Cat Eye Disease: Symptoms, Signs, and What to Do Now

If your cat is squinting, keeping one eye closed, rubbing their face, or has yellow-green eye discharge, treat it as pain until a vet proves otherwise.

Cats often hide discomfort, but eyes are different: squinting, cloudiness, swelling, or coloured discharge deserves prompt attention.

The Quick Answer

Cat eye problems are not all the same. Some are mild conjunctivitis. Some are scratches or ulcers on the surface of the eye. Some are pressure problems inside the eye. From the outside, they can look surprisingly similar to one another — which is why guessing at the cause rarely helps.

That is why the safest rule is simple:

If your cat is squinting, keeping an eye closed, rubbing at an eye, has cloudy or coloured discharge, or the eye looks swollen, book a same-day vet check.

Do not wait several days to see if it clears. Eye surface injuries can worsen quickly, and painful eye conditions can threaten vision if treatment is delayed.

The Sign Owners Miss: Squinting Means Pain

Cats do not usually squint one eye for no reason. A half-closed eye, rapid blinking, or hiding from bright light can mean the eye is painful.

VCA's veterinary guidance on conjunctivitis lists excessive tearing, cloudy, yellow, or green discharge, redness, squinting, and keeping the eyes closed as signs that should be examined by a veterinarian immediately.¹ Their corneal ulcer guidance is even more direct: ulcers are very painful, and cats commonly squint, blink rapidly, keep the lids tightly closed, rub the eye, or develop discharge.²

That matters because a sore eye may look "small" from the couch. The cat may still eat, walk around, and act mostly normal. But an eye that is painful enough to close is already asking for help.

Use This Table to Decide Right Now

What you see	What to do
Squinting, blinking fast, or keeping one eye closed	Same-day vet check
Yellow, green, cloudy, or thick discharge	Same-day vet check
Eye looks cloudy, blue-white, bloodshot, swollen, or bulging	Urgent vet or emergency vet
Cat is rubbing the eye with a paw or on furniture	Prevent rubbing and call your vet
Eye problem after a fight, scratch, fall, chemical exposure, or shampoo accident	Urgent vet
Different pupil sizes, dilated pupil, obvious vision loss, or bumping into things	Emergency vet
Mild clear watery eye but cat is bright and not squinting	Call your vet for advice; monitor closely

If you are unsure, call the clinic and describe the eye. With eyes, a false alarm is much better than waiting on an ulcer, glaucoma, or trauma.

Common Cat Eye Problems That Can Look Alike

Conjunctivitis

Conjunctivitis is inflammation of the conjunctiva, the pink membrane that lines the eyelids and covers the white part of the eye. It can make the eye red, swollen, watery, or gunky.

In cats, conjunctivitis is often linked with infectious causes such as feline herpesvirus, calicivirus, bacteria, Chlamydophila felis, or Mycoplasma. Non-infectious causes include foreign material under the eyelid, irritants, allergies, eyelid abnormalities, or another eye disease.¹

Conjunctivitis can affect one or both eyes. It is common, but it is not always trivial. A cat with conjunctivitis can also have corneal involvement, pain, or an underlying respiratory infection.

Corneal scratch or ulcer

The cornea is the clear surface at the front of the eye. A scratch or ulcer can happen after a claw injury, rough surface, plant material, shampoo or chemical irritation, or feline herpesvirus.²

Corneal ulcers can be hard to see without special testing. Your vet may use fluorescein stain, a dye that sticks to damaged areas of the cornea and makes ulcers visible.²

This is one reason home guessing is risky. A cat can have a painful ulcer even when the eye just looks watery or half-closed.

Glaucoma

Glaucoma means the pressure inside the eye is too high. It is less common in cats than in dogs, but it is serious.

Warning signs can include a partially closed eye, squinting, rubbing, watery discharge, a red or bloodshot eye, swelling or bulging, a cloudy or bluish cornea, a dilated pupil, lethargy, or sudden vision changes. Acute glaucoma is an emergency and can cause blindness unless the pressure is reduced quickly.³

Any eye that looks swollen, bulging, cloudy-blue, or suddenly blind deserves emergency attention.

