Why Are My Cat's Eyes Red?

Conjunctivitis is the inflammation of ocular conjunctiva (the outermost part of the eye). In humans it is known as pinkeye thanks to the color change in the eyeball. The actual eye may be varying shades of red or pink thanks to the inflammation. Conjunctivitis is perhaps the most common reason for your cat to have red eyes. It can have different causes, but will present with redness and bloodshot eyes.

If your kitty has red eyes caused by conjunctivitis, it is likely the result of a viral infection caused by feline herpesviruses. This can be complicated by opportunistic bacteria. It can affect not only one eye (unilateral), but commonly affects both eyes (bilateral) thanks to its acute contagiousness.

When our cat suffers from viral infection induced conjunctivitis, our cats eyes will be red and swollen. As it develops, it is possible for pus to exude and the eyes to close over as the crust sticks eyelashes together. This type of infection is similar to that which occurs in kittens which have yet to open their eyes (at around 8 to 10 days). Here we will see secretion come through as the swollen eyes begin to open. At this stage you won't be able to see if they are red, but you will see the swelling.

Allergies can cause the cat's eyes to become red also. If this occurs, the eyes will need cleaning and an antibiotic treatment will likely be administered. This can only be done by a veterinarian. If untreated, this condition can cause ulcers which can lead to loss of the eye, especially in kittens.

A corneal ulcer (ulcerative keratitis) is an injury which occurs in the cornea, sometimes as a result of the untreated conjunctivitis mentioned above. The typical cause of dendritic ulcers is the herpesvirus. Dendritic cells are part of our immune system which is in contact with the external environment^[1]. Ulcers are classified according to depth, size and origin, so it is necessary for a vet to see them so they can be categorized properly. In the most serious cases of ulcers on the eye, a perforation can occur which is a very serious eye condition. This is another reason to emphasize the importance of seeing a vet.

An ulcer can explain why our cat's eyes are red, but they will also develop pain, excessive tearing, purulent discharge and the eyes will remain shut. You can also see changes in the cornea such as roughness or pigmentation. To confirm the diagnosis, the veterinarian will place a few drops of the substance fluorescein in the eye. If an ulcer is present, this substance will cause it to turn green.

In addition to untreated conjunctivitis, corneal ulcers are often caused by trauma. This could be a scratch or the entrance of a foreign body to the eye which we will discuss further below. It can also form from abscess or tumors which form on the eye socket. Chemical or thermal burns can also lead to scarring and corneal ulcers.

The most superficial corneal ulcers in cats usually respond well to antibiotic treatment. During the course of antibiotics, we will have to attach an Elizabethan collar to prevent further damage. And if the ulcer is not solved with drugs, it will be necessary to resort to surgery. It is also important to note that a perforated ulcer is considered a surgical emergency.

If you see your cat with red eyes, it might be explained as a result of an allergic reaction. Cats can react to different allergens in different ways and may depend on the individual cat. Alopecia, miliary dermatitis, feline eosinophilic complex, itching, persistent cough, sneezing and respiratory problems can all occur as well as redness in the eye.

If we think our cat may be allergic to something, the vet will be the best way to find the root allergen. This most commonly occurs i cats which are 3 years old or under. The ideal is to avoid exposure to the allergen, but if this is not always possible, you will have to treat the symptoms.

As we have discussed, while conjunctivitis causes a cat's eye to turn red, the cause of conjunctivitis is variable. Foreign bodies can cause a cat's eye to turn red and watery. If this occurs, the cat will likely try to rub their eye to remove it. It is sometimes obvious that the cat has something in their eye, but not always. It usually depends on the size of the object. Foreign bodies which enter a cat's eye are most commonly plant material such as a splinter or other organic material. However, dust, glass, metal or other objects can get in there.

If we can see the foreign body is obvious and large enough to see, then we may be able to extract it ourselves. First we can try flushing it out with water by wetting clean gauze and squeezing it over the eye. Even better is if we use saline solution. If it does not come out with flushing, but we see it come out of the eye, we might be able to remove it with a cotton swab or gauze soaked in saline solution. However, we need to be careful we don't do more damage to the eye, so if you are unsure of what you are doing, then it is best to let a professional do it. Also, you will be unlikely to do this on your own as you will need to restrain the cat.

If we cannot see the foreign body or it seems to be irretrievably stuck, then we should immediately go to the vet. An object inside the eye can lead to ulcers or infections.

The main characteristic of the ocular alteration uveitis is the inflammation of the uvea, the pigmented part of the eye. It usually occurs due to systemic disease, but it can be brought on by trauma such as experienced during a fight or when hit by a car. There are different types of uveitis in cats depending on the area which is affected. It is an inflammation which causes pain, edema, decreased intraocular pressure, contraction of the pupils, closed eye, tearing, retraction of the eyeball, inflammation of the third eyelid and redness. This can be a serious condition if untreated, so it is very important to take an affected cat to the vet.

Among the systemic disease which can cause uveitis are toxoplasmosis, feline leukemia, feline immunodeficiency, infectious peritonitis, some types of mycosis, bartonellosis or herpesvirus. An untreated case of uveitis can result in cataracts, glaucoma, retinal detachment or even blindness. Treatment for uveitis will depend on the cause. In some of the more acute cases such as cancer, then the eye may need to be removed. However, less severe cases may need anti-inflammatory treatment as well as keeping their immune system strengthened. If glaucoma is present this must be treated concurrently. This is why taking your cat to the vet is so important as the right course of treatment is not always straight forward.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

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