Method for preferential outer retinal stimulation
First Claim
1. A method of focused phosphene generation in retinal tissue through deeper intermediate retinal cellular electrical stimulation to the exclusion of direct ganglion cellular electrical stimulation comprising the steps of:
- positioning at least one stimulating electrode in the vicinity of retinal tissue; and
applying a long duration stimulation signal to the at least one electrode such that deeper intermediate retinal cells are preferentially stimulated over the retinal ganglion cells and proximal overlying surface axons.
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Accused Products
Abstract
A method of focused phosphene generation through deeper intermediate retinal cellular electrical stimulation to the exclusion of direct ganglion cellular electrical stimulation comprises the steps of: a) positioning a stimulating electrode in the vicinity of retinal tissue; and b) applying a long duration stimulation signal to the electrode such that deeper intermediate retinal cells are preferentially stimulated over the retinal ganglion cells and proximal overlying surface axons. The long duration stimulation signal is preferably a biphasic signal having a negative and a positive phase pulse which is applied in cathodic fashion. To preferentially stimulate the deeper intermediate retinal elements the duration of the long duration stimulation signal is greater than 0.5 millisecond per phase pulse, and preferably equal to or longer than 2 millisecond per phase pulse. The biphasic signal is preferably adjusted to simulate a monophasic signal by adjusting the magnitude of the negative pulse in relation to positive pulse, and by adjusting the duration of the positive pulse in relation to the negative pulse to maintain approximately net zero charge introduction. Preferably, the ratio of the negative pulse to the positive pulse is approximately 10:1 or greater.
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Citations
20 Claims
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1. A method of focused phosphene generation in retinal tissue through deeper intermediate retinal cellular electrical stimulation to the exclusion of direct ganglion cellular electrical stimulation comprising the steps of:
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positioning at least one stimulating electrode in the vicinity of retinal tissue; and applying a long duration stimulation signal to the at least one electrode such that deeper intermediate retinal cells are preferentially stimulated over the retinal ganglion cells and proximal overlying surface axons. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of preferentially stimulating intermediate retinal elements comprising the steps of:
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positioning a stimulating electrode in proximity to retinal tissue; and applying a biphasic stimulation signal having a duration greater than about 0.5 milliseconds to the electrode. - View Dependent Claims (18, 19)
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20. A method of producing focused phosphenes in retinal tissue comprising the steps of:
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positioning a stimulating electrode in proximity to retinal tissue; and generating a biphasic stimulation signal having a negative and a positive pulse and including an intra-pulse delay therebetween, each of said pulses having a duration greater than or equal to about 2 milliseconds and a magnitude, said biphasic stimulation signal having a relationship between said magnitude and said duration of said negative and said positive pulses such that the total charge supplied is approximately zero; and applying said biphasic stimulation signal to the electrode in a cathodic fashion.
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Specification