uvea Flashcards
function of uveal tract
vascular supply
light regulation
blood aqueous barrier
accomodation
formation of aqueous humor
nonpigmented epithelium of the ciliary body
epithelial portion of BAB-tight junctions
formation of aqueous
active aqueous production
bicarbonate
heterochromia iridis
>1 color in 1 iris or between 2 irides in 1 animal
often concurrent coat color dilution
usually incidental
persistsent pupillary membranes
remnants of embryonic vasculature
airse from iris collarette
usually resorbed by 6 weeks of age
iris to iris-incidental
iris to lens-cataract
iris to cornea-corneal opacity
no therapy
Merle ocular dysgenesis
associated with Merle gene
Dachshund, collie, australian shepherd, great dane
heterochromia iridic
iris hypoplasia
iris coloboma-chunk of iris missing
corectopia-pupil in wrong spot
no tx
Uveal cysts
arise from pigmented epithelium of iris and/or ciliary body
spontaneous in formation or in response to inflammation
free floating or anchored
main r/o: melanoma
Dx by characertistic appearance, transillumination
usually incidental
usually no tx
iris atrophy
age related thinning of the iris-moth eaten appearance, scalloped pupillary margin
diminished PLRs
dyscoria
no therapy
Primary uveal neoplasia
cats & horses-Melanoma
dogs-melanocytic neoplasia
feline diffuse iris melanoma
insidious hyperpigmentation of the iris face
r/o: benign melanosis/nevus
could be metastasis from liver, lungs, regional LNs
differentiating between feline diffuse iris melanoma and benign melanosis/nevus
raised from iris surface-Purkinje 2 image raised
rapid spread
distortion of thickening of iris
interference with pupil shape or function
extension into sclera
associated uveitis or glaucoma
extent of hyperpigmentation
feline diffuse iris melanoma tx
continued monitoring-take photo
laser photocoagulation-small lesions only could disperse neoplastic cells
enucleation:histopath
Canine uveal melanocytic neoplasia
usually in anterior uvea
DDx: uveal cyst, limbal melanoma
Dx: transillumination, U/S, gonioscopy
Tx: monitor with photos, laser photocoagulation-small, enucleation-histopath
secondary uveal neoplasia
lymphosarcoma
DDx: uveitis
clin sxs: uveitis, nodules on iris, diffuse thickening of iris, destruction of iridal architecture
uveal neoplasia: tx
primary-sector iridectomy, laser ablation, enucleation
secondary: chemotherapy, enucleation
blood ocular barriers
prevent movement of porteins, low-molecular weight solutes into the eye
tight junctions
Uveitis
inflammation of the vascular tunic of the eye
breakdown of the blood-ocular barrier
protein and inflammatory cells present
anterior uveitis
iris and/or ciliary body
iridocyclitis, iritis, cyclitis
posterior uveitis
choroid
choroiditis, chorioretinitis
panuveitis
anterior and posterior uveitis
endophthalmitis
panuveitis and inflammation of the ocular cavities
panophthalmitis
all tunics of eye inflamed
clinical signs of anterior uveitis
non-specific signs: blepharospasm, elevated third eyelid, epiphora
more specific sxs: episcleral injection, deep corneal vascularization, corneal edema, aqueous flare, miosis, hypopyon, keratic precipitates, hyphema, iris swelling congestion, anterior chamber fibrin, rubeosis iridis, iris color change, iris hemorrhage
does absence of aqueous flare rule out uveitis?
no!
