Immune-Mediated Eosinophilic Keratoconjunctivitis (IMEKC) is a unique syndrome found in cats. A particular type of white blood cell, the eosinophil, normally responds when the body is affected by allergies or parasites. In patients with IMEKC, these white blood cells invade the cornea and conjunctiva and give the eye a pink-white and chalky appearance. We often take a sample of the cells on the surface of the cornea and look at them under a microscope to confirm the diagnosis. Although we still do not know the cause of this bizarre syndrome, there is anecdotal evidence for an association with Feline Herpesvirus (FHV-1).
Even though we do not know the actual cause of IMEKC, treatment with topical medications (prescription eyedrops) is usually successful. It may take several weeks for resolution of the problem and clinical signs can recur, especially if treatment is stopped. As with any immune-mediated ocular disease, it is important to know that some level of maintenance therapy is usually needed for the entire life of your cat, even when the eye looks normal! Therefore, periodic rechecks are recommended.