Page 1175 - Problem-Based Feline Medicine

57 – THE BLIND CAT OR CAT WITH RETINAL DISEASE 1167

attenuated retinal blood vessels and optic disc cupping. There may be evidence of the primary
cause, e.g. chronic uveitis or neoplasia.
NEOPLASTIC
● Metastatic intra-retinal neoplasia (p 1184)
Adenocarcinoma and lymphosarcoma are the most reported metastatic neoplasias in the eye. They
usually present as uveitis, but choroidal lesions can be seen causing swelling underneath the retina,
which has a brownish appearance or retinal detachment.

● Trauma-associated ocular sarcoma (p 1184)
Affected cats range from 7–15 years of age, and have a history of prior ocular trauma. Cats present
with signs of anterior uveitis, and may show glaucoma, and white to pink masses in the vitreous, if
it can be visualized.
Nutritional

● Taurine deficiency retinopathy (feline central retinal degeneration – FRCD) (p 1181)
Usually seen in cats that are fed dog food or vegetarian diets. Early appearance is of a focal hyper-
reflective area in the area centralis. As the disease progresses, this coalesces to form a broad
hyper-reflective band superior to the disc. Eventually there is irreversible blindness, with a hyper-
reflective tapetum and attenuated retinal blood vessels.
INFLAMMATION/INFECTIOUS
Viral:
● Feline leukemia virus (p 1179)
More commonly presents as a uveitis with changes to the iris appearance, and abnormal pupil size and
shape. Retinal detachment may occur if the neoplasia involves the choroid.
● Feline infectious peritonitis virus (FIP) (p 1179)
Cats with ocular signs are typically less than 1 year of age, and initially do not have systemic signs
of FIP. Ocular disease usually presents as anterior uveitis and hypopyon. Advanced cases show
serous retinal detachment and may have neurological signs. Other systemic signs develop as the
disease becomes chronic.
Fungal:
● Chorioretinitis caused by other fungi (p 1176)
Blastomyces dermatitidis, Coccidoides immitis, Histoplasma capsulatum. Usually presents as ante-
rior uveitis. Examination of the retina shows focal granulomas with a cloudy vitreous. Blindness
occurs in advanced cases.
● Cryptococcus neoformans* (p 1174)
Presenting ocular signs are usually anterior uveitis. Examination of the retina shows focal granulo-
mas, with a cloudy vitreous. Blindness occurs in advanced cases. Mucopurulent nasal discharge
and nasal swelling, or skin nodules may be present.
Protozoal:
● Chorioretinitis caused by Toxoplasma gondii** (p 1172)
The most common ocular presentation is anterior uveitis. The retinal change is chorioretinitis.
Blindness occurs in cats with retinal detachment and optic neuritis. Other systemic signs of

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