The first time I noticed Luna’s watery eye, I thought she was crying.
I know that sounds silly. Cats don’t cry emotional tears like humans. But there she was, sitting on the windowsill, and a single tear rolled down her cheek from her left eye. Not both eyes. Just the left one.
I scooped her up. I checked her face. I looked in her eye. It was a little red around the edges. The tear was clear—not yellow or green. She blinked at me like “Mom, what are you doing?”
She wasn’t acting sick. She ate her dinner. She played with her toy mouse. She purred when I pet her. But that watery eye stayed. For days. Then weeks.
I did what I always do: I panicked quietly and Googled extensively.
“Cat has watery eye in one eye only.” “Feline eye discharge.” “Is my cat crying?”
The internet gave me a thousand answers, ranging from “it’s nothing” to “your cat is dying.” Neither was helpful.
So I called my vet. And what I learned surprised me. A single watery eye is different from two watery eyes. The causes are different. The urgency is different. And most of the time? It’s not an emergency—but it’s also not something to ignore forever.
If your cat has one watery eye right now, and you’re trying to figure out what’s happening, you’re in the right place. Let me walk you through what I learned about feline epiphora (that’s the fancy medical term for excessive eye watering). Because Luna’s watery eye turned out to be something simple. But it could have been something else entirely.
What Is Epiphora? (The Fancy Word for Watery Eyes)
Epiphora is the medical term for excessive tearing. It’s not a disease itself—it’s a symptom. Like a fever or a cough, it’s your cat’s body telling you that something is wrong somewhere in or around the eye.
Normal tearing: Cats produce tears constantly to keep their eyes lubricated and clean. The tears drain through tiny holes in the inner corners of the eyes (called puncta) and go down the nasolacrimal duct into the nose. That’s why your nose runs when you cry.
Epiphora: Either your cat is producing too many tears, or the tears aren’t draining properly. The result is overflow—tears spilling down the face.
One watery eye vs. two watery eyes: This distinction matters a lot.
| Symptom | Likely Causes |
| One watery eye | Blocked tear duct, foreign object, injury, corneal ulcer, eye infection, entropion (eyelid rolling inward) |
| Two watery eyes | Allergies, upper respiratory infection, conjunctivitis (often viral), anatomical issues (flat-faced breeds) |
Luna had one watery eye. That told my vet to look for something affecting only one eye, not a whole-body issue.
The Tear Drainage System (How It Should Work)
To understand what’s going wrong, you need to know how a cat’s tear drainage system works.
Step 1: Tears are produced by glands above the eye.
Step 2: Tears spread across the eye when your cat blinks.
Step 3: Excess tears drain into tiny holes in the inner corner of the eye (the upper and lower puncta).
Step 4: Tears travel down the nasolacrimal duct (a tiny tube) and empty into the nose.
Step 5: Your cat swallows the tears (gross but true).
If any part of this system is blocked, inflamed, or damaged, you get overflow. Think of it like a sink: if the drain is clogged, water spills over the edge. Your cat’s eye is the sink. The puncta and nasolacrimal duct are the drain.
Cause 1: Blocked Tear Duct (The Most Common)
This is what Luna had. And it’s the most common cause of a single watery eye in cats.
What’s happening: The nasolacrimal duct (the tube from the eye to the nose) is partially or completely blocked. Tears can’t drain, so they spill over the lower eyelid.
Why does it get blocked?
- Debris or mucus (most common)
- Inflammation from a past eye infection (scar tissue narrows the duct)
- Congenital abnormality (cat was born with a narrow or malformed duct)
- Tumor or growth (rare, but possible in older cats)
What it looks like:
- Watery eye (clear discharge) that is constant or comes and goes
- Often worse after sleeping (tears accumulate while the eye is closed)
- The eye itself may look completely normal—no redness, no squinting
- Tear staining (reddish-brown fur below the eye, especially in light-colored cats)
Real story: Luna’s watery eye was worse in the morning. I’d wake up, and her left eye would be wet, with a little crust in the corner. By afternoon, it was better. My vet did a simple test: a drop of fluorescein dye in the eye, then waited to see if it came out her nose. In the right eye, the dye appeared at her nostril within 30 seconds. In the left eye? Nothing. Blocked tear duct.
Treatment:
- Warm compress and gentle massage (to try to dislodge debris) – twice daily for 1-2 weeks
- Flushing the duct (vet does this under sedation or local anesthesia) – a saline flush often clears the blockage immediately
- Surgery (for chronic or congenital blockages) – rare, but an option if flushing doesn’t work
Prognosis: Excellent. Most cats respond to flushing and never have the problem again. Luna’s duct was flushed once. She’s been dry-eyed for two years.
Cause 2: Conjunctivitis (Pink Eye)
This is inflammation of the conjunctiva—the pink tissue around the eye. It can affect one eye or both.
