Corneal staining is a useful differential diagnostic tool, but one that is sometimes misunderstood.
"When interpreting the results, clinicians must keep in mind that an intact epithelium can retain various dyes without there being any true abnormality."
"Despite its thinness, the cornea is a very complex structure. Using stains to evaluate the epithelium can provide a lot of insight about the cornea and the rest of the ocular surface because the cornea is contiguous at its margins with the conjunctiva," Dr. Bloomenstein added.
The utility of ocular surface staining with vital dyes also depends on selection of the appropriate agent, as well as its placement, amount, and the timing of the evaluation. The vital dyes most commonly used for ocular surface staining are sodium fluorescein, lissamine green, and rose Bengal.
"The major limitation of rose Bengal is that it stings. Lissamine green can be used instead in most situations. It is worth having rose Bengal on hand, however, because of its ability to differentiate herpetic lesions," Dr. Cunningham said.