Feline Herpesvirus Conjunctivitis: Symptoms, Treatment and Eye Emergency Signs

By Dr Duncan Houston

A red, watery or partially closed eye in a cat may look like a minor irritation, but feline eye disease can worsen quickly.

Feline herpesvirus type 1, or FHV-1, is one of the most frequent causes of conjunctivitis and keratitis in cats. It can cause anything from mild watery discharge to severe corneal ulceration, permanent scarring or loss of the eye.

The mistake I see most often is treating every recurrent red eye as “just another herpes flare”. Herpesvirus is common, but foreign bodies, scratches, Chlamydia, Mycoplasma, glaucoma, uveitis and corneal sequestra can produce very similar signs and require very different treatment.

Quick Answer

Feline herpesvirus conjunctivitis causes redness, swelling, tearing, discharge and squinting. The virus usually remains latent after the initial infection and may reactivate later, particularly during periods of stress or illness.

Any cat with squinting, persistent eye closure, corneal cloudiness, a visible spot or indentation on the eye, severe swelling or apparent loss of vision needs prompt veterinary examination. These signs may indicate a painful corneal ulcer or another condition capable of threatening the eye. (ABCD cats and vets)

Feline Herpes Eye Disease at a Glance

Question	Practical answer
What causes it?	Felid alphaherpesvirus 1, commonly called FHV-1
What are the common signs?	Redness, tearing, swelling, discharge, squinting and corneal ulceration
Which cats are most vulnerable?	Kittens, shelter cats, cats living in large groups and immunocompromised cats
Does the virus go away?	No. Most infected cats develop lifelong latency
Can signs return?	Yes. Reactivation may cause recurrent conjunctivitis or keratitis
Is it contagious?	Yes, between cats through ocular and respiratory secretions
Can people or dogs catch it?	No known natural cross-species transmission occurs
Do antibiotics cure it?	No. They only treat secondary bacterial infection
Which antivirals are used?	Cidofovir, trifluridine, idoxuridine, ganciclovir and oral famciclovir
When is it urgent?	Squinting, cloudiness, severe swelling, visible corneal change or loss of vision

FHV replicates within the conjunctiva, cornea and upper respiratory tract before establishing lifelong latency within sensory neurons. (ABCD cats and vets)

What Is Feline Herpesvirus Conjunctivitis?

The conjunctiva is the thin pink membrane lining:

• The inside of the eyelids

• The surface of the third eyelid

• The white tissues surrounding the eye

Conjunctivitis means inflammation of this membrane.

FHV infects conjunctival and corneal epithelial cells. The resulting cell damage causes inflammation, swelling and ocular discharge. In some cats, the infection remains limited to the conjunctiva. In others, it spreads onto the cornea and produces keratitis or ulceration. (ABCD cats and vets)

Is Conjunctivitis the Same as a Corneal Ulcer?

No.

Conjunctivitis affects the pink tissues around the eye.

A corneal ulcer is a defect in the clear outer surface of the eyeball itself.

A cat with simple conjunctivitis may have redness and discharge but remain relatively comfortable. A cat with a corneal ulcer commonly develops:

• Persistent squinting

• Eye closure

• Rubbing

• Increased tearing

• Corneal cloudiness

• Light sensitivity

• Visible corneal irregularity

Dendritic, branching corneal ulcers are considered highly characteristic of acute FHV infection when they are identified. (ABCD cats and vets)

How Does Feline Herpesvirus Become a Lifelong Problem?

After the primary infection settles, FHV enters sensory nerves and becomes latent, most notably within the trigeminal ganglia.

The virus is no longer actively damaging the eye during true latency. It remains dormant within nerve cells and may reactivate later.

Potential reactivation triggers include:

• Moving house

• Boarding

• Surgery or hospitalisation

• Introduction of another animal

• Social conflict

• Pregnancy or nursing

• Significant illness

• Immunosuppressive medication

• Major environmental disruption

Reactivation may cause obvious conjunctivitis, keratitis or respiratory signs. It may also produce viral shedding without any visible clinical disease. (ABCD cats and vets)

Does Every Stressful Event Cause a Flare?

