Getting your sight back – thanks to an artificial retina
Second Sight's "Argus II" implant.
A new prosthetic retina enables those patients blinded by the disease "retinitis pigmentosa" to regain some form of vision. The company Second Sight, whose European branch is hosted by EPFL’s Science Park, has just received authorization to commercialize the product in Europe.
For those patients suffering from retinitis pigmentosa, we can literally speak in terms of “light at the end of the tunnel”. Second Sight Medical Products, whose European base is located in EPFL's Science Park, has developed a prosthetic retina which enables them to regain the ability to identify their surroundings. The company has just received EC certification, which will allow it to commercialize the invention in Europe.
This degenerative disease causes patients to progressively lose their sight. They generally lose night vision between 10 and 20 years of age, then peripheral vision between 20 and 30 years of age, finally becoming completely blind at around age 40. The disease affects around one person in 4000, and is the most frequent cause of blindness in middle-aged people in developed countries. Its origin is in a genetic mutation of the rods and cones – the two photo-receptive cells of the retina.
The role of the implant offered by Second Sight is to bypass the damaged cells. A small camera fixed on a pair of spectacles records an image, which is then converted into electrical impulses and transmitted to a receiver located at the back of the eye. Implanted on the retina, it sends these impulses to the neurons, and the impulses are then interpreted by the brain to re-construct an image.
“The kind of sight that our product gives the patient is not like that we have naturally, and can’t replace it”, explains Grégoire Cosendai, Director of Second Sight’s European office. The device brings mainly an additional level of comfort in their daily life; for example in moving around or cooking.”
Today, the prosthetic retina has already been implanted in 30 patients as part of the clinical trials. All of them have regained the ability to discern day from night. Twenty-nine of them can manage to find an object in a room, and 57% can detect movement around them. Eighty per cent can distinguish text on a computer screen, although some people need more time than others to achieve this. Finally, seven patients noticed a clear improvement in their visual acuity, and manage to read, for example, newspaper headlines. “The results depend on the positioning of the implant on the retina, but also on the way that the latter reorganizes itself afterwards, and this differs from one person to another”, adds Grégoire Cosendai.
Second Sight is now working on the second stage of the project: to improve the system in cooperation with three research teams at EPFL. These are the Laboratory of Biomechanical Orthopedics, the Laboratory of Microsystems, and the Laboratory of Applied Mechanics and Reliability Analysis. The objective is to develop a system that will enable the conversion of the camera image into electrical impulses that the brain can recognize. This will then help in understanding the differences in the results obtained in the patients, and to then adapt the device to the specific needs of each person.