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Cattle > Equine and farm ophthalmology > Flashcards

Equine and farm ophthalmology Flashcards

1
Q

What is different about the shape of equine eyes

A

Oval globe, corneal and pupil

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2
Q

Corpora nigra function

A

Unclear - could relate ti shading eye from light from above

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3
Q

What is different about the blood vessels in the equine fundus

A

Fundus is ‘paurangiotic’
- Blood vessels only spread away from optic disc ~an optic disc diameter; so see pink oval

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4
Q

What are stars of Winslow

A

Choroidal vessels coming through tapetum to take blood to choriocapilaris

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5
Q

Things to remember with using atropine in the horse

A

Need lots to cause dilation
Risk of colic; so should auscultate the abdomen at the same time

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6
Q

What is a habrenema granuloma

A

When flies uptake gut worm larvae and land on eyes

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7
Q

What could we use to treat periocular sarcoids

A

Excision, cryo, heavy metal injfection, BCG injection to stimulate immune response

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8
Q

In which type of horse do we see congenital cataracts

A

In Morgan horse
= dominant

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9
Q

What is mucupurulent discharge a sign of in young vs old horses

A

Young; inperforate nasolacrimal punta
Old; squamous cell carcinoma

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10
Q

How could we treat an ocular squamous cell carcinoma

A

Excision, radiotherapy using strontium 90, cryo, 5-fluorourical, mitomycin

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11
Q

What can cause equine recurrent uveitis

A

Main one is leptospira
Ochocerca
Brucella
toxoplasma
(or idiopathic)

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12
Q

Treatment for equine recurrent uveitis

A

Topical atropine, steroids, surgery to remove fibrin and breakdown synechiae

Can inject plasminogen activating factor into eye

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13
Q

What signs on a prepurchase exam could indicate horse has suffered from equine recurrent uveitis and may be at risk again

A

Synechiae between iris and lens
Anterior cataract
Butterfly lesion around optic disc may be related

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14
Q

What is aniridia

A

Virtually no iris due to defect in corneal stem cell population; probably related to pax-6 homeo

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15
Q

Which horses might we see melanoma in the eye of

A

Grey

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16
Q

When might we see iris hypoplasia

A

in colour filute equids
his iris can billow forward due to aqueous pressure and look like an iris cyst

17
Q

Is glaucoma common in horses and what might cause it

A

No not common
Could occur secondary to uveitis or a tumour

18
Q

What can be normal in an equine fundus but may look worrying

A

Nibbles out of the fundus that looks like colobomas

19
Q

If we see a dot in the lens during equine vetting which areas are likely to develop into cataract and which aren’t

A

If in nucleus or epithelium; probably won’t cause an issue
If in the stroma, more likely to cause an issue as it can grow as the lens grows

20
Q

Proliferative vs exudative optic neuropathy

A

Proliferative: see slowly growing white mass on the optic disc; doesn’t affect vision

Exudative: similar sign but due to disc swelling from optic neuritis and will lead to blindness

21
Q

What is the cause of infectious bovine keratoconjunctivitis (New forest eye)

A

Moraxella bovis
- Piliated form (pilli can attach to corneal surface)

Mycoplasma coinfection may be involved

22
Q

Treatment for new forest eye

A

Long acting antibiotics either subconjunctival (painful)
or IM

23
Q

What signs do we see with silage eye (listeriosis)

A

Corneal oedema
Uveitis (because bacteria go deep)

24
Q

What might anophthalmos be assocaited with

A

Vit A deficiency in utero
May also see caudal spinal defects

25
Q

Which type of cows do we see a squint in (esotropia)

A

Kerry blue

26
Q

What does it mean about aetiology of a cataract if it is found in nucleus

A

It has had it since in utero

27
Q

Which cattle breed is optic disc coloboma inherited in

A

Charolais

28
Q

Which cattle breed gets corneal oedema due to endothelial degeneration

A

Kerry blue

29
Q

What can cause periocular hair colour changes (cattle)

A

Copper toxicity

30
Q

Which cattle breeds are predisposed to squamous cell carcinoma

A

Those with depigmented periocular regions e.g Hereford and Hereford crosses

31
Q

How does lymphoma in the eye of cattle with BLV present

A

Orbital tumour with gradual exophthalmos

32
Q

Which sheep type do we see eyelid coloboma and where

A

Jacob sheep
Middle of lid

33
Q

What is bright blindness

A

Bracken asscaited retinal degeneration in sheep
Due to toxic agent Ptaquiloside (can also cause anaemia)

34
Q

Signs of infectious bovine keratoconjunctivitis

A

Conjunctival hyperaemia
Corneal ulceration; can lead to perforation

Cattle (20 decks)

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