Retinal Prosthesis Dissertation - Student Home Pages

a voltage drop up to 6 V is expected across the retinal tissue.”. “The total power
consumption of the device is contributed from two sources, namely the power
consumption of the stimulus chip itself and the power dissipated into the load (retinal
tissue).”, “When added to the previous 3 mW associated with the stimulator circuits,
this accounts for intraocular power dissipation on the order of 5 mW.”, “This chip uses
a simple synchronous protocol and timing control.”
[53]
A Computational Model of Electrical
Stimulation of the Retinal Ganglion Cell
“Since the dendritic arbor of a single ganglion cell may spread up to 500 µm in diameter
and overlap the dendritic field of other ganglion cells, stimulation of dendrites might
lead to larger perceived spots than if the soma was preferentially stimulated.”, “Still
another possibility is that the soma is excited directly, which would yield a potential
resolution of around 10 m in humans.” [49]
Architecture Tradeoffs in High-Density
Microstimulators for Retinal Prosthesis
” In both methods, retinal neurons are electrically stimulated which bypasses the
damaged photoreceptors thereby creating visual excitation. The discussions in this paper
will refer to the epi-retinal approach.” … “Fig. 1 shows the block diagram of the epiretinal
prosthesis system. It comprises of two units – implant and external. While the
external unit is powered by battery, power for the implant unit is transmitted wirelessly
through a high efficiency power amplifier , rectified and regulated into DC voltages
required by the electronics .”, “ For 1024 stimulation sites (32 x 32 array), the number
of interconnect leads between the microstimulator and tissue are 1025 and 2048 for
configurations in Fig. 8(a) and (b) respectively.”, “For example, a 256-output