aqueous flare
aka Tyndall phenomenon, plasmoid aqueous
cells, proteins, inflammatory debris within aqueous reflect light
light beam traversing the anterior chamber-connecting Purkinje images 1 and 2
presence of flare=anterior uveitis
miosis
restriction of the pupil
also resistance to pharmacologic dilation
hypopyon
white cells in the anterior chamber
keratic precipitates
inflammatory debris on corneal endothelium
found on posterior side of purkinje image 1
like a scar
hyphema
blood in anterior chamber
clinical signs of posterior uveitis
vitreous opacities, tapetal hyporeflectivity, retinal hemorrhage, altered pigmentation of nontapetal fundus, retinal detachment
tapetal hyporeflectivity
indicates active lesion
cells or fluid obscuring view of tapetum
diagnosis of uveitis
clinical hx: red eye, cloudy eye, squinting, tearing, visual deficits, blindness, signs of systemic dz
hypotony (<10 mmHg)
diagnostic work up
first: complete PE, CBC, Chem23, UA, FIV/FeLV test
second: thoracic/abdominal rads, abdominal u/s, LN aspirates, ocular u/s, aqueous or vitreous aspirates, histopath
potential etiologies
immune-mediated/idiopathic, neoplastic, infectious
pretty much anything
idiopathic
most common “cause”
dx of exclusion
more likely to be unilateral vs bilateral
systemic disease etiology
more likely bilateral than unilateral
lens induced uveitis
T cell tolerance to low levels of lens antigen
increased exposure to antigen overwhelms this tolerance
antigen in anterior chamger incites intraocular inflammation
pacolytic uveitis vs phacoclastic uveitis
cataract removal
phacolytic uveitis
slow leakage of lens protein
most obvious with hypermature/resorbing cataract
chronic, low grade inflammation
phacoclastic uveitis
sudden release of lens protein
secondary to penetraing ocular trauma, lens rupture
rapid progression, severe inflammation
Golden retriever uveitis
pigmentary uveitis of golden retrievers
unknown pathogenesis
average age 8.6 years
Characteristics: uveal cyst formation, increased iris melanin, melanin deposition on lens capsule (radial), Glaucoma, cataract
dx: clinical appearance
no effective treatment/anti-inflammatories
leads to blindness and glaucoma
FeLV/FIV
FeLV itself doesn’t cause uveitis
secondary to superinfection, lymphoma, anemia, spastic pupil syndrome
FIV-Direct viral tissue damage, superinfection
FIP
ocular lesions more common in dry form
granuloma formation, vasculitis, immune complex deposition
“mutton fat” keratic precipitates
Canine distemper virus
chorioretinits +/- optic neuritis
therapy for uveitis
treat underlying cause, address inflammation, address pain, minimize sequelae
abx-topical if ulcer present, systemic if uveitis caused by infection
anti-inflammatory therapy
very important
topical if anterior only
need systemic if posterior involved
Corticosteroids, NSAIDs, Other immunomodulating drugs
Topical corticosteroids
first choice for anterior uveitis
predniolone acetate, dexamethasone
NOT hydrocortisone
CI if corneal ulcer is present
high dose at first then taper off
caution in small dogs, cats and diabetics
systemic corticosteroids
prednisone, prednisolone
anti-inflammatory to immunosuppressant doses-gradually taper
can be used wtih topical meds
can be used in the presence of corneal ulcer
first r/o infectious dz
do not use with NSAIDs
Topical NSAIDs
diclofenac, flurbiprofen, nepafenac
may be used alone or with topical and/or sytemic corticosteroids
frequency of use depends on severity of inflammation
problems: decrease aqueous outflow, incite collagenolysis, inhibit platelet aggregation, systemic absorption
caution in cats, small dogs, concurrent renal disease
Systemic NSAIDs
Carprofen, meloxicam, tepoxalin, etc
may be used toa ugemtn topical medication
may be used with infectious disease
do not use with systemic corticosteroids
pain management
anti-inflammatory therapy
mydriatic/cycloplegic therapy (atropine)
atropine
parasympathetic/anticholinergic
stabilizes blood-aqueous barrier
onset 30-60 mins; slowed with inflammation
use lowest dose required to achieve mydriasis
Cycloplegic-paralysis of ciliary body
decreases formation of posterior synechia
CI if glaucoma present, KCS
may cause profuse salivation
patient monitoring
recheck 1 weeks after dx
check IOP, severity of aqueous flare, appearance of clinical signs
Synechia
anterior-cornea to iris
posterior-iris to lens
arise from pupillary zone or peripheral ciliary zone
Sequelae of uveitis
synechia
iris atrophy
cataract
lens luxation
Glaucoma
iris bombe
phthisis bulbi
chorioretinal scarring
iris bombe
360 degrees posterior synechia
prevent movement of aqueous from posterio chamber to anterior chammber
narrows idiocorneal angle
elevation of IOP
Chorioretinal scarring
tapetal hyperreflectivity with pigment clumping
