Improvement of stimulation electrodes for retinal prosthesis through electrophysiological investigations with cultured retinal cells and isolated retina.

Aims of this grant

Develop smaller retinal electrodes to achieve greater visual acuity
Develop dipolal retinal electrodes capable of producing sharper images than monopole retina electrodes.

Principal Researcher on this research project

Background:

At present retina implant technology is in clinical trials with a 60 electrode model capable of allowing basic orientation. Additionally a 200 electrode model is in development also.

However finer resolution is obviously required. It is thought that at least 1,000 electrodes are required to allow facial recognition.

One of the problems with electrical stimulation of the retina, is that the electrodes need to be as small as possible to only stimulate a few nerve cells. The second problem is that nearby nerve cells can be stimulated as a side effect. Both of these problems lead to poor resolution.

This research is investigating the use of novel electrodes that have both negative and positive electrodes side by side (dipolar), to discover if this increases the resolution. At present most retina implants use monopolar stimulation.

Principal findings

The initial findings of this research are promising, and show that there is the potential to achieve finer resolution of nerve cell stimulation with dipole electrodes, and that this is superior to monopole electrodes.

Publications arising from this research

Niall MacCarthy, Marcella Burke, John Alderman "A Low Cost High Resolution Fabrication Process for Disposable MEAs" 6th International Meeting on Substrate-Integrated Micro Electrode Arrays, Reutlingen, Germany 2008 Page 321 [LINK]