A patient had transient traumatic posterior annular keratopathy characterized by the appearance of endothelial rings corresponding to epithelial and subepithelial foreign particles. The transient endothelial changes occur within several hours after the initial injury and disappear within several days.
Forstot SL, Gasset AR. Transient Traumatic Posterior Annular Keratopathy of Payrau. Arch Ophthalmol. 1974;92(6):527-528. doi:10.1001/archopht.1974.01010010541017