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Small Animal Medicine II > Uvea & Retina Disease > Flashcards

Uvea & Retina Disease Flashcards

1
Q

What is phthisis bulbi?

A

small eye due to hypotony (low IOP)

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2
Q

What are the 3 layers of the retina?

A
  1. FIBROUS - cornea, sclera
  2. VASCULAR - iris, ciliary body, choroid
  3. NERVOUS - retina, optic nerve
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3
Q

What is persistent pupullary membrane (PPM)? Where in the eye are they found?

A

presence of remnants of fetal vasculature in the anterior chamber usually not containing blood

  • iris-iris
  • iris-cornea (pictured)
  • iris-lens
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4
Q

What breeds have high incidence of persistent pupillary membranes (PPM)? When can visual impairment occur?

A

Basenjis and Welsh Corgis

iris-lens and iris-cornea

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5
Q

What can PPMs be confused with? How can this be avoided?

A

anterior synechia

will arise from the iris collarette region

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6
Q

Anterior synechia vs iris-iris PPM:

A

arises from iris collarette! (inner division)

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7
Q

What is dyscoria? What is it most likely the result of?

A

abnormal pupil shape

anterior synechia, iris atrophy, iris tumor

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8
Q

What is corectopia?

A

abnormal location of the pupil making it nonfunctional, common in Merle Ocular Dysgenesis

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9
Q

What is coloboma?

A

sector defect in iris, common in Merle Ocular Dysgenesis

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10
Q

What causes primary iris atrophy? How does the iris look?

A

atrophy of the pupillary constrictor muscle associated with age and breed (Poodles, Yorkies, Siamese)

moth-eaten appearance of the iris with mydriasis and decreased PLR

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11
Q

How is the eye affected by iris atrophy?

A
  • vision problems not common
  • may cause photophobia
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12
Q

What are 3 causes of secondary iris atrophy?

A
  1. chronic glaucoma
  2. severe ocular trauma
  3. chronic uveitis

(not commonly bilateral)

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13
Q

What are the 2 most common primary uveal neoplasia in dogs and cats? 2 most common secondary? What is neoplasia the most common differential for?

A

PRIMARY = melanoma, adenoma/adenocarcinoma

SECONDARY = lymphoma, multiple myeloma

severe uveitis and hyphema

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14
Q

Where do iridociliary cysts arise from? What are 3 major differences compared to neoplasia?

A

posterior pigmented epithelium of the iris

  1. fluid-filled
  2. free-floating
  3. ovoid to spherical
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15
Q

When do iridocilliary cysts cause clinical signs? What are thin-walled ones indicative of? What breed is commonly affected?

A

push iris forward —> glaucoma, inflammation

uveitis

Golden retrievers - pigmentary uveitis

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16
Q

What structures are involved with anterior and posterior uveitis? Panuveitis?

A

ANTERIOR - iris and ciliary body (iridocyclitis)

POSTERIOR - choroid (chorioretinitis, choroiditis)

PAN = all uveal tissue

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17
Q

What causes uveitis?

A

breakdown of the blood-ocular barrier

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18
Q

What is the responsibility of the blood-ocular barrier? What are the 2 parts of it?

A

keeps large molecules, like proteins, RBCs, and fibrin, from passing into aqueous/vitreous humor, maintaining an optically clear media

  1. blood-aqueous - tight junctions at iris vessels and nonpigmented ciliary processes
  2. blood-retinal - retinal capillaries and retinal pigment epithelium tight junctions
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19
Q

What is the hallmark sign of anterior uveitis? What is specifically seen with the breakdown of the blood-retinal barrier?

A

aqueous flare due to influx of proteins, blood, and WBCs into aqueous humor

retinal edema/detachment

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20
Q

How is aqueous flare graded?

A

trace to 4+ due to intensity of aqueous flare

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21
Q

What are some clinical signs of uveitis? How does it affect IOP?

A
  • rubeosis iridis
  • hypopyon/hyphema - WBC/RBC infiltration is heavy, will settle in ventrum
  • ciliary flush/brush border - deep blood vessels on cornea
  • corneal edema
  • keratic precipitates
  • miosis
  • intraocular fibrin
  • iris swelling/color change
  • retinal granulomas/detachment

hypotony (LOW IOP)*

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22
Q

What are 7 sequelae of severe uveitis?

