CURRENT SOLUTIONS

[9]

Gabel and Sachs have stated that the problem regarding fixation of the electrode implant has been resolved.  A solution to the long term biocompatibility is also underway with new and improved biomaterials electrode implantations. Stimulation following implantation of epiretinally inserted electrode arrays in four dogs show that long term biocompatibility in these studies were verified by using visual evoked potentials or electroretinography.  [8]  The study showed that after 10 weeks, the patient implanted with an retinal electrode 4 x 4 array was able to see phosphenes and simple shapes.  The future of retinal electrode implantations will include increasing the electrode array.  The electrodes will have to be small enough but be able to function collectively.  If one cell is stimulated, that will result in a cascade of cells neighboring the target cell to also be stimulated.  The future research will have to solve this problem, there is yet to have sufficient studies with an array bigger than a 4 x 4.  The visual system is a complex system that uses several feedback/feed forward mechanisms to excite and inhibit cells and in the future we need to come up with the technology that will mimic this in vivo.  Visual prosthetics could possibly aid people who were born blind by placing an electrode in the visual cortex and directly stimulating the brain.  Since the visual pathway is not established for these individuals one could target the area of interest directly.  Research is also being conducted in this field of visual prosthetics.