Abstract: A reflected light barrier is provided which includes a light source and a transmitting lens located for transmitting light from the light source along a beam path having a transmitting axis. A retroreflector is positioned for receiving the light transmitted by the transmitting lens and retroreflects the transmitted light. A light detector is disposed on the same side of the retroreflector as the light source. A receiving lens having a receiving optical axis is disposed in front of the light receiver for collecting a portion of the retroreflected light and focusing the portion of retroreflected light onto the light detector. The transmitting lens and the receiving lens are arranged next to one another. An optical device is disposed along the beam path between the transmitting lens and the receiving lens for transmitting and redirecting the transmitted and retroreflected light so that an increased portion of retroreflected light is oriented onto the receiving optical axis of the receiving lens.