A
  1. secondary glaucoma
  2. posterior synechiae
  3. cataract + lens subluxation/luxation
  4. retinal detachment
  5. phthisis bulbi
  6. blindness
  7. pupul occlusion/iris bombe’ - apposition of the iris to the lens or anterior vitreous
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23
Q

What are the 2 most common presentations in patients with anterior uveitis?

A
  1. red, painful eye - blepharospasm, closed eye, rubbing, hyperemia
  2. cloudy eye - corneal edema, aqueous flare
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24
Q

How can uveitis be differentiated from other causes of red eyes?

A

must identify the cause

  • systemic disease
  • history of illness
  • trauma
  • travel history
  • physical exam, signalment
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25
Q

What are the 4 main diagnostics for uveitis? What is commonly also needed to identify the cause?

A
  1. STT - r/o tear film disease
  2. fluorescein stain - r/i or r/o ulcer as cause
  3. tonometry - expect IOP <10, unless secondary glaucoma is occurring
  4. indirect ophthalmoscopy - observe fundic changes

additional diagnostic testing - PE, CBC/chem/UA, radiographs/abdominal U/S, serology (infectious disease), aspirates, cytology

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26
Q

What are some causes of uveitis in dogs and cats?

A
  • infectious
  • immune-mediated - lens-induced, uveodermatologic syndrome
  • trauma - blunt, penetrating
  • neoplasia
  • toxic/drug-induced
  • metabolic
  • reflex uveitis - corneal ulcer
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27
Q

What drugs and metabolic diseases can cause uveitis?

A

DRUGS - Lantanoprost, Pilocarpine

METABOLIC - hyperlipidemia, diabetes

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28
Q

What are 5 specific infectious causes of uveitis in cats?

A
  1. FLV
  2. FIV
  3. FIP
  4. toxoplasmosis
  5. bartonellosis

(especially in younger cats!)

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29
Q

What 3 topical medications are recommended for uveitis?

A
  1. steroids (severe cases) - Prednisolone, NeoPolyDex
  2. NSAIDs (milder cases) - Ketorolac, Nepafenac, Bromfenac
  3. cycloplegic/mydriatic - atropine, tropicamide
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30
Q

What is the purpose of using cyclopegics and mydriatics for treating uveitis? When is their use contraindicated?

A

dilates pupil and paralyzes ciliary body to decrease pain and sequelae

if IOP is elevated —> need glaucoma medication!

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31
Q

What treatment is recommended if uveitis is present with IOP >15-20? Why is this so important?

A

Dorzolamide and Timolol (normal is considered elevated if uveitis is present!)

secondary glaucoma and increased IOP can cause swelling and fibrous membrane formation

32
Q

What 2 systemic medications can be used to treat uveitis? What is contraindicated?

A
  1. NSAIDs - if systemic disease does not contraindicate
  2. corticosteroids

using oral NSAIDs and steroids together!

33
Q

How are other systemic medications used when treating uveitis?

A

based on the underlying cause:

  • tickborne disease - tetracyclines (Doxycycline)
  • fungal disease - itraconazole, fluconazole
34
Q

What are the 2 major indications for fundic exams?

A
  1. clinical signs of systemic neurologic, neoplastic, or infectious diseases
  2. cases of vision abnormalities
35
Q

What are the 3 major ways of performing a fundic exam?

A
  1. direct ophthalmoscopy - difficult, more magnification causes more distortion and hard ot see whole fundus
  2. indirect ophthalmoscopy - better overview of fundus, less magnified
  3. panoptic - larger view than direct with better magnification than indrect
36
Q

How does the retina, choroid, retinal pigment epithelium (RPE), tapetum, and sclera appear on a fundic exam?

A
  • retina = translucent with cross-like blood vessels
  • choroid = multiple blood vessels with pigmentation all around the fundus
  • RPE = dark pigmentation concentrated in the ventrum and surrounding tapetum
  • tapetum = shiny part of the choroid, seen on the dorsal aspect
  • sclera = white and fibrous with lamina cribriosa (middle = nerve fibers of retina combine) - not commonly seen on exam
37
Q

Where is the tapetum found on a fundic exam?

A

shiny part of choroid seen in the dorsal (superior) fundus —> dorsal to optic nerve!