No.

Many cats experience stress without developing signs. Other cats develop recurrent ocular disease even when the owner cannot identify an obvious trigger.

Stress reduction can form part of long-term management, but it cannot guarantee that reactivation will never occur.

What Are the Signs of Herpes Conjunctivitis?

Conjunctival Signs

Common signs include:

• Red conjunctiva

• Conjunctival swelling

• Watery discharge

• Mucous discharge

• Yellow or green discharge when secondary infection develops

• Prominent third eyelid

• Repeated blinking

• Rubbing the face or eye

Marked conjunctival swelling is called chemosis. The swollen tissue may partially cover the eye, particularly in kittens with severe primary infection. (Merck Veterinary Manual)

Corneal Signs

When FHV affects the cornea, signs may include:

• Squinting

• Keeping the eye closed

• Excessive tearing

• Blue or white corneal cloudiness

• A superficial corneal defect

• A branching dendritic ulcer

• Blood vessels growing across the cornea

• Corneal pigmentation

• Reduced vision

Ulcerative herpes keratitis may recur throughout the cat’s life and can be slow to heal. (ABCD cats and vets)

Respiratory Signs

Eye disease may occur alone or with:

• Sneezing

• Nasal discharge

• Nasal congestion

• Fever

• Reduced appetite

• Lethargy

• Coughing in more severe disease

Young kittens may develop severe upper respiratory disease, pneumonia or rapidly progressive systemic illness alongside their ocular signs. (ABCD cats and vets)

Why Are Kittens at Greater Risk?

Primary FHV infection is often most severe in young kittens, particularly those from shelters, colonies, rescue environments or unvaccinated litters.

Severe conjunctival inflammation can cause the eyelids and third eyelids to adhere to surrounding tissues. These adhesions are called symblepharon.

Symblepharon may involve:

• One eyelid adhering to another

• The third eyelid adhering to the conjunctiva

• The conjunctiva adhering to itself

• The conjunctiva growing onto and adhering to the cornea

These adhesions can obstruct vision, alter eyelid position, interfere with tear drainage and permanently damage the ocular surface. Early medical treatment may reduce some developing adhesions, although established corneal adhesions can be difficult to correct and some kittens require surgery. (ACVO Public)

What if a Kitten’s Eyes Are Glued Shut?

Do not prise the eyelids apart forcefully.

Gently soften external discharge with warm sterile saline or clean warm water, then arrange prompt veterinary examination. The eye beneath may have severe conjunctivitis, ulceration, retained discharge or adhesions that need controlled opening, flushing and medication.

A kitten that is not eating, is becoming weak or has both eyes severely affected may require hospitalisation, fluids and nutritional support in addition to eye treatment. (ABCD cats and vets)

How Worried Should You Be?

Lower Risk

Your cat has:

• Mild watery discharge

• Mild redness

• The eye remains fully open

• No cloudiness

• No rubbing

• Normal appetite and activity

• Signs present for less than 24 hours

What it may mean: Mild conjunctival irritation or an early viral flare is possible.

What to do: Gently clean the discharge, prevent rubbing and arrange veterinary advice if the redness persists beyond 24 hours or begins worsening.

Moderate Concern

Your cat has:

• Persistent redness

• Increasing discharge

• Mild intermittent squinting

• Conjunctival swelling

• Sneezing or nasal discharge

• Recurrent episodes in the same eye

• No visible corneal cloudiness

What it may mean: Viral conjunctivitis, Chlamydia, Mycoplasma or another ocular disorder may be present.

What to do: Arrange a veterinary examination within the next day. The cornea should be stained before medication is selected.

