What does Rose Bengal primarily stain regarding herpes simplex dendrites?

Rose Bengal primarily stains the borders of herpes simplex dendrites due to its mechanism of action and selective affinity for certain cellular components. When applied to the eye, Rose Bengal binds to intracellular components of damaged corneal epithelial cells, which often occur at the edges of the dendritic lesions caused by herpes simplex virus. This selective staining highlights the inflammation and cellular disruption associated with viral keratitis, making the boundaries of the dendrites more visible.

The importance of this staining pattern is that it aids in the diagnosis of herpes simplex keratitis by providing a clearer visual of the affected areas, particularly the leading edges of the dendrites, where cell death and viral replication may be occurring. This understanding helps clinicians differentiate between herpes simplex keratitis and other types of corneal wounds or infections, guiding appropriate treatment.