Cibis recently published an account of a new technique of illumination for microscopy.1 Figure 1 illustrates some of the major differences between microscopy with transmitted and Cibis illumination. Note how details which are not visible with ordinary illumination suddenly appear, such as zones of discontinuity in the lens. There are also striking color changes in the cornea, iris pigment, and so forth. Subtle color differences appear, for instance between ciliary muscle and surrounding connective tissue. In the present work I have attempted to analyze this method in order to be better able to interpret what is seen, to plan further applications, and to be able perhaps to extend the technique.
The Production of Color
Color in an object is produced by seven basic mechanisms: Light striking an object
DREWS RC. An Analysis of the Illumination Technique of Cibis. AMA Arch Ophthalmol. 1958;59(4):579-583. doi:10.1001/archopht.1958.00940050135015