Design, Development and in-vitro Testing of a Bi-Directional Retinal Stimulator System – BiMEA

Abstract

Purpose : Retinal stimulation in patients with degenerative retinal diseases has been gaining attention over the last decades. However, up to now a meaningful restoration of sight is not sufficiently achieved. Different approaches have been investigated, yet simultaneous recording and eliciting visual potentials with a single device has not been in the realm of possibilities. Our group designed, developed, and tested a bidirectional retinal stimulator (BiMEA) system with penetrating electrodes, which can both record retinal potentials and stimulate retinal ganglion cells. Here, we describe the establishment of an in-vitro setup to analyze the stimulation and recording properties of the BiMEA system.

Methods : The BiMEA system consists of two parts: a charge controlled stimulation unit connected with a recording amplifier, and a penetrating retinal electrode array to stimulating and to record. Our group tested the ability of the penetrating electrodes to record retinal activity in-vitro in different depth of rd10 mouse retinae using a commercially available recording and amplification system. The capability of the penetrating electrodes to stimulate isolated retinae was tested. Also, the stimulation/recording unit was tested for its capability of charge controlled stimulation and simultaneous recording of mouse retinae using a commercially available stimulator and recording device. Additionally, both the BiMEA stimulation/recording unit and the BiMEA penetrating electrodes were tested in-vitro with isolated rd10 mouse retina.

Results : During the in-vitro experiments we recorded spontaneous retinal activity in isolated mouse retinae using the BiMEA penetrating electrodes. Different patterns of retinal activity were recorded corresponding to various depths of retinal intrusion by the electrodes. The BiMEA stimulating unit was able to apply charge controlled stimulation in a saline solution and in retinae with a epiretinal electrode array. Also, retinal activity was recorded using the BiMEA.

Conclusions : Using the BiMEA system, we were able to show the principle of bidirectional retinal stimulation. The newly developed bidirectional stimulator was able to both stimulate retinal ganglion cells and record spontaneous activity in isolated mouse retina. Being able to modulate stimulation patterns according to the recorded changes in retinal activity can be a great benefit for efficient retinal stimulation.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.