Unit 2 Flashcards
1
Q
What is the Uveal Anatomy (aka vascular tunic)
A
Anterior uvea- iris ciliary body
Posterior uvea- choroid
2
Q
Where does the aqueous humor exit
A
The iridocorneal angle at the base of the iris
3
Q
What are the functions of the iris (4)
A
Protection, nutrition, controls light entry, removes waste and aqueous humor
4
Q
What are the functions of the ciliary body
A
Produces aqueous humor and lens accommodation
5
Q
Where can persistent pupillary membranes bind the iris to
A
Iris to iris, iris to cornea, iris to lens
6
Q
Which persistent pupillary membrane location formation is generally benign
A
The iris to iris
7
Q
What can persistent pupillary membranes that bind the iris to the cornea cause
A
Corneal opacities, chronic corneal edema, and may interfere with vision
8
Q
What uveal disease is acquired but some breeds predisposed to, may rupture and cause pigment dispersion but are generally not clinically significant
A
Iris cysts
9
Q
Is iris atrophy a congenital disease and is it clinically significant?
A
No it is an acquired disease of older dogs that isn’t usually clinically significant
10
Q
What are the clinical signs of uveitis
A
Miosis (look for asymmetry), change in iris color (red or dark), low IOP or >5mm difference between eyes), sclera injection and maybe conjunctival hyperemia, pain, aqueous flare
11
Q
What are the potential causes of aqueous humor flare (the actual substances)
A
Increased cells and protein, hypopyon (pus in the AC), Hyphema (blood in the AC), Fibrin
12
Q
Explain the Tyndall effect
A
The ability to see light passing through a liquid becuase of the dispersion of light in colloidal solutions
13
Q
What are potential sequelae of uveitis
A
Glaucoma, synechia (lens sticking to other areas), cataracts, retinal detachments, loss of vision, blindness, enucleation
14
Q
T/F most causes of uveitis are secondary
A
True
15
Q
List examples of primary causes of uveitis
A
Lens-induced uveitis (cataracts), blunt injury, reflex uveitis from corneal ulceration, intraocular tumors
16
Q
T/F diabetes can cause uveitis
A
True
17
Q
T/F cataracts can cause uveitis but uveitis can also cause a cataract
A
True
18
Q
How does a cataract cause uveitis
A
The lens proteins leak through the capsule and cause inflammation
19
Q
What is the first step when treating uveitis
A
Looking for the underlying cause
20
Q
How should you treat uveitis
A
Treat the underlying cause and also control the inflammation with topical NSAIDS or steroids (if there are no ulcers)
21
Q
Should you use systemic anti inflammatories for uveitis and why or why not
A
Not without a work up because it may worsen the uveitis or obscure diagnostics
22
Q
How should you treat iris melanosis in a cat
A
You should monitor or enucleate if the eye is inflamed or there is increased pressure.
23
Q
Is iris melanoma always malignant
A
No it can be benign, but there is no way to tell early in the disease without enucleation and benign can later become a tumor
24
Q
What are the three structural elements of the lens. Which part becomes the lens fibers and which is the barrier
A
There is the lens capsule which is the barrier, the lens epithelium which multiplies to become the lens fibers, and the lens fibers (they are antigenic protein)
25
A normal lens should have what 3 features
Absence of blood vessels, lack of pigmentation, and perfect orderly arrangement of lens fiber cells
26
What is the primary source of nutrition for the lens
The aqueous humor
27
What is retroillumination and what can it detect
When light is reflected from the iris or tapetum to help detect subtle structures in the anterior segments or lens. The abnormalities will appear dark against the light background
28
How will cataracts impact retroillumination
They will alter/interrupt the tapetal/red reflex
29
How does nuclear sclerosis differ from cataracts
Nuclear sclerosis is a normal age related change because the lens nucleus increases in density because of lens fiber addition. Looks like a lens within a lens. Nuclear sclerosis does not significantly affect vision in animals nor does it block the tapetal/red reflex
30
What is a lens coloboma
A notch defect (missing tissue) seen at the equator of the lens that is congenital
31
What is microphakia
A small lens, is congenital
32
What is Spherophakia
A rounded lens, it is congenital
