gms | German Medical Science

Artificial Vision 2017

The International Symposium on Visual Prosthetics

01.12. - 02.12.2017, Aachen

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The very large array retinal stimulator: a final update

Meeting Abstract

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  • Tibor Karl Lohmann - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany
  • F. Haiss - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany
  • C. Barz - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany; Institute for Neuroscience and Medicine INM-2, Research Centre Jülich, Germany
  • C. Werner - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany
  • A.M. van der Meer - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany
  • K. Schaffrath - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany
  • A.C. Schnitzler - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany
  • G. Rößler - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany
  • F. Waschkowski - Institute for Materials in Electrical Engineering I, RWTH Aachen University, Aachen, Germany
  • W. Mokwa - Institute for Materials in Electrical Engineering I, RWTH Aachen University, Aachen, Germany
  • P. Walter - Department of Ophthalmology, University Hospital RWTH Aachen, Aachen, Germany

Artificial Vision 2017. Aachen, 01.-02.12.2017. Düsseldorf: German Medical Science GMS Publishing House; 2017. Doc17artvis17

doi: 10.3205/17artvis17, urn:nbn:de:0183-17artvis177

Published: November 30, 2017

© 2017 Lohmann et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

Text

Objective: Degenerative retinal diseases, i.e. Retinitis pigmentosa, lead to a severe decline of visual function. Over the last decades crucial progress in artificial vision conquering imminent vision loss has been achieved. We developed a large array epiretinal stimulator and tested its biocompatibility, surgical feasibility and functionality. The goal of the study is to show the system’s capability of recovering central vision as well as a meaningful visual field in a safe and feasible way.

Materials & Methods: The Very Large Array Retinal Stimulator (VLARS) measures 12mm in diameter and mounts 250 individual Iridium-sputtered gold electrodes. The electrodes have a diameter of 100µm and vary in density. Firstly, the surgical approach was tested in cadaverous pig eyes before implantations in 10 rabbits were performed. The rabbits were examined at various points of time clinically and via fundus photography, ultrasound and OCT-imaging. After enucleation, histopathological staining was performed. Secondly, the array’s ability to elicit cortical responses in rabbits’ V1 visual cortex was tested in an acute setting.

Results: The implantation in cadaverous porcine eyes established a suitable method for semi-chronical implantations in rabbits. During the surgery in rabbits, retinal detachment was observed in three cases. Intravitreal bleeding also occurred in three cases. In post-surgical examinations foremost corneal edema, slight hyphema and insufficient adhesion to the retinal pole were adverse events. In the acute stimulation experiment the array’s capability of eliciting cortical responses corresponding to distant areas of the retina was shown.

Discussion: Overall the implantation surgery is feasible and safe. The acute stimulation proved the possibility of recovering a meaningful visual field due to the size of the stimulator. A task for future studies will be a better, less traumatic attachment to the retinal surface to further enhance the stimulating capabilities.