Abstract: An apparatus for changing the direction of light incident on a surgical loupes, the loupes having two optical barrels each optical barrel having an optical assembly with an optical axis. The apparatus includes at least one optical member for redirecting light incident onto said optical assemblies from a desired direction at an angle to the optical axis of said optical assemblies; an attachment member to secure said at least one optical member to the barrels; and an alignment member for calibrating the orientation of the at least one optical member relative to the optical assemblies of the barrels so that the at least one optical member is oriented to redirect the light from said desired direction generally along the optical axes of said optical assemblies of the barrels.

Abstract: An optical system which may be a component of apparatus for assaying a fluid sample with radiation is capable of exciting fluorescence in fluorescent material and includes a totally internally reflecting, unitary elongated substrate transmissive to both the excitation radiation and to the fluorescence. The fluorescent material includes at least a moiety of an antibody-antigen complex that includes a tag that will provide the fluorescence when excited by an evanescent wave generated by the excitation radiation. The substrate includes an elongated fiber and an integral lens formed to guide the optical radiation into the fiber within the bounds of a critical angle to assure total internal reflectance. A hollow elongated enclosure is disposed concentrically about and spaced from the fiber so as to provide an interspace of capillary dimensions.