an optical noninvasive pressure sensing assembly capable of accurately indicating relatively minute pressure changes . the present invention generally includes a light source , such as a light emitting diode or normal room illumination , positioned to reflected light off of a surface of a membrane . the membrane is in contact with the fluid in which the pressure is to be measured so that changes in the pressure in the fluid cause movement of the membrane . a charge coupling device camera captures light reflected off of the membrane and the reflected light is analyzed to determine the relative movement of the membrane based on the change in the pattern of the reflected light .