Cat’s eye discharge has many potential causes

A cat with unilateral, chronic eye discharge improved with topical and oral treatments, but the owner can’t sustain the expense for all the medications and asks for help. Veterinarian Michael Brown offers some possible causes for the chronic discharge and notes that some of those need lifelong treatment. Dr. Brown suggests an over-the-counter supplement that could help but emphasizes that the owner should work closely with a veterinarian to determine the best course of action for the cat’s eye problem.

I have a 5-year-old male domestic shorthair tabby cat (Pokey) that I have had for about 3 years now. Ever since I got him, he has had a black discharge from his right eye, and I was told that he had it from birth. It’s not bad, but I have been cleaning it for him with a paper handkerchief and an eye rinse.

A veterinarian gave me an antibiotic to put in his eye. I finished the tube and renewed it several times, and although it helped, it never cured the situation. Recently, because Pokey couldn’t really open his right eye one day, I went to a new vet who gave me (for almost $200) another tube of antibiotic (neomycin  and polymyxin B sulfates  and dexamethasone ophthalmic ointment) to put directly in the eye, a suspension of Clavamox (a liquid suspension by mouth), and an oral paste Enisyl-F (an oral paste by mouth).

Pokey can open his eye completely and it’s completely clear of the discharge, but the oral paste was not completely used up. I called to see if it needed to be completely used up (like an antibiotic), and the vet said he had to take it for the rest of his life.

I’m a senior citizen, living on Social Security, trying to maintain a house on a limited income, so the cost of this is rather scary, but I’d try to continue to maintain it for him if it wasn’t for the fact that he hates taking the Enisyl-F.

Can you suggest anything else that I can do to maintain a clear eye for Pokey? Or is it not too bad for him to have the discharge? I’ve seen many dogs with a dark stain by the corner of the eye, sometimes staining quite a section of the face, and although it’s not pretty, if it doesn’t do any harm, I’d hate to spoil Pokey’s personality just for beauty.

Your cat Pokey likely had a condition called conjunctivitis. In cats, there are several infections of the eye that are possible causes that include feline herpes, bartonellosis, mycoplasma and chlamydia. Numerous other infections are possible but are rare in this area.

In the northeast, feline herpetic conjunctivitis is by far the most common cause of upper respiratory and eye infection. The clinical signs include tearing, squinting, conjunctivitis, corneal ulcers, sneezing and coughing. Many kittens are exposed to the herpes virus during birth. Every cat mounts a different immune response to this challenge.

The bottom line for your cat is this: topical (eye) antiviral therapy is preferred for this condition (idoxuridine, cidofovir) when an active infection is present. Antibiotics and steroids do not treat herpes infections. Oral L-Lysine is used to help prevent recurrence, as the virus lives in the body forever. You may use Lysine tablets by mouth (over the counter nutritional supplement) to help keep costs minimized. You need to speak to your veterinarian about the appropriate dose for your cat and for advice on how to administer a pill to a cat (crumble in food, dissolve in water, etc.). The tearing may persist as the viral infection may reduce normal function of the tear duct, thus causing the drainage from the eye. This is sometimes permanent. Feline herpes cannot be transmitted to a person or other species so there is no risk to anyone in the house.

Bartonella (cat scratch fever) is a potential zoonotic disease, especially to immunocompromised individuals, and if your cat tests positive for this condition, specific therapy is recommended. Good hygiene with the litter box and the owners’ hands is always recommended, regardless. Please speak to your veterinarian about any concerns you may have about Pokey.

— Michael Brown, DVM, MS, Diplomate, ACVO

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