Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Equine Spec. Topics - Clinical Practice > Eyeballs > Flashcards

Eyeballs Flashcards

1
Q

What abnormality of the eye is indicated by a horse’s eyelashes pointing downward?

A

(Enophthalmos)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A horse’s indirect PLR will be more/less (choose) prominent than a dogs.

A

(Less, horses have more decussation at the chiasm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What muscle is mainly responsible for closing the eyelid of a horse?

A

(Orbicularis oculi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a normal schirmer tear test result for a horse?

A

(> 20 mm/min)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

You expect lesions of the lens to be dark/light (choose) when using the retroillumination technique.

A

(Dark, you are using the light reflecting off the of tapetum lucidum to highlight abnormalities of the lens, they will appear black; if you use transillumination those same lesions will appear white)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

(T/F) The optic disc is located in the nontapetal fundus of the equine eye.

A

(T)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are Stars of Winslow?

A

(The small black dots in the tapetal fundus of the horse that are normal choroidal vessels)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What bones form the orbital rim of a horse’s orbit?

A

(Frontal, lacrimal, zygomatic, and temporal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A majority of the extraocular muscles are innervated by what cranial nerve?

A

(Oculomotor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What nerve innervates the lateral rectus muscle of the eye?

A

(Abducens)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What nerve innervates the dorsal oblique muscle of the eye?

A

(Trochlear)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What two muscles associated with the eye are innervated by the abducens?

A

(Lateral rectus and retractor bulbi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When do orbital fractures not require surgical treatment?

A

(When they are minor non-displaced orbital fractures, other cases (displaced or comminuted fractures) require surgical correction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are some causes of enophthalmos in horses?

A

(Orbital fractures, resorption of orbital fat, dehydration in foals (also see entropion), and sympathetic denervation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In addition to buphthalmos, what other signs are suggestive of glaucoma in horses?

A

(Corneal edema and Haab’s striae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are some causes of exophthalmos in horses?

A

(A retrobulbar mass, orbital cellulitis/abscessation, or trauma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Orbital cellulitis is associated with enophthalmos/exophthalmos (choose).

A

(Exophthalmos)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why can the IOP be elevated in some cases of orbital cellulitis?

A

(Because all the inflammation of the surrounding structures is compressing the globe)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are some causes of orbital cellulitis?

A

(Direct trauma, seeding of septic emboli, foreign body, or uncontrolled septic endophthalmitis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Branches of which cranial nerves provide sensory innervation to the structure of the eye?

A

(Trigeminal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which two cranial nerves provide motor innervation to the structures of the eye?

A

(Facial and oculomotor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In which population of horses is entropion more likely to occur?

A

(Sick foals, dehydration leads to endophthalmos and entropion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why should you minimally debride eyelid lacerations prior to correction?

A

(To preserve as much of the eyelid margin as possible)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the two layers closed when repairing an eyelid laceration?

A

(Tarsoconjunctival and musculocutaneous layer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What suture pattern is used to appose the eyelid margin carefully?

A

(Figure of 8)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can be done about the eye experiencing ptosis in a case of facial nerve paralysis?

A

(Topical lubrication should be applied 4-6 times daily, if an ulcer is present treat it and potentially a partial temporary tarsorrhaphy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does the treatment of conjunctivitis depend on?

A

(The underlying cause because there almost always is one)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the most common neoplasm of horses?

A

(Sarcoids)

29
Q

What breeds are at an increased risk of developing sarcoids? What about a decreased risk?

A

(Increased risk → QH, Appaloosas, Arabians; decreased risk → standardbreds)

30
Q

(T/F) Metastasis of sarcoids is rare but recurrence is very common.

A

(T)

31
Q

What is the most common neoplasm of the equine eye and ocular adnexa?

A

(Squamous cell carcinoma)

32
Q

Of the locations that SCC can be found associated with the eye, which has the worst prognosis and why?

A

(Eyelid, bc you need to be aggressive with your margins but that means removing more of the eyelid margin and increasing your chance of inducing chronic keratitis)

33
Q

What are the three stages of squamous cell carcinoma?

A

(Solar elastosis (precancerous lesions, no neoplastic changes yet), carcinoma in situ (lesion has not invaded through the basement membrane yet, prognosis better than invasive SCC), and invasive SCC (has invaded the basement membrane))

34
Q

When SCC involves what ocular structure can excision alone be successful?

A

(The third eyelid, can get better margins easier since you can just remove the whole third eyelid (not as much of a worry when doing this in horses compared to dogs))

35
Q

What can occur secondarily in cases of imperforate nasal puncta?

A

(Imperforate nasal puncta results in severe epiphora which is fine until the discharge becomes mucopurulent d/t a secondary bacterial overgrowth)

36
Q

(T/F) In cases of imperforate nasal puncta, you can just find where the punctum should be and cut it open with no further work necessary.

A

(F, need to hold it open while it heals, usually suture a catheter in place and leave for 4-6 weeks)

37
Q

You’re presented with a horse that has a pretty obvious corneal ulcer and after blocking you get a better look at it, it looks to be deep and has a clear ring around it, there are signs of uveitis as well. What should be at the top of your differential list and what diagnostic do you want to do to confirm?

A

(Keratomycosis and cytology)

38
Q

How do you know when to take a horse who had an ulcer off of their topical antibiotic regimen?

A

(When the eye no longer has any fluorescein uptake, that indicates the ulcer is healed)

39
Q

What is the frequency topical antimicrobials are applied to an eye with an ulcer dependent on?

A

(The severity of the ulcer)

40
Q

What should be given to pre-operatively manage a case of corneal perforation before it can get to surgery?

