Visual prosthesis

1. A visual prosthesis apparatus comprising:

a camera for capturing a video image;

a video processing unit associated with the camera, the video processing unit configured to convert the video image to stimulation patterns, the video processing unit is configured to stop transmitting the stimulation patterns to the retinal stimulation system when the retinal stimulation system does not transmit valid back telemetry data; and

a retinal stimulation system configured to stop stimulating neural tissue in a subject's eye, and return an error signal to the video processing unit, based on the stimulation patterns when an error is detected in a forward telemetry received from the video processing unit.

2. The visual prosthesis apparatus of claim 1 , wherein the retinal stimulation system is configured to notify the video processing unit of the error.

3. The visual prosthesis apparatus of claim 2 , wherein the video processing unit is configured to stop transmitting the forward telemetry to the retinal stimulation system for stimulating neural tissue in the subject's eye until the error is resolved.

4. The visual prosthesis apparatus of claim 2 , wherein the video processing unit is configured to limit power transmitted to the retinal stimulation system.

5. The visual prosthesis apparatus of claim 1 , wherein the forward telemetry comprises the stimulation patterns.

6. A method for limiting power consumption in a visual prosthesis apparatus comprising a retinal stimulation system and a video processing unit, the method comprising:

determining if the retinal stimulation system is transmitting valid back telemetry data to the video processing unit by sending data without stimulation signals; and

transmitting power and data to the retinal stimulation system only as long as the retinal stimulation system transmits the valid back telemetry data.

7. A method of claim 6 , further comprising:

periodically transmitting power to the retinal stimulation system until the retinal stimulation system transmits the back telemetry.

8. A visual prosthesis apparatus comprising:

a camera for capturing a video image; and

a video processing unit associated with the camera and associated with a retinal stimulation system, wherein the video processing unit is configured to convert the video image to stimulation patterns and transmit the stimulation patterns to the retinal stimulation system for stimulation of neural tissue in a subject's eye, and the video processing unit is configured to stop transmitting the stimulation patterns to the retinal stimulation system when the retinal stimulation system detects an error in a forward telemetry received from the video processing unit, and does not transmit valid, non-error, back telemetry data.

9. The visual prosthesis apparatus of claim 8 , wherein the retinal stimulation system is configured to notify the video processing unit of the error.

10. The visual prosthesis apparatus of claim 9 , wherein the retinal stimulation system is configured to stop stimulating neural tissue in the subject's eye until the error is resolved.

11. The visual prosthesis apparatus of claim 9 , wherein the video processing unit is configured to limit power transmitted to the retinal stimulation system.

12. A method for limiting power consumption in a visual prosthesis apparatus comprising a retinal stimulation system and a video processing unit, the method comprising:

a) transmitting power and data via forward telemetry to the retinal stimulation system;

b) determining if the retinal stimulation system is transmitting an error signal in the back telemetry to the video processing unit;

c) stop transmitting the power and the data via forward telemetry to the retinal stimulation system when the retinal stimulation system does not transmit valid, non-error, back telemetry data;

d) transmitting the power to the retinal stimulation system for a predetermined amount of time;

e) determining if the retinal stimulation system is transmitting an error signal in the back telemetry during the predetermined amount of time;

f) stop transmitting power to the retinal stimulation system when the retinal stimulation system transmits an error signal in the back telemetry during the predetermined amount of time; and

g) repeating features d) through f) until the retinal stimulation system transmits the back telemetry without an error signal.