Keratitis is inflammation of
the cornea in which the cornea
becomes cloudy, resulting in loss of transparency. The signs are excessive
tearing, squinting, pawing at the eye, avoiding light, and protrusion of the third eyelid. There are
different types of keratitis; all are serious diseases and can lead to partial
or complete blindness. All types of
keratitis must be treated by a veterinarian.
Ulcerative keratitis is a painful corneal inflammation that occurs as a
complication of keratoconjunctivitis sicca or
corneal ulcer. The cornea appears dull
and hazy, then cloudy, and finally milky white and relatively opaque. Treatment
is similar to that described for Corneal Ulcer.
Infectious keratitis occurs when a bacterial infection complicates
ulcerative keratitis, keratoconjunctivitis sicca, or corneal ulcer. The most
common invading bacteria are Staphylococcus, Streptococcus, and Pseudomonas. In
addition to eye pain, infectious keratitis is characterized by a purulent
discharge from the eye. The eyelids are swollen and matted. This might, at
first, suggest conjunctivitis (which could seriously delay diagnosis and
treatment), but recall that conjunctivitis is not usually accompanied by signs
of a painful eye.
Treatment is similar to that described for Corneal Ulcer. It is important to
use topical antibiotics selected following
culture and sensitivity tests.
Fungal keratitis is uncommon in dogs, but may occur with the prolonged use of topical
antibiotics. The diagnosis is made by fungal culture. It is treated with
Interstitial keratitis (blue eye) is a corneal inflammation in which a
bluish-white film appears over the clear window of the eye. It is caused by the
same virus that causes infectious hepatitis, and at one time it
occurred after vaccination with CAV-1 (vaccines with this version of
the hepatitis virus are no longer used). Signs appear 10 days after exposure.
The eyes begin to water and the dog squints and avoids light. Most dogs recover
completely within a few weeks. In some cases the eye remains permanently
Vascular keratitis is caused by neovascularization-the process by which the
transparency of the cornea is lost due to an ingrowth of blood vessels and
connective tissue. You can see blood vessels growing onto the cornea with your