33
What is the most common cause of cataracts in dogs
Genetics/ inherited
34
How does diabetes cause cataracts
Hyperglycemia—> hexokinase pathway becomes over saturated and the glucose is shunted to aldose reductase which turns it into sorbitol with alters the osmotic gradient. Causes lens fiber swelling, rupture, vacuole formation and cataracts
35
What is more likely to develop cataracts from diabetes dogs or cats
Dogs
36
What disease causes bilateral cataracts, that are complete, develop rapidly, and cause blindness
Diabetes
37
What is the most common cause of cataracts in cats and horses and are they good candidates for cataract surgery
Uveitis/ post-inflammatory cataracts, usually not good candidates
38
What is lens capsule rupture associated with in cats and knowing this how should you treat it
Associated with risk of post-traumatic sarcoma development so you should consider enucleation
39
What classification is the earliest stage of cataract disease
Punctate cataracts
40
Describe what classifies a cataract as incipient
When <10% of the lens is affected and there is no vision loss and the tapetal reflection is apparent
41
What describes a cataract that is incomplete/immature
10-99% of the lens is affected but the tapetal reflection is still apparent
42
Will a complete cataract have a menace
No, there is vision loss
43
What is a resorting/hypermature cataract
There may be a tapetal reflection and it appears “sparkly and wrinkled”
44
What is the only surefire way to cure a cataract
Surgical removal of the opacity- use ultrasonic energy with irrigation and aspiration to remove the lens and replace it with an intraocular lens implant
45
What must you do with a post-op cataract surgery patient
Control the uveitis with topical anti-inflammatories, monitor the IOPs, systemic antibiotics and anti0inflammatories and recheck them frequently
46
What causes a primary lens luxation and what breeds are predisposed
Anomalous zonules and terriers
47
What are causes of secondary lens luxation
Chronic inflammation, glaucoma/ buphthalmia (enlargement of the eye), intraocular mass, trauma
48
Where can lens luxate to
Anteriorly (in front of the iris)
Posteriorly (falls back into the vitreous)
49
What is a hallmark sign of a lens luxation
An aphakic crescent
50
What is glaucoma
A group of diseases united by elevated intraocular pressure impairing normal optic nerve and retinal health and function
51
What is normal intraocular pressure and what is it usually dictated by
10-25 mmHg and dictated by a balance between aqueous humor production and outflow
52
Where and how is aqueous humor made
The ciliary body through passive diffusion and also active diffusion which uses carbonic anhydrase to release HCO3 into the posterior chamber which Na and water follow
53
Describe the flow of the aqueous humor
Posterior chamber—> through pupil—> into anterior chamber—> through iridocorneal angle into venous sinuses OR via the uveoscleral pathway (Supra-ciliary/choroidal space) OR through the iris/ciliary body stroma to the choroidal circulation
54
What are the two causes of primary elevated IOP
Iridocorneal angle closure and accumulation of proteoglycans in trabecular meshwork (in the ciliary cleft)
55
What are the five secondary causes of elevated IOP
Infiltration of iridocorneal angle (ICA) with inflammatory or neoplastic cells, neovascularization of iris spanning the IC angle, Synechiation (iris sticking to other things), lens luxatio/subluxation, vitreous pupillary block or obstruction of ICA
56
How fast can elevated intraocular pressure cause irreversible damage to the optic nerve
Within 24-48 hours
57
T/F acute glaucoma isn’t a “neurologic” emergency
False
58
If you control the intraocular pressure will damage to the optic nerve stop?
No it can still continue because a cascade of apoptosis has begun
59
What is staphyloma and what is it a clinical sign of
Uveal bulging via thinned sclera from chronic stretching/atrophy, clinical sign of glaucoma
60
What is gonioscopy and what can it be used to evaluate
Evaluation of intracorneal angle with special lenses to assess the angle opening and abnormalities to help determine if there is primary glaucoma
61
What signs may tell you if there is potential for restoration of vision with glaucoma?
What would indicate a bad prognosis?
