Uvea

Question 1

what are the 3 components of the uvea

Answer 1

anterior uvea - iris, ciliary body

posterior uvea - choroid

Question 2

muscles of the iris

Answer 2

sphincter muscle - parasympathetic (CN III)

dilator muscle - sympathetic

Question 3

what is the purpose of the blood ocular barrier

Answer 3

allows for selective nutrition of avascular intraocular structures

prevents free passage of cells or proteins into the anterior chanber

allows clear media for vision

Question 4

2 componenets of the blood ocular barrier

Answer 4

blood-aqueous barrier - iris blood vessels, ciliary body

blood-retinal barrier - retinal blood vessels, retinal pigmented epithelium

Question 5

clinical signs of uveitis depend on ______ and _____ of barrier disruption

Answer 5

clinical signs of uveitis depend on location and severity of barrier disruption

Question 6

inflammation in uveitis is driven by _______

Answer 6

prostaglandins

responsible for: miosis, decreased IOP, iris hyperpigmentation

Question 7

ocular pain is mediated by ….

Answer 7

spasm of the ciliary body

Question 8

clinical signs of ocular pain

Answer 8

blepharospasm

epiphora

photophobia

hidding or agressive behaviors

Question 9

common rule outs for miosis

Answer 9

bright light

Horner’s syndrome

brain trauma

drugs (latanoprost)

uveitis (via prostaglandins)

Question 10

aqueous flare

Answer 10

proteins (and cells) which leak into the anterior chamber

visualizing light scatter through turbid environment (tyndall effect)

Question 11

dyscoria is often caused by _______

Answer 11

posterior synechia

Question 12

is this anterior or posterior synechia

Answer 12

posterior synechia

Question 13

is this anterior or posterior synechia

Answer 13

anterior synechia

often distorts the ocular surface

Question 14

iris bombe is a risk factor for ….

Answer 14

secondary glaucoma via obstruction of aqueous from posterior chanber through the pupil

Question 15

hypopyon

Answer 15

white blood cells settling in the anterior chamber

typically severe inflammation/break down of BOB

Question 16

hyphema

Answer 16

RBCs settling in the anterior chamber

occurs primarily from uvetitis; also consider coagulopathies and hypertension

Question 17

what is decreased IOP called

Answer 17

hypotony

• if you find a low reading, consider the effects of uveitis:*
• • blood ocular barrier disruption = leaky*
• • inflammation of ciliary body = decreased aqueous production*

Question 18

what is the most clinically significant sequelae of chronic uveitis

Answer 18

secondary glaucoma

Question 19

exogenous causes of canine uveitis

Answer 19

blunt or perforating trauma

corneal ulceration (reflex uveitis)

Question 20

endogenous causes of canine uveitis

Answer 20

lens induced

infectious

neoplastic

metabolic

auto-immune

Question 21

what causes “blue eye” in some dogs

Answer 21

canine adenovirus I

Question 22

most common primary neoplasm in canine eye

Answer 22

melanocytoma

• DDx: uveal cyst*
• benign, enucleation is typically recommended*

Question 23

characteristics of uveal cysts

Answer 23

spherical

transluminate

can be attached to pupil margin or free floating

only rarely need to be treated

Question 24

common fungus casuing uveitis in cats

Answer 24

cryptococcosis

signs: “roman nose,” gramuloatous chorioretinitis

Question 25

primary feline uveal tumor

Answer 25

feline diffuse melanoma - most common

only primary melonocytic tumor in companion animals that commonly displays malignant characteristics (check liver, spleen and lungs)

Question 26

characteristics of feline diffuse iris melanoma that can assist in diagnosis

Answer 26

rapid progression (weeks to months)

texture is velvety

dyscoria due to invasion of iris musculature

pigmented cells floating in anterior chamber

Question 27

freckle or melanoma?

Answer 27

can be hard to differentiate, need histopathology (enucleation) to confirm

Question 28

metabolic causes of endogenous uvetitis in cats

Answer 28

hypertension - renal disease, hyperthyroidism

Question 29

uveitis therapy

Answer 29

treat primary cause (if known)

all cases need anti-inflammatory therapy - systemic/topical coritcosteroids or NSAIDs, atropine, doxycycline

Question 30

when should corticocosteroids not be used to treat uveitis

Answer 30

in the presence of corneal ulcers

Question 31

what is wrong with this cat

Answer 31

given atropine as a mydriatic - has a bitter taste and may cause hyper-salivation

Question 32

what are some pros to using atropine in the treatment of uveitis

Answer 32

induces cycloplegia (paralysis of the ciliary body - alleviates pain from spasm)

reduces risk of posterior synechia

stabilizes blood-ocular barrier