Page 1281 - Problem-Based Feline Medicine

61 – THE CAT WITH A CLOUDY EYE 1273

Diagnosis Pathogenesis

A tentative diagnosis is based on a history or signs of In contrast to dogs, genetic cataract is rare in cats, but
eye trauma and the presence of a mature or imma- has been reported.
ture cataract.
Congenital cataract is seen when the lens development
In acute cases, lens material is visible in the anterior is disrupted or altered in the early embryonic develop-
chamber. ment of the eye.
In chronic cases, chronic uveitis is evident after an eye As the nucleus is the first part of the lens to develop,
injury. this is the usual area of cataract development seen in
young cats (nuclear cataract). As the cat ages, the lens
Ocular ultrasound is a very useful tool for detecting
cortex may become cataractous and the eye develops
lens rupture. Look for the normal position of the lens
a mature cataract.
as seen by the anterior and posterior hyperechoic line
defining the anterior and posterior lens capsule. In
high-quality machines with a 10-MHz probe, the lens Clinical signs
shape and position can be visualized quite easily. Any
change to the appearance or lack of hyperechoic lines is Cloudy lens in a young cat with no history of illness
suspicious for lens rupture. and no sign of inflammation in the eye.
Vision is reduced or absent if both eyes are affected.
Treatment

If there is corneal edema and the anterior chamber is Diagnosis
filled with blood and protein, treat the eye with broad-
Diagnosis is based on the classical appearance of a
spectrum antibiotics topically and systemically.
cloudy lens in a young healthy cat, which has no evi-
Inflammation should be controlled initially with
dence of ocular inflammation.
NSAIDs. If the lens is ruptured, corticosteroids sys-
temically will be needed to control the lens-induced
uveitis, which is an immune reaction in the eye against Treatment
the exposed lens fibers.
Cataract surgery can be done by a trained ophthal-
If the injury has recently occurred, and the cornea and mologist if the globe and retina is normal.
anterior chamber allows visualization of the lens, a len- ● Ocular ultrasound should be done to determine
tectomy should be performed immediately. This treat- whether the retina is detached. A 10-MHz probe
ment is controversial because of the danger of sarcoma should be used. Detached retinas are seen as faint
formation later in life. lines bulging into the vitreous between the optic
Cataract surgery can be performed later if a mature disc and ora serrata.
cataract develops. ● Electroretinography can be done to determine
whether the retina has normal rod and cone function.
Cats with an injured lens have a high risk of developing
ocular sarcoma, and enucleation should be considered.

DIABETIC CATARACT
CATARACT SECONDARY TO
NON-INFECTIOUS UVEITIS Classical signs
● Rare finding in older cat with diabetes
Classical signs
mellitus.
● Nuclear cataract in a young healthy cat that ● Cloudy lens with immature to mature
with no evidence of ocular inflammation. cataract.