Argus II Retinal Prosthesis Approved in Europe
March 3, 2011 - The Argus II is an electronic device that may restore some degree of vision to people who have completely lost their sight as a result of retinal disease. It is made by the US-based company, Second Sight. Although the device is not yet available anywhere in North America, it was approved for sale in Europe earlier this week. Company spokespeople confirm that Canada is on a short list of countries where they hope to gain approval for the device.
The Argus II is intended for people who have completely lost their sight because of retinal degenerative disorders such as retinitis pigmentosa or macular degeneration. In these conditions, gradual loss of the light-sensing cells of the retina, called photoreceptors, limits sight. The Argus II may benefit people in the most advanced stages of these diseases, when vision is completely lost. The prosthesis does not restore normal vision, but it does allow wearers to see coarse visual patterns and shapes; with training, they learn to interpret these new sensations, and this can help them navigate through their daily lives.
The Argus II system works by converting video images captured from a miniature camera, housed in the patient’s glasses, into small electrical pulses that are transmitted wirelessly to electrodes in the retina. These electrodes bypass the damaged photoreceptors, stimulating the retinal cells that send electrical signals to the brain where they cause glowing and flashing sensations. Although these are quite different from normal visual sensations, with appropriate training patients learn to interpret them, thereby gaining some functional vision. Because the success of this system relies on the ability of the brain to receive and interpret these signals, it can only be used by people who once had vision.
The device has been tested in a three-year clinical trial including 30 people in Europe and the United States. Dr. Lyndon da Cruz of the Moorfields Eye Hospital in London, UK , says that “nearly all patients [in the trial] had a stable, safe and functioning system and that a majority of patients could recognize large letters, locate the position of objects and the best could read short words.” The company is already working on a more advanced device, with more electrodes, whch may allow users to “see” more detail. Other companies are also working on similar devices (see our recent story on the electronic chip being developed by Retina Implant AG).
Initially, four treatment centres will be established in Europe, where the electrodes of the Argus II will be surgically implanted and where people can learn to use the devices. These European centres are in Paris and Geneva, as well as London and Manchester. In addition to seeking approval for implantation of the device in patients in North America, the company is working to obtaining insurance coverage for the device and the surgical procedure to implant it. Currently this device costs an estimated $100,000 USD.
You can read more about the Argus II device on the Second Sight website.