If the glaucoma is acute, there is a positive menace, dazzle reflex, or consensual PLR to the fellow eye, and a normal optic nerve head these are all good signs
Chronic glaucoma (>72hr), buphthalmic, absent reflexes and a grey/dark, round and cupped optic nerve head are all bad signs
62
What are signs glaucoma may be primary in nature (inherent angle problem)
No other ocular disease, breed predisposition, abnormal drainage angle (gonioscopy)
63
What are ocular diseases that can result in secondary glaucoma
Lens luxation, intumescent cataract, uveitis, neoplasia, vitreous prolapse
64
What are differences in how primary and secondary glaucoma are treated
Primary usually involves therapy to open the angle and decrease aqueous production and secondary involves treating the underlying cause and therapy to decrease aqueous production
65
American cocker spaniel, chows, huskies, bouviers, and basset hounds are prone to what
Primary angle closure glaucoma
66
T/F primary glaucoma acute attacks may spontaneously return to normal and vision may return
True
67
When is a likely time of day that a primary angle closure glaucoma cause may experience an acute attack
At night (dim light), because the pupil dilates and obstructs the angle
68
What is goniodysgenesis
There is dysplasia of the pectinate ligaments, they do not develop normally and instead of delicate strands they form broad thickened fibers that are large sheets with “flow holes”
69
What makes up the posterior segment
Vitreous, choroid (tapetum), retina, optic nerve
70
What is the primary vitreous
The hyaloid vessel system that becomes the vitreous but during development is vascular and provides nutrients to the lens, the vessels all but go away in development
71
What accounts for 75% of the volume of the globe
Vitreous
72
What is the vitreous mostly made of
Water
73
What are the functions of the vitreous
Provides structure and keeps the retina pressed against the back of the eye (mechanical support), metabolic support for the retina and lens, some refraction
74
What is the common developmental abnormality of the vitreous
Persistent hyaloid artery or remnant
75
What is a bergmeister’s papilla and what is it common in
A small tuft of tissue at the optic nerve head that is a remnant of the hyaloid artery and is a normal finding often in large animals
76
What is persistent tunica vasculosa lentis, what can occur from it
A network of fine, white strands extending from posterior lens capsule that is the remnants of embryonic blood supply, inherited in Dobermans and Stanford shire terriers and sporadic in other breeds but can become hyperplastic
77
What is asteroid hyalosis
Condensed calcium phospholipid particles suspended in vitreous, look like sparkly or starry pin-point opacities (snow globe appearance), an aging change
78
What is syneresis
Liquification of vitreous
79
What is notable about vitreal hemorrhage
Will be very slowly resorted (months), but the underlying cause is a sequela to trauma, systemic disease, etc.
80
Neurosensory retina layers look like what
Nothing!
81
What part of the retina can you see in the neurosensory retina layers
The blood vessels
82
What part of the retina has opacity to it so you can see it
Retinal pigmented epithelium
83
Where do retinal detachments occur and why
The space that is formed between the neurosensory retina and retinal pigmented epithelium because these layers are formed separately so they aren’t attached
84
Do birds have retinal blood vessels
No, only mammals do
85
What part do the retinal blood vessels nourish
The inner third of the retina (the outer 2/3 nourished by choroid)
86
In an albino animal what can you see instead of the retinal pigment
The choroid behind it and its blood vessels
87
Which retinal pattern is poorly vascularlized
Paurangiotic retinal pattern
88
What retinal pattern is a zigzag of the retina and choroid because there are no retinal blood vessels and is seen mostly in birds
What do they also have for nourishment
Anangiotic retinal pattern
There is also a pectin
89
What are the outermost cells of the sensory retina
Photoreceptors (rods and cones)
90
What cells are highly light sensitive but provide minimal detail
Rods
91
What cells are less light sensitive but good detailed vision and color
Cones
92
What receives input from the photoreceptors and transmits it to the ganglion cells
Integrating neurons
93
What transmits visual info to the brain and the axons form the nerve fiber layer and optic nerve
Ganglion cells
94
Describe how the electrical signal travels through the eye
