Figure 7: Light microscopy of semithin sections of the interaction of A. castellanii trophozoites with hamster cornea. The most representative time points are shown. (a) Control hamster cornea incubated with Bacto Casitone medium for 24 h. No evidence of damage was observed. (b) After 1 h of interaction numerous trophozoites (arrows) were observed penetrating the most superficial layers of hamster’s cornea. (c) After 8 h a trophozoite (T) migrated toward wings epithelial cells; part of the corneal epithelium remained, but the normal tissue structure had been lost. (d) At 16 h superficial and some middle (wings) cells of the corneal epithelium had been separated from the rest of the tissue. A trophozoite phagocyting an epithelial cell is shown (arrow). (e) After 24 h of interaction A. castellanii trophozoite had migrated toward the basal cells. (f) In other areas of interaction most of the epithelium had been lost. A trophozoite (T) reached the corneal stroma layer while another was seen phagocyting a detached cell (arrow). Bar = 10 μm.