Uveitis in Cats: When a Red or Cloudy Eye Signals Illness

Uveitis in cats is inflammation inside the eye, and it matters far beyond the eye itself, because in cats it is so often a sign that something is wrong in the body as a whole. The signs are a red, cloudy, or painful eye, usually with squinting and a dislike of light. The causes range from infections like feline leukemia and toxoplasmosis to high blood pressure, diabetes, and tumors, which is why a vet treats a case of uveitis by examining the whole cat, not just the eye. It is painful and can threaten sight, so a red or squinting eye is a reason to see the vet promptly. This is a guide to what uveitis is and why it matters, not a diagnosis for your own cat.

The short version: a red, cloudy, or squinting eye, especially one your cat seems to guard or keep shut in bright light, needs a prompt vet visit. Uveitis is painful and can lead to glaucoma and blindness if left alone. Just as important, it is frequently the visible tip of a whole-body illness, so expect your vet to run bloodwork and examine your cat all over, not just to hand you eye drops.

What is uveitis in cats?

Uveitis is inflammation of the uvea, the vascular middle layer of the eye. VCA describes the anatomy: the uvea is the part of the eye made up of the iris (the thin, circular structure that gives the eye its color and controls the size of the pupil), the ciliary body (part of the wall of the eye that makes the fluid that fills the eye) and the choroid (middle layer of the eye). When these inflamed, blood-rich tissues swell and leak, the eye becomes red, cloudy, and sore, which is why cat eye inflammation of this kind looks and feels so different from a simple surface irritation.

It can come on at either speed. As VCA notes, uveitis may occur suddenly (acute uveitis) or may develop more slowly (chronic uveitis), so it is not always a dramatic red eye overnight. Sometimes it is a subtly hazy, slightly off eye that creeps in over weeks.

The signs: a red, cloudy, painful eye

The thing to understand first is that this hurts. VCA is direct: uveitis is a painful condition, and some cats with uveitis will paw at the sore eye while others will avoid any touch. Because cats hide pain so well, the outward signs are often subtle guarding of the eye rather than obvious distress.

A few signs are worth learning to spot. VCA notes that a cat with uveitis may keep the affected eye shut or may squint (blepharospasm) or blink spasmodically, so a cat squinting one eye, holding it half closed when the other is open, is a classic picture. Light bothers her too: most cats will avoid bright lights (photophobia). And the eye itself changes color and clarity, since in most cases the visible parts of the eye will be intensely red, including the sclera (the white part of the eye) and the conjunctiva, and the eye may look cloudy or hazy, sometimes with a change in the color of the iris. A red eye in cats that also squints and shies from light is a very different thing from the painless bluish haze of normal aging, which is covered in the guide to vision and hearing changes. If in doubt, the pain and redness are the tell.

What causes uveitis in cats? Often a whole-body illness

Feline uveitis is never just an eye problem, and that is what sets it apart. VCA makes the point plainly: a complete and thorough physical examination of your cat must be performed since uveitis is a symptom of many generalized illnesses. The inflamed eye is often a window into the rest of the body.

The list of uveitis in cats causes is long, and infections lead it. VCA lists viral infections including feline leukemia (FeLV), feline immunodeficiency virus (FIV), and feline infectious peritonitis (FIP), along with bacterial, fungal, and parasitic causes. Toxoplasmosis is a notable parasitic one: Cornell notes that toxoplasmosis can also affect the eyes and central nervous system (CNS), producing inflammation of the uvea, or pigmented part of the eye (uveitis). Beyond infection, VCA's list includes metabolic disease such as diabetes, high blood pressure, immune-mediated disease, trauma, and eye tumors, which is where cancer such as lymphoma can present in the eye. In many cats a single cause is never pinned down, but the search for one is the whole point.

Why the vet examines the whole cat

Given that list, it makes sense that the vet does not stop at the eye. Because uveitis is so often a symptom of illness elsewhere, the work-up reaches into the body: an eye examination to confirm the inflammation and measure eye pressure, and then blood tests, urine analysis, and sometimes imaging to hunt for the underlying disease. Some of those diseases matter for the household too, since a few of the infectious causes, such as the feline retroviruses, are contagious between cats, so a diagnosis can prompt testing or protecting other cats at home. None of this is to alarm you, but it is why a red eye earns more than a bottle of drops.

Uveitis in cats treatment

Treatment runs on two tracks at once: calming the inflammation in the eye, and treating whatever is driving it. For the eye, anti-inflammatory medication, often corticosteroid or other drops, reduces the pain and the damage, and controlling the inflammation also lowers the risk of the complications, chiefly glaucoma, that can follow. VCA notes that the signs of uveitis are similar to glaucoma, and the two are linked, since untreated uveitis can raise eye pressure over time.

For the underlying cause, the treatment is specific. An infection is treated directly: for toxoplasmosis, for instance, Cornell notes that treatment usually involves a course of an antibiotic called clindamycin, either alone or in combination with corticosteroids if there is significant inflammation of the eyes. A cat with high blood pressure needs that controlled; a cat with diabetes needs it managed. This is why naming the cause matters so much: the drops may settle the eye, but the disease behind it decides how the cat does overall.

How the eye can look, and what it may mean

Use this to describe what you are seeing to your vet, not to diagnose, since only an eye exam can confirm uveitis.

Frequently asked questions

What is uveitis in cats? It is inflammation inside the eye, specifically of the uvea, the middle layer that includes the iris. It makes the eye red, cloudy, and painful. In cats it is important because it is often a sign of a body-wide illness, from infections to high blood pressure, rather than a problem confined to the eye.

Why is my cat's eye red and squinting? A red, squinting eye that shies from light is a classic sign of uveitis, a painful inflammation inside the eye. It needs a prompt vet visit, both to relieve the pain and protect sight, and to look for an underlying cause, because in cats this often points to illness elsewhere in the body.

Is uveitis in cats an emergency? It is not usually a middle-of-the-night emergency, but it is a prompt one. Uveitis is painful and can lead to glaucoma and blindness if untreated, so a red, cloudy, or squinting eye should be seen within a day or so, sooner if the eye is very red, enlarged, or clearly agonizing.

Can uveitis in cats be cured? Often it can be controlled well, and sometimes cured, depending on the cause. Inflammation from a treatable infection or a single event may resolve fully, while uveitis tied to a chronic disease is managed alongside that disease. Early treatment gives the eye the best chance and lowers the risk of lasting damage.

Does uveitis mean my cat has a serious disease? Not always, but it is a reason to look. Because uveitis is a symptom of many generalized illnesses, from feline leukemia to high blood pressure, your vet will check for those. Sometimes no cause is found and the eye is simply treated, but the search is worthwhile because some of the causes are serious and treatable.

The bottom line

An eye is a small thing to watch, but in a cat it can be a large window. A red, cloudy, squinting eye is not only sore in itself; it may be the first visible sign of an illness working quietly elsewhere, which is why the right response is a prompt vet visit and a willingness to look further than the eye. Biscuit's eyes are clear and comfortable, and I would know fast if one turned red or she started holding it shut against the light, because that is the kind of change I would have seen the same day. That is the real lesson of uveitis in cats: treat the eye, yes, but ask what the eye is trying to tell you about the rest of her.

Sources

• VCA Animal Hospitals, Uveitis in Cats
• Cornell Feline Health Center, Toxoplasmosis in Cats