To date, chip-based retinal implants have only permitted a rudimentary restoration of vision. However, modifying the electrical signals emitted by the implants could change that. This is the conclusion of the initial published findings of a project sponsored by the Austrian Science Fund FWF, which showed that two specific retinal cell types respond differently to certain electrical signals – an effect that could improve the perception of light-dark contrasts.
“Making the blind really see – that will take some time”, says Frank Rattay of the Institute of Analysis and Scientific Computing at the Vienna University of Technology – TU Wien. “But in the case of certain diseases of the eyes, it is already possible to restore vision, albeit still highly impaired, by means of retinal implants.”
To achieve this, microchips implanted in the eye convert light signals into electrical pulses, which then stimulate the cells of the retina. One major problem with this approach is that the various types of cells that respond differently to light stimuli in a healthy eye are all stimulated to the same degree. This greatly reduces the perception of contrast. “But it might be possible”, Rattay says, “to stimulate one cell type more than the other by means of special electrical pulses, thus enhancing the perception of contrast.” Within the framework of an FWF project, he and his team have discovered some promising approaches. Together with colleagues Shelley Fried of Harvard Medical School and Eberhard Zrenner of University Hospital Tübingen, he is now corroborating the simulated results with experimental findings.
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