penetrating keratoplasty may be an alternative surgical option. Other endothelial dystrophies (ie, congenital hereditary endothelial dystrophy and posterior polymorphous dystrophy) were discussed previously under Congenital Anomalies.

Figure 6-25 Fuchs dystrophy. A, Slit-beam illumination of cornea shows “beaten bronze” appearance of Descemet membrane. B, Corneal button from penetrating keratoplasty shows endothelial cell loss, with few surviving endothelial cells

(E). Numerous guttae are seen in Descemet membrane, either protruding into the anterior chamber (arrows) or buried within thickened Descemet membrane (arrowhead). The result of endothelial decompensation is diffuse stromal edema (note loss of interlamellar clefts) and bullous keratopathy (asterisk). C, Specimen from Descemet stripping endothelial keratoplasty (DSEK) shows few endothelial cells (E) and numerous guttae (arrows). (Part A reproduced from External Disease and Cornea: A

Multimedia Collection. San Francisco: American Academy of Ophthalmology; 2000. Parts B and C courtesy of George J. Harocopos, MD.)

Neoplasia

Primary conjunctival intraepithelial neoplasia may extend from the limbus and involve the corneal epithelium. This condition is described further in Chapter 5. In rare cases, intraepithelial squamous neoplasia may arise in the cornea.