It is generated by the photoreceptor cells and transmitted to the integrating neurons and to the ganglion cells to the nerve fiber layer to optic nerve moving in a posterior direction
95
What are the supporting cells of the retina
Retinal muller cells
96
What is the outermost later of the retina
The retinal pigmented epithelium
97
Is it normal for the retinal pigmented epithelium to have pigment over the tapetum
No, normally there is not pigment over the tapetum
98
The optic nerve head is also known as
Optic disk or optic papilla
99
What does the choroid contain
Blood vessels (choriocapillaris and choroidal vessels), pigment, and tapetum
100
What is the job of the tapetum
It is posterior to reflect the light photons back to the retina to enhance light sensitivity
101
Because the tapetum is between the retina and the choroid how does blood supply get through to the retina
Vessels that travel through the tapetum (creates stars of Winslow)
102
What reflexes assess light reflexes and perception (not vision)
Pupillary light reflexes and dazzle reflex
103
What tests assess vision
Behavior (history, cotton bal tracking, maze testing), menace response
104
What is uses to assess retinal electrical activity (retinal function only)
Electroretinography
105
How can you visualize the posterior segment when the anterior segment is opaque
Ocular or orbital ultrasonography
106
How can you look at the vessels of the retina
Fluorescein angiography
107
What is ophthalmoscopy
Looking at the fundus/back of the eye- the composite image of layered structures of the posterior segment
108
What are the three major layers of the fundus
Fiberous tunic, vascular (uveal) tunic, nervous tunic
109
What is the outermost and innermost layer of the fundus
Outermost- sclera
Innermost- retinal vessels
110
Pigment and vascular variations can vary, in eyes with little pigment in the choroid (like blue eyes) what does the eye normally look like
You will see lots of retinal and choroidal vessels and may even see some sclera poking through
111
The tapetum is always what (position wise)
Superior (when present)
112
What color is the tapetum normally in dogs and cats
Dogs- yellow, green, orange, blue, purple (as puppies)
Cats- yellow, green
113
What animals often lack a tapetum
Color dilute animals like merles, because fundus color varies with coat color
114
T/F large dogs often have small tapetums
False, tapetal size varies with size of dog, large dog= large tapetum
115
In primary glaucoma therapy what therapeutics are used to decrease aqueous humor production
Carbonic anhydrase inhibitors, betel blockers, or cyclo-destructive procedures (laser, cryo, chemical)
116
In primary glaucoma therapy what therapeutics are used to enhance drainage
Mitotics- prostaglandins, pilocarpine
Goniovalve implantation
117
When are miotics contraindicated for glaucoma
Secondary glaucoma and/or lens luxation
118
What are two glaucoma therapies that are emergency “band-aids” to allow other treatments time to work or give time to get to surgery
Osmotic diuretics (mannitol) or aqueocentesis (tap the eye)
119
T/F topical steroids are contraindicated for glaucoma but NSAIDS are not
False, topical NSAIDS are contraindicated but steroids are not. Systemic steroids and NSAIDS are sometimes used
120
If one eye has primary glaucoma what is the likelihood the other eye will get it too
The “good” eye will develop glaucoma usually within 8 months
121
Betaxolol (beta blocker) or Demecarium bromide (acetylcholinesterase inhibitor) are used how
As prophylactic therapy for primary glaucoma, but eventually will fail
122
What is more common, secondary or primary glaucoma
Secondary is twice as common
123
What is a common sign of glaucoma associated with uveitis
The intraocular pressure is high when normally it is low with uveitis
124
What are the common treatments for secondary glaucoma from uveitis
Workup and treat the uveitis and use topical carbonic anhydrase inhibitors, beta-blockers, or beta agonists
125
How are two ways uveitis can cause secondary glaucoma
Obstruction of the filtration apparatus through inflammatory cells/fibirn accumulating in the intracorneal angle
Pre-iridal fibrovascular membrane (rubeosis iridis)- granulation tissue on the anterior surface of the iris
126
What are common causes for primary instraocular tumors and are they usually benign or malignant
Melanoma, melanocytomas, ciliary body adenocarcinoma, adenomas
In dogs primary tumors are usually benign to the body (but can devastate the eye) but in cats they have metastatic potential
127
Feline glaucoma is usually primary or secondary
Secondary from uveitis, neoplasia, or feline aqueous humor misdirection syndrome (FAHMS)
128
