A pixel cell circuit comprises an electrode, one or more main photosensitive elements electrically coupled to the electrode for outputting a stimulation signal to the electrode responsive to light illumination, and a shunt arrangement comprising a shunt switch electrically coupled in parallel across the one or more photosensitive elements, and a control arrangement operatively coupled to the shunt switch and configured for placing the shunt switch in an open state responsive to incident light received at the pixel cell and placing the shunt switch in a closed state if no incident light is received at the pixel cell.