Visual Prosthesis for Phosphene Shape Control

• US 20090287276A1
• Filed: 05/14/2009
• Published: 11/19/2009
• Est. Priority Date: 05/14/2008
• Status: Active Grant

• Current Assignee: Cortigent Incorporated
• Original Assignee: Second Sight Medical Products, Inc.
• Inventors: Weiland, James D., Greenberg, Robert J., McMahon, Matthew J., Humayun, Mark S., Nanduri, Devyani
• Granted Patent: US 9,254,385 B2
• Time in Patent Office: Days
• US Class Current: 607/54
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/36046 of the eye

Abstract

The present invention is an improved method of stimulating visual neurons to create artificial vision. It has been found that varying current of visual stimulation can create varying percept brightness, varying percept size, and varying percept shape. By determining the attributes of predetermined current levels, and using those attributes to program a video processor, more accurate video preproduction can be obtained.

The present invention also includes an electrode array having alternating large and small electrodes in rows at a 45 degree angle to horizontal in the visual field.

Claims

1. A method of inducing the perception of an image comprising:

Providing a neural stimulator including at least one electrode suitable to stimulate visual neural tissue;

Providing a plurality of stimulation signals;

Determining a size of percept for each of said plurality of stimulation signals; and

Stimulating neural tissue based on a source image and one of said plurality of stimulation signals providing a preferred size of percept.

2. The method according to claim 1, where said plurality of stimulation signals vary in current.

3. The method according to claim 1, wherein said plurality of stimulation signals vary in total charge.

4. The method according to claim 1, wherein said preferred size of percept is a minimum percept.

5. The method according to claim 1, further comprising stimulating neural tissue based on said source image and a subset of said plurality of stimulation signals wherein the size of percept is invariant.

6. The method according to claim 1, wherein said preferred size of percept is determined by said image.

7. The method according to claim 6, wherein a smaller size percept is preferred in a detailed image portion and a larger size percept is preferred in a non-detailed image portion.

11. The method according to claim 8, further comprising providing an array of electrodes suitable to stimulate visual neural tissue, and performing the method of claim 5, independently for each electrode.

8. A method of inducing the perception of an image comprising:

Providing a neural stimulator including at least one electrode suitable to stimulate visual neural tissue;

Providing a plurality of stimulation signals;

Recording a percept shape for each of said plurality of stimulation signals; and

Stimulating neural tissue based on a source image and one of said plurality of stimulation signals based on said recorded percept shape for each of said plurality of percept signals.

9. The method according to claim 8, where said step of recording is recording precept shapes and stimulation signals in a look up table.

10. The method according to claim 9, further comprising comparing said percept shapes with said image and stimulating visual neural tissue with a stimulation signal associated with the precept shape that most closely corresponds to said image.

12. The method according to claim 8, further comprising stimulating neural tissue based on said source image and a subset of said plurality of stimulation signals wherein the shape of percept is invariant.

13. A visual prosthesis comprising:

a video processor converting a video image into neural stimulation patterns; and

an array of electrodes suitable to stimulate visual neurons in accordance with signals from said video processor;

wherein said electrodes vary in size in a non-linear pattern.

14. The visual prosthesis according to claim 13, wherein said non-linear pattern is alternating larger and smaller electrode.

15. The visual prosthesis according to claim 13, where said electrodes are formed in rows at an angle to horizontal in the visual field.

16. A visual prosthesis comprising:

a video processor converting a video image into neural stimulation patterns; and

an array of electrodes suitable to stimulate visual neurons in accordance with signals from said video processor;

wherein said electrodes are formed in rows at an angle to horizontal in the visual field.

17. The visual prosthesis according to claim 16, where said angle is 45 degrees.

18. The visual prosthesis according to claim 16, wherein said electrodes vary in size in a non-linear pattern.

19. A visual prosthesis comprising:

A video processor converting a video image into visual neural stimulation patterns including means for altering said stimulation parameters in response to perceived percept shapes; and

an array of electrodes suitable to stimulate visual neurons in accordance with signals from said video processor.

20. The visual prosthesis according to claim 19, further comprising a memory storing stimulation parameters and corresponding perceived image shapes.

21. The visual prosthesis according to claim 19, wherein said stimulation parameters include current.

22. The visual prosthesis according to claim 19, wherein said stimulation parameters include total charge.

23. A visual prosthesis comprising:

a video processor converting a video image into neural stimulation patterns; and

an array of electrodes suitable to stimulate visual neurons in accordance with signals from said video processor;

wherein said electrode array is suitable to be centered in at least two directions over the fovea of the retina in a topological plane parallel to the retina.