Feline Herpesvirus Eye Infection in Cats

Feline herpesvirus eye infection usually refers to eye disease caused by feline herpesvirus-1, often shortened to FHV-1. This virus is a very common cause of conjunctivitis in cats and can also affect the cornea, leading to keratitis or painful corneal ulcers. Many cats are first exposed as kittens, especially in shelters, catteries, or multi-cat homes. After the first infection, the virus often stays in the body in a dormant state and may reactivate later.

When flare-ups happen, signs can range from mild watery eyes to marked redness, squinting, thick discharge, and obvious eye pain. Some cats also have sneezing or nasal discharge at the same time because FHV-1 is part of feline upper respiratory disease complex. Eye involvement matters because the cornea is delicate. A painful ulcer or deeper corneal injury can threaten vision if care is delayed.

This condition is common, but it is not one-size-fits-all. Some cats have short, mild episodes that respond to conservative care. Others have recurrent disease, chronic irritation, corneal scarring, or related conditions such as dry eye or corneal sequestrum. Your vet will help match treatment to your cat’s symptoms, eye exam findings, overall health, and your goals for care.

Diagnosis usually starts with a full history and eye exam. Your vet will ask when the signs began, whether one or both eyes are affected, whether your cat has had past flare-ups, and whether there are respiratory signs like sneezing. Because many cats carry FHV-1 after earlier exposure, diagnosis is often based on the pattern of disease, exam findings, and response to treatment rather than one test alone.

A careful eye exam is important because feline herpesvirus can cause conjunctivitis, keratitis, and corneal ulcers. Your vet may use fluorescein stain to look for an ulcer on the cornea. They may also check tear production, eyelid position, the third eyelid, and whether the eye pressure or deeper structures suggest another problem. If the case is severe, recurrent, unusual, or not responding as expected, your vet may recommend additional testing such as corneal cytology, culture in selected cases, or PCR testing from eye or oral swabs.

PCR can help detect feline herpesvirus DNA, but results need context. A positive test does not always prove that the current flare is caused by active herpes infection, because some cats are carriers or may have been vaccinated. That is why your vet usually interprets testing alongside the exam. In chronic or complicated cases, referral to a veterinary ophthalmologist may be the most practical next step.

The underlying cause is infection with feline herpesvirus-1. This virus spreads mainly from cat to cat through secretions, close contact, aerosol droplets, and contaminated hands or objects. It is especially common where cats live closely together, such as shelters, rescues, breeding settings, and multi-cat homes. Kittens are often infected early in life.

One reason this condition is so common is that herpesviruses can become latent. After the first infection, the virus may remain dormant in the body for life and reactivate later. Stress, illness, surgery, crowding, immune suppression, or other health changes may trigger flare-ups. That means a cat can seem well for long periods and then develop eye signs again.

Risk factors for more severe or recurrent eye disease include young age, crowded housing, poor ventilation, concurrent upper respiratory infection, and immune compromise. Cats with feline leukemia virus or feline immunodeficiency virus may have more trouble with chronic eye inflammation. Not every red eye in a cat is herpes, though. Your vet may also consider chlamydial conjunctivitis, mycoplasma, trauma, foreign material, entropion, dry eye, eosinophilic keratitis, or other corneal disease depending on the exam.

Prevention focuses on reducing exposure and lowering the chance of flare-ups. Feline herpesvirus is common and vaccination does not completely prevent infection, but routine vaccination is still important because it can reduce disease severity. Good hygiene also matters. Wash hands between cats, avoid sharing bowls or bedding during outbreaks, and isolate cats with active respiratory or eye signs when possible.

Stress reduction can help many cats with recurrent herpes flare-ups. Changes in routine, crowding, boarding, illness, and surgery may all play a role in reactivation. Keeping a stable environment, supporting appetite and hydration during illness, and following your vet’s plan for early treatment can make episodes easier to manage. In multi-cat homes, prompt attention to sneezing or eye discharge may help limit spread.

Do not use leftover eye drops or human eye medications unless your vet tells you to. Some medications are not appropriate if a corneal ulcer is present. Because red eyes can have many causes, the safest prevention strategy is early veterinary evaluation when signs first appear, especially in kittens or cats with a history of recurrent eye disease.

The outlook is often good when feline herpesvirus eye disease is recognized early and treated appropriately. Many cats improve within days to a couple of weeks, especially when the problem is limited to conjunctivitis. Even so, herpesvirus behaves differently from a one-time infection. Because the virus can remain latent, some cats will have future flare-ups.

Recovery can take longer when the cornea is involved. Corneal ulcers, chronic keratitis, dry eye, or corneal scarring may require more visits and more medication. Some cats develop recurrent disease that needs a long-term management plan rather than a one-time fix. In severe cases, chronic inflammation can affect comfort and vision.

The best prognosis usually comes from early care, good follow-up, and quick reassessment if the eye becomes more painful, cloudy, or closed. If your cat has repeated episodes, ask your vet what pattern they are seeing and what options make sense for home management, recheck timing, and referral if the disease becomes chronic or complicated.