Page 1242 - Problem-Based Feline Medicine

1234 PART 15 CAT WITH EYE PROBLEMS

QUICK REFERENCE SUMMARY
Diseases causing abnormalities confined to the cornea
DEGENERATIVE

● Calcific degeneration (p 1252)
Rare in cats. Seen as a band of gritty white material in the anterior stroma, usually secondary to
chronic herpetic keratitis. Known as a band keratopathy.
● Corneal sequestrum (feline keratitis nigrum)** (p 1241)
Presents with an axial (central) area of staining (light brown to black) in the cornea, usually unilat-
eral. Most common in brachycephalic breeds such as Persians and Himalayans. Approximately
80% are associated with herpetic keratitis. In the early stages there is no ulceration, but chronic
lesions may have ulcerated borders, and there may be intense deep stromal vascularization associ-
ated with these ulcerated lesions. It is a focal area of stromal degeneration surrounded by an
inflammatory zone.
ANOMALY
● Stromal dystrophy of Manx cats (p 1252)
A rare condition in young Manx cats that starts with axial stromal edema and progresses to a dif-
fuse corneal edema with a thickened stroma full of bullae (fluid-filled vesicles). A blinding corneal
disease with no treatment possible.
● Endothelial dystrophy (p 1252)
Seen in Domestic Short Hair cats. A very rare condition seen in young cats evident as a cloudy blue
cornea caused by diffuse corneal edema secondary to an endothelial dystrophy. There is no specific
cause, and no treatment is possible.
METABOLIC
● Lysosomal storage diseases with ophthalmic manifestations (p 1253)
GM 1 gangliosidosis, GM 2 gangliosidosis, mannosidosis, mucopolysaccharidosis 1 (MPS1).
Mucopolysaccharidosis 2 (MPS2) may be associated with corneal changes. The cornea shows
opacity caused by vacuoles in the keratocytes and endothelial cells. Seen in young animals that
also have neurologic signs of ataxia, muscular tremors and paralysis.
INFLAMMATION/INFECTIOUS

● Feline herpes virus 1 (FHV-1) keratitis*** (p 1237)
Cats may have a history of FHV-1 infection as kittens, with acute upper respiratory tract signs,
salivation, sneezing, pyrexia, lethargy and anorexia. Often appears as a unilateral disease in older
cats. The epithelium may show dendritic lesions (finger-like projections of thickened epithelium
that stain with rose bengal stain) in early cases. Chronic cases show irregular (geographic) ulcera-
tion to the level of the superficial stroma. Scarring and vascularization of the cornea follows after
repeated inflammatory episodes.
● Bacterial ulcerative keratitis* (p 1248)
Usually secondary to corneal trauma. Ulcers stain positive with fluorescein dye. There is a variable
presentation depending on the depth of the ulcer and the type of infection. Pseudomonas infection
may cause a “melting ulcer” (keratomalacia) with digestion of stromal tissue by bacteria and cellu-
lar enzymes.