High Concern

Your cat has:

• Persistent squinting

• A partly or completely closed eye

• Corneal cloudiness

• A visible white, blue, brown or black area

• Severe conjunctival swelling

• Repeated rubbing

• Thick discharge

• Reduced appetite

• A kitten with sealed or markedly swollen eyes

What it may mean: A corneal ulcer, sequestrum, severe keratitis or another painful ocular disease may be present.

What to do: Seek same-day veterinary care. Do not use leftover eye medication.

Critical

Your cat has:

• A visible hole, crater or deep indentation in the cornea

• Fluid or tissue protruding from the eye

• Sudden loss of vision

• Major eye trauma

• Severe bleeding

• An eye that appears ruptured or collapsed

• Open-mouth breathing

• Collapse or minimal responsiveness

What it may mean: Corneal perforation, globe rupture, severe respiratory disease or another sight-threatening emergency may be present.

What to do: Attend an emergency veterinary hospital immediately.

When Is This an Emergency?

Eye pain should be taken seriously.

Seek immediate or same-day veterinary care if your cat has:

• Persistent squinting

• An eye that remains closed

• Corneal cloudiness

• A visible ulcer, spot or surface defect

• Sudden colour change within the eye

• Severe redness with a small or irregular pupil

• A rapidly enlarging or bulging eye

• Sudden apparent blindness

• Significant trauma

• Chemical exposure

• Severe swelling

• A kitten whose eyes are sealed by discharge

• Open-mouth breathing or marked systemic illness

Corneal ulcers may deepen, become infected or perforate. Glaucoma and uveitis can also cause redness and squinting but require entirely different treatment from conjunctivitis. (Merck Veterinary Manual)

What Else Can Look Like Herpes Conjunctivitis?

Possible condition	Important clues
Chlamydia felis	Marked conjunctivitis and chemosis, often beginning in one eye before affecting both
Mycoplasma felis	Conjunctivitis with ocular discharge, sometimes with respiratory signs
Corneal scratch or foreign body	Sudden onset, marked pain and often one eye affected
Entropion or abnormal hairs	Repeated irritation from eyelid or hair contact
Feline calicivirus	Respiratory disease and oral ulcers, sometimes with conjunctivitis
Eosinophilic keratoconjunctivitis	Raised pink-white plaques, corneal vessels and chronic irritation
Corneal sequestrum	Tan, brown or black area of dead corneal tissue
Uveitis	Small pupil, internal cloudiness, pain and colour change within the eye
Glaucoma	Enlarged or firm eye, dilated pupil, pain and loss of vision
Nasolacrimal obstruction	Persistent tearing without severe conjunctival inflammation
Dry eye or tear-film disease	Thick discharge and recurrent surface irritation
Tumour	Persistent focal swelling or an irregular mass, particularly in an older cat

Chlamydia and Mycoplasma are important infectious alternatives because they can produce clinically significant conjunctivitis and may require systemic antimicrobial treatment rather than antiviral therapy. (ABCD cats and vets)

What To Do Right Now

1. Prevent Rubbing

Use an Elizabethan collar when your cat is pawing at the eye.

Rubbing can convert a superficial lesion into a deeper ulcer and can introduce bacteria into damaged corneal tissue.

2. Clean Discharge Gently

Use:

• Sterile saline

• Clean lukewarm water

• Soft lint-free gauze or cotton pads

Use a separate clean pad for each eye. Wipe from the inner corner outwards without pressing directly on the eyeball.

3. Keep the Cat Indoors

This allows you to monitor the eye and prevents additional trauma, dust exposure and transmission to unfamiliar cats.

4. Separate Symptomatic Cats

During an active respiratory or ocular episode:

• Use separate food and water bowls

• Use separate bedding

• Wash hands after treatment

• Clean ocular and nasal discharge promptly

• Avoid sharing grooming equipment

FHV spreads through ocular and respiratory secretions and is especially important in crowded feline populations. (ABCD cats and vets)

5. Record the Eye

Take a clear photograph in natural light once or twice daily.

Monitor:

• Eye opening

• Redness

• Swelling

• Discharge

• Corneal clarity

• Appetite

• Sneezing

• Medication response

Do not repeatedly use a phone flash on a painful or light-sensitive eye.

