Page 1287 - Problem-Based Feline Medicine

62 – THE CAT WITH ABNORMAL PUPIL SIZE, SHAPE OR RESPONSE 1279

QUICK REFERENCE SUMMARY
Diseases causing abnormal pupil size, shape or response
RETINA AND OPTIC NERVE

DEGENERATIVE
● Hereditary progressive retinal photoreceptor dysplasia or degeneration (p 1290)
Young to middle-aged cat with a history of gradual onset vision loss, especially in Abyssinian
cats, but also described in Persians and Siamese. Rare.
● Feline central retinal degeneration (FRCD) (p 1285)
Slow onset of vision loss and loss of normal papillary light reflex. Possible history of a diet poor
in taurine.
METABOLIC

● Hypertensive retinopathy*** (p 1282)
Old cat with sudden onset of vision loss, dilated and poorly or non-responsive pupils.
Fundoscopic signs ranging from retinal hemorrhage and localized subretinal exudate to extensive
bullous retinal detachment.
● Anemic retinopathy (p 1288)
Blind, weak cat with profound anemia and retinal hemorrhages and partial to complete loss of
papillary light reflexes.
● Hyperviscosity retinopathy (p 1288)
Rare condition causing blindness and loss of pupil reflexes due to retinal damage. Extremely
dilated tortuous retinal vessels with monoclonal globulin spike on protein electrophoresis.
NUTRITIONAL
● Taurine deficiency retinopathy* (p 1285)
Slow onset of vision loss and loss of normal papillary light reflex. History of a diet poor in tau-
rine, e.g. dry dog food diet, or a diet high in plant fiber.
INFECTION

● Infectious chorioretinitis** (p 1283)
Caused by protozoa (Toxoplasma gondii), fungi (Cryptococcus neoformans, blastomycosis, histo-
plasmosis, coccidoidomycosis), parasites (ophthalmomyiasis (fly larval migration)). Abnormal
pupil responses result from retinopathy or central nervous system involvement. Variable signs
occur including retinal detachments, retinal hemorrhages, subretinal exudates, subretinal granulo-
mas, pre-retinal hemorrhages, together with systemic signs of infection such as fever, depression,
inappetence and weight loss.
● Feline infectious peritonitis (FIP) virus** (p 1284)
Fibrinous peritonitis, CNS disease or fibrinous uveitis in a young cat with variable vision loss
and/or abnormal pupil reflexes. Anorexia and/or pyrexia.
TOXIC
● Drug toxicity to fluoroquinolones*-** (p 1284)
Sudden-onset blindness and absent papillary light reflexes associated with recent administration
of a fluoroquinolone, e.g. enrofloxacin.

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