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LA DX & TX II > Final Exam - Equine Uvea > Flashcards

Final Exam - Equine Uvea Flashcards

1
Q

what is seen in this photo? is it normal?

A

corpora nigra/granula iridica - yes

dangling tissue from top of pupil

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2
Q

how is the normal pupil oriented in the horse?

A

horizontally oriented

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3
Q

where is the iridocorneal angle visible at in horses?

A

at the nasal & temporal limbus

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4
Q

what are the stars of winslow?

A

end-on capillaries of the choroid that are visible in the tapetum

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5
Q

what horses typically don’t have a tapetum lucidum?

A

blue eyed horses

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6
Q

T/F: iris-to-iris persistent pupillary membranes are seen in all horses

A

true

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7
Q

what is seen in this photo? is it normal?

A

iris-to-iris persistent pupillary membranes

yup

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8
Q

what is seen in this photo? is it normal?

A

lack of tapetum & pigmented RPE exposing choroidal vessels

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9
Q

what color eyes do you think this horse has?

A

blue - atapetal subalbinotic fundus

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10
Q

what is this condition called?

A

heterochromia iridis

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11
Q

what is uveitis?

A

inflammation of the uvea & break down of the blood barrier

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12
Q

what is the most common cause of blindness in horses?

A

equine recurrent uveitis

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13
Q

what horses are at risk for equine recurrent uveitis?

A

drafts, appaloosas, & european warm bloods

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14
Q

does primary uveitis mean equine recurrent uveitis?

A

nope! must have 2 or more episodes to be considered equine recurrent uveitis

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15
Q

what is panuveitis?

A

involves the entire uvea

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16
Q

T/F: it is important to differentiate between acute uveitis & ERU because acute has many potential causes & ERU is an immune-mediated process

A

true

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17
Q

what causes the development of ERU?

A

primary uveitis + environmental factors + genetic makeup + immune system dysregulation

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18
Q

___________ is most commonly linked to ERU

A

leptospirosis

19
Q

what are the 2 paths of the development of ERU?

A

infectious agent in the eye - agent is similar to retinal/uveal self antigens -> stimulates immune-mediated destruction

immune-mediated event -> intrinsic ocular proteins stimulate recurrent autoimmune destruction

20
Q

is the presence of an infectious organism needed for continued disease of ERU?

A

nope

21
Q

what are the 3 stages of ERU?

A

acute - how the disease presents during the early stages of a flare up

chronic - complications following several days of unrelenting inflammation or following multiple recurrent episodes of uveitis

end stage - complications of chronic unresolved inflammation leading to permanently blind eyes

22
Q

what are the secondary risks you are trying to avoid for horses with acute uveitis?

A

corneal degeneration/ulceration

glaucoma

cataracts

retinal detachment

phthisis bulbi

23
Q

what clinical signs are associated with acute uveitis?

A

aqueous flare, iris color changes, epiphora, conjunctival hyperemia, etc

24
Q

what ophthalmoscope aperture setting is best for assessing aqueous flare?

A

small disc

25
Q

what defines chronic uveitis?

A

cases that are refractory to therapy that remain painful & require persistent care with topical steroids negatively impacting corneal health long term

secondary glaucoma is a risk factor

26
Q

what clinical signs are associated with chronic uveitis?

A

band keratopathy!!!!!

iris hyperpigmentation, posterior synechia, granula iridica atrophy, secondary cataracts

27
Q

how is band keratopathy treated?

A

topical EDTA/antimicrobials, diamond burr debridement, & superficial keratectomy

28
Q

what is band keratopathy?

A

mineral deposition in the cornea seen with chronic uveitis that increases the animal’s risk of non-healing corneal ulcers

29
Q

what lesion is shown in these photos?

A

band keratopathy

30
Q

what lesion is shown here that is associated with chronic uveitis?

A

vitreal degeneration

31
Q

what lesion is shown here that is associated with chronic uveitis?

A

peripapillary retinal degeneration - butterfly lesions & bullet hole scarring

32
Q

what are the causes of blindness in end stage uveitis?

A

permanent corneal edema

complete cataracts

extensive synechiation

secondary glaucoma - impaired outflow secondary to chronic inflammation

retinal detachment/degeneration

phthisis bulbi

33
Q

what lesion is shown here in this horse with end stage uveitis?

A

phthisis bulbi

34
Q

what serum titers may you consider for a horse with uveitis?

A

lepto, toxoplasma, lyme, & brucella

35
Q

what are the treatment goals when working on a horse with uveitis?

A

preserve vision

decrease pain & inflammation

minimize permanent ocular damage

prevent or minimize recurrence

if possible - treat specific cause of uveitis

36
Q

what treatment is indicated for equine uveitis?

A

treat aggressively & longer than usual - at least 2 weeks

topical steroids, topical nsaids, & atropine

systemic nsaids

systemic abx based on suspicion of disease

37
Q

what surgical options do you have for treating uveitis in horses? what are your best candidates?

A

cyclosporine implant - sustained release that decreases severity of flare ups & extends time between flare ups - takes 30-45 days to reach therapeutic levels & works for 2 years

visual candidates in the early stages of disease with controlled inflammation

38
Q

what therapy may you consider for horses with uveitis that aren’t surgical candidates?

A

low dose gentamicin intravitreal injection

good results for controlling inflammation & preventing recurrence

39
Q

what complications are associated with horses with chronic uveitis being treated with low dose gentamicin therapy?

A

cataracts & retinal degeneration

40
Q

what is the prognosis for horses with chronic uveitis (ERU)?

A

overall poor prognosis for vision!!!

50% will become blind despite therapy, some will be euthanized or enucleated, & others fully recover

41
Q

what lesion is shown in this photo? what common locations are they seen in?

A

anterior uveal cysts - benign, fluid filled structure that may transilluminate

corpora nigra, pupil margin, free floating in anterior chamber, & attached to the iris or ciliary body

42
Q

when is treatment indicated for anterior uveal cysts?

A

when vision is impaired or the horse is spooking - refer for laser deflation

43
Q

what lesion is seen in this photo? what animals are affected by it?

A

uveal melanoma - primary tumor

more common in gray horses - no metastasis!!!!!!! but rapid growth in the eye can occur & cause secondary glaucoma

44
Q

what treatment options do you have for uveal melanoma?

A

monitor with photo documentation

sector iridectomy

enucleation

LA DX & TX II (44 decks)

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