Ophthomology Flashcards

1
Q

What are some unique anatomical features of the equine eye?

A

Horizontal elliptical pupils, laterally positioned globes, corpora nigra, paurangiotic retinal vascular pattern, Stars of Winslow

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2
Q

What are some potentially requirements to perform an equine ophthalmic exam?

A

Restraint, sedation, topical anesthetic, nerve block

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3
Q

Which motor nerve do you block for an ophthalmic exam?

A

Auriculopalpebral nerve. Branch of CN VII

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4
Q

Where are the three points that the auricopalpebral nerve can be blocked?

A
  1. ) highest point of zygomatic arch
  2. ) caudal to bony process of frontal bone of zygomatic arch
  3. ) caudal to posterior ramus of mandible
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5
Q

What sensory nerve do you block for an equine ophthalmic exam?

A

Frontal (supraorbital) nerve block

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6
Q

What is the most common cause of blindness in horses? What is it called in laymen’s terms?

A

Equine recurrent uveitis (ERU). Moon blindness

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7
Q

T/F: There is only one cause for ERU.

A

False. There are many!

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8
Q

What is the pathogenesis of moon blindness in equine?

A

Invasion of antigen into eye -> deposition of Ag/Ab complexes -> continued presence of antigen (hence the recurrence)

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9
Q

T/F: The continued presence of live infectious organisms are needed for ERU disease

A

False. Just the antigen!

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10
Q

What are some clinical signs for active uveitis?

A

Aqueous flare, miosis, corneal edema, hyphema, hypopyon

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11
Q

What are some clinical signs for chronic uveitis?

A
Posterior synechia
Iris hyperpigmentation
Granula iridica atrophy
Secondary cataracts
Vitreal degeneration
Retina edema and degeneration
Retinal detachment
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12
Q

What are some lesions/scars you may witness in a fundus exam on a horse with chronic uveitis?

A

Chorioretinitis scar, bullet-hole scarring, butterfly lesions

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13
Q

How would you treat band keratopathy on a horse with chronic uveitis?

A

keratectomy or DBD

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14
Q

What signs of chronic uveitis can cause blindness?

A

Corneal edema, cataract, synechiation, 2ary glaucoma, retinal detachment

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15
Q

What are some work-ups you would want to perform to diagnose a horse with uveitis?

A

physical exam, deworm history, CBC, chem,

Titers: lepto, toxo, lyme, brucella

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16
Q

What are your treatment goals for horses with uveitis?

A

preserve vision, decrease pain, minimize any permanent damage, prevent recurrence, treat underlying cause (if possible)

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17
Q

What is a good systemic NSAID to use for a horse with uveitis?

A

Flunixin meglumine

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18
Q

What is a good systemic corticosteroid to use on a horse with uveitis?

A

Prednisolone, dex

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19
Q

What is a good systemic antibiotic to use on a horse with uveitis?

A

doxycycline

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20
Q

What mydriatic would you want to use for a horse with uveitis?

A

Atropine 1%

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21
Q

T/F: You want to treat equine uveitis very aggressively and for a long time.

A

True

22
Q

What is a technique for giving cyclosporine into the equine eye to fight uveitis, and is effective for over 2 years?

A

Cyclosporine implants

23
Q

T/F: Most horses with uveitis, no matter how good the treatment, will go blind

A

True

24
Q

What does subpalpebral lavage (SPL) allow?

A

Safe drug administration, comfort, less medication wasted

25
Q

T/F: SPL’s are very difficult to implant and need to be referred.

A

False. Easy peasy!

26
Q

What disinfectant solution do you use to treat eyelid lacerations in horses? (Hint: It’s not chlorihex)

A

Diluted betadine solution (0.2%)

27
Q

What are some clinical signs seen with corneal ulceration in the horse?

A

blepharospasm, epiphora, edema

28
Q

What might cause a corneal ulcer in a horse to become keratomalacic?

A

Secondary bacterial or fungal infections, endogenous proteinases, iatrogenic steroid administration

29
Q

What are factors of a corneal ulcer to assess when examining a horse with said condition?

A

The integrity of the globe, anterior chamber depth, depth of ulcer, neovascularization, infiltrates, reflex uveitis

30
Q

How do you diagnose corneal ulceration in a horse?

A

Corneal cytology, corneal swab

31
Q

How do you treat an acute, uncomplicated corneal erosion in a horse?

A

Topical broad spectrum antibiotics (TID), atropine 1% (BID), rechecks

32
Q

How do you treat a complicated corneal ulcer in a horse?

A

Topical broad spectrum antibiotics (q 1-2 hrs), antifungals (q 6-8 hrs), topical antiproteinase therapy, atropine 1%, NSAIDs, subpalpebral lavage, eye cup

33
Q

T/F: You cannot use topical steroids in a horse with corneal ulceration.

A

True!

34
Q

How deep of the stromal should be ulcerated before considering surgical treatment?

A

50%

35
Q

What is the surgical treatment for equine corneal ulceration?

A

conjunctival graft

36
Q

What is a stromal abscess?

A

It is when there is a small puncture wound in the corneal that seals, but leaves an infection or FB inside.

37
Q

What are some clinical signs seen with stromal abscesses?

A

Infiltrates, corneal edema, vascularization, reflex uveitis

38
Q

T/F: You need to treat stromal abscesses aggressively.

A

True

39
Q

What is the pathogenesis for eosinophilic keratitis in horses?

A

We don’t know!

40
Q

What are some clinical signs seen with eosinophilic keratitis?

A

blepharospasm, conjunctival hyperemia, mucus discharge, white plaques, vascularization, superficial corneal ulceration, peripheral cornea

41
Q

How do you diagnose eosinophilic keratitis?

A

corneal cytology

42
Q

How do you treat eosinophilic keratitis?

A

topical corticosteroids, topical mast cell stabilizer (alomide), topical cyclosporine

43
Q

T/F: the prognosis for eosinophilic keratitis in horses is usually very good.

A

True

44
Q

What is the most common periocular and ocular tumor in horses?

A

ocular squamous cell carcinoma

45
Q

T/F: Ocular SCC’s are common slow in metastasis, and do not recur often

A

False. They ARE slow in metastasis, but recurrence is common

46
Q

What locations are most prone is ocular/periocular SCC in horses?

A
3rd eyelid
medial canthus
limbus
lower eyelid
cornea, conjunctiva, orbit
47
Q

How do you medically treat SCC in horses?

A

immunotherapy and chemotherapy

48
Q

Which surgical therapies are used for SCC in the equine eye?

A

3rd eyelid, enucleation, exenteration

49
Q

What structures of the would affected with SCC would you perform cryotherapy?

A

Cornea, eyelid, 3rd eyelid

50
Q

What structures of the eye affected with SCC would you perform brachytherapy?

A

Eyelid, conjunctiva

51
Q

T/F: The smaller the lesion of SCC in the eye, the worse the prognosis.

A

False.

52
Q

What are the three things you want to do with an equine with SCC?

A

Biopsy, aggressive treatment, and RECHECK!