Ocular (eye) Herpes In Cats

Dec 8, 2014 · Updated May 23, 2015 · ·
  1. Anne
    You may have heard of herpes disease in humans but did you know that there is also a cat version of Herpes? This tricky virus usually attacks the cat's respiratory system but in many cases - especially with young kittens - it goes directly for the eyes, causing a severe viral eye infection that can cost the cat its eyesight.

    What is Feline Herpes Virus?

    The vast majority of cats are exposed to Feline Herpes Virus (FHV-1) at some point in their lives. This extremely infectious pathogen can cause a respiratory infection, known as Feline Viral Rhinotracheitis or FVR for short. You can read more about FVR, its symptoms, prevention and treatment in our article about the topic - Feline Herpes and Rhinotracheitis.

    Like other herpes viruses, FHV-1 employs an interesting strategy. Following the initial infection, it literally hides from the body's immune system. Its place of hiding? Nerve ends, where it can stay dormant for weeks, months, years and even a lifetime. In some cats, when the virus senses an opportunity, such as increased stress and a weakening of the immune system, it resurfaces, causing renewed infection.

    The feline herpes virus usually infects the respiratory system and sometimes causes a chronic condition with flare-ups at various intervals. However, sometimes the eyes are directly affected by the virus, as it burrows into the facial nerves leading to the eyes. When that happens, the virus attacks eye tissue directly, creating herpetic lesions inside the eye. These lesions can scar the cornea, leading to significant vision impairment and even blindness.

    What are the symptoms of feline ocular (eye) herpes?

    Herpes-induced eye infections often follow the respiratory infection known as Feline Viral Rhinotracheitis. Squinting, runny eyes and conjunctivitis are actually often displayed as part of the respiratory infection, even when the eye itself has no herpetic lesions. They do not necessarily imply the cat's eyes are directly infected.

    Your vet will examine your cat's eyes in order to determine the presence of the virus-induced lesions in the eye itself. He or she may also test for the presence of the virus in the cat's body. When the virus does attack the it multiplies in the eye itself while damaging eye cells and creating lesions. Left untreated, bacteria can then lodge itself in the lesions and create a secondary - and often more serious - infection.

    Many stray and feral kittens lose their eyesight when a bacterial infection sets in following a viral herpes infection.

    Treatment of feline ocular herpes

    Treatment is very important in cases of eye herpes. Without treatment there is a risk of permanent damage to the eye and even blindness. Oral anti-viral drugs may be prescribed to fight the overall herpes infection in the body, however they cannot reach the eye's surface where the virus attacks, as that part of the eye has no blood vessels to deliver the drug by. That's why an important part of the treatment involves using anti-viral drops and ointments to be administered diligently on the surface of the cat's eye.

    Your vet will prescribe special eye-ointment for the treatment. Do not use OTC antiviral ointments in your cat's eye! The wrong kind of ointment can damage the cat's delicate eyes and cause pain.

    In most cases, your veterinarian will also prescribe antibiotics to fight or prevent secondary bacterial infection.

    Prevention of feline ocular herpes

    Vaccinating your kitten for feline herpes is your first line of defense. With feline herpes virus being so common, it's imperative to vaccinate the kitten on schedule. The vaccination is not 100% effective in preventing infection, but in addition to the protection from initial infection, vaccinated cats are less likely to develop a major disease. Boosters for this vaccine may be needed later on during the cat's lifetime. Consult with your vet regarding the best vaccination schedule for your cat, as this may depend on the cat's overall health and living conditions.

    Many owners of "herpes kitties" still choose to supplement their cat's diet with the amino acid L-lysine. Unfortunately, recent studies show that this isn't effective against feline herpes virus.

    Even if you choose to use l-lysine, please remember that no supplementation can replace topical anti-viral medication in the case of an active ocular herpes infection. Forgoing proper medical treatment for this condition could make your cat blind, so please follow the vet's orders and take good care of your cat's eyes!

    Ocular Herpes in Cats - Things to Remember

    To recap, here are a few things to remember about eye herpes in cats -
    • Ocular herpes is caused by the same virus that causes the common respiratory disease in cats known as Rhinotracheitis.
    • The feline herpes virus is not contagious to humans or dogs.
    • The feline herpes virus is very infectious between cats.
    • Once a cat gets the virus, he or she is a carrier for life and may develop a chronic condition.
    • Vaccination for FVR is your first line of defense in protecting your cat from feline herpes.
    • Only your vet can determine if your cat has eye herpes or not.
    • Topical anti-viral drugs are the treatment of choice for ocular herpes. Only use the ones prescribed by your vet!
    • L-lysine supplementation is thought to prevent recurrent outbreaks of feline herpes, but at this point it is not backed by substantial scientific evidence.


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  1. dittersmom
    Hi everyone. I'm posting this to share my experience with my cat and her eye problems. I got Ditter, my cat, from a shelter in 2007. She was anywhere between 1-3 years old. I had 3 other adult cats at home. Ditter seemed okay for a good number of years and then she developed eye problems, I would guess around 2011-2012. With her 1st visit with the vet (for this problem) it was found there was an ulcer on her eye. The doctor treated her there, as did I afterwards at home. The doctor had taken a culture. Her eyes cleared up.....for the time being. Then it started happening on a regular basis. The vet said she had Herpes of the eye. From then on, it seemed that as soon as it would start to get better, then a flare up would start. She dealt with this for 2-3 years on a constant basis. It is said that the herpes is contagious to other cats. I am not dismissing that in the least. My other cats, however, are fine, even today. I was living in another state away from my family and where I grew up.
    In early 2014, I wanted to move back so my brother let me and the kitties stay at his house. I met someone soon after. Our relationship was (and is) a great one....so I moved in with him late 2014. My poor cat was still dealing with the eye issues on a continual basis, and after I moved in with the BF, I had to take her to a new vet within days. Then something strange happened. After this flare up, all the way to today, she hasn't had a single eye issue. Thinking back, I can only think of one thing that changed in her life, besides the moves. The cat litter. My BF has 2 cats of his own. The big "change" was that I had been a huge fan of "scoop away" cat litter. I used this continually from 2011-2012 up until the time of the final move. My BF uses "World's Best Cat Litter". I have come to the conclusion that this was the culprit. She went from eye problem to eye problem continually for all that time, where just when it seemed she'd be getting over it, and BAM, it would start all over. Now she hasn't had a problem since Nov 2014. It is now almost April 2016. If your cat is dealing with the same problem, try changing the cat litter. It is interesting to note, which I didn't realize then, was that the years prior to this problem, I had been using clay litter. But I trusted my vet when he gave his diagnosis, never thinking it was the litter, as the symptoms didn't occur immediately after the change from clay to scoop away. When I questioned how could she get this, she's an indoor cat and no one else has it, I was told "she may have caught it from another cat if yours was in a window and another cat from outside came up to her". Well, anyway, do the change if you are having problems. Try anything except the standard scooping kind. Stay away from those that are perfumed. I've had great success with "the worlds best cat litter" but I think the clay is okay too.