HSV Lesions: Epithelial and Stromal Fluid Diffusion

Fig. 1.11  a–b Small HSV lesions (arrows) close to each other. Fluorescein sodium has disappeared from the tear film. Fluorescein diffusion into the epithelium appears as bright green halos surrounding disrupted, or eroded, areas. In addition, the whole area between them is stained green. Whether such diffusion occurs within the epithelium only or also concerns the subepithelial tissues cannot be judged in a two-dimen- sional photograph; however, it can be detected in optical section of the cornea (cf. Fig. 1.12)

light beam

tear lm

epithelium

stroma

endothelium

Left: Tear film overlying the corneal epithelium is stained green with fluorescein sodium

Right: Fluorescein sodium has penetrated through surface disruptions into the epithelium and the underlying stroma; the dye has disappeared from the tear film

Fig. 1.12  a–b (a) Two small HSV lesions (arrows) close to each other. (b) Optical section through the corneal epithelium and stroma in the area of the upper lesion shown in (a,arrow).By diffusion of fluorescein sodium, the epithelium and the stroma stain green