6. Do Not Use Leftover Eye Drops

The previous bottle may:

• Be contaminated

• Contain the wrong antibiotic

• Contain a corticosteroid

• Be expired

• Be inappropriate for a corneal ulcer

A steroid-containing drop can reactivate FHV and worsen ulcerative keratitis. It may contribute to corneal breakdown or sequestrum formation in susceptible cats. (Merck Veterinary Manual)

7. Monitor Appetite and Breathing

Cats with concurrent nasal congestion may stop eating because they cannot smell food.

Offer warmed, aromatic wet food and seek veterinary advice promptly if an adult cat eats little or nothing for approximately 24 hours. Kittens and medically fragile cats should be assessed sooner. (ABCD cats and vets)

How Is Herpes Conjunctivitis Diagnosed?

Complete Eye Examination

The veterinarian should assess:

• Eyelids

• Conjunctiva

• Third eyelid

• Corneal clarity

• Pupil shape and size

• Vision

• Tear production where indicated

• Intraocular pressure where indicated

• Evidence of foreign material or trauma

Fluorescein Staining

Fluorescein dye adheres to exposed corneal tissue and reveals ulcers.

Fine branching dendritic ulcers are considered characteristic of acute FHV keratitis. Larger geographic ulcers may develop as epithelial damage progresses. (ABCD cats and vets)

Fluorescein staining is essential before considering corticosteroid eye medication.

Cytology

Conjunctival or corneal cytology may help identify:

• Bacteria

• Neutrophilic inflammation

• Chlamydial inclusions

• Eosinophils

• Mast cells

• Abnormal or neoplastic cells

Eosinophilic keratoconjunctivitis is confirmed by identifying eosinophils or mast cells in corneal or conjunctival samples. (PubMed Central (PMC))

PCR Testing

PCR is the preferred laboratory method for detecting FHV DNA.

Samples may be collected from:

• Conjunctiva

• Cornea

• Oropharynx

• Nose

• Aqueous humour

• Biopsy tissue

However, a positive qualitative PCR result does not automatically prove that FHV caused the current eye problem. It may reflect low-level shedding, latency or chronic infection. Higher quantitative viral loads are more supportive of active replication. (ABCD cats and vets)

When PCR is planned, the laboratory should be contacted before fluorescein dye or topical anaesthetic is applied because these substances can affect some assays. (ABCD cats and vets)

Are Herpes Antibody Tests Useful?

Generally, no.

Many vaccinated or previously infected cats have antibodies, while some infected cats have low or undetectable titres. Antibody testing cannot reliably distinguish vaccination, past exposure, latency and active ocular disease. (ABCD cats and vets)

How Is Feline Herpes Conjunctivitis Treated?

Treatment depends on:

• Whether the cornea is involved

• Severity of pain

• Primary versus recurrent disease

• Presence of secondary bacterial infection

• Ability to administer eye drops

• Concurrent respiratory disease

• Age and general health

• Whether another diagnosis remains possible

A mildly affected cat with an intact cornea may require little more than lubrication, cleaning and monitoring. A painful cat with ulcerative keratitis generally needs antiviral therapy, protection from self-trauma and close rechecks.

Which Topical Antivirals Are Used?

Cidofovir

Compounded 0.5% cidofovir is often one of the most practical topical choices.

Advantages include:

• Demonstrated efficacy against ocular FHV

• Generally good tolerance

• Administration approximately every 12 hours

• Better owner compliance than medications requiring treatment every few hours

Long-term use should still be monitored because chronic cidofovir exposure has been associated with nasolacrimal complications in people, and prolonged feline use should not continue without rechecks. (Merck Veterinary Manual)

Trifluridine

Trifluridine has strong antiviral activity and remains an important treatment option.