What Not to Do at Home

Do not use human eye drops unless your vet specifically tells you to. Some drops are unsafe for cats, and steroid-containing drops can make certain corneal injuries much worse.

Do not use leftover pet eye medication from a previous problem. Eye diseases can look similar but need different treatment.

Do not try to flush the eye aggressively. If there is a chemical exposure, call a vet or emergency clinic immediately for instructions.

Do not let your cat keep rubbing the eye. Rubbing can turn a scratch into a deeper injury. If you have an Elizabethan collar and your cat tolerates it, put it on while you arrange veterinary care.

Do not wait because "it is only one eye." One-sided squinting is often exactly how scratches, ulcers, foreign bodies, and trauma show up.

What You Can Do Before the Vet

Keep your cat indoors and in a dim, calm room. Bright light can make painful eyes feel worse.

Take a clear photo or short video if your cat will tolerate it. Capture both eyes in the same frame if possible. This helps show whether one pupil, eyelid, or eye surface looks different.

Stop them rubbing the eye. Use an E-collar if you have one and your cat tolerates it. If the collar causes major stress, focus on quiet supervision and get veterinary advice.

Call the clinic and say exactly what changed:

• Which eye is affected
• When it started
• Whether the cat is squinting or keeping the eye closed
• Whether discharge is clear, cloudy, yellow, green, or bloody
• Whether the eye looks cloudy, red, swollen, or bulging
• Whether there was a fight, scratch, fall, plant material, dust, shampoo, chemical, or smoke exposure
• Whether your cat is eating, hiding, lethargic, vomiting, sneezing, or coughing

What Happens at the Vet

Your vet will look at the eyelids, conjunctiva, cornea, pupils, and the inside structures of the eye. Depending on the signs, they may use:

• Fluorescein stain to check for corneal ulcers
• Tear testing if dry eye is suspected
• Eye pressure testing if glaucoma or uveitis is possible
• An ophthalmoscope or light exam to assess deeper structures
• Swabs or other testing if infection is suspected

Treatment depends on the cause. It may involve antibiotic eye drops or ointment, antiviral treatment if feline herpesvirus is suspected, pain relief, anti-inflammatory treatment, an E-collar, or referral to a veterinary ophthalmologist for severe ulcers, glaucoma, trauma, or internal eye disease.

The important part is that the treatment should match the diagnosis. "Red eye" is not one disease.

When It Is an Emergency

Seek emergency care now if you see:

• Eye swelling or bulging
• Cloudy, blue-white, or opaque eye surface
• Sudden blindness or bumping into objects
• One pupil much larger than the other
• Blood in or around the eye
• A known scratch, fight wound, thorn, chemical, or shampoo exposure
• Severe pain, constant squinting, or the eye held fully shut
• Lethargy, collapse, breathing trouble, repeated vomiting, or a cat who seems very unwell

These signs can point to trauma, glaucoma, deep ulceration, infection, or internal eye disease. The goal is not just comfort. It is protecting vision.

The PetCare AI Way to Think About It

Eye changes are a good example of when a calm checklist helps and delay does not.

PetCare AI can help you describe the signs clearly, decide whether the pattern sounds same-day or emergency, and prepare the details your vet will ask for. It cannot stain the cornea, measure eye pressure, remove a foreign body, or prescribe the right medication.

If your cat is squinting or keeping an eye closed, the most useful answer is usually: get the eye checked today.

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Not sure how urgent your cat's eye signs are? Run a free 60-second triage with PetCare AI - describe what the eye looks like, when it started, and whether your cat is squinting, rubbing, or acting unwell.

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Sources

Footnotes

1. VCA Animal Hospitals, Conjunctivitis in Cats. https://vcahospitals.com/know-your-pet/conjunctivitis-in-cats ↩ ↩²

2. VCA Animal Hospitals, Corneal Ulcers in Cats. https://vcahospitals.com/know-your-pet/corneal-ulcers-in-cats ↩ ↩² ↩³

3. VCA Animal Hospitals, Glaucoma in Cats. https://vcahospitals.com/know-your-pet/glaucoma-in-cats ↩