Bionic Vision Becomes a Reality
(August 17th, 2015) As the population ages blindness will become more prevalent, mostly due to retinal diseases. At present no effective treatments exist, but the Argus II bionic retinal eye implant is able to provide some vision restoration.
It is estimated that globally around 40 million people are blind and more than 250 million people are visually impaired. In the developed world, many people can get help through the use of glasses or the removal or cataracts and therefore retinal diseases are thought to account for around 70% of visual impairment.
The retina is a multi-layered neural tissue surrounding the back of the eye. In the outer retina the light sensitive rods and cones (photoreceptors) sit on a layer of supporting pigmented cells. They send the signal generated in response to light through further neural cells before it finally passes through the optic nerve into the visual cortex of the brain and an image is generated. There are a number of conditions affecting the outer retina (rods, cones and pigmented cells) including retinitis pigmentosa (RP) and age-related macular degeneration (AMD). In both cases, vision is gradually lost due to death of the photoreceptors, and, at present, no effective treatments exist.
The US firm Second Sight, however, developed a bionic retinal implant. The implant has been used to restore sight in a handful of RP patients and, earlier this year, was also successfully implanted into the eye of an AMD patient in Manchester, UK. The Argus II implant receives visual information from a miniature camera mounted on glasses worn by the patient. These images are converted into electrical pulses and transmitted wirelessly to an array of electrodes attached to the retina stimulating the remaining healthy cells in the inner retina which send the information to the brain. The implant gives the patient some vision, and can be useful for face recognition and identifying objects and shapes.
However, the technology is still quite primitive and the sight offered to the patient is still very limited. Noel Hemmings, Technology Coordinator at Action for Blind People (UK), and a sufferer of retinitis pigmentosa told me “I think the Argus II is an exciting breakthrough. Even though it will not restore someone's sight fully, the fact that a person who saw nothing at all may be able to make out doorway's, kerb edge's, step's, etc. after the treatment will essentially change their lives (not to mention reduce potential accidents/injury therefore saving the NHS money). I was also relieved to read that lots of thought is going into the rehabilitation post op. It is obvious to people that someone who has lost their sight needs some form of rehabilitation but it is equally important that this is received when re-gaining sight as it could potentially be as big a shock to someone's system.”
Sue Drew, from RP Fighting Blindness (UK) said the charity “welcomes any research that brings us closer to treatments for inherited retinal disease, and is always excited to hear about any developments in the field. We are following the progress of retinal implant technology carefully and look forward to future developments.”