The effect of stimulation electrode array size on the temperature of the retinal tisssue in visual prostheses

Visual perception which is one of the most valuable perception for human beings may be lost due to various degenerative retinal diseases such as Age Related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP). These diseases cause severe damage across visual pathway and irreversible blindness. Recently, the progress in the fields of bioengineering, micro technology, neuroscience provides multi-disciplinary research opportunity about design and implementation of visual prosthesis. This becomes a promising strategy for restoration of visual perception. It is shown that visual percepts, called phosphene, are obtained via stimulation of remaining nerve cells in the literature. Temperature changes of retinal tissue and its surrounding because of electrical stimulation is one of the critical points that must be taken into consideration in design phase of a visual prosthesis. In this study, the effect of length of stimulation electrode array on temperature induced in retinal tissue is investigated with developed 2-D model, and simulation is solved using Finite Element Analysis. It is seen that as the length of the stimulation electrode array, which touches to retinal tissue, increases, the temperature has a lowering trend in the tissue. Additionally, it is observed that the temperature has the highest values near the stimulation electrode array and it has a decremental tendency away from there.