What’s happening: The conjunctiva becomes inflamed due to infection (viral or bacterial), allergens, or irritants. The inflammation causes increased tear production AND can block the puncta (drainage holes).
What it looks like:
- Watery eye (clear discharge at first)
- Eye may be red (bloodshot) or pink
- Swollen tissue around the eye
- Squinting or blinking excessively
- Discharge may become thick, yellow, or green if bacterial infection develops
- May start in one eye and spread to the other (especially with viral infections)
Common causes of conjunctivitis in cats:
- Feline Herpesvirus (FHV-1) – the most common cause. Most cats are exposed as kittens. The virus flares up during stress.
- Feline Calicivirus – another common respiratory virus
- Bacterial infections (Chlamydia, Mycoplasma) – more common in young cats or multi-cat households
- Allergies (less common in cats than dogs, but possible)
- Irritants (dust, smoke, perfumes, cleaning sprays)
Treatment: Depends on the cause.
- Viral (herpesvirus): L-lysine supplements, antiviral medication (famciclovir), supportive care
- Bacterial: Antibiotic eye drops or ointment (terramycin, erythromycin)
- Allergies: Remove the allergen, antihistamines (under vet guidance)
When to worry: If your cat’s eye is red, swollen, and has yellow or green discharge, see a vet within 24 hours. Bacterial conjunctivitis won’t resolve on its own and can damage the eye.
Cause 3: Corneal Ulcer (The Painful One)
This is a scratch or erosion on the surface of the eye (the cornea). It’s as painful as it sounds.
What’s happening: Your cat scratched their eye—maybe during a cat fight, maybe from rubbing on something sharp, maybe from a foreign object (grass seed, dust). The scratch exposes nerve endings, causing pain, squinting, and excessive tearing.
What it looks like:
- Watery eye (often the first sign)
- Squinting (the eye is painful in bright light)
- The eye may look cloudy or bluish
- Redness around the eye
- Your cat may paw at the eye or rub their face on furniture.
- Reluctance to open the affected eye
How it’s diagnosed: The vet puts a drop of fluorescein dye in the eye. The dye sticks to scratches, which glow green under a special light.
Treatment:
- Antibiotic eye drops (to prevent infection)
- Pain medication
- An Elizabethan collar (cone) to prevent rubbing
- In severe cases: surgery (corneal graft)
Urgency: This is not a “wait and see” situation. Corneal ulcers are painful and can worsen rapidly. See a vet within 24 hours.
Real story: A client’s cat, Oliver, had a watery eye and was squinting. The owner thought it was allergies. She waited a week. By the time she came to me, Oliver’s eye was cloudy and he wouldn’t open it at all. The vet found a deep corneal ulcer that was close to rupturing. Two weeks of intensive eye drops and a cone later, Oliver recovered. But he lost some vision in that eye. If she had come in earlier, that might not have happened.
Cause 4: Entropion (The Eyelid Rolling In)
This is a structural problem where the eyelid rolls inward, causing eyelashes and fur to rub against the cornea.
What’s happening: The lower eyelid (or sometimes the upper) curls inward. Every time your cat blinks, hair and skin scrape the surface of the eye. This causes constant irritation, tearing, and pain.
What it looks like:
- Constant watery eye (usually one eye, but can be both)
- Squinting
- Redness
- Your cat may keep the eye partially closed
- You may be able to see the eyelid curling inward (look closely at the lower lid)
Which cats are at risk:
- Persians, Himalayans, and other flat-faced breeds (genetic predisposition)
- Maine Coons and Ragdolls (less common)
- Cats who have had chronic eye infections (scar tissue pulls the eyelid inward)
- Senior cats (loss of eyelid tone)
Treatment: Surgery (entropion repair). The vet removes a small strip of skin below the eye and sutures the eyelid back into the correct position. It sounds scary, but it’s a routine procedure with a high success rate.
Prognosis: Excellent. Most cats are completely cured after surgery.
Cause 5: Foreign Object (Something Stuck in the Eye)
This is exactly what it sounds like: a tiny piece of something is stuck under the eyelid, irritating the eye.
Common culprits:
- Grass seeds or awns (very common in outdoor cats)
- Dust or sand
- Cat fur (especially if your cat sheds a lot)
- Litter dust (clay litters are the worst offenders)
What it looks like:
- Sudden onset of watery eye (one eye)
- Squinting
- Your cat may paw at the eye or rub their face on the carpet
- The eye may be red
- You might be able to see the object if you look closely (use a bright light)
What to do:
- Do NOT try to remove it yourself unless you can clearly see it on the white part of the eye and it’s easy to reach. Using tweezers near a cat’s eye is dangerous.
- Flush the eye with sterile saline (contact lens solution works, as long as it’s preservative-free). Tilt your cat’s head down, aim for the inner corner, and squeeze.
