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.
Heartworm disease, so named
because the adult worms live in the right side of
the heart, continues to be a major problem for many species of animals.
Heartworms are spread by mosquitoes, and thus are found throughout the world.
In the United States the prevalence is highest along the southeastern Atlantic
and Gulf Coasts, but heartworm has been found in all 50 states. The disease is
less prevalent at higher elevations.
The highest infection rates (up to 45 percent) in dogs
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
Pigmentary keratitis results when melanin pigment is deposited in the
cornea. This is a separate process, but is often associated with vascular
keratitis. Both conditions interfere with vision and may progress to
Vascular and pigmentary keratitis may, in some cases, be the result of a
chronic corneal irritation such as that caused by entropion or
lagophthalmos(inability to completely close the eyes). Removing the initiating
process may reverse the keratitis.
Pannusis a specific type of nonpainful pigmentary keratitis found in German
Shepherd Dogs and their crosses, and also in Belgian Tervurens, Border Collies,
Greyhounds, Siberian Huskies, Australian Shepherds, and other breeds. It occurs
in dogs over 2 years old. An immune-mediated disease is suspected to be the
cause. Pannus may be associated with dogs who live at high altitudes, due to
the decreased ozone layer. A distinguishing feature of pannus is redness and
thickening of the third eyelid, but this may not always