Its limitations include:

• Frequent administration

• Significant stinging in some cats

• Stress during repeated dosing

• Potential corneal toxicity when used beyond approximately three weeks

A medication that is theoretically excellent but impossible to administer safely six times daily may not be the best choice for that particular cat and household. (Merck Veterinary Manual)

Idoxuridine

Idoxuridine can be compounded as an ophthalmic solution or ointment.

It usually requires frequent initial dosing and may be difficult to source. It must not be administered systemically. (ABCD cats and vets)

Ganciclovir

Topical ganciclovir has useful antiviral activity and may be available as a gel or compounded preparation.

It generally requires more frequent administration than cidofovir but may be well tolerated in selected cats. (ABCD cats and vets)

When Is Oral Famciclovir Used?

Famciclovir is the principal systemic antiviral used for feline herpesvirus.

It may be particularly useful when:

• Both eyes are affected

• Eye-drop administration is difficult

• Respiratory and ocular disease occur together

• Keratitis is moderate or severe

• Disease is recurrent

• Several ocular surfaces are affected

• Topical treatment has not been sufficient

Current feline dosing is much higher than many owners expect from human medicine and must be calculated specifically for the individual cat. Kidney function, treatment duration and clinical response influence the protocol. (ABCD cats and vets)

Possible adverse effects include reduced appetite, vomiting or diarrhoea. Contact the prescribing veterinarian if the cat stops eating or becomes unwell during treatment.

Which Oral Antivirals Should Be Avoided?

Valacyclovir is contraindicated in cats because it can cause severe hepatic, renal and bone-marrow toxicity.

Acyclovir has poor activity against FHV and may cause systemic toxicity. It is not a preferred oral treatment. (Merck Veterinary Manual)

When Are Antibiotics Needed?

Antibiotics do not kill FHV.

Topical antibiotics may be prescribed when there is:

• Mucopurulent discharge

• A corneal ulcer vulnerable to secondary bacterial infection

• Cytological evidence of bacteria

• Significant epithelial damage

• Concern for mixed infection

Systemic antibiotics may be needed when:

• Chlamydia felis is suspected or confirmed

• Mycoplasma felis is clinically important

• Respiratory disease is accompanied by fever, lethargy or anorexia

• Pneumonia or systemic bacterial disease is present

Repeating antibiotic ointment for every recurrence without examining the cornea may temporarily change the discharge while missing the actual cause. (ABCD cats and vets)

What Other Supportive Treatments Help?

Lubricating Eye Drops

Preservative-free veterinary lubricants may:

• Improve ocular comfort

• Protect a compromised tear film

• Reduce friction between inflamed tissues

• Support corneal healing

Hyaluronate-containing products may be used as lubricants, but they do not kill FHV and should not replace antiviral treatment when the cornea is infected.

Pain Relief

Corneal ulcers are painful.

Veterinary pain management may include systemic analgesics and, in selected cases, pupil-dilating medication to relieve painful ciliary spasm. The correct choice depends on intraocular pressure, pupil appearance and whether uveitis is present.

Nutrition and Hydration

Cats with concurrent respiratory disease may need:

• Warmed palatable food

• Fluids

• Appetite support

• Saline nebulisation

• Feeding-tube support in severe cases

Food intake is particularly important in kittens, obese cats and cats with prolonged nasal congestion. (ABCD cats and vets)

Can Corticosteroid Eye Drops Be Used?

Not during active ulcerative herpes keratitis.

Topical corticosteroids can:

• Increase viral reactivation

• Worsen corneal ulceration

• Delay epithelial healing

• Increase the risk of secondary infection

• Contribute to corneal sequestrum formation

They should not be started until the cornea has been stained and ulceration has been excluded. (ABCD cats and vets)

Corticosteroids or other immune-modifying eye medications may still be needed for diseases such as stromal keratitis or eosinophilic keratoconjunctivitis. In these cases, treatment requires careful balancing of immune suppression and antiviral control, often with veterinary ophthalmology involvement.

Does L-Lysine Help?

Current evidence does not support L-lysine for the prevention or treatment of feline herpesvirus infection.

