Marc Patrick H. Zapf

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OBJECTIVE The prospective efficacy of a future peripheral retinal prosthesis complementing residual vision to raise mobility performance in non-end stage retinitis pigmentosa (RP) was evaluated using simulated prosthetic vision (SPV). APPROACH Normally sighted volunteers were fitted with a wide-angle head-mounted display and carried out mobility tasks in(More)
The feasibility of implants for prosthetic vision has been demonstrated by research and commercial organizations. In most devices, an essential forerunner to the internal stimulation circuit is an external electronics solution for capturing, processing and relaying image information as well as extracting useful features from the scene surrounding the(More)
Retinitis pigmentosa (RP) causes visual field (VF) constriction due to progressive loss of photoreceptors, typically from the retinal periphery to the fovea. Retinal prostheses offer vision restoration via electrode implantation and stimulation near the fovea, thereby eliciting articifial percepts, so-called phosphenes in the center VF. Although foveal(More)
Simulated prosthetic vision (SPV) in normally sighted subjects is an established way of investigating the prospective efficacy of visual prosthesis designs in visually guided tasks such as mobility. To perform meaningful SPV mobility studies in computer-based environments, a credible representation of both the virtual scene to navigate and the experienced(More)
M P Zapf, T PK Breckel, I Mutschler, A Aertsen, A Schulze-Bonhage, J Hennig, O Speck, T Ball Epilepsy Center, University Hospital, Freiburg, Germany/Bernstein Center for Computational Neuroscience, Albert Ludwig University, Freiburg, Germany/Neurobiology and Biophysics, Faculty of Biology, Albert Ludwig University, Freiburg, Germany/Department of(More)
Retinal implants have proven their ability to restore visual sensation to people with degenerative retinopathy, characterized by photoreceptor cell death and the retina's inability to sense light. Retinal bionics operate by electrically stimulating the surviving neurons in the retina, thus triggering the transfer of visual sensory information to the brain.(More)
OBJECTIVE The prospective efficacy of peripheral retinal prostheses for guiding orientation and mobility in the absence of residual vision, as compared to an implant for the central visual field (VF), was evaluated using simulated prosthetic vision (SPV). APPROACH Sighted volunteers wearing a head-mounted display performed an obstacle circumvention task(More)
1 Epilepsy Center, University Hospital Freiburg, Germany 2 Bernstein Center for Computational Neuroscience, University of Freiburg, Germany 3 Neurobiology and Biophysics, Faculty of Biology, University of Freiburg, Germany 4 Department of Psychiatry, University of Basel, Switzerland 5 Medical Physics, Dept. Diagnostic Radiology, University of Freiburg,(More)
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