Optho Final Flashcards
What is the difference in superficial and deep blood vessels in the eyes?
superficial - branch like trees
deep - like a hedge
What is pannus? What causes it?
chronic superficial keratitis, non painful, progressive
cause - immune mediated, starts laterally
What breed gets pigmentary keratopathy?
pugs
What dog breeds get limbal melanoma?
GSD, golden retrievers, labs
What makes up feline corneal sequestrum?
necrotic corneal stroma
What is the tx for feline corneal sequestrum?
surgical resection
What causes yellow corneal opacity?
cellular infilatration - infection
What breeds get episcleritis?
cocker spaniels, collies
How is esoniophilic keratitis in cats treated?
cyclosporine
topical steroids - less common
megesterol acetate
How can you tell the difference between nuclear sclerosis and cataracts?
nuclear sclerosis is transparent, can see through it with ophthalmoscope
What are the different stages of cataracts?
Incipient (less than 10%) Immature Mature - solid opaque marble, PLR normal Hypermature - capsule wrinkled Morgagnian - liquefication
What enzyme is the rate limiting step in pathogensis of diabetic cataract formation?
aldose reductase
What breeds are predisposed to primary lens luxation?
jack russells and related breeds - zonular dysgenesis
What is the most common cause of lens luxation in cats and horses?
uveitis
Term for a space between the lens equator and pupillary margin that happens in lens subluxation.
aphakic crescent
What iris abnormality is characterized by irregular pupillary ruff and holes in iris stroma and is an aging change?
iris atrophy
What are the most common primary tumors of the uvea in dogs, felines and equines?
dogs - melanocytomas, ciliary body adenomas
feline - diffuse iris melanoma
equine - melanoma
What are the most common secondary tumors of the uvea in dogs and cats?
lymphosarcoma
How can you differentiate between a melanoma and a uveal cyst?
transillumination - cysts transilluminate whereas melanomas are solid
What is the most common cause of uveitis in all species?
idiopathic
What are some common causes of uveitis in dogs?
cataract, reflex uveitis (ulcers), idiopathic, lipemic aqueous, uveodermatologic syndrome
What are common causes of uveitis in cats?
bartonella, crypto, histo toxo (systemic dzs)
By what 2 mechanisms can uveitis lead to glaucoma?
PIFVM (membrane) Iris bombe (360 synechiae)
What is the unconventional outflow pathway of aqueous?
vitreous - uveal tract - supraviliary suprachoidal space - adjacent sclera
What breeds are predisposed to primary glaucoma?
basset, boston, cocker, lab, shih tzu, fox terrier
What CS are associated with acute glaucoma?
corneal edema, mydriasis, episcleral injection, blindness, pain
What CS are associated with chronic glaucoma?
blindness, cupped optic nerve, tapetal hyperreflectivity, buphthalmos, descemets striae, lens luxation
What is the normal intraocular pressure of domestic species?
12-24 mmHg
What 2 causes of glaucoma cause a PIFVM to form and consequently glaucoma?
uveitis
tumors with angiogenic factors
What drugs for glaucoma decrease aqueous humor production only?
CAIs
What 3 classes of drugs for glaucoma act by increasing aqueous humor outflow?
PG analogs (latanoprost) cholinesterase inhibiters (demacarium) parasympathomimetics (pilo)
What 2 classes of drugs for glaucoma both decrease humor production and increase outflow?
sympathomimetics (dipivefrin) beta blockers (timolol)
How should acute glaucoma be treated in the vet clinic?
measure IOP, give 1 drop latanoprost or dorzolamide/timolol every 5 mins for 30 mins, recheck IOP, repeat cycle until under 25 mmHg
What breeds are predisposed to persistent hyperplastic primary viterous?
dobies and staffordshires
What developmental problem results in calcium or lipid deposits in vitreous that move when the eye is moved?
asteroid hyalosis
Name the 10 layers of the retina.
Ret. pig epi Photoreceptors Ext limiting memb outer nuclear outer plex inner nuclear inner plex ganglion cells nerve fibers int limiting memb
Which species have holangiotic retinas?
small animals and ruminants
Which species have paurangiotic retinas?
equine and marsupial
Which species have merangiotic retinas?
rabbits
Which species have anangiotic retinas?
birds
Is collie eye anomoly progressive?
no
What lesions are seen in collie eye anomoly?
coloboma at 6 o clock, detachment, blindness, choroidal hyperplasia, hemorrhage, vermiform streaks
What retinal disease is characterized by bilateral acute diminished vision in subdued light with loss of peripherals and mydriasis?
progressive retinal atrophy
What retinal disease is characterized by sudden onset of day and night blindness with sluggish PLRs and PU PD?
sudden acquired retinal degeneration (SARD)
What retinal disease of cats is characterized by cigar shaped lesion in area centralis and hyperreflective tapetum?
feline central retinal degeneration
What is the cause of feline central retinal degeneration?
lack of taurine
What is the most common cause of retinal detachment?
systemic hypertension
What are probable causes of retinal hemorrhage?
hypertension, coagulopathies (NOT trauma)
What CS are associated with optic neuritis?
No PLRs, visual deficit, optic disc swollen, irregular dilated retinal vessels
What are some causes of optic neuritis?
GME, distemper, crypto, blasto, histo, toxo
Term for elevation of disc surface above retina. What does it indicate?
papilledema - indicates occupying mass causing increased CSF pressure
Are inactive retinal lesions hypo or hyper-reflective?
hyperreflective
What are unique features of the ruminant eye?
increased # of corneal layers
corpora nigra
horizontal pupil
complete bony orbit
What are unique features of the camelid eye?
ribbon like pupillary ruff, NO tapetum
What are unique features of the pig eye?
no tapetum, incomplete orbit
What are unique features of the avian eye?
thinner cornea
How is SCC in cow eyes treated?
surgical excision + other treatment such as cryoablation
What is the most common structure to be affected by lymphoma in a cow?
orbit (retrobulbar)
How can you differentiate mycoplasma and chlamydophila in small ruminants?
mycoplasma - may cause ulceration, intracyto inclusions
What are the effects of mareks disease in a chickens eye?
systemic neoplasia that affects uveal tract causing inflammation, cataract, blindness
What nerve is blocked for examination of the equine eye? how?
CN VII, caudal aspect of zygomatic arch, 1-2 ml lidocaine with 25g needle
What are the 2 most common ocular tumors of horses?
SCC
periocular sarcoid
How long can atropine have an effect on a normal horse pupil?
2-4 weeks
What are the 3 most common sequelae of equine recurrent uveitis?
cataract, retinal detachment, glaucoma
What is the best treatment for equine recurrent uvieitis? MOA?
suprachoroidal cyclosporine A implant - prevents T cell mediated destruction
Which exotic animals have a large venous plexus in the posterior orbit and care should be taken during enucleation?
ferrets, rabbits, mice/rats
Which exotic animals have a anangiotic fundus?
chinchilla, bird, reptiles
Which exotic animasl has a holoangiotic fundus?
ferret, mice/rats
Which exotic animal has a paurangiotic fundus?
guinea pig
What are CS of encephalitozoon infection in rabbits?
intralenticular abscess, cataracts, lens capsule rupture
What is the tx for encephalitozoon in rabbits?
fenbendazole + NSAIDs
larger - phacoemulsification
What bacteria causes conjuctivitis in rabbits?
pasturella multocida
What bacteria causes conjuvtivitis in chinchillas?
chlamydophila
What underlying disease causes dacryocystitis in rabbits?
dental disease
WHat are some causes of chromodacryorrhea in rats/mice?
blood sampling from orbital venous sinus, environmental irritants, bacteria, viruses
What are the 2 agents that cause conjuctivitis in birds?
mycoplasma and chlamydophila psittaci
What is the treatment for conjunctivitis in birds?
topical fluoroquinolones or tetracyclines
What is the underlying disease that causes subspectacular abscesses in snakes?
ascending infections thru nasolacrimal duct from oral cavity dz
What is the treatment for subspectacular abscesses in snakes?
drainage window in spectacle, culture and topical antibiotics, treat stomatitis