Specular microscopy: from speculative to spectacular microscopy

The evolution of confocal microscopy for in vivo qualitative analysis of the cornea seems to follow a path similar to that followed by specular microscopy after its reintroduction almost 20 years ago. The purpose of this report is to present the evolution of our own research data, starting with speculation concerning the attribution of morphological features and finishing with cell-to-cell correlation with special techniques. We present representative clinical but mainly experimental data from relocation studies using flat preparation, especially developed sequential vital staining techniques, and scanning electron microscopy as compared with specular microscopy. Starting from speculative attribution of the observed morphological features, we were capable of classifying morphological data on the endothelium and the surrounding structures into preendothelial, endothelial, retroendothelial, and non-endothelial features. Specular microscopy allows the detailed study of cellular and even intracellular structures and is probably one of the most spectacular ways of doing noninvasive in vivo microscopy in humans.