- If flushing doesn’t work, see a vet. They can numb the eye and remove the object with specialized tools.
Urgency: If you can’t flush it out within a few minutes, see a vet within 24 hours. A foreign object can scratch the cornea and cause an ulcer.
Cause 6: Uveitis (Internal Eye Inflammation)
This is inflammation inside the eye itself (not on the surface). It’s less common but more serious.
What’s happening: The uvea (the middle layer of the eye) is inflamed. This can be caused by infection (FIV, FeLV, toxoplasmosis, feline infectious peritonitis), trauma, or autoimmune disease.
What it looks like:
- Watery eye
- The eye may look cloudy or have a different color
- The pupil may be smaller in the affected eye (or irregularly shaped)
- Redness around the colored part of the eye (not just the white part)
- Your cat may be sensitive to light
- Often accompanied by other symptoms (lethargy, fever, poor appetite)
Urgency: This is an emergency. Uveitis is painful and can lead to glaucoma and blindness if not treated. See a vet immediately.
Cause 7: Breed Predisposition (Flat-Faced Cats)
If you have a Persian, Himalayan, Exotic Shorthair, or British Shorthair, watery eyes might just be… part of life.
What’s happening: Flat-faced (brachycephalic) cats have shallow eye sockets and prominent eyes. Their tear ducts are often compressed or abnormally shaped. Tears don’t drain well. The result? Chronic epiphora.
What it looks like:
- Constant watery eyes (usually both, but one can be worse)
- Severe tear staining (reddish-brown fur below the eyes)
- The eyes themselves look healthy (no redness, no squinting, no discharge)
What to do:
- Regular cleaning (wipe the fur below the eyes daily with a warm, damp cloth)
- Tear stain removers (Angel’s Eyes, Eye Envy – use with caution, some contain tylosin which is an antibiotic)
- Vet check to rule out other causes (entropion is common in Persians and may need surgery)
Real story: A client’s Persian cat, Gizmo, had watery eyes since kittenhood. The owner assumed it was normal for the breed. At age 5, Gizmo started squinting. The vet found that Gizmo had entropion that had gone undiagnosed for years because everyone thought the tearing was “just a Persian thing.” After surgery, Gizmo’s eyes were dry for the first time in his life.
Lesson: Don’t assume watery eyes are “just the breed.” Have a vet check at least once to rule out treatable causes.
The Tear Staining Problem (Red-Brown Fur)
If your cat has had a watery eye for a while, you’ve probably noticed the fur below the eye turning reddish-brown. This is tear staining.
What causes the color: Tears contain porphyrins (iron-containing molecules). When tears sit on fur, the porphyrins oxidize and turn red-brown. It’s not blood. It’s not dangerous. It’s just cosmetic.
How to clean tear stains safely:
- Warm water on a soft cloth (daily)
- Diluted hydrogen peroxide (1 part peroxide to 10 parts water) – use sparingly, avoid the eye
- Cornstarch (apply dry, wipe off) – absorbs moisture
- Commercial tear stain removers (read labels carefully – avoid those with bleach or antibiotics unless prescribed)
What NOT to use: Human makeup remover, bleach, alcohol, or anything with fragrances.
The real solution: Treat the underlying cause of the watering. Once the eye stops watering, the staining will grow out with the fur.
The “When to Worry” Decision Guide
Not all watery eyes are emergencies. But some are.
Call your vet TODAY if your cat’s watery eye also has:
| Symptom | Why It’s Urgent |
| Squinting or keeping the eye closed | Pain (corneal ulcer, uveitis, foreign object) |
| Redness (especially around the colored part of the eye) | Uveitis, glaucoma, or infection |
| Cloudiness or bluish tint to the eye | Corneal ulcer or glaucoma |
| Thick yellow or green discharge | Bacterial infection |
| Your cat is rubbing or pawing at the eye | Foreign object or pain |
| Your cat seems lethargic, not eating, or has a fever | Systemic illness (FIV, FeLV, FIP, toxoplasmosis) |
Schedule a non-emergency vet visit this week if:
- Watery eye has been present for more than a week with no other symptoms.
- Tear staining is getting worse despite cleaning.
- Your cat is a flat-faced breed and has never had an eye exam.
- The watery eye comes and goes (intermittent blockage or allergies).
You probably don’t need a vet immediately if:
- Watery eye started today, the eye looks normal, and your cat is acting fine.
- You can see a foreign object and flush it out easily.
- Your cat has a history of a blocked tear duct, and this looks the same as last time.
But when in doubt? Call the vet. Eyes are fragile. A $50 exam is cheaper than emergency surgery.
At-Home Care for Watery Eyes (Safe Things to Try)
While you’re waiting for the vet or managing a chronic condition, here’s what you can do at home.
