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Why Does My Cat Have Eye Discharge?

CatMonitor
Quick Answer

Clear, watery discharge is usually from a mild URI or irritant. Brown or reddish tear staining is often normal. Yellow or green discharge means infection and needs vet treatment. Any squinting, swelling, or cloudiness of the eye should be seen promptly.

What You Need to Know

Eye discharge in cats is extremely common and most often associated with feline upper respiratory infections (URIs). Since most cats have been exposed to feline herpesvirus at some point (it's estimated that up to 90% of cats carry it), recurrent eye discharge during stress is very common.

Clear, watery discharge from both eyes is usually associated with a mild URI, seasonal irritants, or a herpesvirus flare-up. It may also be caused by blocked tear ducts (more common in flat-faced breeds) or mild conjunctivitis.

Yellow or green discharge indicates bacterial infection — either primary bacterial conjunctivitis or secondary bacterial infection on top of a viral URI. This requires veterinary treatment with appropriate antibiotic eye drops or ointment.

Brown or dark tear staining (most visible on light-colored cats) is usually cosmetic and results from normal tear production oxidizing on the fur. However, if it's new or one-sided, it should be investigated for blocked tear ducts or eyelid problems.

One-sided eye discharge is more concerning than bilateral discharge. It may indicate a corneal ulcer, foreign body, blocked tear duct, or, in rare cases, a retrobulbar tumor. Any eye that appears significantly different from the other warrants a vet check.

Kittens with severe, sealed-shut eye infections (often from chlamydia or herpesvirus) need urgent treatment to prevent permanent eye damage.

Common Causes

  1. Feline herpesvirus flare-up — stress-triggered, recurring clear to colored discharge
  2. Upper respiratory infection — accompanying sneezing and nasal discharge
  3. Bacterial conjunctivitis — yellow/green discharge, redness
  4. Blocked tear duct — tears overflow onto face, especially in flat-faced breeds
  5. Corneal ulcer — usually one eye, with squinting and tearing
  6. Chlamydophila infection — often one-sided, redness, young cats
  7. Allergies — clear discharge, both eyes
  8. Foreign body — hair, litter dust, or debris under the eyelid

Breed Variations

Persians, Himalayans, and Exotic Shorthairs have flat faces that predispose them to chronic tear overflow and eye discharge — their tear ducts are often compressed by the facial structure. These breeds need regular eye cleaning. Scottish Fold cats may have eye issues related to their cartilage condition. Siamese cats can be more prone to squinting (convergent strabismus is normal in Siamese).

When to Worry

See a vet promptly if the discharge is yellow or green, if your cat is squinting or holding the eye closed, if one eye looks different from the other (size, cloudiness, redness), if there is swelling around the eye, if a kitten's eyes are sealed shut with discharge, or if the eye appears cloudy or has changed color.

When NOT to Worry

Small amounts of clear or slightly brown discharge in the inner corners of the eyes, especially in flat-faced breeds, is usually normal maintenance. If your cat has occasional watery eyes during a URI that resolves on its own, and they're eating and acting normally, you can monitor.

Home Care Tips

Gently wipe discharge from the eyes with a warm, damp cotton ball — use a separate cotton ball for each eye to avoid cross-contamination. For cats prone to tear staining: keep the area clean and dry, wipe daily. If eyes are sealed with dried discharge: apply a warm compress for a few minutes to soften before gently wiping. Do not use human eye drops without vet approval. L-lysine supplements may help cats with recurrent herpesvirus flare-ups (evidence is mixed, but it's safe).

When to See a Vet

If symptoms persist for more than 24–48 hours, worsen, or are accompanied by lethargy, loss of appetite, or pain, see your vet promptly.

When in doubt, call your vet. A quick phone consultation can help you decide if an in-person visit is needed.

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