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 possibleA deep or melting ulcer, marked cloudiness, bulging or apparent vision loss requires emergency ophthalmic assessment.
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 a break in the clear outer surface of the eye. The cornea contains many sensory nerves, so even a small ulcer can be intensely painful. Cats may squint, keep the eye closed, rub at the face, avoid bright light or produce excessive tears. The surface can look cloudy or develop a visible defect.
Ulcers have many causes. Trauma from a claw or foreign material, eyelid abnormalities, reduced tear-film protection and feline herpesvirus are important possibilities. Herpesvirus is especially relevant because it can produce characteristic branching or recurrent superficial ulcers and may reactivate after stress. In brachycephalic cats, prominent eyes and reduced corneal protection can increase exposure and injury risk.
A simple superficial ulcer may heal quickly once the cause is removed, while deeper ulcers can progress towards perforation. Infection can accelerate corneal breakdown. A melting ulcer, in which enzymes rapidly digest corneal tissue, is an emergency because the eye can rupture.
The veterinarian also examines eyelid position, tear production and the depth and edges of the lesion.
A red or cloudy eye should not be treated with leftover drops. Corticosteroid-containing eye medication can delay healing and worsen certain infectious ulcers, especially herpes-associated disease. The central goal is to protect the eye, control pain and identify why the corneal surface was damaged in the first place.
Corneal disease should be thought of in terms of depth as well as surface area. A tiny but deep defect can threaten the integrity of the eye more than a broad superficial scratch. That is why repeated staining and close rechecks are often necessary even when the visible redness seems to be improving.
Squinting is one of the most important early warning signs of corneal pain. It confirms loss of the corneal surface and helps define the size and pattern of the lesion.
Screening & Early Detection
A cat that suddenly keeps one eye partly closed, tears excessively, rubs the face or develops corneal cloudiness should be examined promptly even if the eye looked normal earlier in the day.
Fluorescein staining is the standard first test. The veterinarian also checks beneath the eyelids and third eyelid for foreign material and evaluates whether entropion, prominent facial conformation or poor tear-film quality is contributing.
Deep, irregular or rapidly worsening ulcers may need cytology and bacterial culture before treatment is intensified. Herpesvirus is considered when ulcers recur or have a characteristic pattern, although diagnosis is often clinical rather than based on PCR alone.
There is no screening blood test for corneal ulceration. Early detection depends on recognising pain quickly. A visibly deep crater, sudden bulging of the cornea, pus-like material, marked cloudiness or apparent loss of vision requires urgent ophthalmic assessment because perforation can occur.
Diagnosis relies on fluorescein stain, which adheres to exposed corneal tissue and makes an ulcer visible. Cytology or culture may be required for deep, infected or melting ulcers.
Treatment & Management
Treatment is matched to ulcer depth and cause. Simple superficial ulcers are commonly managed with topical medication to prevent or control bacterial infection, lubrication where appropriate and effective pain relief. An Elizabethan collar may be needed to prevent rubbing.
Herpes-associated disease may require topical or systemic antiviral treatment. Corticosteroid eye drops are avoided while an active corneal ulcer is present because they can impair healing and worsen infection. Deep or melting ulcers require intensive treatment, sometimes with frequent antimicrobial drops, anti-collagenase therapy and referral to a veterinary ophthalmologist.
Surgery is considered when the cornea is dangerously thin, perforated or unable to heal with medical treatment. Procedures may provide structural support while healthy tissue repairs the defect.
Follow-up staining confirms that the surface has healed before medication is stopped or changed. Cats often look more comfortable before the cornea is fully repaired, so treatment should not end simply because squinting has improved. Recurrent ulcers need investigation for herpesvirus, eyelid disease or exposure rather than repeated treatment as unrelated injuries.
Deep or infected ulcers can deteriorate within hours, so the prescribed recheck interval is part of treatment rather than an optional follow-up.
Breeds or species affected
Abyssinian
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American Bobtail
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American Curl
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American Shorthair
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American Wirehair
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Arabian Mau
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Aegean
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Australian Mist
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Balinese
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Bengal
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Birman
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Bombay
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British Longhair
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British Shorthair
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Burmese
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Burmilla
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Chartreux
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Chausie
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Colorpoint Shorthair
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Cornish Rex
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Cymric
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Devon Rex
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Domestic Longhair
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Domestic Medium Hair
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Domestic Shorthair
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Donskoy
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Egyptian Mau
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European Shorthair
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Exotic Shorthair
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Havana Brown
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Highlander
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Himalayan
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Japanese Bobtail
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Khao Manee
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Korat
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Kurilian Bobtail
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LaPerm
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Lykoi
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Maine Coon
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Manx
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Minuet
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Minskin
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Munchkin
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Nebelung
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Norwegian Forest Cat
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Ocicat
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Oriental Longhair
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Oriental Shorthair
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Persian
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Peterbald
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Pixiebob
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RagaMuffin
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Ragdoll
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Russian Blue
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Savannah
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Scottish Fold
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Scottish Straight
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Selkirk Rex
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Siamese
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Siberian
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Singapura
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Snowshoe
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Somali
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Sphynx
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Thai
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Tonkinese
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Toybob
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Toyger
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Turkish Angora
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Turkish Van
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Bambino
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Cheetoh
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Dwelf
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Elf Cat
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Genetta
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Kinkalow
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Lambkin
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Serengeti
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Skookum
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Ukrainian Levkoy
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