for example the light pipe 4 may be of the type generally described in u s patent application ser no 261 688 now u s pat no 4 422 719 filed on may 7 1981 by donald e orcutt the disclosure of which is embraced herein by reference for the application disclosed optimum illumination has been found to be available from a polycarbonate thermoset fiber optic strand which is enclosed in a 0 01 inch thick casing of tetrafluoroethylene having an outer diameter of 1 8 inch the light entering light pipe 4 at the light source is dispersed all along its path the balance being conducted to the tip the rate of dispersion can be controlled during the manufacturing process for the present application it has been found that optimum illumination is available by lateral dispersion from the light pipe 4 to provide adequate work light for the surgical nurses assistants and anaesthesiologists by extending the cord to surround the instrument stand or using a separate light pipe connected to the source for that purpose by using low level of light during surgery the surgeon and his assistants can easily locate the instruments in the tray and can continue to work in the microscope.