Abstract
Purpose :
Stimulation via temporally interfering (TI) electric fields is attracting attention as a means of activating neural tissues distant from the stimulation electrodes. This stimulation strategy can be advantageous to suprachroidal retinal prosthesis in which stimulation electrodes are relatively distant from the target neurons of retina. The purpose of this study is to establish methods of direct measurements and visualization of the electric field generated when retina is stimulated using TI.
Methods :
A phantom eye was constructed from a custom-made dish (dia.=24 mm). We placed 25 silver electrodes (dia.=0.5 mm) along the inside wall of the annular chamber at 6 mm from the bottom (Fig. 1). Sinusoidal waves of 1.4 mA amplitude were applied to the two selected electrodes. The frequencies of sinusoidal waves were 2 kHz for the first electrode and 2.05 kHz for the second, respectively. The electric field was recorded using two pairs of PTFE insulated platinum-iridium wires (dia.= 0.05mm), each pair making a 0.35 mm- spaced dipole electrode and aligned orthogonally to each other at the tip. These recording electrodes were connected to an oscilloscope via differential probe.
Results :
The interference of two sinusoidal electric fields was successfully observed as shown in Fig.2. Phases of envelopes were 180 degrees different between X component and Y component, which was consistent with the theoretical prediction.
Conclusions :
We successfully visualized the envelope waveform generated by TI. Our future work will include a qualitative and quantitative comparison of results from measurements and numerical calculation.
This is a 2021 ARVO Annual Meeting abstract.