Specular microscopy is a noninvasive, photographic technique that allows for the analysis and visualization of the corneal endothelium. The corneal endothelium is a single layer of cells on the inner surface of the cornea. This layer of cells faces the chamber formed between the cornea and the iris, the colored part of your eye. This layer of cells is highly specialized, and controls the fluid around the cornea to keep it in a slightly dehydrated state that is required for it to be transparent.