Page 1259 - Problem-Based Feline Medicine

60 – THE CAT WITH ABNORMALITIES CONFINED TO THE CORNEA 1251

A dry and lusterless cornea with superficial ulcera-
FLORIDA KERATOPATHY (“FLORIDA
tion and superficial neovascularization is typically seen.
SPOTS”)/MYCOBACTERIAL KERATITIS
Lack of eyelid closure or corneal sensation is evi-
dent. To test corneal sensation, use a thin piece of Classical signs
rolled cotton wool or a thread of cotton, and touch the
● Focal gray-white opacities in the anterior
cornea from the side of the eye. Try not to allow easy
stroma of the cornea.
visualization of the test material, otherwise the animal
● Usually affects both eyes.
will respond to the visual stimulus and not the touch
● Only recognized in the southeastern USA.
stimulus. In a normal cornea, the eyelids should close
immediately the cornea is touched.
Clinical signs
Cases with corneal denervation have the same signs as
those with lack of blink reflex. Even when the blink One, or more commonly both, corneas have focal
reflex is normal, and the tear film is normal, if the white to gray opacities in the anterior stroma, varying
cornea has no innervation it will develop a neu- in diameter from 1–8 mm in size.
rotropic keratitis.
The condition is asymptomatic as cats show no signs
of ocular pain or irritation, and there is no associated
Diagnosis
inflammation in the cornea.
A diagnosis is based on history and signs of trauma or
The condition has only been described in the USA,
ear infection affecting the facial or trigeminal nerve.
and is suspected to be associated with infection.
Lack of corneal reflex or blink reflex is definitive.
● Rhinosporidium was initially diagnosed from his-
Chronic keratitis which is usually mild, and accompa- tological samples. However, ultrastructural exami-
nied by varying degrees of superficial ulceration and nation of affected cornea showed vacuoles with
vascularization. amorphous material and rod-like organisms char-
acteristic of mycobacteria that stain positively
Differential diagnosis with Ziehl–Neelsen carbolfuchsin stain.
Herpetic keratitis.
● These cases have superficial ulcers with neovascu- Diagnosis
larization of varying degrees, but the blink and
A tentative diagnosis is based on geographical loca-
corneal reflex remains intact.
tion and signs of a cornea with multiple focal opacities
in the anterior stroma and the cat shows no irritation or
Treatment
inflammation.
Topical treatment with artificial tear solutions is of
A definitive diagnosis is based on histological find-
great benefit. The eyes need to be treated frequently for
ings.
best results.
Temporary closure of the eyelids with a tarsorrhaphy is
Differential diagnosis
useful short term.
A focal lesion with acid-fast bacilli that progresses to
In chronic cases, the eyelids may be permanently
form a fleshy white lesion has been described in the
closed centrally to protect the cornea. Refer to oph-
northwest USA.
thalmology texts for surgical techniques.
Histology shows an inflammatory response with infil-
Prognosis tration of neutrophils and mononuclear cells.
Signs often improve after a period of 3–6 months This lesion is said to resemble the skin lesion in cat
when nerve function is improved or restored. Other leprosy, and is thought to be a different disease to
cases need to be managed for life. “Florida spots”.