The most common cause of corneal disease in cats is probably feline herpesvirus-1 (FHV-1). The tissue damage is most severe in immunologically naive cats. Epithelial keratitis is first treated with topical antiviral drugs, such as 0.1% idoxuridine, 3 to 5 times daily. If there is no response within 2 weeks, the author switches to 1% trifluridine solution. Systemic acyclovir is used as a last resort. Antiviral therapy is generally combined with oral L-lysine therapy (500 mg PO daily). In chronic cases, L-lysine therapy should be continued indefinitely. A unique corneal disease, sometimes called "Florida keratopathy," is seen in cats and dogs in the Gulf states. It is believed to be caused by a virus, protozoa, or fungus; is characterized by multiple white to gray corneal opacities that affect 1 or both corneas; and is not progressive or painful. Persians and Himalayans are especially susceptible to corneal sequestrum, which seems to be a nonspecific response to chronic corneal injury. The condition may be more likely to be caused by FHV-1 in nonbrachycephalic breeds. Eosinophilic keratitis may also be seen as a result of FHV-1 infection, as most of the corneas from affected cats contain FHV-1 DNA. A rare condition of corneal hydrops is occasionally seen in cats and is characterized by acute, severe corneal edema.

COMMENTARY: The incidence of feline herpesvirus infection is not known, but it can certainly be a chronic irritation for many cats and their owners. The use of L-lysine therapy may be helpful in reducing viral shedding, decreasing the duration of FHV-1 infection, and lessening the severity of clinical signs.

Corneal disease of cats. Nasisse MP. ACVIM PROC, 2005, pp 15-16.