Prof. Dr. Dr. h.c. mult. Eberhart Zrenner
Organization: Werner Reichardt Centre for Integrative Neuroscience
Phone number: +49 (0)7071 29 84786 or 87311
Department: Centre for Ophthalmology, Institute for Ophthalmic Research
Position: Head of Research Group
Area: CIN Members
Scientific topic: Restoring Vision by Subretinal Neuroprostheses
Field of Research
Research on neuronal circuitry in degenerated retina allows to understand electric excitability of inner retina neurons by subretinal multielectrode arrays positioned in contact with bipolar cells. Electronic devices consisting of 1500 photodiodes, amplifiers and electrodes, positioned on 3 x 3 mm chips, have been developed, tested and implanted in the subretinal space of 11 blind patients. Proof of concept has been shown that this technique allows blind patients to read letters and to combine them to words, detect and describe unknown objects correctly (banana, fork, knife, cup) approach persons and differentiate at least seven shades of grey. The main questions presently are how to improve this technique for long term application, approach limits of spatial resolution, threshold excitation, damage thresholds, biocompatibility with tissue, biostability of devices, signal processing for improved contrast vision as well as influence of learning and role of saccades. Moreover biochemical hybrids that form chemical synapseshave been lined out and models for mechanisms of electrical excitation of retinal neurons by multielectrode arrays have been developed.
Multielectrode array studies in normal and degenerated explanted retinae on thresholds and spatial distribution in rats and mice; calcium imaging; modelling of characteristics of bipolar cell excitation in response to multilocal electrical stimulation; extension of technology from electrical stimulation to hybrids that additionally involve chemical stimulation by glutamate; clinical studies in blind RP-patiens with subretinal implants by means of psychophysics and noninvasive electrophysiology.
clinical neurosciences; computational neuroscience; degeneration / regeneration; neuro-prosthetics; visual perception; visual system
- Zrenner E. Artificial vision: Solar cells for the blind. Nature photonics 6: 344-345 (2012)
- Zrenner E. Bartz-Schmidt KU, Benav H, Besch D, Bruckmann A, Gabel V-P, Gekeler F, Greppmaier U, Harscher A, Kibbel S, Koch J, Kusnyerik A, Peters T, Stingl K, Sachs H, Stett A, Szurman P, Wilhelm B, Wilke R. Subretinal electronic chips allow blind patients to read letters and combine them to words. Proc. R. Soc B - Biol.Sci. 278, 1489-1497 (2011)
- Stingl K, Bartz-Schmidt KU, Besch D, Braun A, Bruckmann A, Gekeler F, Greppmaier U, Hipp S, Hörtdörfer G, Kernstock C, Koitschev A, Kusnyerik A, Sachs H, Schatz A, Stingl KT, Peters T, Wilhelm B, Zrenner E. 2013 Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS. Proc R Soc B - Biol Sci 280: 20130077. http://dx.doi.org/10.1098/rspb.2013.0077
- Zrenner E. Fighting Blindness with Microelectronics. Science Transl. Med. 5: 210ps16 (2013); DOI: 10.1126/scitranslmed.3007399 (http://www.sciencetranslationalmedicine.org/cgi/content/short/5/210/210ps16)