A novel finite element method based retinal stimulation strategy to decrease stimulation threshold and electrode crosstalk

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JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, vol.32, no.2, pp.563-573, 2017 (SCI-Expanded) identifier identifier


Degenerative eye diseases damage outer layer of the retina and cause to lost the vision. Visual prostheses are the systems which enable to elicit visual perception through electrical stimulation of the regions that remain intact using electrode arrays at these regions bypassing damaged parts. Spatial resolution of the visual prostheses is far away from the desired value. The main problem is that the number of electrodes couldn't be increased because of electrode interaction. In this study, Central-Weighted Time Shifted Stimulation Strategy which is developed using Finite Element Method is presented which aims both to increase spatial resolution and to decrease power dissipation needed for stimulation and temperature rise on the tissue. This strategy uses semi-cone shaped electrode design and configuration, stimulation approach which is time shifted, weighted depending on the position. Results are compared to the results with conventional electrode layout and stimulation. It is seen that proposed strategy provides discriminable electric field and current density distributions. While stimulation current threshold is 10 mu A for conventional method, it ranges 0.5-2 mu A for proposed strategy. Furthermore, power dissipation and temperature rise on the tissue are 4.19 mW/mm3 and 1.38 degrees C respectively for conventional method, they are 0.239 mW/mm3 and 0.4 degrees C for proposed strategy. It is concluded that proposed strategy makes a significant contribution to the studies on developing high resolution retinal implant systems in terms of resolution, power dissipation and limitation of temperature rise on the tissue.