Differentiation and assessment of corneal endothelial changes associated with diseases of the anterior segment of the eye.

Recent work has shown changes in the corneal endothelium accompanying corneal epithelial disease and anterior uveitis. It is important to differentiate these acute changes from other changes such as guttatae or corneal pigment deposition and to assess the magnitude of their effect upon the corneal endothelium. We have used specular microscopy to study changes in the corneal endothelium and Descemet's membrane and to study deposits on the back of the corneal endothelium and correlate them with changes in the endothelium by the use of conventional specular microscopy and by relief images which give a three dimensional view of the area concerned. This has particularly been applied to the conditions of superficial punctate keratopathy, keratoconjunctivitis sicca, corneal abrasions and exposure keratopathy, iritis and cyclitis, pseudoexfoliation of the lens capsule, anterior segment pigment dispersal syndrome, bullous keratopathy as well as corneal guttatae and pigment granules on the posterior cornea. Preendothelial lesions have been distinguished from endothelial and retrocorneal lesions by this technique aiding elucidation of the state of the endothelium. The changes which we noted occurred either at the level of Descemet's membrane (including formation of small rounded dark blebs less than one cell in diameter, larger blebs one to three cells in diameter, and guttatae, usually larger than the foregoing and sometimes very numerous), or at the level of the posterior endothelial surface (including small shiny nodular deposits, often numerous, due to pigment granules, and keratitic precipitates and inflammatory debris, the former usually large and the latter smaller, more irregular and sometimes very numerous). The differentiation and assessment of these various changes are discussed.