Visibility of the ring of Schwalbe and the trabecular zone; an interpretation of the posterior corneal embryotoxon and the so-called congenital hyaline membranes on the posterior corneal surface.

About two years ago our attention was drawn to glassy ring-like structures at the periphery of the posterior surface of the cornea. It soon became evident that these bands corresponded to the so-called posterior embryotoxon of the cornea (Embryotoxon corneae posterius, Axenfeld 1 ), posterior marginal dysplasia of the cornea (Streiff 2 ), congenital hyaline membranes on the posterior surface of the cornea (Mann 3 ), or peripheral refractile postcorneal rim (Graves 4 ). Once our interest in this subject was awakened, we devoted a close study to the limbus of all patients whom we saw and performed a slit-lamp gonioscopic examination on those who presented to external slitlamp study an unusual appearance of the limbus or of the periphery of the cornea. These clinical investigations were followed by a careful study of 600 pathologic specimens of eyes, and this study, in turn, prompted us to extend our investigations to the chamber angle of