’ said Lewis. ‘It's really just pure joy to get something right, because I've never done it before, well, not for the last 16 or 17 years anyway.'
The chip has 1,600 pixels, but the image is refreshed regularly as the eye moves. Although this is not many pixels compared to a standard phone camera, the chip has the advantage of being connected to the human brain, which has over 100 billion neurons of processing power.
Using dials on a small wireless power supply held in the hand, Lewis can adjust the sensitivity, contrast, and frequency to obtain the best possible signal for different conditions.
'Restoring sight to the blind using an electronic device presents huge challenges for the technology, the surgery and above all, the patient,’ said Professor Robert MacLaren, who is leading the trial.
'For a blind person, having independence is a very important aspect of their vision, so if we can give someone enough vision so that they can see where they are in the home, they can go out, they can walk to the bus stop...they can see people around them – they're basically aware of their surroundings – then we've achieved a great deal.
'It may not be enough to read things yet, but just enough to navigate would be sufficient. And also you must not forget that we're at the very beginning of a very exciting technology.'