Page 1210 - Problem-Based Feline Medicine

1202 PART 15 CAT WITH EYE PROBLEMS

Clinical signs The iris may have red cells on the surface mixed with
protein and white blood cells. Leakage of cells and pro-
New blood vessels growing across the anterior surface
tein occurs because of disruption of the endothelial
of the iris give the iris an injected pink discoloration.
cells on the blood vessel walls, and results in varying
The vessels are fragile, and are often associated with degrees of hyphema and hypopyon. Lymphosarcoma
hyphema. does not usually cause frank hemorrhage.
Pre-iridal fibrovascular membrane (PIFM) formation The pupil will be distorted (dyscoria) if the iris is
is associated with angiogenic factors released by grossly distorted with infiltrated cells.
proliferating intra-ocular neoplasms, retinal hypoxia
Glaucoma is often an associated complication.
associated with retinal detachment, or chronic ocular
inflammation. These abnormalities may be evident on Regional lymph nodes may be enlarged, or other signs
careful examination of the eye. of multicentric lymphosarcoma present.

Secondary glaucoma may occur. Diagnosis

A tentative diagnosis is based on the appearance of the
Diagnosis
iris, which is typically thickened, with a fleshy color
Diagnosis is based on the characteristic appearance change, and may have focal hemorrhage on the surface.
of the fibrovascular membranes on the anterior stromal
Serology for FeLV may support the diagnosis.
surface of the iris.
White blood cell cytology looking for abnormal
Occasionally an underlying cause may be apparent,
plump-shaped lymphocytes with large prominent
such as a ciliary body epithelial tumor at the pupil
nucleoli in the peripheral blood is useful in cases with
space, or a total retinal detachment.
lymphosarcoma.
Biopsy of regional lymph nodes is indicated if there is
IRIS NEOPLASIA*
lymphomegaly. Fine-needle biopsy of the liver or spleen
should be performed if there is organomegaly.
Classical signs
An anterior chamber paracentesis using cytology
● Iris tinged with blood +/- free red cells in
to demonstrate neoplastic lymphocytes can be done,
the anterior chamber.
but is not usually necessary, as the above tests usually
● Iris is pale and thickened.
will confirm the diagnosis.
● Pupil may be distorted.
See the main reference on page 1297 for details (The THE RED VITREOUS
Cat With Abnormal Iris Appearance and The Cat With
Abnormal Pupil Size, Shape or Response).
HYPERTENSIVE RETINOPATHY***
Clinical signs Classical signs

Ocular neoplasia causing hemorrhage is usually asso- ● Acute onset of vision loss in an old cat,
ciated with lymphosarcoma. It is rare for other forms usually bilateral.
of neoplasia such as melanoma to cause hemorrhage in ● Dilated pupils, non-responsive or poorly
the eye. responsive to light.
● Cloudy vitreous with red areas of
Lymphosarcoma may be associated with FeLV infec-
tion, although often it occurs in negative cats. hemorrhage.
The iris is infiltrated with neoplastic cells, and appears See the main reference on page 1171 for details (The
thickened with a pale fleshy color change. Blind Cat or Cat With Retinal Disease).