Pathogenesis of experimentally produced corneal ulcers in rabbits.

Intracorneal injection of Staphylococcus aureus and Aspergillus fumigatus, both separately and together, produced corneal ulcer in rabbits without pretreatment of the eyes with steroids or antibiotics. Staphylococcus alone produced self-limiting ulcers. Aspergillus alone produced severe deep ulcers ending in perforations. Bacterial infection followed by introduction of fungus produced less severe ulcers than did fungus alone. Established fungal infection followed by super-imposed bacterial infection was the most severe of all. The organisms were demonstrable both in direct smear and by culture. Histopathology showed cellular infiltration by polymorphs and lymphocytes with the organisms in the corneal tissue. The pH of the eyes during the active ulcerative period remained acidic.