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CORNEAL ULCERS First broadcast on www.provet.co.uk
Note for Pet Owners:
This information is provided by
Provet for educational purposes only.
You should seek the advice of
your veterinarian if your pet is ill as only he or she can correctly advise
on the diagnosis and recommend the treatment that is most appropriate for
your pet. Topics on this Page:
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Description
The cornea is the front part of the eye. It is usually very smooth and clear but sometimes ulcers can form . An ulcer is a disintegration of the surface layer of cells which leads to an open sore that heals slowly.
Cause
The cause of the disease is not always known, but the commonest are :
- Trauma - direct injury, scratches from running through bushes and undergrowth, fighting (especially cats)
- Foreign objects in the eye - especially common are grass seeds/awns which get stuck behind the third eyelid (called the nictitans) Occasionally paint or other irritant substances get splashed onto the eye and chemically damage the cornea
- Infections
- Abnormal eyelashes - sometimes two rows develop instead of one.
- Growths on the eyelid which rub on the surface of the eye - eg warts
- Entropion - the eyelid that rolls in can rub on the surface of the cornea
Breed Occurrence
There is increased likelihood of trauma-induced ulcers forming in dogs with eyes
that protrude from the head - pekingese, pugs, and recurrent ulcers are seen in
Boxers and Pembroke Corgis and develop in older dogs.
Signs
Corneal ulcers are painful and cause :
- Runny eyes - excess tear production
- Squinting/blinking - the animal is unable to open it's eyes fully without pain
Complications
Also, chronic infection at the site can really delay healing and lead to infection and inflammation of other parts of the eye ..such as the iris.
Diagnosis
Most ulcers can easily be seen by shining a light across the front surface of
the eye . If not, a sterile dye (eg fluorescein - administered by touching an
impregnated strip to the surface of the eye) can be put into the eye and it
is taken up by the ulcer.
Treatment
The surface of the eye is especially sensitive and great care is needed not to
damage adjacent normal tissues.
The underlying cause must be treated if it is known eg remove foreign objects caught behind the eyelids.
Sterile lubrications applied to the surface of the eye may help reduce frictional damage
Antibiotics are used to treat or prevent infection.
Collagenase inhibitors (eg acetylcysteine) and antiprotease drugs (eg polysulfated glycosaminoglycans) have been used .
Unfortunately, some ulcers do not heal well and further treatment may be needed to stimulate healing. Commonly used methods include :
- surgical removal of dead cells by scraping
- cautery of the ulcer carefully using phenol or iodine solution
- protection of the surface of the eye by using a 3rd eyelid flap
- the use of tissue adhesives (corneal glue- butylanoacrylate)
- conjunctival grafts or flaps
- corneal grafts
- corticosteroids are only used when excessive healing tissue (granulation tissue) forms
If the organism pseudomonas is present treatment is an emergency with antibiotic gentamicin and an anticollagenase drug (eg acetylcystein)
Prognosis
Good for most ulcers, but can be poor for the most severe ulcers, or when
infection affects the whole eye, in which case removal is necessary.
Long term problems
Updated October 2013