The objective of the current invention is to restore 
color vision, in whole or in part, by electrically stimulating undamaged 
retinal cells, which remain in patients with, lost or degraded 
visual function. The invention is a 
retinal color 
prosthesis. Functionally, There are three main parts to this invention. One is external to the eye. The second part is internal to the eye. The third part is means for communication between those two parts. The external part has subsystems. These include an external imaging means, an eye-tracker, a head-motion tracker, a data processor, a patient's controller, a physician's local controller, a physician's remote controller, and a 
telemetry means. The imaging means may include a CCD or 
CMOS video camera. It gathers an image of what the eyes would be seeing if they were functional.Color information is acquired by the imaging means. The 
color data is processed in the video 
data processing unit. The color information is encoded by time sequences of pulses separated by varying amounts of time, and also with the 
pulse duration being varied in time. The basis for the color encoding is the individual 
color code reference. Direct color stimulation is another operational basis for providing color 
perception. The electrodes stimulate the target cells so as to create a 
color image for the patient, corresponding to the original image as seen by the 
video camera, or other imaging means.The physician's test unit can be used to set up or evaluate and test the 
implant during or soon after implantation at the patient's bedside.