A review of available studies found no convincing benefit. Some shelter studies found more severe disease and increased viral shedding in supplemented cats. L-lysine is therefore not recommended as a standard treatment or preventive strategy. (ABCD cats and vets)

Do Probiotics Prevent Herpes Flare-Ups?

Evidence is limited.

One very small pilot study suggested that an Enterococcus faecium probiotic might reduce morbidity in chronically infected cats, but the findings have not been confirmed by larger studies. Probiotics should not replace vaccination, antiviral therapy, nutrition or proper eye treatment. (ABCD cats and vets)

What Long-Term Eye Problems Can FHV Cause?

Recurrent Ulcerative Keratitis

The virus may reactivate within corneal nerves and produce repeated superficial ulcers.

Recurring ulceration can cause:

• Pain

• Scarring

• Corneal blood vessels

• Reduced transparency

• Secondary bacterial infection

• Progressive corneal damage

Stromal Keratitis

Stromal keratitis affects the deeper corneal layers and is often driven partly by the immune response rather than direct surface viral replication.

Signs may include:

• Diffuse cloudiness

• Corneal oedema

• Blood-vessel growth

• Pigmentation

• Reduced vision

Treatment is different from uncomplicated superficial ulceration and may require both antiviral and carefully controlled anti-inflammatory therapy. (ABCD cats and vets)

Symblepharon

Symblepharon involves permanent adhesions between conjunctival or corneal surfaces following severe ulceration.

It is especially important in kittens. Established adhesions may obstruct vision, alter eyelid shape, impair tear drainage or require surgery. (PubMed Central (PMC))

Eosinophilic Keratoconjunctivitis

This immune-mediated disease produces raised pink, white or cream plaques across the cornea or conjunctiva.

FHV is detected in some affected cats and may contribute to or exacerbate the condition, but a direct causal association has not been proven in every case.

Diagnosis requires cytology. Treatment often involves long-term immune-modifying eye medication, with antiviral therapy added when FHV is considered relevant. (ABCD cats and vets)

Corneal Sequestrum

A corneal sequestrum is an area of dead corneal tissue that becomes tan, brown or black.

It is associated with chronic corneal irritation and non-healing ulceration. Contributing factors may include:

• FHV

• Entropion

• Chronic ulceration

• Brachycephalic anatomy

• Breed predisposition, particularly Persian and Himalayan cats

Some superficial sequestra eventually separate, but painful, deep or progressive lesions often require superficial keratectomy and possibly a corneal graft. (ACVO Public)

Can Herpes Conjunctivitis Be Cured?

The active episode can usually be controlled, but latent FHV cannot currently be eliminated from the body.

Many cats experience only one significant episode. Others have occasional mild flare-ups. A smaller group develops chronic or recurrent keratitis requiring repeated or long-term management.

The prognosis is generally good when:

• The cornea remains intact

• Treatment begins early

• Medication can be administered consistently

• The cat continues eating

• Chronic complications are recognised promptly

The prognosis becomes more guarded with deep ulcers, perforation, extensive symblepharon, stromal scarring, sequestrum formation or delayed treatment.

How Can Future Flare-Ups Be Reduced?

Maintain Core Vaccination

FHV vaccination is considered core for cats.

Vaccination does not reliably prevent infection or lifelong latency. It reduces the severity of clinical disease and can reduce viral shedding or shorten the shedding period. (ABCD cats and vets)

Reduce Avoidable Stress

Helpful measures include:

• Predictable routines

• Slow introductions between cats

• Adequate hiding places

• Multiple feeding and litter resources

• Avoiding unnecessary crowding

• Planning medication before predictable stress

• Maintaining good control of chronic disease

Stress reduction helps some cats but cannot completely prevent viral reactivation.

Maintain General Health

Promptly investigate:

• Poor appetite

• Weight loss

• Dental disease

• chronic nasal disease

• immunosuppressive disease

• repeated ocular discomfort

An apparently minor eye flare may become more severe when another illness is reducing the cat’s ability to control latent infection.

