Cats’ eyes deteriorate as they get older, but this doesn’t mean that eye discharge is “normal.” Cats with runny eyes will feel very uncomfortable and may struggle to see clearly.
If you look at the color and texture of your cat’s eye discharge, this may help you determine the underlying cause. We’ll explore the causes of eye discharge in cats, the symptoms, and treatments.
- 1 Why Do Older Cats Have Eye Problems?
- 2 What Causes Runny Eyes in Cats?
- 3 Signs of a Systemic Infection
- 4 How Do Contagious Diseases Spread between Cats?
- 5 Can Eye Discharge Be Treated?
- 6 Other Eye Problems in Senior Cats
- 7 How to Promote Good Eye Health in Senior Cats
- 8 Why Does My Cat Have Runny Eyes?
Why Do Older Cats Have Eye Problems?
Cats over the age of 10 are more likely to have eye problems, but why should this be?
- They may have a weakened immune system so are more susceptible to infections.
- Some older cats find it hard to absorb all the nutrients from their diet. A nutrient deficiency might cause Their eye problems.
- Old age can make grooming a lot harder, leaving senior cats open to infections.
- Older cats are more injury prone due to arthritis, and deteriorating bone health, so they may damage an eye through injury.
- Diabetes, high blood pressure, and hyperthyroidism can cause eye problems, and these conditions are more common in old age.
So, if you have a senior cat, you should make her eye health a priority.
Basic Anatomy of the Cat’s Eye Explained
To understand eye health in cats, it’s vital to understand the components of the eye. These include:
- Pupil – The black center
- Iris – This is the colored area that surrounds the pupil
- Sclera – The whites of the eyes
- Conjunctiva – The pink membrane that surrounds the sclera (the whites of the eyes) and lines the inside of the cat’s eyelids. The outermost edges of the eyeball are covered in this pink membrane sheath.
- Cornea – This is the clear, dome-shaped material that coats the front of the eyeball (made up of 7 extremely thin layers)
- Eyelid / Third Eyelid (Plica) – The third eyelid moves horizontally across the eye and helps to protect the eye if necessary. If the cat is in good health, it is usually not visible
- Tear Ducts – These control the number of tears released into the eye.
If you can get your head around the basic anatomy of the cat’s eye, it’s easier to understand the different types of eye discharge and what they mean.
Symptoms of Eye Discharge in Cats
If your cat has weeping eyes, you’ll want to know what’s causing this issue. Before we explore the underlying causes of runny eyes, ask yourself: which of these symptoms does your cat have?
- Conjunctivitis – Conjunctivitis refers to any inflammation of the eye’s conjunctiva. This is the pink membrane which surrounds the whites of the eyes and lines the inside of the cat’s eyelids. Conjunctivitis causes discharge, squinting, and redness.
- Epiphora – This occurs when there are too many tears in the cat’s eyes. As you’d imagine, this causes very wet, drippy eyes and perhaps some staining to the fur underneath the eyes.
- Keratitis (or Corneal Problems) – This is an inflammation of the cornea (the dome-shaped protective later at the front of the eye). The cornea may look rough, ulcerated, or damaged, and this is likely to cause weeping and discharge.
Conjunctivitis, epiphora, and keratitis are not the cause of eye discharge. Rather, they are a collection of symptoms that can be caused by many different factors.
What Causes Runny Eyes in Cats?
The following conditions all have the potential to cause eye discharge in cats:
- Viral diseases such as feline herpesvirus 1 (FHV-1) or feline calicivirus
- Systemic bacterial diseases such as feline infectious anemia (mycoplasma)
- Systemic fungal diseases such as feline blastomycosis
- A localized fungal or bacterial infection inside the eye
- Dust, dirt, or cat hair aggravating the eye
- Tear duct problems
- Parasites, such as toxoplasmosis
If your cat is diagnosed with conjunctivitis, epiphora, or keratitis, at least one of the above causes will be to blame.
