Corneal Injuries and Problems in Dogs
The cornea is the clear part of the
eye. Corneal injuries are extremely painful and require immediate veterinary
attention. Affected dogs will squint, tear, and
avoid light. The third
eyelid often comes out to protect the injured eye. Breeds with bulging
eyes, such as the Pekingese, Maltese, Boston Terriers, Pugs, and some spaniels,
are particularly susceptible to corneal injuries.
Corticosteroids, which are incorporated into many common eye preparations
used in treating conjunctivitis, should not be used in an eye suspected
of having a corneal injury because of the danger the cornea will rupture
into the anterior chamber.
The cornea is covered by a protective surface layer of epithelial cells. Any
irritation, such as a scratch or foreign body, damages this surface layer.
Swelling at the site of the injury, as well as edema, causes the area to appear
hazy and opaque when viewed under magnification. The opaque area also stains
positive with fluoresce in dye.
Corneal abrasions in the upper part of the cornea may be caused by
misdirected eyelashes. Lower corneal opacities suggest an imbedded foreign
body. Abrasions near the inner corner of the eye suggest a foreign body beneath
the third eyelid.
A corneal abrasion usually heals in about three to five days by a process in
which the adjacent epithelial cells enlarge and migrate over the defect. The
injury will not heal, however, if a foreign body is imbedded in the cornea or
beneath one of the eyelids. It is important to check for a foreign body in all
cases of corneal abrasion.
Corneal abrasions and ulcers are diagnosed using a
special fluorescein dye that is applied to the eye. Damaged tissues will pick
up the dye.
Treatment: All corneal injuries must be seen and treated by a veterinarian
to avoid complications, including keratitis and corneal ulcer. Broad-spectrum topical
antibiotic drops or ointments are prescribed every four to six hours to prevent
A topical atropine preparation is used to keep the pupil dilated, which
reduces eye pain. Keep your dog out of bright light, including bright sunlight,
when the pupil is dilated. The atropine has a bad taste and many dogs will foam
at the mouth if they get some in their mouths while you are medicating them.
This will pass in a minute or two.
The eye is examined periodically to monitor progress. Treatment is continued
until the abrasion is healed.
An ulcer is similar to a corneal abrasion, except that an ulcer is deeper
and involves the middle and sometimes the inner layer of the cornea.
Most corneal ulcers are caused by trauma, but some are associated with
keratoconjunctivitis sicca, corneal dystrophy, diabetes mellitus, Addison’s
disease, or hypothyroidism.
Corneal ulcers are extremely painful and cause severe tearing, squinting,
and pawing at the eye. Dogs frequently avoid light. Large ulcers are visible to
the naked eye as dull spots or dished-out depressions on the surface of the
cornea. Small ulcers are best seen after the eye has been stained with