The first clinical instrument for observation of corneal endothelium by specular reflection was developed by Laing in 1975. The corneal specular microscope is a reflected-light microscope that projects light onto the cornea and images the light reflected from an optical interface of the corneal tissue, most typically the interface between the corneal endothelium and the aqueous humor.
The young normal corneal endothelium typically shows a quasi-regular array of hexagonal cells all having nearly the same size. With aging, trauma, and corneal disease, this regularity is lost. The goal of endothelial specular micrsocopy is to enable the status of the endothelium to be obtained by visual observation and morphometric analysis of the endothelial image. In general, the more the endothelial image varies from the normal appearance shown in the above figure, the more compromized the endothelium and the less able is the endothelium to provide its necessary functions that maintain corneal clarity.