A

(Topical and systemic abx, topical antifungals, and topical atropine; all topicals should be solutions bc ointments are contraindicated in perf cases)

41
Q

Of the etiologies possible for corneal perforation, which are associated with a worsened prognosis?

A

(Blunt trauma (bc the eye essentially ripped itself apart, how fun) and anything associated with an infection)

42
Q

Why are fluoroquinolones the antibiotic of choice for treatment of corneal abscesses?

A

(Bc the epithelium is still intact and the abx needs to be able to penetrate, fluoroquinolones are lipophilic and have the best chance of doing that)

43
Q

Band keratopathy is a degenerative condition of the eye characterized by corneal mineralization/calcification and it is often associated with what condition potentially due to the chronic use of topical steroids necessary in tx of that condition?

A

(Chronic uveitis/equine recurrent uveitis)

44
Q

Superficial and mid-stromal immune mediated keratitis can appear quite similarly to corneal abscesses in horses, how can you tell them apart?

A

(Corneal abscesses are very painful whereas IMMK is at most associated with minimal pain)

45
Q

What sets endothelial IMMK apart from the other classifications besides appearance?

A

(Endothelial does not respond to any treatment, the rest do)

46
Q

What is the medical treatment for IMMK (besides endothelial) and what is the duration of that treatment?

A

(Treatment is topical steroids and/or cyclosporine, duration is lifelong)

47
Q

You are presented with a horse that has been exhibiting signs of ocular discomfort for sometime per the owner, when you can get a good look you see a raised pink to white corneal plaque, you take a cytology and see a lot of eosinophils, what is your top differential?

A

(Eosinophilic keratoconjunctivitis)

48
Q

(T/F) Topical corticosteroids should be used in cases of eosinophilic keratoconjunctivitis no matter if there is an ulcer or not.

A

(T)

49
Q

We all know the acute c/s of uveitis by now (hopefully), which an animal with chronic uveitis will have in addition to what other signs?

A

(Cataracts, retinal detachment, secondary glaucoma, and phthisis bulbi)

50
Q

What are some possible etiologies for a case of acute anterior uveitis?

A

(Reflex uveitis from keratitis (ulcer, abscess, etc.), trauma, and sepsis in foals)

51
Q

What are some of the suspected etiologies of equine recurrent uveitis though no one is really sure?

A

(Leptospirosis, Onchocerca cervicalis, immune mediated/hypersensitivity reaction, lots of other ideas)

52
Q

What breed of horse is predisposed to equine recurrent uveitis?

A

(Appaloosas, this can change depending on where you are in the world)

53
Q

What is the difference between classic and insidious equine recurrent uveitis?

A

(Classic cases are intermittently severe versus insidious are chronic low grade cases, these horses will have minimal signs but still have inflammation but go untreated bc they don’t have signs)

54
Q

What are some common clinical signs associated with the anterior segment and equine recurrent uveitis?

A

(Miosis, aqueous flare, hypopyon, and posterior synechiae)

55
Q

What are some common clinical signs associated with the posterior segment and equine recurrent uveitis?

A

(Vitreal debris and/or liquefaction, chorioretinitis, and retinal detachment)

56
Q

For the following diagnostics, state their purpose and/or usefulness in cases of ERU:

  • CBC/chem
  • Lepto serology
  • Conjunctival biopsy
  • Ocular ultrasound
A
  • CBC/chem (not useful or specific)
  • Lepto serology (too much cross reaction to be useful)
  • Conjunctival biopsy (can be done to look for Onchocerca larvae)
  • Ocular ultrasound (useful for looking for retinal detachment)
57
Q

What is the main goal of ERU medical therapy?

A

(Control ocular inflammation, bc there is rarely a definitively identifiable primary problem it can be difficult to eliminate so focus on the inflammation)

58
Q

What drugs are typically included in a medical therapy protocol for treatment of ERU?

A

(Systemic NSAIDs (banamine is best), topical corticosteroids after you check for ulcers, and topical atropine after you check for glaucoma)

59
Q

(T/F) In a case of active ERU, you can place a suprachoroidal cyclosporine implant to take care of the active inflammation and for the long term uveitis control benefits.

A

(F, the eye needs to be inflammation free before placing a suprachoroidal cyclosporine implant)

60
Q

Besides a cyclosporine implant, what other surgical therapies are there for treatment of ERU?

A

(Vitrectomy (mostly for posterior uveitis, reduces inflammation but high incidence of cataracts), and intravitreal gentamicin (can last up to a year))

61
Q

What is the most common and problematic cause of uveal cysts?

A

(Idiopathic cystic corpora nigra)

62
Q

How are uveal cysts distinguished from melanoma?

A

(Light can pass through cysts, not melanoma)

63
Q

What is the treatment for cystic corpora nigra that are causing visual disturbance?

A

(Laser treatment, if not disturbing vision do not need to treat)

64
Q

What are some of the etiologies for chorioretinitis?

A

(ERU, EHV, trauma, others)

65
Q

Bullet hole chorioretinopathy is reportedly caused by an infection with what virus?

A

(EHV-1)

66
Q

How is congenital stationary night blindness diagnosed?

A

(Electroretinogram, this is required bc the retina will appear normal on examination)

67
Q

What are the more common congenital causes of vision loss in a horse?

A

(Cataracts, optic nerve coloboma, and congenital stationary night blindness)

68
Q

What are the more common acquired causes of vision loss in a horse?

A

(ERU and glaucoma, less common are traumatic and exudative optic neuropathy)

69
Q

(T/F) Traumatic optic neuropathy is irreversible.

A

(T, this is when trauma causes a shearing of the optic nerves/chiasm)

Equine Spec. Topics - Clinical Practice (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions