Anterior Chamber/Uvea Flashcards
constriction of the pupil
miosis
if you see miosis, what should be on your short list of rule outs
uveitis
abnormally shaped iris,
most commonly observed with posterior synechia
Dyscoria
Dyscoria is most commonly observed with
posterior synechia
adhesion of the iris to the lens or the cornea
synechia
adhesion of the iris to the lens
posterior synechia
adhesion of the iris to the cornea
anterior synechia
a 360 degree posterior synechia where the aqueous humor becomes entrapped within the posterior chamber which causes the iris to bulge forward like a donut
iris bombe
blood that settles within the anterior chamber
common with uveitis and indicative of a large breakdown in the blood ocular barrier
hyphema
decreased intaocular pressure
consistent with acute uveitis
hypotony
paralysis of the ciliary body.
induced by atropine and useful at alleviating pain from uveitis (ciliary body spasm)
cycloplegia
everything that is anterior to the vitreous (cornea, anterior chamber, posterior chamber, iris, lens, lens zonules, ciliary body)
anterior segment
everything that is behind the lens and zonules (vitreous, retina, choroid, optic nerve)
posterior segment
the anterior chamber is the _______ *
space between the cornea and iris
filled with aqueous humor
what is the anterior chamber filled with
aqueous humor
the space between the iris and the lens
posterior chamber
the posterior chamber is the space between the
iris and lens
What makes up the anterior vs posterior uvea
Anterior Uvea: Iris and Ciliary body
Posterior Uvea: Choroid
What structures are a part of the uvea
Iris
Ciliary body
Choroid
what produces aqueous humor
ciliary body epithelium
What are the functions of the ciliary body
1) Produces aqueous humor
2) where lens zonules arise
3) Ciliary muscle contraction results in visual accommodation via changing tension on the lens
4) Vascular structure
cilary body processes are called
pars plicata
What is the flow of aqueous humor *
1) Ciliary body
2) Posterior chamber
3) Pupil
4) Anterior chamber
5) Iridocorneal angle
6) Venous circulation
Where does aqueous humor drain out of
Iridocorneal angle
what test allows you to look at the iridocorneal angle to see if it is ipen or closed
gonioscopy - pectinate ligament (PL) spans the ICA (should have a lot of holes)
Gonioscopy evaluates the
drainage angle
What are the 3 structures of the iris
1) Sphincter muscle (parasympathetic)
2) Dilator muscle (sympathetic)
3) Major arterial circle- very vascular
What happens in mydriasis
iris dilators contract
constrictors relax
what happens in miosis
iris constrictors contrast
dilators rleax
What are the different zones of the iris
1) Ciliary zones (most peripheral)
2) Iris collarette (can have some vascular reminants- persistent pupillary membranes)
3) Pupillary zone - often darker
heterochromia iridis
two different colored iris (within one eye)
What is the purpose of the blood-ocular barrier
the blood-aqueous barrier prevents passage of protein and cells into the anterior chamber
allows clear media for vision
disruption of the blood-aqeuous barrier =
uveitis
inflammation of the iris and ciliary body
anterior uveitis (Iridocyclitis)
Iridocyclitis
inflammation of the iris and ciliary body (anterior uveitis)
Inflammation of the choroid
posterior uveitis (choroiditis)
inflammation of the entire uvea (iridoyclitis and choroiditis)
panuveitis
inflammation of the entire uvea and intraocular contents
endophthalmitis
inflammation of all ocular and intraocular structures including the slcera
panophthalmitis
What are the clinical signs of uveitis *
Non-specific:
-Epiphora
-Blepharospasm
-Photophobia
-Red eye - ciliary flush (deep blood vessels) or episcleral injection
-Corneal edema- angle is blocked w inflammatory cells in the anterior chamber
Specific:
-Miosis: due to inflammation driven by prostaglandins causing iris sphincter muscle constriction (give atropine)
-Aqueous flare: Increased protein in aqeuous humor - eye looks cloudy
-Keratic Precipitates: cellular and fibrinous deposits on inner cornea (WBCs adhered to endothelium)
-Hypopyon
-Hyphema
-Fibrin
-Lipid
-Lymphoid nodules (cats)
How can you get corneal edema with uveitis
angle is blocked w inflammatory cells in the anterior chamber
Why do you see miosis with uveitis *
due to inflammation driven by prostaglandins causing iris sphincter muscle constriction-
iris has prostaglandin receptors
need to give atrophine to paralyze the muscle and stop the spasm
lots of pain from ciliary body spasm
What is aqeuous flare *
Aqueous humor that has increased protein and cells due to the breakdown in blood aqeuous barrier (leaky anterior uveal tract)
scatters light and makes the eye look cloudy
What is the best way to examine for aqeuous flare
slit beam at the front side of cornea and looking at the side -> shouldnt catch the beam
