The clinical, histochemical, light and electron microscopic evaluation of a case of lattice corneal dystrophy, appears clinically as an atypical granular dystrophy. There is structural and histochemical differentiation of the two dystrophies. Electron microscopy is often an invaluable aid in establishing a definitive diagnosis. The possible sources of the filamentous material found in lattice corneal dystrophy are discussed. It seems that not only keratocytes, but also corneal epithelial cells, occasionally may have the ability to elaborate the abnormal material that is considered to be amyloid in nature.