Retinal Cell Excitation Modeling



As the electrode density of implantable retinal prosthesis increases, simulation becomes a valuable tool to characterize excitation performance, evaluate implant electrical safety, determine optimal geometry and placement of implant current return, and understand charge distribution due to stimulation. To gain an insight into the effectiveness of a retina stimulator, quasi-static numerical electromagnetic methods can help estimate current densities, potentials, and their gradients in retinal layers and neural cells. Detailed discrete three-dimensional models of the retina, implant and surrounding tissue can be developed to account for the anatomical complexity of the human eye and appropriate dielectric properties. This chapter will cover the basics of quasi-static methods that can be used for this purpose. Specifically, authors will focus on the admittance method, the output it produces, and possibilities it offers to determine the potential effectiveness of a retinal stimulator, ranging from evaluating the current density magnitude in the ganglion cell layer, to calculating local activation function in the areas targeted by the electrical stimulation.


Electrode Array Ganglion Cell Layer Action Potential Propagation Branch Current Anodic Stimulation 



Ganglion cell layer


Nerve fiber layer


Specific absorption rate


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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Department of Electrical and Computer EngineeringUniversity of UtahSalt Lake CityUSA

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