During fluorescein staining, which statement is true about staining of the cornea?

• A. The cornea is healthy
• B. There is damage to the cornea
• C. There is no staining
• D. There is excessive staining

Answer: (B)

Fluorescein staining tests corneal epithelial integrity. The dye only highlights areas where the surface epithelium is breached, so a healthy, intact cornea will not show staining. When there is damage, such as an abrasion or ulcer, the dye penetrates the exposed stroma and appears bright green under cobalt blue light, outlining the defect. Therefore, the statement that there is damage to the cornea is true. Staining is not seen in a fully healthy cornea, and labeling it as “excessive” isn’t a separate, standard description—the amount of staining reflects the extent of epithelial loss.