A wiper assembly for a vehicle having at least one vision block within an outer face, generally consisting of a guide cylinder supportable on the vehicle, disposed adjacent and substantially parallel to the face of the vision block; a piston disposed in the guide cylinder and displaceable along the length thereof, provided with a magnetic element; a follower mounted on the guide cylinder, displaceable along the length thereof, provided with a magnetic element magnetically coupled to the magnetic element of the piston for displacement therewith; a wiper carried by the follower, having a portion engaging the outer face of the vision block in wiping relation therewith; and means operatively connectable to a source of fluid under pressure for alternately supplying fluid under pressure to opposite ends of the guide cylinder for reciprocating the piston and correspondingly the wiper along the outer face of the vision block.