Endoscopes

An endoscope can consist of
• a rigid or flexible tube
• a light delivery system to illuminate the organ or object under inspection. The light source is normally outside the body and the light is typically directed via an optical fiber system
• a lens system transmitting the image to the viewer from the objective lens to the viewer, typically a relay lens system in the case of rigid endoscopes or a bundle of fiber optics in the case of a fiberscope
• an eyepiece
• an additional channel to allow entry of medical instruments or manipulators
Before the fiber optics endoscope was invented, they used a semi-flexible tube with a tiny camera attached at the tip to detect stomach ulcers and stomach cancer in its early stage. The first fiber optics endoscope was invented in 1963/64. It paved the way for key-hole surgery. A “fibroscope” is actually a bundle of glass fibres that is able to channel light from one end to the other through total internal reflection.

However, the fiber optics endoscope was not the latest version of endoscope invented. The Rod-lens Endoscopes was one of the more advanced versions. This is because there were many difficulties while using the fiber optics endoscope and 50000 fibres give only a 50000pixel image, therefore, if any fiber breaks, that means that the image would decrease in pixels and quality. After continued flexingm more and more fibres would break and eventually, the whole bundle has to be replaced and it is very expensive. Therefore, the elegant solution that Hopkins produced (in the late 1960s) was to fill the air-spaces between the 'little lenses' with rods of glass. These fitted exactly the endoscope's tube - making them self-aligning and requiring of no other support and allowed the little lenses to be dispensed with altogether. The rod-lenses were much easier to handle and utilized the maximum possible diameter available. With the appropriate curvature and coatings to the rod ends and optimal choices of glass-types, all calculated and specified by Hopkins, the image quality was transformed - even with tubes of only 1mm. in diameter. With a high quality 'telescope' of such small diameter, the tools and illumination system could be comfortably housed within an outer tube. Once again, it was Karl Storz who produced the first of these new endoscopes as part of a long and productive partnership between the two men. Whilst there are regions of the body that will forever require flexible endoscopes (principally the gastrointestinal tract), the rigid rod-lens endoscopes have such exceptional performance that they are to this day the instrument of choice and in reality have been the enabling factor in modern key-hole surgery. (Harold Hopkins was recognized and honoured for his advancement of medical-optic by the medical community worldwide. It formed a major part of the citation when he was awarded the Rumford Medal by the Royal Society in 1984.)
Adapted from Wikipedia.