A pressure sensor includes at least one light conducting opening extending generally parallel to a pressure receiving face of a deformable body and a light emitting and a light receiving device at opposite ends of the light transmitting opening. A cross sectional area of the light transmitting opening, and correspondingly the light transmitting capability of the opening, vary in response to changing pressures applied to the pressure receiving face. This is determined by the light receiver. A measuring circuit for the light receiver is also provided