Conjunctivitis in Cats
Conjunctivitis is the most common eye disorder in cats. It occurs when the pink membrane between the whites of the eye and the eyelid becomes inflamed. This often leads to symptoms such as:
- The conjunctiva becomes very pink/red
- Discharge – may be clear, yellow or green.
- Signs of “cat flu” – drippy nose, lethargy, diarrhea, mild fever, etc.
What causes conjunctivitis? Allergies, injuries or irritating substances can cause it. However, more often than not, conjunctivitis is caused by a systemic infection (an infection that affects the whole body). This could be bacterial or viral.
Signs of a Systemic Infection
Runny eyes indicate that your cat may have caught a virus or another type of contagious disease. This is all the more likely if you recognize the following symptoms:
- The discharge is colored (yellow or green) rather than clear
- The discharge has a mucus-like texture rather than a watery texture
- The discharge is in both eyes
- The cat has flu-like symptoms
Any systemic infection has the potential to cause eye problems, but there are four common diseases vet’s encounter regularly. These include:
1) Feline Herpesvirus-1
Many cats contract feline herpesvirus 1 (FHV-1) at some point in their lives (even cats who’ve been vaccinated against it). Once contracted, FHV-1 can remain dormant for many years – sometimes a whole lifetime. If the virus flares up, this can cause flu-like symptoms as well as eye discharge.
But what causes HPV-1 to flare up? Often, stress is the cause. Humans with the herpes simplex virus often have a flare-up of cold sores when they are particularly stressed, so it’s no surprise that stress affects cats in a similar way.
Noisy households can be a source of stress for older cats. Also, senior cats may struggle to access their food bowl or litter box if they have joint pain. This can cause them to feel very anxious, so make sure your cat can access everything she needs in the household.
As well as causing conjunctivitis, FHV-1 is known to cause keratitis and corneal eye ulcers.
2) Feline Calicivirus
According to icatcare, feline calicivirus (FCV) is extremely contagious between cats (though not communicable between cats and humans). FCV will almost always cause an upper respiratory tract infection and conjunctivitis (runny, inflamed eyes). Notable symptoms include:
- Coughing and gasping for air
- Runny nose
- Reduced appetite
FCV It is a severe disease that must be treated early. In part, because many cats pick up secondary bacterial infections that can become life-threatening. This is the reason why conjunctivitis should always be checked out by a vet.
3) Feline Chlamydia
Feline chlamydia (chlamydohila felis) is also fairly common in cats. In fact, according to VIN, about 30% of cats with conjunctivitis have feline chlamydia.
Cats with chlamydia usually start to have conjunctivitis symptoms in one eye, and the symptoms transfer to both eyes within a couple of days. The discharge begins out watery but then develops into a thick mucus-like texture.
Another factor unique to feline chlamydia is that cats generally don’t have flu-like symptoms. These cats don’t experience a dip in their energy levels or their appetite. So, even if your cat has no flu-like symptoms, a systemic disease might still be to blame.
4) Feline Infectious Anemia (Mycoplasma)
The previous conditions were all viral, but feline infectious anemia (FIA) is a bacterial disease. Essentially, mycoplasmas (a type of bacteria) pass between animals and leech off their blood. Besides conjunctivitis, this disease causes:
- Sudden weight loss
- Lethargy, perhaps breathlessness
If not treated, FIA can lead to severe anemia and death.
How Do Contagious Diseases Spread between Cats?
The four diseases mentioned above can spread between cats (but not between cats and humans). Some are incredibly contagious, such as feline calicivirus.
Cats who go outdoors or cats who live with other pets are more likely to contract diseases. Infectious diseases can pass between animals in many ways. For example:
- Sharing water bowls or food bowls
- Licking/grooming each other
- Sharing a litter box, or going to the toilet in the same patch of earth
- Inhaling the same air for extended periods
- Sharing bedding (even if not using it at the same time).
If your cat has runny eyes, you should isolate her from other animals until you’ve had a chance to visit the vet.
Keratitis (Corneal Problems) in Cats
The cornea is the delicate dome-shaped sheath that covers the front of the eye. It acts as a barrier to dust, dirt, and harmful UVA/UVB rays. It also helps to distribute the liquid evenly across the surface of the eye. This helps the eye stay supple and supports the cat’s vision.
A damaged, inflamed or ulcerated cornea is referred to as keratitis. The symptoms of keratitis include:
- Very dry eyes
- Sore/burning eyes – redness
- Watery discharge
- An uneven or grainy surface to the eye
- The iris (colored part) may have a mottled appearance
- There may be an ulcer or small laceration on the front of the eye
Allergies, minor injuries or fungi can cause corneal problems. For example, a large dust particle or a small piece of cat litter may scrape the surface of the eye.
However, damage to the cornea is more commonly caused by a systemic disease such as FHV-1. This can occur if FHV-1 is left untreated for an extended period of time.
Cats with keratitis should be seen by a vet immediately. A vet should see an ulcerated cornea as this could develop into uveitis.
What is Uveitis?
This is a very serious – though thankfully rare – eye condition. It occurs when the uveal tract becomes inflamed. This is the middle, internal portion of the eye. If left untreated, it will usually lead to blindness.
So, what are the symptoms of uveitis?
- Trying to rub/scratch the eye
- The third eyelid is visible
- Cloudy eye (although a cloudy eye can also indicate cataracts and glaucoma
Corneal ulcers can develop into uveitis. In most cases, the initial cause is a systemic disease such as a virus (FHV-1), a fungal disease (feline blastomycosis) or a parasite (toxoplasmosis).
Epiphora in Cats
Like conjunctivitis and keratitis, epiphora is not a disease in itself. Rather, it is a group of symptoms that can be caused by different diseases. Essentially, epiphora means a surplus of tears in the eyes.
This surplus of tears can be caused by:
- Most commonly, the tear ducts become blocked, so tears cannot drain away normally. This is often seen in Persian breeds of cat. These cats have flat faces, so it is difficult for tears to drain away effectively.
- Corneal ulcers/ keratitis (because the outermost film on the cornea usually helps distribute tears effectively)
- Viral and bacterial infections may also cause excess tears
Cats with epiphora tend to have very wet eyes, and the tears can stain the skin underneath the eyes. In many cases, the wet tears can appear red or brown which is very worrying from the owner’s perspective because it looks like dried on blood.
To help make your cat more comfortable, you may wish to dab away the wetness every hour or so with a 100% cotton pad but don’t use anything stronger than this.
Also, be very gentle as the eye area is extremely sensitive. Early diagnosis and treatment will help your cat feel better as soon as possible.
Can Allergies Cause Eye Discharge in Cats?
If your cat’s eyes start weeping, this doesn’t necessarily indicate an infection. You could be dealing with an allergy instead. Allergies are still serious.
They can be even more challenging to manage because it’s not always clear what is causing the allergic reaction. Common allergens include:
- Dust Mites
- Flea Bites
- Grass pollen
- Fragrances – especially home cleaning products that contain fragrances
- Foods such as beef and fish
If your cat’s eye discharge is clear and quite watery, this is a good indicator that it could be an allergic reaction. Other symptoms of an allergy include:
Some of these symptoms are similar to an upper respiratory tract infection, so it’s best to speak to your vet to help diagnose the issue.
Can Eye Discharge Be Treated?
In most cases, eye discharge can be treated. Your vet will determine if the discharge is caused by a systemic infection, injury, allergy, irritant, or something else, and then recommend an appropriate treatment. This may include:
If your cat has a bacterial infection such as mycoplasma, a course of oral antibiotics will be prescribed.
Even if your cat has a viral infection, she may have developed a secondary bacterial infection – in which case antibiotics may be required.
According to Cornell, the antibiotic clindamycin can also be used to treat the parasitic infection toxoplasmosis.
Idoxuridine, trifluridine, and cidofovir are often used to treated viruses in cats.
These may be used to treat corneal ulcers/keratosis, or conjunctivitis. Eye drops may contain antibiotics or ingredients to soothe the inflammation.
Unblocking Tear Ducts
A common cause of epiphora is blocked tear ducts. Your cat may require surgery to unblock these. Sometimes, it is possible to unblock them using a saline solution, but the cat will still be put under a general anesthetic.