cellular and fibrinous deposits on the inner cornea -> WBCs adhered to the endothelium
sign of uveitis
keratic precipitates
neutrophils in the anterior chamber, settles at the bottom of anterior chamber
sign of uveitis
hypopyon
When might you see fibrin in the anterior chamber
common in cats and horses
treat with tissue-plasminogen activator (TPA)
when might you see lipid in the anterior chamber
Uveitis with Hypertriglyceridemia
1) Mini Schnauzer
2) Cushing’s
3) Diabetes Mellitus
How do you get rid of fibrin in the eye, common in cats and horses
inject treat with tissue-plasminogen activator (TPA)
should go away in minutes
With uveitis, how does intraocular pressure change
decreases
What is the pathogenesis of anterior uveitis
1) cell damage in iris or ciliary body
2) release of arachadonic acid
3) formation of leukotrienes and prostaglandins
4) breakdown of blood-aqueous barrier (blood-ocular barrier)
Exogenous causes of anterior uveitis (ie trauma and corneal ulcers) are unilateral or bilateral
While endogenous causes (ie infectious, neoplastic, immune mediated, idiopathic) are
unilateral (exogenous)
bilateral (endogenous)
What typically causes canine infectious uveitis (typically bilateral) **
Algal: Prototheca
Bacterial: Borrelia*, Brucella, Leptospirosis, Septicemia
Fungal*: Blasto, Coccidiodes, Crypto, Histo
Parasitic: Dirofiliria (ocular larval migrans), Dipteran fly larva (ophthalmomyiasis interna)
Protozoan: Toxoplasma, Leishmania
Rickettsial*: Erhlichia, Rickettsia
Viral: Adenovirus, distemper
what are common causes of canine non-infectious uveitis (unilateral or bilateral) *
- Most common cause in dogs and cats
Immune mediated: Cataracts, IMHA, ITP, uveodermatologic syndrome, vasculitis
Idiopathic: Metabolic (systemic hypertension, coagulopathy, hyperlipidemia)
Neoplasic
Trauma
Scleritis, drug induced (miotics), radiation therapy
What are common causes of feline uveitis *
Bacterial: Bartonella (cat scratch fever)
Fungal: Crypto, Histo, Blasto, Coccidiodes
Parasitic: Diptera (ophthalmomyiasis interna)
Protozoan: Toxoplasma
Viral FIV, FeLV, FIP, Herpes
Noninfectious/Idiopathic **most common (65% of cases): Systemic hypertension or Neoplasia (LSA or melanoma)
65% of uveitis cases in the cat and dog are
idiopathic
What are the 4 F’s ad T of feline uveitis causes
FeLV
FIV
FIP
Fungal
Toxoplasma
If hyphema is present, what should you do? **
Coagulation panel
if cats (systolic blood pressure too)
Uveitis work up
travel history
PE
CBC
Chem
Urinalysis
Thoracic radiographs
Tick titers (4DX)
Fungal titers by geography
Coagulation panel (if hyphema)
blood pressure (cat)
Ocular centesis
an aqeuous humor centesis which is important for your work up of anterior uveitis
-cytology
-culture
-titers (toxo and lepto)
-PCR- FIP
What is a common etiology of anterior uveitis in horses (aside from trauma)
Equine recurrent uveitis (ERU)
-immune mediated disorders
What are common etiologies of anterior uveitis in cows (other than trauma)
infectious
-MCF, IBK (by causing corneal ulcer)
septicemia
What are the signs of anterior uveitis **
1) Ocular discahrge (serous, mucous, mucopurulent)
2) Enophthalmos- retraction of globe from pain and raising of the third eyelid
3) Blepharospasm
4) Red eye- conjunctival and episcleral vascular injection
5) Corneal edema: decrease function of endothelial cells - blue color to cornea due to diffuse edema
6) Corneal Neovascularization: irritation of corneal endothelium ,typically deep vessels
7) Anterior Chamber changes: flare, cells, fibrin, hyphema, keratic precipitates)
8) Iris changes: miosis in acute cases due to ciliary body/iris muscle spasm, sluggish pupillary light response, hyperemia and thickening
What iris changes are seen with anterior uveitis
-miosis in acute cases due to ciliary body/iris muscle spasm
-sluggish pupillary light response
-hyperemia and thickening
What changes to the anterior chamber is seen with anterior uveitis
flare, cells, fibrin, hyphema, keratic precipitates
iris hyperpigmentation is seen with
chronic uveitis
What are signs of chronic anterior uveitis
1) Iris hyperpigmentation
2) Synechia
Anterior: iris to cornea
Posteiror: iris to lens capsule
3) Decreased intraocular pressure
When is anterior synechia typically seen
corneal perforation - pressure loss
iris comes forward to plug the whole
IRIS to CORNEA
When is posterior synchechia typically seen
Uveitis- when iris inflammed becomes sticky and attaches to the lens
IRIS to LENS
causing dyscoria and pigment migration onto lens capsule and changes to pupil appearance
diffuse posterior synchechia and build up of aqeuous humor posterior to iris
iris bombe
what can iris bombe lead to
glaucoma if the fluid is not draining properly
What drug can you give to move iris so it doesnt form a posterior synchechia
atropine
What is a great way to monitor repsonse to therapy with uveitis
Measuring IOP
What is normal IOP
10-20mmHg dog/cat