Safe: Warm Compress
What to do: Soak a soft cloth in warm (not hot) water. Wring it out. Hold it against your cat’s closed eye for 1-2 minutes.
Why it works: The warmth helps loosen debris and may help open a blocked tear duct. It also soothes irritation.
How often: Twice daily.
Safe: Gentle Massage
What to do: After the warm compress, use your fingertip to gently massage the inner corner of the eye (where the tear duct is). Small, circular motions. Light pressure only.
Why it works: Can help dislodge mucus or debris blocking the duct.
How often: Twice daily, for 30 seconds each time.
Safe: Saline Flush (Sterile Only)
What to do: Use preservative-free sterile saline (contact lens solution works). Tilt your cat’s head down. Squeeze saline into the inner corner of the eye. Let it run out.
Why it works: Flushes out dust, debris, and loose discharge.
When to use: If you see visible debris or if the eye seems irritated but not infected.
NOT Safe: Human Eye Drops
Never use: Visine, Clear Eyes, or any redness-relief drops. They contain vasoconstrictors that can damage a cat’s eyes.
Never use: Anything with antibiotics not prescribed by a vet. You could use the wrong type and make the infection worse.
Never use: Anything with steroids (like many allergy drops). Steroids can worsen corneal ulcers.
What the Vet Will Do (So You’re Prepared)
If you take your cat to the vet for a watery eye, here’s what to expect.
Step 1: History and Exam
The vet will ask: When did it start? One eye or both? Any other symptoms? They’ll examine the eye with an ophthalmoscope (magnifying light).
Step 2: Fluorescein Stain Test
A drop of orange dye goes into the eye. The vet shines a blue light. Any scratches on the cornea will glow green. This test also checks if the tear duct is open—if the dye appears at the nose within a minute, the duct is open. If not, it’s blocked.
Step 3: Schirmer Tear Test (if needed)
A small strip of paper is placed under the eyelid to measure tear production. This checks for dry eye (ironically, dry eye can cause watery eyes because the eye produces poor-quality tears that don’t stay on the eye).
Step 4: Eye Pressure Test (tonometry)
A small probe touches the eye to measure pressure. This checks for glaucoma (high pressure) or uveitis (low pressure).
Step 5: Nasolacrimal Duct Flush (if blockage is suspected)
The vet numbs the eye, then inserts a tiny cannula (tube) into the punctum and flushes saline through the duct. If it’s blocked, the flush often clears it immediately.
Cost: Basic eye exam and stain test: $50-100. Duct flushing: $100-200. Advanced testing (pressure, tear production): $50-100 each.
FAQ
Why is only ONE of my cat’s eyes watering?
A single watery eye usually indicates a problem localized to that eye: a blocked tear duct, foreign object, corneal scratch, entropion, or an eye infection that hasn’t spread. Two watery eyes are more likely to be allergies, upper respiratory infection, or a breed-related issue.
Can cat allergies cause only one watery eye?
It’s uncommon but possible. Allergies usually affect both eyes symmetrically. If only one eye is watering, suspect a blocked duct or local irritation first.
My cat’s eye is watering and she’s sneezing. Is that an emergency?
Sneezing + watery eye (especially if both eyes are affected) often points to an upper respiratory infection (herpesvirus or calicivirus). This is usually not an emergency unless your cat stops eating or has difficulty breathing. See a vet within a few days.
How do I clean my cat’s watery eye at home?
Use a soft cloth or cotton ball dampened with warm water. Wipe from the inner corner outward. Use a fresh cotton ball for each wipe. Never use the same cloth on both eyes (you could spread infection). Dry the fur gently afterward.
Can I use Neosporin on my cat’s eye?
No. Never put Neosporin or any triple antibiotic ointment in a cat’s eye. These products contain neomycin, which can cause severe allergic reactions in cats (facial swelling, anaphylaxis). Use only vet-prescribed eye medications.
My cat’s watery eye has brown discharge. Is that normal?
Brown or reddish-brown discharge is usually oxidized tears (tear staining). It’s not an emergency. However, if the discharge is thick, sticky, or has a different color (yellow, green), that’s a sign of infection.
Final Thoughts: Luna’s Happy Ending
Luna’s watery eye turned out to be a blocked tear duct. The vet flushed it. It took 90 seconds. Luna was annoyed but unharmed. The watery eye stopped within 24 hours.
That was two years ago. It hasn’t come back.
But here’s what I learned: I could have ignored it. I could have assumed it was nothing. I could have wiped her eye every day and never known that a simple fix was available.
Don’t be me. Don’t assume.
If your cat has one watery eye that lasts more than a week, see a vet. Not because it’s an emergency. Because it might be an easy fix. And even if it’s not, knowing what you’re dealing with is better than worrying in the dark.
Eyes are precious. Your cat only has two. They depend on you to notice when something is wrong.
You noticed. That’s the first step.
Now take the next one.