  • retina overlies the choroid - can see small blood vessels!
38
Q

What is being pointed out in this fundic exam?

A
  • tapetal fundus
  • optic nerve papilla - border between tapetal and non-tapetal fundus lies the optic nerve
  • physiologic cup (pit) - white, cup-like area in the center of the optic disc
  • conus
39
Q

What is a common difference in fundic exams in younger animals and cats?

A

YOUNG = no tapetum, tiger-stripe choroid

CAT = blood vessels do not cross the optic nerve + myelin

40
Q

How do the retinal patterns differ between dogs and cats, horses, birds, and rabbits?

A

D + C = holangiotic, robust blood vessels spread to periphery

HORSES = paurangiotic, poorly defined, small blood vessels

BIRDS = anangiotic - no blood vessels in retina, pectin overlies optic nerve and gives neutrition

RABBITS = merangiotic, blood vessels seen in central fundus

41
Q

How does retinal, optic nerve, and visual cortex disease differently affect patients?

A

RETINAL = mydriatic pupil, blindness

OPTIC NERVE = mydriatic pupil, blindness

VISUAL CORTEX = blindness, no pupillary abnormalities

  • retina and optic nerves are found before the optic chiasm, resulting in pupillary dysfunction
42
Q

What is the most severe sign of Merle Ocular Dysgenesis? How do the patients present?

A

microphthalmos from birth

Merle-Merle cross = mostly white, deaf, and have minimal vision

43
Q

Merle Ocular Dysgenesis:

A

iris and pupil abnormalities

44
Q

What are the 3 forms of retinal dysplasia?

A
  1. folds - mild to no vision changes
  2. geographic - moderate, usually less vision (one area of detachment)
  3. detachment - severe, usually blind

(usually hereditary in dogs)

45
Q

What is the most common cause of aquired retinal dysplasia? Specific causes in cats, cattle, dogs, and sheep?

A

maternal viral infections

  • CATS = parvovirus, FeLV
  • CATTLE = BVD
  • DOGS = herpes
  • SHEEP = bluetongue
46
Q

How does retinal dysplasia happen?

A

2 primitive layers of the retinal do not form properly and the layers become “jumbled”

47
Q

Retinal dysplasia, retinal folds vs. geographic:

A
  • FOLDS = darker/white folds of tissue
  • GEOGRAPHIC = starburst areas of detachment
48
Q

What hereditary retinal disorder commonly affects collie-like breeds? What are the 4 most common signs?

A

Collie Eye Anomaly - collies, shetland sheepdogs, Australian shepherds

  1. choroidal hypoplasia - abnormal vasculature
  2. optic nerve coloboma - pit, notch, hole (severe cases)
  3. retinal detachment
  4. intraocular hemorrhage
49
Q

What is chorioretinitis? What are some common causes?

A

inflammation of the choroid and retina, a common manifestation of posterior uveitis

  • infectious
  • neoplasia
  • trauma
  • immune-mediated
50
Q

How can chorioretinitis be differentiated from inherited retinal disease?

A

inflammatory: can be unilateral or bilateral but rarely symmetrical —> irregular shape with lesions at different stages

51
Q

What are 4 signs of active chorioretinitis?

A
  1. hyporeflective
  2. fuzzy borders
  3. various sizes
  4. raised lesions

(packets of inflammatory cells - cryptococcosis)

52
Q

What are 3 signs of inactive chorioretinitis?

A
  1. sharp borders
  2. hyperreflective
  3. pigment clumping (arrow)
53
Q

Active chorioretinitis:

A

lesions around blood vessels = inflammatory cells pouring out in response to infection

54
Q

What are the 2 types of retinal detachment?

A
  1. rhegmatogenous - more common in people, tear in the retina leads to fluid accumulation with a separation of the retina from RPE
  2. non-rhegmatogenous - fluid, inflammatory cells, or blood builds up behind a retina that is not broken
55
Q

What are 2 common causes of rhegmatogenous detachment? In what 2 breeds is it heritable? Why?

A

trauma and cataracts

Shih Tzus and Italian Greyhounds —> thin peripheral retinal + vitreal detachment

56
Q

Rhegmatogenous detachment:

A

retinal tear —> treatment would include surgery

  • optic nerve is obscured
  • hyperemia of choroid (blood vessels more obvious)
  • retina veils over the optic nerve
57
Q

What are the 4 most common causes of non-rhegmatogenous detachment? How does treatment compare to rhegmatogenous detachment?

