Changes in the rabbit cornea following vaccinia virus infection were followed both by slit-lamp and by histopathologic examination. The replica method of Wolf provided plastic images of events on the epithelial surface. Two silver staining methods revealed changes in intercellular substance, epithelial cells, keratocytes, nerve fascicles, inflammatory cells, and blood vessels. Lesions caused by vaccinia virus spread slowly and are limited to the most immediate vicinity of the inoculation area. Epithelial changes are first seen in superficial flat cells, which become rounded, and finally explode, leaving their cell membrane behind. Within the epithelial cells, typical intracytoplasmic inclusion bodies are seen. Changes in the keratocytes, stroma, and nerve fascicles are not marked. In all these characteristics, vaccinia virus infection of the rabbit cornea differs markedly from infection by herpes simplex virus.
Darrell RW, Vrabec F. Vaccinia Virus Infection of the Rabbit Cornea. Arch Ophthalmol. 1971;86(5):568-574. doi:10.1001/archopht.1971.01000010570016