What happens with feline aqueous humor misdirection syndrome (FAHMS)
In older cats the aqueous humor gets directed into the abnormal vitreous and shifts the lens and iris diaphragm forward
129
What is often present with feline aqueous humor misdirection syndrome (FAHMS) (other than glaucoma)
Anisocoria and a shallow anterior chamber
130
What are used to treat feline aqueous humor misdirection syndrome (FAHMS)
Topical carbonic anhydrase inhibitors (brinzolamide)
131
Light enters the eye and travels through what (on the retina) to strike what
Enters the eye and travels through the sensory retina to the posterior/outer portion to strike the retinal pigment epithelium and photoreceptors to convert it to an electrical signal
132
T/F the retinal muller cells help transmit the electrical impulse of light energy through the eye
False
133
Which layer of the fundus is orange-red
The vascular tunic/ choroid
134
What layer of the fundus varies with coat color AND can obstruct the choroid
The retinal pigmented epithelium of the nervous tunic, variably pigmented
135
Where is the dog’s optic nerve head
In the tapetum or non-tapetum, usually at the junction
136
Where is the cat’s optic nerve head
In the tapetum
137
How are dog and cat optic nerve heads different in shape
The dog’s is myelinated so it varies in shape because it varies in myelination. The cat’s is in myelinated
138
What are the only “things” that could be in the fundus that shouldn’t be and what colors would they appear
Infiltrate (infection, inflammation, neoplasia)- whitish, edema- grayish, hemorrhage- red
139
How do active lesions in the fundus typically appear (compared to for example a scar)
Active processes are usually raised, have ill-defined edges, and are hyporeflective
140
If a disease causes retinal thickening from infiltrate, how will it often appear during a fundus examination
It will be a hyporeflective area
141
A dog has small gold circles on its fundus that appear to “glint” and shine at you. What are these?
Retinal scars
142
What is a hallmark sign of retinal degeneration
Vascular attenuation
143
When there is a retinal detachment, exactly what two layers are separating
The neurosensory retina and the underlying retinal pigmented epithelium
144
What can cause a retinal detachment
Subretinal fluid (between the neurosensory retina and RPE)- can be serous, exudative/infiltrate, or hemorrhage
Or retinal tears
145
You look into a dog’s eye and are able to preform a “pen-light diagnosis” because when you look into the pupil there is a vascular membrane visible. What are you diagnosing
A complete retinal detachment because the neurosensory layer is not pushed up against the back of the lens
146
What disease is characterized by retinal and tapetal thinning and will appear hyper-reflective and there will be vascular attenuation
This disease is inherited
Progressive retinal atrophy
147
What are the two types of progressive retinal atrophy and do they have varying clinical signs
Photoreceptor dysplasia and photoreceptor degeneration, the clinical signs are usually similar but the age of presentation and progression rate can vary
148
A dog presents because the owner noticed it started bumping into furniture after they rearranged their living room. The owner also says they did notice the dog seemed to be struggling to see on their nightly walks a few months ago but was fine during the day. You look at the dogs eyes and it has mydriasis (larger pupils) at rest. You do a fundic exam and the dog’s tapetum is hyperreflective. What is the best diagnosis for this dog?
Progressive retinal atrophy, they often lose the rods first so they have dim light deficits before progressing to cones and bright light eventually becoming blind. The pupils are larger because they are stretched to try and help the eye see
149
With progressive retinal atrophy might you see a PLR
Yes, even if the dog is blind, but it may progressively decrease
150
In late stages of progressive retinal atrophy what may you see *in* the eye
Secondary cataract formation
151
Describe the steps of retinal atrophy
Photoreceptors (and retina) dying (rods and then cones)—>retinal thinning—> tapetal hyper-reflectivity—> vascular attenuation (because retina auto regulates the blood supply)
152
What happens with retinal dysplasia and how do dogs get it
There is abnormal formation of full thickness areas of neurosensory retina and it folds and creates wrinkles. This is commonly an inherited disease in dogs (don’t breed these dogs!)
153
What breeds are prone to retinal dysplasia
Labradors and springer spaniels
154
Are all retinal dysplasia cases the same?