20-30mmHg horse
How do you treat uveitis **
1) Get rid of antigen
2) Nonspecific therapy: stop inflammation, control pain, prevent sequelae
-Glucocorticocoritcoids- systemic or topical or subconjuctival
-NSAID
-Immune suppressant: azathioprine, cyclosporine, mycophenolate
What is a good topical glucocorticoid for anterior uveitis
1% prednisolone acetate - good cornea penetration
What anti-inflammatories should you do for anterior uveitis *
Glucocorticoids
1) Systemic- prednisone, prednisolone
2) topical- 1% prednisolone acetate (3-4 times a day then taper)
3) Subconjunctival- triamcinolone (always consider the cause and potential for corneal ulceration)
NSAID
1) Topical- diclofenac, ketorolac, flurbiprofen
2) Systemic- flunixin, phenylbutazone, carprofen, meloxicam, firocoxib
Immune suppressants
1) Systemic- azathioprine, cyclosprine, mycophenolate
Aside form NSAIDs, What should you do to relieve pain in anterior uveitis *****
Parasympatholytic
1% atropine sulfate **
1% tropicamide
-Mydriasis: prevent posterior synechia (exercises iris)
-Cycloplegia: relieves ciliary spasm
Anterior uveitis sequela
synechia
iris color change
cataract
secondary glaucoma (most common sequela to uveitis)
most common sequela to uveitis
secondary glaucoma
Uveodermatologic Syndrome (VKH) typically occurs in what breeds
young adult
Akitas, Samoyeds, Siberian husky
What are the clinical signs of Uveodermatologic Syndrome (VKH)
-Anterior and/or Posterior Uveitis (typically bilateral)
-Depigmentation of Skin and Hair (poliosis and vitiligo)
What is the pathogenesis of Uveodermatologic Syndrome (VKH)
immune mediated attack on melanocytes
How do you diagnose Uveodermatologic Syndrome (VKH)
clinical appearance
biopsy
How do you treat Uveodermatologic Syndrome (VKH)
systemic immune suppression
prognosis for vision is guarded to poor due to chronic, severe uveitis and sequela
How might you see lens induced uveitis
lens is immune privileged
lens proteins are antigenic
proteins leaked during cataract formation
-usually mild ut can be severe
tx: topical anti-inflamamtories and/or lens removal
Most common cause of blindness of horse due to secondary glaucoma and cataract formation
Equine Recurrent Uveitis
“Moon blindness”
immune mediated disease
Equine Recurrent Uveitis is common in what breeds
Appaloosas more likely to be effected (anterior uveitis)
German warmbloods (posterior uveitis)
Equine Recurrent Uveitis is primarily immune mediated but what infectious cause might initiate it
Leptospira
What causes persistent pupillary membranes
incomplete absorption of embryonic vascular tissue and mesenchymal strands
originate at the iris collarette
congenital
unilateral or biliteral
persistent pupillary membranes typically regress by
prior to opening of the eyelids at 2 weeks of age in the dog and cat
persistent pupillary membranes originate at the
iris collarette
1) Iris to iris
2) iris to lens
3) iris to cornea
persistent pupillary membranes can be secondary to what in cats
in-utero FHV-1 infection
persistent pupillary membranes often contact the corneal endothelium causing white opacities known as
leukomas
doesnt keep the cornea well hydrated, reuslts in corneal edema
persistent pupillary membranes can contact the anterior capsule causing
focal cataracts
-leave pigment on the anterior lens capsule
where do iris cysts occur *
from posterior pigment of iris
may be attached at pupil margin (cats)
may become free floating (dogs)
What might cause fly biting behavior in dogs
iris cysts
What are consequences of iris cysts
1) fly biting behavior
2) block filtration angle- glaucoma
How do you diagnose iris cysts *
1) Transilluminate - differentiate from iris melanoma
2) Ultrasound probe
In horses, iris cysts arise from
corpora nigra
-laser off
How do you treat iris cysts *
often not necessary unless the cysts cause secondary issues such as secondary changes, increased intraocular pressure
laser off
T/F: most intraocular tumors of dogs are benign
true - iris melanoma/melanocytoma are usually benign
but ciliary body adenoma/adenocarcinoma are malignant but slow to metastasize- often causes secondary glaucoma
In dogs, what intraocular tumor is malignant
ciliary body adenoma/adenocarcinoma are malignant but slow to metastasize- often causes secondary glaucoma
Cat anterior uvea melanoma ***
focal - may be slowly progressive
more aggressive in cats (than in dogs)
Feline Diffuse Iris Melanoma- metastasis to liver and lung, slowly progressive
Iris thickening, dyschoria
What should you do if you noticed a brown marking on the iris of the cat
take a photo and re-evaluate in 3 months
melanoma is slow growing
but eventually can become diffuse causing flotating pigment, iris thickening, dyscoria and potentially metastasis to liver and lung
“ Feline Diffuse Iris Melanoma”
-can always laser off smaller
normal aging atrophy of pupil margin and/or iris stroma
iris atrophy