A
  1. systemic hypertension
  2. infectious/inflammatory/immune-mediated
  3. hereditary/genetic
  4. parasitic disease

medical management

58
Q

Non-rhegmatogenous detachment:

A
  • no retinal tear = fluid pushed retina forward
  • looks like a bulging ballon = fluid buildup behing retina
  • longer detachment required urgent treatment
59
Q

What are the 4 most common causes of retinal degeneration in dogs?

A
  1. progressive retinal atrophy (PRA)
  2. chronic detachment
  3. post-inflammatory (previous chorioretinits)
  4. SARDs (initially no fundic changes)
60
Q

What is a major exception for retinal disease not causing blindness?

A

SARDs

61
Q

What are the 3 most common causes of retinal degeneration in cats?

A
  1. enrofloxacin toxicity
  2. taurine deficiency
  3. progressive retinal atrophy (PRA)
62
Q

What is progressive retinal atrophy (PRA)?

A

genetic disease causing slowly progressive vision loss in purebred dogs —> Poodles, Yorkies, Labradors

  • middle-aged to older
63
Q

What initial signs are seen with progressive retinal atrophy? How does it develop?

A

nyctalopia (night blindness) —> rods affected first

  • mydriasis with sluggish or absent PLR
  • complete blindness
64
Q

What are the 3 major signs on fundic exams indicative of progressive retinal atrophy?

A
  1. vessel attenuation - narrowing/shortening or abscence of blood vessels
  2. tapetal hyperreglectivity - bright tapetum due to thinner retina
  3. optic nerve pallor - nerve fiber layer degeneration to the level of the optic nerve (demyelination)
65
Q

What is sudden acquired retinal degeneration (SARDs)? How does it appear on fundic exam? What signalment is most commonly associated?

A

nonpainful, non-inflammatory loss of photoreceptors

normal!

middle aged, FS, Dachshund/Schnauzer

66
Q

What signs are commonly associated with SARDs?

A

SYSTEMIC —> seems like hyperadrenocorticism

  • weight gain
  • polyphagia
  • PU/PD
  • confusion, restlessness
67
Q

What is the gold standard for diagnosing SARDs?

A

electroretinogram —> flat line!

  • retinal rods and cons not working
68
Q

In what animal is ivermectin toxicity most commonly reported? What clinical signs are seen?

A

dogs —> Collies and Aussies with multidrug resistance gene

  • acute blindness and mydriasis
  • normal to multifocal retinal edema/detachment
  • CNS signs
69
Q

When is prognosis for return of vision with ivermectin toxicity?

A

if dose is <400 mcg/kg

  • lipid therapy and supportive care recommended
70
Q

Why is taurine so important in cats? What ophthalmic sign is associated with a deficiency? How is it treated?

A

it is an essential amino acid that cats are unable to produce themselves —> DCM!

retinal degeneration (feline central retinal degeneration) —> taurine administration will not reverse signs, but it will stop progression of disease

71
Q

What medication is associated with feline retinal degeneration? What is a better option for cats?

A

entrofloxacin (Baytril) —> blindness is most commonly irreversible

better fluoroquinolone = Pradofloxacin

72
Q

What are some common diseases of the optic nerve (retrobulbar)? How do patients present?

A
  • optic neuritis
  • optic nerve hypoplasia
  • optic nerve tumor - meningioma
  • optic nerve dengeneration - glaucoma

uni/bilateral mydriasis based on affected side(s)

73
Q

What are the 2 most common diseases of the optic chiasm? How do patients present?

A

optic neuritis and neoplasia pressing on chiasm (pituitary tumor)

BOTH eyes will be blind and mydriatic

74
Q

Optic nerve disease:

A
75
Q

What are the 2 most common clinical signs associated with visual cortex disease? What is NOT seen?

A

seizures and blindness +/- changes in mentation or other cranial nerves

pupillary abnormalities —> PLR pathway has alread branched off

76
Q

What are the 5 most common causes of visual cortex disease?

A
  1. neoplasia
  2. inflammatory disease - meningoencephalitis
  3. hydrocephalus
  4. toxicity - lead
  5. deficiencies - vitamin A, thiamine

Small Animal Medicine II (57 decks)

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