1. A visual prosthesis apparatus comprising: a camera for capturing a video image mounted on a pair of glasses, adapted to be worn on a user's body; a video processing unit adapted to be worn on a user's body, associated with the camera but separate from the camera, the video processing unit configured to convert the video image to stimulation patterns comprising a housing for enclosing the video processing unit, a speaker on the housing to provide audible alerts to indicate an error condition of the apparatus; an implantable retinal stimulation system configured to stimulate a retina in a blind subject's eye based on the stimulation patterns; a bidirectional telemetry system, including an external coil mounted on the pair of glasses, to send stimulation signals from the video processing unit to the implantable retinal stimulation system, and to send data from the retinal stimulation system to the video processing unit; and a connector on an outside surface of the housing unit configured to a blind user to detachably connect, disconnect, and reconnect the pair of glasses to and from the video processing unit, the connector configured to transmit the video image to the video processing unit and to transmit stimulation patterns from the video processing unit to the external coil; wherein the audible alerts are controlled by the video processing unit and indicate an operational condition of the video processing unit wherein different audible alerts indicate different operational conditions, including a failure condition in the retinal stimulation system that is received through the data.