Page 1195 - Problem-Based Feline Medicine

57 – THE BLIND CAT OR CAT WITH RETINAL DISEASE 1187

Diagnosis is confirmed by demonstration of a mono-
BLINDNESS ASSOCIATED WITH
clonal globulin spike on protein electrophoresis of
MIDBRAIN AND VISUAL CORTEX
plasma.
PROBLEMS
Multiple myeloma is the most frequent cause of a
monoclonal globulin spike.
TOXOPLASMA GONDII*

Classical signs
BLINDNESS CAUSED BY OPTIC
NERVE PROBLEMS ● Blindness with a normal PLR.
● Anterior uveitis and chorioretinitis.
● Other neurological signs of CNS
OPTIC NERVE COLOBOMA
involvement.
Classical signs
See the main reference on page 375 (The Pyrexic Cat).
● Rare condition that occasionally affects
vision. Clinical signs
● Inverted funnel or black hole appearance in
optic disc. Cats with CNS involvement may show blindness, with
● Associated with eyelid agenesis. normal to slow pupillary light reflexes, if the lesions
● Retinal dysplasia also occurs (dark lines on involve the cerebral visual cortex.
tapetal fundus). Uveitis and chorioretinitis may be present. See above
(page 1173).
Blindness may be caused by extensive chorioretinitis
Clinical signs and/or CNS disease involving the visual cortex.
Optic nerve coloboma is a rare lesion in cats.
Diagnosis
It is usually seen as an incidental finding on ophthal-
moscopic examination of cats with eyelid agenesis See the main reference above under chorioretinitis
(coloboma). (page 1173).
Both hereditary and in utero infections have been
suggested as causes. CRYPTOCOCCUS NEOFORMANS*
The coloboma appears as a dark area associated with Classical signs
the optic disc, and has the appearance of an inverted
● Cats of all ages.
funnel or black hole.
● Uveitis with hypopyon and keratic
Vision is rarely affected. precipitates.
● Blindness with or without CNS signs.
Retinal dysplasia may occur concurrently, and appears
as a dark streak or depigmented rosette in the tapetal
fundus. See the main reference on page 25 (The Cat With Signs
of Chronic Nasal Disease).

Clinical signs
Diagnosis
Cryptococcosis affects cats of all ages.
Diagnosis is based on the fundiscopic findings of an
optic disc with a dark hollow appearance. Retinal dys- Blindness may occur with or without CNS signs.
plasia appears as dark lines in the tapetal fundus. Blindness may be central or associated with retinal