Why Does My Cat's Eyes Keep Tearing Up: Nasolacrimal Duct Blockage Causes and Care

Does your cat's eyes always look wet with reddish-brown marks at the corners, like they're "crying"? Actually, cats don't tear up to express emotions—it's a sign something's wrong with their eyes. Nasolacrimal duct blockage is a common cause. Understanding the causes and proper care helps maintain your cat's bright, healthy eyes.

## How Do Tear Stains Form?

Cat tears contain an iron compound called "porphyrin." When tears are produced excessively and flow from the eye corners, porphyrin oxidizes upon contact with air and bacteria on the fur, turning reddish-brown. Over time, this creates noticeable tear stains.

Additionally, tears carry red yeast, which can accumulate over time and make the eye area fur progressively darker—particularly noticeable in white or light-colored cats.

## Common Causes of Cat Tearing

### Nasolacrimal Duct Blockage

The nasolacrimal duct drains tears from the eyes to the nasal cavity. Normally, tears drain smoothly without accumulation. But when the duct is narrow or blocked, tears can only overflow from the eye corners.

**Congenital Blockage:**

* Related to facial structure
* More common in flat-faced, short-nosed cats (like Persians, Exotic Shorthairs)
* Greater duct curvature makes tear drainage difficult

**Acquired Blockage:**

* Upper respiratory infections (feline herpesvirus is a common cause)
* Previous conjunctivitis or nasolacrimal duct inflammation
* Post-inflammation narrowing of the nasolacrimal duct

### Eye Infections or Inflammation

* Conjunctivitis, keratitis
* Bacterial or viral infections
* Accompanying symptoms: red, swollen eyes; yellow-green discharge; frequent blinking

### Allergies and Environmental Irritants

Environmental irritants can cause increased tear production:

* Household dust, perfume, secondhand smoke
* Cat litter dust
* Outdoor pollen
* Cleaning product residue

### Food Allergies

Certain food ingredients may trigger allergic reactions, leading to increased eye secretion. Common allergens include grains and specific meat proteins.

### Ear Infections

The ear canal and eyes share connected nerves, so ear infections can sometimes affect eye secretion.

## Identifying Different Symptoms

| Discharge Characteristics | Possible Cause | Recommended Action |
|---------------------------|----------------|-------------------|
| Clear and watery | Irritation, allergies, mild blockage | Observe and maintain cleanliness |
| Reddish-brown and sticky | Nasolacrimal duct blockage, chronic irritation | Home care; see vet if persistent |
| Yellow-green | Bacterial or viral infection | See vet promptly |
| Single eye tearing | Foreign object, unilateral blockage, injury | Examine eye and see vet |

## Home Care Methods

### Daily Cleaning

1. Dampen a cotton ball with warm water or use pet-specific wet wipes
2. Gently wipe from the eye corner outward
3. Use a different cotton ball for each eye to prevent cross-contamination
4. Avoid products containing alcohol or irritating ingredients

### Nasolacrimal Duct Massage

For mild blockage, try massage to help drainage:

1. Clean around the eyes with a wrung-out warm towel
2. Gently massage from the bridge of the nose toward the eyes
3. Focus on the nasolacrimal duct area on both sides of the nose
4. About 5-10 minutes each time, 2-3 times daily

### Trim Eye Area Fur

Long-haired cats should have fur around the eyes trimmed regularly to avoid:

* Fur irritating the eyes
* Tears soaking fur and worsening stains
* Bacteria growing in moist fur

### Nutritional Supplements

* **L-lysine**: Common eye and nasal health supplement for cats, especially helpful for cats previously infected with feline herpesvirus
* **Lutein**: Eye health ingredient, free-form has better absorption
* **Omega-3 fatty acids**: Helps reduce inflammation

## Environmental and Dietary Adjustments

### Environmental Control

* Clean regularly to reduce dust
* Avoid using perfume or air fresheners near your cat
* Choose low-dust cat litter
* Maintain good indoor air circulation

### Dietary Considerations

* Choose hypoallergenic or single-protein food
* Avoid known allergens
* Ensure adequate water intake

## When to See the Vet?

See a veterinarian promptly in these situations:

* Eye discharge turns yellow-green
* Eyes are visibly red, swollen, or won't open
* Cat frequently scratches eyes with paws
* Single-eye tearing persists for several days
* Accompanied by sneezing, nasal congestion, decreased appetite
* Tear staining suddenly worsens

## Possible Veterinary Examinations and Treatments

### Examination Items

* Detailed examination with ophthalmic instruments
* Schirmer test for tear production
* Fluorescein staining to check for corneal damage
* Nasolacrimal duct patency testing

### Treatment Approaches

* **Mild infections**: Eye drops or ointment
* **Nasolacrimal duct blockage**: Duct flushing with antibiotics
* **Feline herpesvirus**: Long-term L-lysine supplementation, antiviral medication as needed
* **Severe blockage**: May require surgical intervention

## Breeds Prone to Tear Staining

These breeds are more likely to have tear stain issues due to facial structure:

* Persian
* Exotic Shorthair
* Himalayan
* British Shorthair
* Scottish Fold

Owners of these breeds should pay extra attention to daily eye cleaning and regular eye health checks.

Cat tearing is common but shouldn't be ignored. Through daily cleaning, environmental adjustments, and appropriate nutritional supplements, tear stain problems can be effectively improved. If symptoms persist or worsen, seek veterinary care promptly to find the root cause and give your cat bright, healthy eyes.

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**References:**
* [貓咪流眼淚怎麼辦？獸醫解析淚痕原因 - 怪獸部落](https://litomon.com/blog/cattearmark/)
* [貓流眼淚怎麼辦？獸醫解答 - 康健雜誌](https://www.commonhealth.com.tw/article/90773)
* [貓咪眼睛流淚、有紅褐色分泌物？- Cat Garden Hotel](https://www.catgardenhotel.com/2025/05/11/cat-eye-tears-discharge/)
* [貓咪一直流眼淚、眼屎多？- 吉米哈利動物醫院](https://jamesherriotah.com/health-education/ophthalmology-education/cat-keeps-crying/)
* [貓咪臉上總是有淚痕？- 里德貓砂](https://leedecat.com/貓咪臉上總是有淚痕獸醫師告訴你原因及改善方法/)

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