A vehicle mirror assembly comprising a reflective element for reflecting incident light, the reflective element having a viewable side, a dimming element for varying the intensity of light reflected from the viewable side, a photo-electric power cell for powering the dimming element for varying the intensity of reflected light and a controller for controlling the dimming element in response to ambient light conditions, wherein, in use, the intensity of the light reflected from the viewable side is reduced in low ambient light conditions. In other embodiments a power source is defined, for providing interment power to power the dimming element for varying the intensity of light reflected, the power being supplied by the photo-electric power cell.