Page 1271 - Problem-Based Feline Medicine

61 – THE CAT WITH A CLOUDY EYE 1263

Perforating injuries are very painful and show changes If there is a penetrating corneal lesion, examine the
in the anterior chamber such as hyphema and protein eye carefully for signs of iris prolapse and lens rup-
leakage with fibrin. ture. These cases need to be referred to a veterinary
ophthalmologist whenever possible.
● If there is a corneal tear that is well sealed with
a fibrin plug, protect the cornea with a third eyelid
Treatment
flap or temporary tarsorrhaphy. Dilate the pupil
As a general rule, eliminate the cause of the ulcer and with atropine and use a topical broad-spectrum
provide protection for the cornea using lubrication, antibiotic drop. NEVER use an ointment when
appropriate antibiotics where necessary and surgical there has been a penetrating corneal injury, because
techniques to close and protect the eye. ointment bases that enter the anterior chamber will
cause an intense and chronic foreign body uveitis.
Superficial epithelial erosions heal rapidly with mini-
Animals with acute eye injuries should be given
mal treatment. The use of antibiotics is not encouraged
systemic NSAIDs to minimize the effects of an
as they are rarely infected. Support with artificial tear
intra-ocular prostaglandin reaction. The eye should
solutions will make the eye more comfortable.
also be protected from infection with systemic broad-
Corneas with deep ulcers that have stromal loss need spectrum antibiotics.
to be protected with surgical techniques such as third
When there is an iris prolapse, microsurgery is
eyelid flaps or temporary tarsorrhaphies (see references
required to suture the cornea. The iris needs to be gen-
for texts that show details of these surgical techniques).
tly teased back into the anterior chamber, and the cham-
● Antibiotics are often used topically to prevent
ber flushed to remove blood and fibrin. Viscoelastic
secondary infection. If the ulcer is infected, then
solutions are then used to space the anterior chamber,
appropriate antibiotics should be used after culture
and the corneal deficit is sutured with interrupted 8/0
of a swab taken from the edge of the ulcer.
to 10/0 nylon or absorbable suture material. This is very
● Artificial tear solutions will lubricate the eye and
specialized surgery that requires specialist training,
make the cat feel more comfortable.
magnification and specialized instrumentation. The pupil
● Atropine ophthalmic drops (most commonly 1%)
is then dilated with atropine, infection prevented with
are used to dilate the pupil and to prevent ciliary
broad-spectrum topical and systemic antibiotics and
muscle spasm. They should be used two to three times
NSAIDs given to minimize inflammation.
daily until the pupil is dilated, and daily thereafter
(NOTE: atropine drops are very bitter and often
make cats salivate profusely). For this reason 1% CORNEAL SCARRING FROM INJURY*
atropine ointment is often used, as the drug does not
run down the tear duct as fast. Classical signs
Where a Pseudomonas infection is suspected or con- ● Range from faint cloudiness of the
firmed by laboratory analysis, the cat must be treated superficial stroma to dense opacity.
vigorously with aminoglycoside (commonly gento- ● Variable position, size, shape and density
mycin or tobramycin in gentomycin-resistant cases) or of scar.
fluoroquinalone (some generations such as flucloxacillin ● History of previous severe inflammation or
are effective) antibiotics topically every 15 minutes to trauma.
1 hour until the infection is controlled. They may also
be used systemically but particular care should be used
Pathogenesis
with aminoglycosides in cats as they are ototoxic and
nephrotoxic. Toxicity may occur from frequent topical Scarring may be secondary to disease processes or
use, so monitor cases carefully. trauma.
NEVER use topical corticosteroids when a corneal Scars form secondary to stromal damage. When stroma
ulcer is present, as this will predispose to keratomala- is infected or lost from ulceration, keratocytes meta-
cia (melting ulcer). plase into fibrocytes.