Page 1328 - Problem-Based Feline Medicine

1320 PART 15 CAT WITH EYE PROBLEMS

WHAT? Pathogenesis
The condition appears to occur secondary to enoph-
The most common causes of altered eyelid appearance
thalmos in cats. Enophthalmos can be caused by loss
include:
of fat or reduction in masseter muscle mass within the
● Failure of embryonic tissues to differentiate or
orbit.
rarify resulting in eyelid agenesis or abnormal
cilia. These conditions will commonly be first rec- The defect can also occur secondary to chronic ble-
ognized in a young cat. pharospasm caused by painful corneal diseases.
● Inflammation of infectious or non-infectious
etiology.
– Infectious causes include bacteria, dermatophyte
fungi or external parasites. Clinical signs
– Non-infectious causes include allergic causes
Usually the central portion of the lower eyelid mar-
such as food allergy, inhalant allergy, bacterial
gin rolls inwards towards the globe. Lid hair adjacent
hypersensitivity, insect bite hypersensitivity or
to the margin may appear moist or be coated in con-
contact allergy to topical drugs; immune-
junctival mucus.
mediated responses to components of the skin
around the eyelids occur in pemphigus erythe- Corneal surface disease is present from the eyelid
matosus or pemphigus foliaceous. hair rubbing on the cornea. This can include superfi-
● Neoplasia. cial ulceration, sequestrum formation, and a vascular
– Squamous cell carcinoma occurring in non- response from the limbus adjacent to the area of lid
pigmented skin is the most common neoplastic irritation.
disease seen in the eyelid.
Chronic discharge occurs ranging from mucoid to
– Basal cell carcinomas, mast cell tumors or fibro-
mucopurulent.
sarcomas are less common, while sebaceous
gland tumors occur rarely.
● Neurological disease.
– Sympathetic ptosis or ptosis due to injury to Diagnosis
the dorsal branch of the oculomotor nerve
Diagnosis is based on the characteristic sign of an
may occur with trauma, inflammation or neopla-
inward rolling eyelid margin with secondary corneal
sia involving the nervous system.
changes and chronic ocular discharge.
● Trauma.
– Cats are renowned for injuries caused by claws
inflicted during fighting with other cats.
Treatment
DISEASES CAUSING AN ABNORMAL
EYELID APPEARANCE Surgical procedures such as the modified Hotz–Celsus
procedure involving removal of a strip of skin and
orbicularis muscle adjacent to the area of entropion
ENTROPION** seem to work adequately for cats. Some cats seem to
have an oversized palpebral fissure, resulting in inade-
Classical signs quate tension of the lower eyelid. Occasionally a per-
manent lateral canthal closure in addition to the
● Lower eyelid is curled inwards.
Hotz–Celsus procedure is recommended to reduce
● Chronic ulcerative keratitis caused by
palpebral fissure size.
eyelid hair rubbing on the cornea.
● Mucoid to mucopurulent discharge. The condition will recur if the inciting cause is not
corrected.