A retinal implant that doesn't need an external camera
Last week, the U.S. Food and Drug Administration approved the first implant that can restore eyesight to blind people: the Argus II from Second Sight Medical Products, which uses a pair of sunglasses with a tiny video camera.
Now, researchers from the University of Tübingen in Germany have developed a system that has helped several patients to see… without the use of an external camera.
Like the Argus II, this device only works in people with diseases such as retinitis pigmentosa, which destroys the light-sensing cells (photoreceptors) in the eye but leaves the vision-processing neurons intact.
But rather than rely on an external camera, the alpha-IMS subretinal implant (pictured) can detect light entering the eye -- taking the place of broken photoreceptors and bridging the communication gap between the eye and the brain.
A small grid of 1,500 light-sensitive pixels implanted underneath the retina converts light into electrical signals, which are then transferred to the retina via electrodes. The brain processes the information into visual perception.
A dial behind the ear adjusts for brightness, and the whole device is powered wirelessly by a battery in the pocket.
The end result of the retinal implant is a diamond-shaped field of vision. Almost all of the nine participants reported regaining some vision both indoors and out, and they can look around by moving their eyes rather than having to move their head.
Some details, reported by the Verge:
Close-up, previously-blind patients were able to detect mouth shapes such as smiles; the absence or presence of glasses on the face of a passer-by; objects such as telephones and cutlery; and even finer details such as signs on doors. In the far-vision range, patients could make out the horizon line, houses, trees, and rivers. Cars were located based on their bright reflections, while at night one patient was able to recognize moving cars by their headlights.
The work was published in Proceedings of the Royal Society B.
Image from K. Stingl et al., 2013