Corneal Ulceration
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
Emergency presentation is possibleRapid deepening, leakage, iris in the wound or loss of pupillary response requires emergency ophthalmic referral.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
A corneal ulcer is loss of the cornea’s surface epithelium, usually after trauma from plant material, dust, a foreign body or eyelid injury. The exposed stroma is painful and readily colonised by bacteria or fungi. Horses are especially prone to aggressive fungal keratitis, so a seemingly small scratch can progress rapidly.
Signs include sudden squinting, tearing, light avoidance, swollen eyelids, corneal cloudiness and a small pupil from reflex uveitis. Simple superficial ulcers have no stromal loss or infiltrate and often heal within about a week. Complicated ulcers show white or yellow infiltrate, stromal loss, malacia or “melting”, deepening, vascularisation or failure to heal. A descemetocele leaves only the deepest membrane and can perforate with minimal pressure.
Pain intensity does not reliably indicate depth, and the horse may open the eye as sensory nerves are destroyed even while melting worsens. Topical corticosteroid is dangerous in an ulcer because it suppresses defence, slows healing and promotes fungal and collagenase activity. Leftover combination eye ointment should never be applied before fluorescein testing.
Complications include stromal abscess, iris prolapse, severe uveitis, cataract, loss of vision and rupture of the globe. Prognosis is excellent for an uncomplicated superficial lesion and guarded with central deep fungal infection or perforation. Every equine ulcer warrants veterinary examination and scheduled rechecks; improvement in squinting alone is not proof that the cornea has regained thickness.
The equine cornea's large exposed surface and fungal-rich environment make contaminated plant injuries particularly hazardous. Enzymes from microbes and inflammatory cells can liquefy stroma, creating a melting ulcer that deepens over hours. A descemetocele may stain only around its edge, and reduced pain can perversely accompany worsening depth when corneal nerves are destroyed.
Central scarring can impair vision even after infection and pain have resolved.
Screening & Early Detection
The eye is examined with focal illumination after vision and pupillary responses are assessed. Fluorescein dye adheres to exposed stroma and maps most epithelial defects; a descemetocele may have a dark unstained centre surrounded by green. Eyelids and conjunctival sacs are searched for a retained foreign body, and tear production, facial nerve function and corneal sensitivity are considered in recurrent cases.
Stromal loss, infiltrate or malacia prompts corneal cytology plus bacterial and fungal culture before medication when possible. Tonometry and anterior-chamber examination assess reflex uveitis and glaucoma risk. Photographs and measurements document depth and spread. A sealed stromal abscess may not retain fluorescein despite deep infection, so stain negativity does not make every cloudy painful cornea safe for steroid.
Simple ulcers are rechecked within several days; complicated ulcers may need daily or more frequent assessment. Rapid deepening, leakage, iris in the wound or loss of pupillary response requires emergency ophthalmic referral. The horse is protected from rubbing during examination and transport.
Treatment & Management
A simple ulcer receives a topical broad-spectrum antibiotic, atropine for painful reflex uveitis and systemic anti-inflammatory medication as required. A fly mask and safe darkened environment reduce irritation. Topical anaesthetic is used only for examination because repeated use is toxic to the cornea and delays healing.
Complicated ulcers need intensive topical antibacterial and antifungal therapy, often through a subpalpebral lavage catheter so frequent dosing is safe. Autologous serum, EDTA or another anticollagenase is added for melting. Cytology and culture refine treatment, but broad therapy starts immediately when perforation risk is high. Systemic antibiotics are reserved for vascularised or perforated disease and other defined indications.
Deep defects, progressive malacia, descemetocele or lacerations involving at least half the corneal thickness require surgical stabilisation with a conjunctival, amniotic or corneal graft. A ruptured eye with visual potential receives emergency microsurgery; a blind irreparably painful globe may require removal. Corticosteroid is withheld until epithelium is intact and infection excluded. Return to work waits for a stable healed cornea and adequate vision, with rechecks for stromal abscess or recurrent uveitis.
A protective cup or mask prevents rubbing without pressing directly on the painful globe.
Breeds or species affected
Akhal-Teke
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Anglo-Arabian
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Arabian
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Barb
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Caspian
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Kathiawari
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Marwari
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Shagya Arabian
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Thoroughbred
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American Quarter Horse
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American Paint Horse
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Appaloosa
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Australian Stock Horse
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Brumby
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Waler
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Morgan
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Standardbred
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American Saddlebred
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Tennessee Walking Horse
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Missouri Fox Trotter
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Rocky Mountain Horse
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Peruvian Paso
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Criollo
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Mustang
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Canadian Horse
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Andalusian
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Lusitano
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Lipizzaner
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Friesian
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Dutch Warmblood
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Hanoverian
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Holsteiner
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Oldenburg
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Westphalian
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Trakehner
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Selle Français
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Belgian Warmblood
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Danish Warmblood
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Swedish Warmblood
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Swiss Warmblood
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Australian Warmblood
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Irish Sport Horse
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Cleveland Bay
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Württemberger
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Zangersheide
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Knabstrupper
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Orlov Trotter
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Camargue
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Icelandic Horse
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Pony of the Americas
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Quarter Pony
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Miniature Horse
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Clydesdale
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Shire
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Percheron
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Belgian Draft
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Suffolk Punch
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American Cream Draft
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Ardennes
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Breton
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Boulonnais
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Comtois
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Dutch Draft
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North Swedish Horse
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Norwegian Fjord
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Haflinger
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Gypsy Cob
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Irish Draught
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Welsh Pony and Cob
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Connemara Pony
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New Forest Pony
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Dartmoor Pony
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Exmoor Pony
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Shetland Pony
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Highland Pony
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Fell Pony
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Dales Pony
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Australian Pony
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Finnhorse
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Black Forest Horse
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