Avoid Sharing Eye Medication

One cat’s bottle may transmit organisms to another cat or introduce contamination into a healing eye.

Do not allow the bottle tip to touch the eye, eyelid or fur.

Common Herpes Eye Disease Mistakes

Assuming Every Red Eye Is Herpes

Foreign bodies, glaucoma, uveitis, Chlamydia and corneal trauma can look very similar.

Using Leftover Steroid Eye Drops

Steroids can rapidly worsen active corneal ulceration.

Treating Discharge Without Staining the Cornea

The most important question is not simply what colour the discharge is. It is whether the cornea is intact.

Assuming a Positive PCR Proves Causation

Low-level FHV shedding can occur without the virus causing the current disease.

Relying on Antibiotics Alone

Antibiotics do not suppress viral replication.

Using L-Lysine Instead of Effective Treatment

Current evidence does not support it.

Stopping Medication as Soon as the Eye Looks Better

Corneal disease may remain active after the visible discharge improves. Follow the veterinarian’s treatment and recheck plan.

Waiting Several Days With a Closed Eye

Squinting and persistent eye closure indicate pain until proven otherwise.

Frequently Asked Questions

Can feline herpesvirus spread to people or dogs?

No known natural cross-species transmission occurs. FHV is adapted to felids and is primarily spread between cats. (ABCD cats and vets)

How long does herpes conjunctivitis last?

An uncomplicated acute episode often improves within approximately one to two weeks. Corneal ulceration, secondary infection or chronic immune-mediated keratitis can take considerably longer and may recur. (ABCD cats and vets)

Does every cat with herpes need antiviral medication?

No. The need for antiviral treatment depends on severity, recurrence, corneal involvement and the cat’s overall condition. Painful keratitis, ulceration and severe primary disease make antiviral treatment more important.

Why does my cat keep getting conjunctivitis in the same eye?

Recurrent FHV is one possibility, but persistent unilateral disease also raises concern for a foreign body, eyelid abnormality, nasolacrimal obstruction, sequestrum, chronic ulcer or tumour.

Can a vaccinated cat still get herpes conjunctivitis?

Yes. FHV vaccines reduce the severity of illness but do not reliably prevent infection, latency or every recurrence. (ABCD cats and vets)

Final Thoughts

Feline herpesvirus is common, but a painful eye should never be dismissed as routine.

The most important points are:

1. FHV is a leading cause of feline conjunctivitis and keratitis.

2. Most infected cats develop lifelong latency.

3. Reactivation may cause recurrent eye or respiratory signs.

4. A red eye is not automatically herpesvirus.

5. Squinting means the eye is painful until proven otherwise.

6. Dendritic corneal ulcers are highly characteristic of acute FHV.

7. PCR can support the diagnosis but does not prove causation by itself.

8. Topical antibiotics treat secondary bacterial infection, not the virus.

9. Cidofovir is often practical because it requires less frequent administration.

10. Famciclovir is the main systemic antiviral used in cats.

11. Valacyclovir must not be used in cats.

12. Corticosteroid eye drops can worsen active herpetic ulcers.

13. L-lysine is not supported by current evidence.

14. Kittens can develop permanent symblepharon and corneal damage.

15. Eosinophilic keratitis and corneal sequestra require different long-term management.

16. Vaccination reduces disease severity but does not prevent all infection.

17. A closed, cloudy, injured or suddenly blind eye requires prompt veterinary care.

The mistake that causes the greatest harm is treating recurrent discharge while failing to examine the cornea.

Conjunctivitis is uncomfortable. A missed corneal ulcer can cost the cat its vision.

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ASK A VET™ can help you organise eye photographs, symptom timelines, medication schedules and questions about recurrent flare-ups while you work directly with your veterinary team. A cat with a closed or cloudy eye, severe pain, sudden vision loss, visible corneal damage or open-mouth breathing still requires immediate hands-on veterinary care.