Page 1323 - Problem-Based Feline Medicine

64 – THE CAT WITH ABNORMAL GLOBE POSITION OR SIZE 1315

Clinical signs “Ulcerative keratitis caused by corneal perforation (cat
fight wounds)” and on page 1246 “Blunt trauma”.
Globe is caudally displaced into the orbit (enophthalmos).
Generalized atrophy of the muscles of mastication Clinical signs
and/or facial expression is evident, and the zygomatic
arch is prominent. Painful, closed eye with serous discharge and some-
times bleeding.
Lower lid entropion is sometimes seen.
Cornea is cloudy and anterior chamber may be full of
Ocular signs are usually always bilateral because they
blood and protein.
relate to systemic illness.
Globe appears small compared with the ipsilateral eye,
Generalized poor body condition is evident, and atro-
and there are signs of aqueous leakage with wetting of
phy of other muscle groups and bony prominences are
the skin and haircoat around the eye, which occurs in
more obvious. There may also be associated loss of
association with rupture of the cornea or sclera.
hydration of connective tissue, if the weight loss is sec-
ondary to chronic renal disease.
Diagnosis
Diagnosis
A presumptive diagnosis is based on clinical signs and
Diagnosis is based on the appearance of a normal- history.
sized globe, which is sunken into the orbit, and
a thin emaciated cat. PTHSIS

Laboratory investigation is required to determine the
cause of the weight loss. Common causes include hyper- Classical signs
thyroidism and chronic renal disease.
● Small globe size compared to the opposite
● Hyperthyroidism is associated with increased thy-
side.
roxine concentrations, and often increased alanine-
● Globe is covered by the third eyelid.
amino-transferase (ALT) activity.
● Signs of previous inflammation within the
● Chronic renal disease is associated with variable
eye.
increases in BUN, creatinine and serum phosphate
● Intra-ocular pressure is usually low.
and poorly concentrated urine (<1.030). Serum
● Rare in cats.
potassium may be low in the early stages, and high
in the late stages of the disease.
Clinical signs
Treatment
The globe size is small compared with the ipsilateral eye.
Treatment involves correcting or controlling the med-
There is unusual coverage of the globe by the nictitat-
ical condition causing weight loss.
ing membrane because of small size.
Pthisis occurs secondary to chronic uveal inflammation
COLLAPSE OF THE GLOBE*
or severe penetrating trauma. Signs of chronic uveal
inflammation are evident, for example:
Classical signs
● Abnormal pupil shape.
● Small globe size compared to the opposite ● Changes in iris color due to fibrovascular mem-
side. branes on the anterior surface of the iris.
● Painful closed eye. ● Keratic precipitates, which are gray to tan-colored
● Serous discharge from leaking aqueous. opacities on the posterior surface of the cornea, and
are usually located ventrally.
See the main reference for details in “The Cat With ● Synechia, which are visible as adhesions of the iris to
Abnormalities Confined to the Cornea” on page 1243, the anterior lens capsule, and may cause irregularity