Page 1256 - Problem-Based Feline Medicine

1248 PART 15 CAT WITH EYE PROBLEMS

● Antibiotics are often used topically to prevent sec- epithelial cells and neutrophils and macrophages
ondary infection. If the ulcer is infected, then present in the ocular discharges.
appropriate antibiotics should be used after culture
of a swab taken from the edge of the ulcer.
Clinical signs
● Artificial tear solutions will lubricate the eye and
make the cat feel more comfortable. Signs are the same as for ulcerative keratitis
● Atropine ophthalmic drops (most commonly 1%)
Eyes with bacterial ulceration may be much more
are used to dilate the pupil and to prevent ciliary
painful than an eye with an uninfected ulcer. The dis-
muscle spasm. They should be used two to three
charge is likely to be mucopurulent rather than
times daily until the pupil is dilated, and daily
serous, and can be quite copious as there may be con-
thereafter (NOTE: atropine drops are very bitter and
current conjunctivitis.
often make cats salivate profusely). For this reason
1% atropine ointment is often used, as the drug Eyes are photophobic and there is guarding of the
does not run down the tear duct as fast. affected eye. Cats will resist handling of the eye.
NEVER use topical corticosteroids when a corneal Ulcers stain positive with fluorescein dye, except
ulcer is present, as this will predispose to keratomala- where a descemetocele is present.
cia (melting ulcer).
Corneal edema will be much more obvious and
intense when there is infection. The entire cornea may
BACTERIAL ULCERATIVE KERATITIS* be quite cloudy and look very soft and jelly-like when
there is a melting ulcer or keratomalacia. Ulcers are not
Classical signs as well defined.

● Painful, edematous eye. When visible, the anterior chamber may be cloudy.
● Mucopurulent discharge. Often there is secondary uveitis causing cloudiness of
● Cornea may have a soft gelatinous the anterior chamber, because protein and cells are
appearance (melting ulcer/keratomalacia). excreted from the iris and ciliary body.
● Ulcers are not as well defined.
Ulcers that develop into a melting cornea are devastat-
● Anterior chamber, where visible may be
ing conditions. They appear as a rapidly developing
cloudy.
cloudy edematous cornea that has a gelatinous soft
● Positive staining of the stroma with
appearance. The eye is extremely painful, and the
fluorescein dye, except where a
threat of rupture is very high. They are often infected
descemetocele is present.
with Pseudomonas spp.
Pathogenesis Diagnosis
There may be a history of trauma or a cat fight. The
There are no specific primary bacterial conditions that
diagnosis is made on clinical examination by finding
affect the cornea in cats. Infections are secondary to
a painful eye showing a stromal deficit.
injury.
The ulcer will stain with fluorescein, except in the case
Ulcers become infected secondarily, usually with
of a descemetocele.
Streptococcus spp. or Staphylococcus spp., which are
the common pathogens associated with eye infections. Where the cornea is soft and gelatinous, a swab should
be taken from the lesion, and sent to the laboratory for
Pseudomonas infection may cause a “melting ulcer”
culture and sensitivity.
(keratomalacia). The cornea loses definition and
becomes quite soft and jelly-like. This is caused by Cytology is useful to help choose immediate treatment.
protease enzymes secreted by the bacteria, and by self- Using a Wrights stain, Streptococcus spp. and Staphy-
digestion of stroma by enzymes secreted from dying lococcus spp. appear as single cocci or bunches of round,