CONDITION
Eosinophilic Keratitis in Cats
Eosinophilic keratitis is a condition in which the surface of the eye—the cornea—becomes inflamed and infiltrated by a particular type of immune cell called an eosinophil. Over time, this can lead to a characteristic pink, fleshy, or granular appearance on part of the cornea, often starting at the outer edge and spreading inward. The condition is seen almost exclusively in cats and tends to affect one or both eyes. Owners often notice a change in the appearance of the eye itself: a cloudy, pink, or roughened patch on the normally clear surface, sometimes accompanied by mild redness or discharge. The eye may look irritated, and some cats squint or rub at the affected side. Because the cornea is involved, the visual clarity of that eye can be reduced, though many cats continue to navigate well, particularly if only one eye is affected or the change has been gradual. This page explores the signs that may prompt concern, what is understood about the immune process driving the condition, how it is investigated and distinguished from other causes of corneal change, and the range of approaches used to manage it over time.
Why this matters now
Eosinophilic keratitis can appear at any age, but tends to be recognised most often in young to middle-aged cats, typically between two and six years old. There is no strong sex predisposition, and whilst the condition is seen across many breeds, domestic shorthair cats represent the majority of cases simply by population size. In some cats, a history of feline herpesvirus infection elsewhere in the eye or upper respiratory tract may precede the development of corneal changes, though this link is not present in every case.
The condition often begins as a small, subtle area of discolouration or roughness at the outer edge of the cornea, where it meets the white of the eye. Over weeks to months, this patch may gradually spread towards the centre, becoming more raised, vascular, and opaque. The rate of progression varies widely between individuals; some cats develop extensive corneal involvement within a few months, whilst others show only slow, limited change over years. Without intervention, the affected area may eventually obscure a significant portion of the visual field, though total blindness from this condition alone is uncommon.
Signals & patterns
Early signals
Pink or cloudy patch on the eye
A small area at the edge of the cornea may take on a faint pink, greyish, or frosted appearance, distinct from the usual clear surface. This is often noticed first in good light or when looking directly at the cat's face.
Mild squinting or blinking
The affected eye may be held slightly more closed than the other, or the cat may blink more frequently on that side. This can reflect subtle irritation or discomfort, though many cats show no obvious distress.
Watery or mucoid discharge
A small amount of clear or slightly thick discharge may collect at the inner corner of the eye. This is often intermittent and may be more noticeable in the morning or after sleep.
Increased redness at the eye margin
The tissues around the affected part of the cornea, particularly near the outer edge where the white of the eye meets the cornea, may appear more pink or injected than usual. This reflects increased blood vessel activity in response to the inflammation.
Later signals
Thickened, granular surface texture
The affected area may develop a raised, rough, or cobblestone-like appearance, sometimes described as fleshy or proliferative. This texture can be visible to the owner and may catch the light differently from the surrounding cornea.
Spreading opacity towards the centre
The initial patch may enlarge and move inward across the cornea, gradually obscuring more of the clear surface. The cat may begin to show subtle changes in behaviour, such as hesitating before jumping or misjudging distances, particularly if both eyes are involved.
Visible blood vessels crossing the cornea
Fine red lines or networks of blood vessels may become apparent on the surface of the cornea, extending from the edge towards the affected area. These represent the body's attempt to supply the inflamed tissue with immune cells and nutrients.
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
Last reviewed: Invalid Date ·