Researchers to probe troubling eye condition in horses

Eosinophilic keratitis is described as an emerging issue in British equine ophthalmology. Photo: Animal Health Trust

British researchers are hoping a new study will cast fresh light on the distressing eye ailment, eosinophilic keratitis, in horses.

Researchers from the Animal Health Trust are appealing for information from British vets who have seen recent cases of the inflammatory disease that affects the conjunctiva and cornea.

They described eosinophilic keratitis as an emerging issue in British equine ophthalmology.

Despite increased awareness of the condition worldwide, the cause and development of the disease remain poorly understood. It is probably underdiagnosed, they said.

The trust is looking to explore the cause of the disease and determine why some horses are particularly susceptible, exploring, among other things, environmental factors and parasitic infestation that may be a factor in the condition.

Many of the clinical signs of the disease are non-specific and similar to other corneal conditions such as blepharospasm, chemosis, conjunctival hyperaemia, epiphora or perilesional oedema.

More specific signs include caseous mucoid discharge and white/yellow plaques often localised in the peripheral cornea. The degree of pain varies and concurrent ulceration is almost always present. Conjunctivitis may also occur in association with the keratitis or as a unique disease entity.

Eosinophilic keratitis can have variable clinical presentations, from a thick caseous accumulation to a more superficial plaque of “ground-glass” appearance. They may present as chronic non-healing ulcers that respond quickly to the use of topical steroids and/or ciclosporin, or present with marked eye discomfort and require superficial keratectomy to resolve the condition.

Two different corneal locations are classically (though not exclusively) involved in the condition: the medial perilimbal cornea, often under the third eyelid, or the lateral perilimbal cornea, which may progress axially towards the central cornea.

The charity is also helping to improve and assist with diagnosis by providing free cytology tests for corneal scrapes to try to diagnose the condition earlier and therefore avoid secondary complications that could lead to permanent visionary impairment.

Vets who have seen cases that have either been diagnosed or that they suspect to be eosinophilic keratitis this year are being urged to contact Sonia Gonzalez-Medina on 01638 751000 Ext: 1203 or

More information can be found here

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