There are a number of endothelial corneal dystrophies to which Fuchs name has been attached, including two that are early in onset, or even congenital (CHED1; 121700), (CHED2; 217700) and at least three that have an adult onset, one (Fuchs endothelial dystrophy, early onset; 136800) which has a relatively early onset and two considered to have a late onset: the one described here and another known as Fuchs Endothelial Dystropy, Late Onset 2 (613267). Evidence for multiple distinct types comes from genotyping which reveals considerable genetic heterogeneity in spite of similar phenotypes (see Genetics). All are progressive and degenerative with various degrees of visual disability. Most have histologic changes in both the endothelial cells and Descemet membrane.
The entity described here likely is the classical disease described in the older literature. It is certainly the most common, occurring in 4% of the population over the age of 40 years and for unknown reasons is more often found in females. Guttae are formed as excrescences of Descemet's membrane and develop initially in the central cornea, beginning about the 5th decade, gradually increasing in number and size toward the periphery. They tend to be relatively large, sharply peaked and often positioned at the cell-cell junctions of endothelial cells. These are often best visualized by corneal transillumination. Histologically, the posterior portion of Descemet membrane contains bundles and sheets of abnormal collagen. Progressive corneal edema follows as endothelial cells are lost and the remaining ones are unable to maintain normal stromal hydration. Fingerprint lines may be present. The corneal edema may involve both stroma and epithelium and in advanced stages may lead to painful epithelial erosions. The disease is relentless and early blurring of vision progresses to significant visual handicaps often requiring corneal transplantation in the 7th and 8th decades.
Corneal guttae are common in older individuals but usually are located more peripherally. The diagnosis of Fuchs can best be made where the guttae are concentrated centrally and associated with stromal and epithelial edema.