ABSTRACT
This paper describes a new method for determining corneal surface detail utilizing a modified Zeiss photo slit lamp. This system projects a grid onto the cornea through a cobalt blue filter. The tear film is stained with fluorescein, causing the projected grid pattern to be visible on the corneal surface. A video image of the grid is then digitized by an image processor which calculates surface detail by evaluating the distortion of the grid lines. Information on curvature and surface detail is obtained across the full corneal surface, both the central optical axis and peripherally beyond the limbus.
ABSTRACT
Although reactions of molecular crystals are much more widespread than has been generally appreciated (53), the great sensitivity of their rates to seemingly trivial changes in molecular structure clearly provides a major stumbling block to the general utilization of such processes. A key to understanding the effects of structural changes has been provided by the demonstration of anisotropy of such reactions discussed in this article. It is recognized, however, that many factors in addition to those aspects of the crystal structure utilized in the discussion above may play a part in determining reactivity of crystalline solids with gases. The recent ready availability of crystal structure data for molecular crystals should lead to a more rapid development of the principles governing the packing of such crystals and their reactivity. The resulting control of such reactions should not only provide the means of causing them when they are desired, as, for example, for synthesis, but also the means of preventing them when they are to be avoided, as in the stabilization of pharmaceuticals. Finally, it appears that we have only just begun to exploit the potential reaction specificity and the exciting possibilities resulting from the unique symmetry properties of the crystalline state.
