Page 1311 - Problem-Based Feline Medicine

63 – THE CAT WITH ABNORMAL IRIS APPEARANCE 1303

Cytology of aqueous humor usually reveals lympho- Clinical signs
cytes and occasional plasma cells.
PIFMs appear as new vessels growing across the
anterior surface of the iris, giving the iris a pink dis-
Treatment coloration.

There is no cure for this disease. Once the nodules Because PIFM formation is associated with intra-
have been formed they will never go away completely ocular neoplasms, retinal detachment or chronic
with therapy, however treatment will control the inflammation, these abnormalities may be evident on
inflammation and reduce the incidence of the second- careful examination of the eye.
ary sequelae.
PIFMs may be associated with secondary hyphema or
Topical corticosteroids. glaucoma.
● Prednisolone acetate
Occasionally the vessels in PIFMs may be visible leav-
Prednefrin Forte (Allergan - 1%) applied q 8–12 h.
ing the pupil margin and migrating across the anterior
Sterofrin (Alcon - 0.5%) q 6–8 h reducing to effect.
lens capsule.
Topical NSAIDs.
● Flurbiprofen (Ocufen 0.03%) applied q 8–12 h.
Diagnosis
Mydriatics such as atropine are rarely indicated
Diagnosis is based on the characteristic appearance
because of the side effects of salivation seen in cats and
of the fibrovascular membranes on the anterior stromal
the chronic nature of the disease.
surface of the iris.
Treat glaucoma with:
Occasionally an underlying cause may be apparent, e.g.
● Continuing steroid or NSAID therapy.
a ciliary body epithelial tumor at the pupil space or a
● Topical carbonic anhydrase inhibitors (Dorzol-
total retinal detachment.
amide 2% topically tid).
● Topical beta-blockers, e.g. timolol maleate 0.5%
applied bid–tid. Differential diagnosis
Laser cyclo-photo-coagulation in chronic cases non- Iris neoplasia, especially secondary neoplasms of the
responsive to medical treatment. iris arising in some other part of the body, e.g. lympho-
sarcoma resulting in hyphema.
Glaucoma will often be refractory to treatment.
Acute inflammation resulting in pinkish injection of the
anterior iris surface.
PRE-IRIDAL FIBROVASCULAR
MEMBRANES*
Treatment
Classical signs
There is no treatment for PIFMs except for treatment of
● New vessels growing across the anterior
the underlying chronic diseases, which may be associ-
surface of the iris giving the iris a pink
ated with the condition. Once formed the PIFMs will
injected appearance.
remain permanently on the iris surface.
● ± Intra-ocular neoplasm, detached retina
and/or uveitis.
IDIOPATHIC UVEITIS*
Pathogenesis Classical signs
Pre-iridal fibrovascular membrane (PIFM) forma- ● Signs of uveitis.
tion is associated with angiogenic factors released by ● Extensive laboratory investigations fail to
proliferating intra-ocular neoplasms, retinal hypoxia identify possible etiology.
or chronic inflammation.