The proposed research project is a continuation of investigations leading to the development of miniature instruments for visualization, biopsy and surgery in the diagnosis and treatment of digestive diseases. The proposed designs employ special methods of fabrication of microlenses, large-aperture optical fibers for illumination, miniature imaging multifibers made of glass and plastics, and the development of efficient multicolor laser illuminators. Novel techniques in image transmission will be investigated which are smaller and/or simpler to fabricate than devices presently employed and which can be effectively utilized through the instrument channel of an endoscope. The design of specific instruments is conducted in close collaboration with medical researchers from the earliest concepts in order to appropriately direct the relevant developments in materials and components. The choice of instruments and the construction of their prototypes are diverse to assure the widest range of functional design, thus allowing for effective extensions into other designs. A close cooperation with industry has been established to provide for a speedy and effective transfer of the resulting design methods and to gain access to existing technology, thus eliminating duplication of effort. Results of work in the development of specific prototype instruments and their clinial applications are disseminated through publications in medical and engineering periodicals and through papers read in appropriate workshops and seminars. Patent protection is sought whenever appropriate to stimulate interest of commercial firms in the product development and marketing of new instruments. It is the intention that this research project serve engineering and clinical researchers in the development of optical instrumentation in medicine.