From the Idea to Its Realization: The Evolution of Minimally Invasive Techniques in Neurosurgery
Figure 11
Principle of a rigid endoscope. (a) Standard rigid endoscope with high air to glass ratio. (b) Rod lens Hopkins endoscope. The reverse relation of glass to air and better coating of the lenses improves the light transmission 80-fold in comparison to the standard endoscope.
