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The Warsaw Voice » Special Sections » August 1, 2014
AGH University of Science and Technology
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Building an Electronic Eye
August 1, 2014   
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Researchers from the AGH University of Science and Technology have contributed to a groundbreaking project in the United States aiming to develop an electronic retina implant that could restore sight to blind people in the coming decade.

The project offers hope to those whose retinas have been damaged beyond repair by diseases such as age-related macular degeneration.

The project’s centrepiece is an array of 512 microelectrodes that is being tested in computer-simulated environments and on live retinas extracted from the eyes of rats.

A major role in the project has been played by Polish researchers, especially Professor Władysław D±browski, an electronics engineer from the Faculty of Physics and Applied Computer Science at the AGH University of Science and Technology in Krakow. While visiting the European Organization for Nuclear Research (CERN) in Geneva, Professor D±browski met Professor Alan Litke, a physicist from the University of California, and the two decided to work together at CERN. Their meeting became important to the eye implant project when Litke encouraged Professor D±browski, who worked on laboratory equipment for experiments at CERN, to take part in human retina research conducted at the University of California. The researchers were later joined by Eduardo J. Chichilnisky from Stanford University along with a team of neurophysiologists.

The Polish contribution to the American project is a pair of innovative electronic devices designed and built by researchers from the AGH University of Science and Technology. One is a microchip for electric stimulation of living neural networks and the other one is a microelectrode array with 512 electrodes. These complicated tools allow for highly accurate registration of signals triggered by the researchers and they can also send back electric impulses. In a nutshell, the devices do what cells in a healthy retina do.

Paweł Hottowy, Ph.D., from the AGH UST Faculty of Physics and Applied Computer Science and a member of the project team, explains that by learning as much as possible about retina cells, the researchers will be able to get a better insight into degenerative diseases of the retina. Hottowy adds that “it will be possible to apply an electric current to the implant so it stimulates retina cells in an orderly rather than erratic fashion.”

The retina essentially consists of two cell layers. One of them contains cells that capture light, while the cells in the other layer process the light into electric impulses that carry information to the brain over the optic nerves. The brain then decrypts the information to produce images. It might seem the trick is to just place a tiny camera in one of the layers and implant electrodes in the other layer to stimulate its cells. This approach does not really work, however, as shown by patients with a prosthetic retina comprising a camera with 60 electrodes. Instead of a sharp picture, all their eyes can see is a bright spot moving over a black backdrop. Hottowy says that such implants contain too few electrodes.

What the Polish and American researchers take into account is that each cell in a healthy retina has a different task assigned to it, such as informing the brain that “it’s bright” or “it’s dark.” In other words, before an intelligent implant can be developed, researchers need to know with the utmost precision which cell in a damaged retina needs to be stimulated and when and how this should to be done. The point is to find out how to control electric impulses so as to prevent cells from sending out information all at the same time. Otherwise, incoherent signals like those would cause chaos, making it impossible for the brain to decrypt the correct image.

Since different retina cells specialize in different tasks, the experimental array consists of 512 microelectrodes, instead of just 60 as in a rival implant that is already available commercially. The researchers control the microelectrodes, analyze every move the electrodes capture and every signal they generate. The challenge now is to build an implant capable of stimulating retina cells in a way that mimics what happens in a healthy retina, regardless of how far apart the cells are located.

Teresa Bętkowska
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