Eye Discharge in Cats — Symptom Decision Guide

A practical guide to assessing cat eye discharge: what different types look like, likely causes (herpes, chlamydia, mycoplasma, blocked tear duct, corneal ulcer), red flags, and when to see a vet.

Quick Assessment

• Is this an emergency?

• Most common cause: viral conjunctivitis from feline herpesvirus (FHV-1) or secondary bacterial infection causing mucopurulent discharge.
• When to see a vet: any persistent, worsening, or thick (mucopurulent) discharge, or if your cat shows pain, vision changes, or systemic signs (fever, reduced appetite).

What this symptom looks like

Eye discharge in cats varies by cause and often gives the best early clue:

• Serous (watery, clear): thin, watery tears; eyes may look wet or teary but not gunky.
• Mucopurulent (thick, yellow, green or white): sticky crusts on the eyelids and corners of the eye; may accumulate and glue the lids shut after sleep.
• Bloody (hemorrhagic): pink or red-tinged tears or smears of blood on the fur below the eye.

Possible causes (ranked by likelihood)

Sources: Merck Veterinary Manual; Cornell Feline Health Center (see citation section).

Decision tree — quick reference

• If watery/clear discharge + sneezing or nasal discharge → likely viral (FHV-1) or upper respiratory infection → action: isolate from other cats, clean eyes with saline, make vet appointment within 48 hours; vet may recommend supportive care and diagnostics.

• If watery/clear discharge + no respiratory signs + tears pooling and brown staining at the medial canthus → likely blocked nasolacrimal duct/epiphora → action: schedule a vet visit for lacrimal flush/assessment; gentle cleaning at home.

• If thick yellow/green (mucopurulent) discharge + one or both eyes red and swollen → likely bacterial conjunctivitis or Chlamydia/Mycoplasma → action: see a vet within 24–48 hours for cytology/diagnostics and topical or systemic therapy.

• If severe squinting, pawing at eye, cloudy cornea, or corneal surface looks irregular → likely corneal ulcer or foreign body → action: urgent veterinary exam (same day); do NOT apply pressure or attempt to remove objects yourself.

• If bloody discharge or blood-tinged tears → consider trauma, coagulopathy, or severe ulceration → action: urgent veterinary care (same day) to assess bleeding source and underlying cause.

• If single cat in multi-cat household becomes affected, others develop similar signs → likely contagious cause (FHV-1, Chlamydia, Mycoplasma) → action: isolate affected cat(s), call vet for advice about testing and treatment to reduce spread.

Home assessment steps (what to check and what to measure)

When it's an emergency (red flags)

Seek immediate veterinary care (same day or emergency clinic) if your cat has any of the following:

• Severe eye pain: continuous squinting, rubbing or pawing at the eye, hiding due to pain.
• Sudden loss of vision or major change in pupil size.
• Profuse bleeding from the eye or blood in tears.
• Proptosis (eye protruding from the socket) or obvious eyelid trauma.
• Large foreign body embedded in the eye.
• Signs of systemic collapse: very high fever (>105°F), collapse, severe lethargy, difficulty breathing.

When to schedule a vet visit (non-urgent but needs attention)

Make an appointment within 24–72 hours if any of these apply:

• Thick yellow/green (mucopurulent) discharge lasting more than 24–48 hours.
• Discharge that recurs or persists despite basic home cleaning.
• One eye has persistent signs while the other remains normal.
• Accompanying respiratory signs (sneezing, nasal discharge) or other cats affected.
• Any sign of corneal involvement: cloudiness, visible spot, or increased squinting.

Home care — safe things to do while monitoring

Do:

• Gently clean the discharge: use sterile saline or clean, lukewarm water and a soft gauze or cloth; wipe from the corner of the eye outward and use a fresh cloth for each eye.
• Isolate the affected cat from other cats if a contagious cause is suspected until a vet advises.
• Keep your cat calm and reduce stress (FHV-1 can be triggered by stress).
• Keep litter tray and feeding bowls clean; disinfect surfaces and wash hands after handling the affected cat.
• Apply warm compresses (not hot) for a few minutes to loosen crusts before cleaning.

• Use human eye drops or over-the-counter medications without veterinary advice.
• Attempt to apply topical antibiotics, steroid eye drops, or oral antibiotics unless prescribed by your veterinarian.
• Rub or press on the eye; do not remove embedded objects yourself.

What to tell your vet (helpful information to prepare)

Provide concise, specific information to help the veterinary team:

• Onset and duration: when you first noticed discharge and how it has changed.
• Type of discharge: clear/watery, thick/colored, bloody.
• Which eye(s) are affected and whether it is spreading.
• Any recent trauma, fights, foreign body exposure, chemical exposure, or new household products.
• Household history: other cats with similar signs, new cat or kitten introductions, shelter or cattery exposure.
• Vaccination status (especially for FHV-1), and current medications.
• Any home treatments tried and whether they helped or made things worse.
• Measured temperature if you took one, and any changes in appetite or behavior.

How vets diagnose (what to expect at the clinic)

Veterinary exam may include fluorescein staining to detect corneal ulcers, conjunctival swabs for cytology or PCR (to test for Chlamydia, Mycoplasma, FHV-1), and lacrimal flushing if a blocked duct is suspected. Your vet may also examine for eyelid abnormalities, foreign bodies, and perform systemic workup if indicated.

Final notes and precautions

Eye discharge is a common symptom with many causes ranging from mild (allergic or transient viral) to vision‑threatening (corneal ulcers, severe trauma). When in doubt, early veterinary assessment preserves vision and limits spread to other cats. Avoid home medications other than saline cleaning unless directed by your veterinarian.

Citation sources:

• Merck Veterinary Manual — Diseases of the Eye in Cats (overview of conjunctivitis, corneal ulcers, lacrimal disease).
• Cornell Feline Health Center — resources on feline upper respiratory infections and conjunctivitis.

Frequently Asked Questions