Keep your Cat’s Eyes Clean
While your cat is in recovery, you can help her to keep her eyes clean. You can dab a fresh cotton pad on her eyes every hour or so to remove the discharge (run the pad under cool water if necessary).
Remember, wear gloves or wash your hands thoroughly afterward. Though most systemic diseases cannot spread between cats and humans, the parasite toxoplasmosis is potentially contagious between cats and humans.
If your cat is diagnosed with this, your vet may offer you specific advice on how to handle your cat while in recovery.
As a preventative measure, vaccinations should be given for common, contagious diseases such as FCV and FHV-1. It’s best for these to be administered to kittens and for booster shots to be given every 1-3 years.
Finally, don’t forget to separate your cat from other animals while she is healing. Most conditions should clear up in 2 – 3 weeks given the right treatment.
Other Eye Problems in Senior Cats
We’ve discussed common conditions that cause eye discharge in older cats. When it comes to senior cats, there are some other eye conditions you should be aware of.
These conditions don’t necessarily cause runny eyes, but they can severely impact a cat’s quality of life. These include:
This condition occurs when too much pressure builds up in the eye. Eventually, this can cause damage to the optic nerve. The cause of glaucoma is not fully understood, but it seems to be linked to diabetes and kidney disease.
These diseases are more common in older age, so it is a condition to be aware of in senior cats. Symptoms include extreme sensitivity to light, lethargy, and bulging eyes.
Cloudy eyes can also be a sign of cataracts. A cataract is a film that grows over the eye, sometimes due to diabetes. This film will limit the cat’s vision. The effects can range from very mild to severe.
This happens when the sebaceous glands in the eyelid become blocked.
Poor grooming can contribute to this condition. If your cat has a sty, the eye may be swollen and red, but there probably won’t be any discharge.
How to Promote Good Eye Health in Senior Cats
Unfortunately, eye health does deteriorate over time. If you are caring for a senior cat, there are some extra things you can do to encourage good eye health:
Feeding your cat a balanced and complete diet will help. Your cat may also benefit from additional doses of lutein, vitamin C, vitamin E, and zeaxanthin.
It’s best to speak to your vet before adding these to your cat’s diet, especially if she has a pre-existing health condition.
Keep your cat clean and groomed to prevent sties and eye infections. Make sure there are no long, wispy pieces of hair aggravating her eyes.
Make sure your cat is a healthy weight. The average cat needs 20 calories per pound of body weight, per day.
This will help to prevent diabetes and other chronic diseases that can impact eye health. Also, if your cat stays a healthy weight, she’ll be more able to groom herself.
Annual Check-up at the Vet
This is extremely important as your cat ages. Some conditions such as cataracts develop very slowly, but an eagle-eyed vet will be able to spot them.
If cataracts are caught early, it’s possible to slow down their development.
Why Does My Cat Have Runny Eyes?
Given the sheer variety of causes, you might still be unsure of what is wrong with your cat. Take a close look at your cat’s eyes and think about the color and texture of the discharge, as well as the color of the eye itself. Then, refer to this summary:
- Dark Pink/Red Eyes (the outermost edges of the eyeball) – The conjunctiva is inflamed, so your cat probably has conjunctivitis. The most common cause is a bacterial or viral infection, but there are other causes too.
- Green or Yellowish Discharge – This usually indicates a bacterial, viral, or fungal infection.
- Clear, Watery Discharge – Allergy or epiphora (excess tears)
- Clear Mucus–like Discharge – Systemic infection – bacterial, viral or fungal
- Brown/Red Stained Fur Under the Eyes – Epiphora (excess tears)
- Mottled Iris – Keratosis/Corneal ulcer.
There are, of course, exceptions to the above. For example, bacterial/viral infections usually produce an eye discharge that has a yellow tinge to it, but the discharge can occasionally be colorless, too.
Remember, even if you think you know what’s causing your cat’s discharge, you shouldn’t delay taking her to the vet. Most of the conditions discussed in this article are serious and require timely treatment.