Corneal infections

What is a corneal infection?

When the outer layer of the cornea (epithelium) is injured, bacteria can create an area of infection. Enzymes released by the bacteria and by locally present white blood cells can digest the cornea creating a deep ulcer. Deep corneal ulcers may lead to rupture of the eye.

What causes a corneal infection?

Most corneal infections are started by a minor injury to the cornea. Other possible contributing factors include tear film abnormalities (common in dogs) and herpes virus infection in cats.

Are certain breeds of dogs prone to developing a corneal infection?

Yes. Dogs and cats with prominent eyes such as the Pug, Boston Terrier, Shih Tzu, Lhasa Apso, Persian, Himalayan, etc., are more prone to corneal injuries and infections, although any breed may develop this condition.

How do I recognize that my pet has a corneal infection?

You may notice that the affected eye is suddenly red, painful, and held shut. Occasionally the eye will have a bluish appearance. Rarely, a dog will exhibit little or no pain and will only have a slight change in the appearance of the eye.

How is a corneal infection diagnosed?

The depth and severity of the corneal infection can be determined by a veterinary ophthalmologist using special equipment (slit lamp) and testing (cytology, culture and susceptibility testing).

How is a deep corneal infection treated?

Most corneal infections are initially treated with a combination of eye drops. To control the infection and the enzymatic activity, the drops are instilled every 1-2 hours for the first day of treatment. If the infection has created a lesion deeper than ½ the corneal thickness, surgical grafting is the most prudent treatment. Even with aggressive medical treatment the eye is at risk of rupturing, surgery is often recommended.

Will my pet have any permanent damage or vision loss from the infection?

The potential for vision depends upon the initial severity and location of the infection. Vision is regained to some degree, in most eyes that have had a deep infection. If the eye is ruptured or the ulcer is very large, significant scarring may lead to visual impairment of varying degree after treatment.

How often does my pet need to be re-examined?

The frequency of re-examination is dependent upon the severity of the infection and the type of treatment needed. Ulcers treated without surgery should be examined every 1-2 days until healing is certain. Ulcers treated surgically are evaluated in 3-5 days and again in 10-14 days. If needed the base of the graft will be excised with topical anesthesia 6-8 weeks after the surgery.