• This experimental study conducted in cats found that electrochemically-treated porous platinum electrodes are effective at stimulating localized retinal areas when implanted in a scleral pocket.

    These results could have implications for the development of a retinal prosthesis and should be useful for creating the optimal scleral pocket.

    The investigators studied seven eyes of seven cats. They focally stimulated small retinal areas with electrochemically-treated bulk electrodes (φ = 500 µm) placed in a scleral pocket.

    They used retinal functional imaging to determine whether the retina was activated, as well as to determine the effect of suprachoroidal-transretinal stimulation array placement in the scleral pocket on the activation threshold.

    They found that the threshold current decreased with each of the following: a reduction in the residual scleral thickness, an increase in retinal elevation, and an increase in electrode impedance.

    They concluded that the minimum current necessary to stimulate the retina was influenced by residual scleral thickness and the firmness of contact between electrodes and adjacent sclera.