Nonulcerative Keratitis in Donkeys

Nonulcerative keratitis means the cornea is inflamed, but there is no surface ulcer. The cornea is the clear front window of the eye. When it becomes inflamed, it can turn hazy or blue-white, develop blood vessels, and become painful. In donkeys, the veterinary literature is limited, so your vet often applies what is known from horses and equine ophthalmology more broadly.

This is not one single disease. It is a descriptive term that can include immune-mediated keratitis, eosinophilic keratitis, irritation-related inflammation, dry-eye-associated corneal disease, or deeper corneal problems where the surface still looks intact. Some donkeys have mild discomfort and a cloudy eye. Others develop marked pain, recurrent flare-ups, or vision changes.

The key point for pet parents is that a cloudy eye is never something to watch for long at home. Eye disease can change quickly in equids, and treatment choices depend on whether the cornea is truly nonulcerative, infected, or ulcerated. That is why an eye exam with your vet matters early.

In many donkeys, the exact trigger is not obvious on day one. One important category is immune-mediated keratitis, where the body’s inflammatory response targets the cornea even though there is no simple scratch on the surface. Equine specialists also describe eosinophilic keratitis, a related inflammatory condition that can affect horses and has been reported in at least one donkey.

Other possible causes include chronic irritation from dust, plant material, wind, UV exposure, poor eyelid function, or reduced tear quality. Dry-eye-type disease is less common in equids than in dogs, but poor tear film can still leave the cornea inflamed and vulnerable. Parasites, previous trauma, and recurrent uveitis can also contribute to corneal inflammation or make the eye look similarly abnormal.

A deeper corneal infection, especially a stromal abscess, can sometimes look nonulcerative because the outer corneal layer remains intact and fluorescein stain may be negative. That is one reason your vet may treat a cloudy eye cautiously at first. The appearance alone does not always tell whether the problem is sterile inflammation, infection, or a combination of both.

Diagnosis starts with a careful eye exam. Your vet will look for corneal cloudiness, blood vessel growth, discharge, eyelid problems, pupil changes, and signs of deeper inflammation such as uveitis. A fluorescein stain is one of the most important first tests because it helps show whether the corneal surface is ulcerated. If stain is negative, that supports a nonulcerative process, but it does not rule out deeper infection.

Your vet may also assess tear production, eyelid closure, and the inside of the eye if the cornea is clear enough. In some cases, sedation is needed so the eye can be examined safely and thoroughly. If infection is suspected, your vet may recommend corneal cytology, culture, or referral to a veterinary ophthalmologist.

Because donkeys are less studied than horses, diagnosis often relies on equine ophthalmology principles plus the individual donkey’s history and exam findings. Repeat exams are common. Eye disease can evolve quickly, and a case that looks nonulcerative early may later reveal ulceration, abscessation, or recurrent inflammation.

Not every case can be prevented, especially if the problem is immune-mediated. Still, good eye care can lower risk. Use a well-fitted fly mask when insects, bright sun, or wind are a problem. Reduce exposure to dusty bedding, sharp hay stems, and overgrown pasture plants that can irritate the eye. Check your donkey’s eyes regularly so subtle cloudiness or tearing is caught early.

Prompt treatment of eyelid problems, conjunctivitis, corneal scratches, and recurrent uveitis may also reduce secondary corneal inflammation. If your donkey has had previous eye disease, ask your vet how often rechecks should be scheduled during high-risk seasons.

Do not apply leftover eye drops from another animal unless your vet says they are appropriate. In equids, the wrong medication can delay healing or worsen infection. Early examination is often the best prevention against a small eye problem becoming a much larger one.