No there is a continuum of severity, mild animals may be normal but severe animals may be blind
155
How does a retinal fold appear on a fundic exam
Dull/dark grey-green dots or linear folds surrounding hyper-reflective tapetum
156
You see a large horseshoe-shaped area of grey-green on the fundic exam with hyper-reflective foci and some pigmentation. What could this be?
Geographic retinal dysplasia, a severe form of retinal dysplasia
157
You do a fundic exam on a dog and you don’t see any blood vessels, and you can’t see the optic nerve, you just see a big dark area blocking some of the tapetum. What is happening
There is compete retinal detachment and the retinal is hanging off of the optic nerve and is covering it
158
A Labrador presents with retinal dysplasia and bowed legs that look like a basset hounds. What is occurring
This is oculochondrodysplasia and autosomal recessive disease that causes retinal dysplasia and inhibits growth of radius, ulna, tibia, and causes hip dysplasia
159
What happens with Collie eye anomaly
A congenital lesion that causes bilateral disease that can vary from choroidal hypoplasia to optic disc coloboma to retinal detachment and if severe enough hemorrhage associated with the retina detachment
160
What does an eye with choroidal hypoplasia look like
It has a pale yellow-white lesion (exposed sclera) with abnormal tortuous choroidal vessels and the retina may also have tortuous vessels
161
A female middle aged dog presents to you becuase the owner says she suddenly started running into things, she is getting into the garbage and jumping up on counters to steal food (and she never used to), and is drinking more and having to go out more to urinate.
On presentation the dog’s pupils are dialated and you are unable to get PLRs.
What is your best diagnosis and how can you confirm this diagnosis?
Sudden acquired retinal degeneration syndrome
You can do an electroretinogram to differentiate if the blindness is neurologic or retinal and in this case it will be extinguished immediately (flat line)
162
What bloodwork abnormalities may you see with sudden acquired retinal degeneration syndrome and what other disease will this look like
Elevated Alk Phos, and maybe elevated ALT, cholesterol, total bilirubin
Looks like hyperadrenocortisism
163
Which is more common chorioretinitis (infection spreading from choroid and extending to retina) or the other way around, retinochoroiditis
Chorioretinitis is way more common
164
You do a fundic exam and notice an area where the blood vessels appear raised (are in a different plane). This area is also grayish and has irregular and poorly delineated margins. What is occurring here?
This is likely chorioretinitis
165
In active chorioretinitis how can you tell a tapetal lesion from a non-tapetal lesion
Tapetal lesions are often grey-ish or brown-ish areas of hyporeflectivity and non-tapetal lesions are more grey-ish to white areas
166
What do inactive areas of chorioretinitis inflammation/ scarred areas look like
There is depigmentation with variable pigment clumping and vessel attenuation. The optic nerve may also be pale with atrophy
167
T/F there are tons of infectious causes that can cause chorioretinitis
True! It can be from fungal, parasites, viral, bacteria, algal, and more
168
If you suspect chorioretinitis what should be your first diagnostic step
A minimum database then maybe titers, BP
169
Should you use topical medications to treat uveal inflammation from chorioretinitis
No they won’t penetrate
170
What layers separate in a retinal detachment
The neuroretina separates from the retinal pigmented epithelium
171
How do bullous/ exudative retinal detachments differ from Rhegmatogenous
Bullous are more common and are due to subretinal fluid or exudate
Rhegmatogenous is usually secondary to a retinal tear or vitreal traction bands (fibrous bands) form because of vitreal hemorrhage or inflammation and pull retina off of RPE
172
You are doing a fundic exam and you see what appears to be the retina “billowing forward” and it is in a different plane of focus. The retinal vessels also appear distorted and pushed away. What could be happening
There is a bullous retinal detachment
173
Where might you see retinal vessels in a complete retinal displacement (hint you can use a “penlight diagnosis”)
Displaced anteriorly so that you can see them through the pupil on the back of the lens
174
What are 6 differentials for Bullous retinal displacement
Hypertension, hypoproteinemia, hyperviscosity, polycythemia, uveodermatologic syndrome, idiopathic/spontaneous
175
How does a disinsertional Rhegmatogenous retinal detachment appear
The optic nerve is often obscured as the retina hangs in front of it in a grayish fold and the tapetum will be hyper-reflective and there will be a lack of retinal vessels
176
What are some etiologies that are associated with Rhegmatogenous retinal detachments
Congenital abnormalities (ex. Collie eye anomaly)
Shah Tzus/ Lhasa apsos (primary vitreous abnormality)
Secondary to intraocular inflammation or trauma
After cataract surgery
177
What are two ways to repair retinal detachment
Laser retinopexy (burning rows of chorioretinal adhesions around the detachment to prevent it from going further
Retinal reattachment
178
What is it called when the optic nerve appears small, round, gray or is absent
Micropapilla or optic nerve hypoplasia
179
What is a coloboma
A congenital defect or absence of an ocular structure
180
What can be found in the Collie Eye Anomaly (hint it has to do with the optic nerve)
An optic nerve coloboma (a pit on or within the optic nerve)
181
What is papilledema
Passive, non-inflammatory optic nerve disk swelling
182
What is papilledema associated with and what is it not associated with
It is associated with increased intracranial pressure due to the mass lesion but it is not associated with vision loss
183
What is inflammation of the optic nerve called
Optic neuritis
184
T/F optic neuritis only effects one eye typically, only involves the optic disk, and causes slow progressive blindness and miosis
False, it can be unilateral or bilateral and it can involve any segment of the optic nerve and is associated with sudden blindness and fixed dilated pupils (mitosis)
185
How does optic neuritis differ when there is intraocular involvement vs. retrobulbar involvement
With intraocular the disk is swollen, raised, hyperemic or has hemorrhages, and the disk margins are indistinct
Retrobulbar involvement the optic disk appears normal
186
What are some infectious causes of optic neuritis
Fungal- Blastomycosis, crypto, histo, toxo
Canine distemper virus
187
What is an immune mediated cause of optic neuritis
Granulomatous meningoencephalitis
188
How do you do a diagnostic evaluation of optic neuritis
Treat and manage as a neurological disease- CBC/chem/UA, chest radiographs, titers, neurologic evaluation, MRI or CT, CSF tap
189
Optic nerve head cupping is secondary to
Chronic glaucomatous optic neuropathy
Ganglion cell loss—> loss of optic nerve and axons
190
What is optic nerve atrophy associated with
Chronic progressive retinal atrophy, previous optic neuritis, post proptosis, glaucoma
191
What is it called when there is immediate vision loss with a PLR deficit immediately after a traumatic proptosis
Traumatic optic neuropathy
192
What chorioretinal disease in cats is usually associated with eyelid agenesis
Focal chorioretinal and optic nerve colobomas
193
What infectious diseases is retinal dysplasia associated with
Feline panleukopenia and FeLV
194
What occurs when a cat has a taurine deficiency
Since it is an essential amino acid in the feline diet, if it is not present feline central retinal degeneration can occur
195
How would a feline eye look on a fundic exam if the cat has a taurine deficiency
There would be two hyper-reflective lesions that coalesce to form a horizontal band over the disk resulting in retinal degeneration
196
What comorbidity may you see with taurine deficiency retinal degeneration
Dialated cardiomyopathy
197
What disease is found in Abyssinian, Persian, Siamese, and DSH cats and what will you see on a fundic exam
Rod-cone dysplasia and rod-cone degeneration
Tapetal hyper-reflectivity and vessel attenuation occur with feline retinal dysplasia/degeneration
198
What drug can cause feline retinal degeneration (even at the recommended dose)
Enrofloxacin
199
What are causes of chorioretinitis in cats
Viral (FeLV, FIP, FIV), bacterial, fungal (crypto, histo, Blastomycosis), parasitic
200
What can cause hyphema, vitreal hemorrhage, retinal hemorrhages and vessel tortuosity, and varying retinal detachment in older cats (will have dilated pupils or acute vision loss)
High blood pressure- hypertensive chorioretinopathy
201
What other diseases can hypertensive chorioretinopathy be associated with
Cardiac disease, renal disease, and/or hyperthyroidism
