Brainscape's Knowledge GenomeTM

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


See full index

Equine Clinical Practice Exam 1 > Diseases of the Globe > Flashcards

Diseases of the Globe Flashcards

1
Q

The overall visual field of the horse is:

A

350 degrees

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

The horse can see ______ degrees with monocular vision, and _____ degrees with binocular vision

A

146 degrees
65 degrees

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

Before any sedation is induced, you should evaluate:

A

Cranial nerves

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

Which cranial nerves are commonly assessed in horses?

A

Menace response
Dazzle reflex
Palpebral reflex
PLRs

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

Which ocular muscle is very strong in horses, often requiring orbital nerve blocks for a proper ophthalmic exam?

A

Orbicularis oculi

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

Which ocular nerve blocks in horses block the motor and sensory function of the eye?

A

Auriculopalpebral (motor)
Supraorbital or frontal (sensory)

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

For ocular nerve blocks, what size needle is used and what volume/choice of anesthetic?

A

25 gauge needle
1-2 mL
Lidocaine, bupivacaine, or mepivacaine

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

What are the landmarks for an auriculopalpebral nerve block?

A

On the zygomatic arch, caudal to the bony process of the frontal bone

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

What are the landmarks for an supraorbital nerve block?

A

Palpation of the supraorbital foramen
*Thumb: below dorsal orbital rim
*Middle finger: supraorbital fossa
*Index finger: straight down midway between other two fingers

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

Supraorbital nerve block desensitizes:

A

Sensation to central upper eyelid
Blocks the ophthalmic branch of Trigeminal nerve

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

Auriculopalpebral nerve block stops motor output from:

A

Orbicularis oculi muscle, mostly upper eyelid
Blocks palpebral branch of auriculopalpebral nerve (Facial nerve)

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

Tear production in horses should be:

A

> 20mm/min

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

IOP in horses should be:

A

15-30mmHg

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

What would give indication for irrigation of nasolacrimal duct?

A

Epiphora, mucoid ocular discharge, nasal puncta diacharge

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

Describe the process of flushing the NLD retrograde:

A
  1. Start at distal nares opening
  2. 5 or 6 polyethylene urinary catheter
  3. 12 to 20 mL syringe with sterile eyewash +/- fluoroscein stain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the process of flushing the NLD normograde:

A
  1. Start at proximal eyelid puncta (lower eyelid puncta usually larger)
  2. 8 to 20g IV Cannula
  3. Excessive force can damage NLD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What drug is commonly used to dilate the pupil of horses for a complete ophthalmic exam?

A

1% Tropicamide
(done ~20 minutes prior to exam)
*lasts 4-6 hours

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

The optic disc should appear:

A

Oval, salmon-pink, in the non-tapetal fundus

19
Q

The equine fundus is unique because:

A

Tapetum is fibrous (Stars of Winslow)

20
Q

Indirect fundoscopy produces:

A

Inverted and reversed image

21
Q

A sunken appearance to the globe has 3 likely etiologies, including:

A

Enophthalmos
Microphthalmos
Phthisis bulbi

22
Q

Enophthalmos is defined as:

A

Recession of the globe; usually secondary to loss of orbital contents

23
Q

Causes of enophthalmos (4)?

A
  1. Orbital fractures
  2. Resorption of orbital fat
  3. Dehydration in foals (entropion)
  4. Sympathetic denervation (Horner’s Syndrome)
24
Q

Microphthalmia is defined as:

A

Congenital anomaly resulting in a small globe

25
Q

Phthisis bulbi is defined as:

A

Gradual shrinkage of the globe due to chronic inflammation and low IOP
*Non-visual
*Should be enucleated if painful

26
Q

What causes phthisis bulbi?

A

Damage to the ciliary body causing decreased aqueous humor production

27
Q

A “bulging” appearance to the globe has two etiologies, which are:

A

Bupthalmos
Exophthalmos

28
Q

Buphthalmos is defined as:

A

Enlarged globe associated with chronically increased IOP secondary to glaucoma

29
Q

In addition to Bupthalmos, what other signs might be present indicative of glaucoma?

A
  1. Diffuse corneal edema
  2. Haab’s striae
30
Q

Prognosis for Bupthalmos?

A

Doesn’t usually respond well to meds, prognosis for vision not good

31
Q

Exophthalmos is defined as:

A

Anterior displacement of a normal sized globe, usually due to a space occupying lesion posterior to the globe

32
Q

Causes of exophthalmos?

A
  1. Retrobulbar mass
  2. Orbital cellulitis/abscess
  3. Trauma (reduced orbital space)
33
Q

On digital retropulsion of the globe, pain indicates _______ and no pain indicates _______

A
  1. Pain: inflammatory process
  2. Nonpainful: neoplasia/cystic mass(es)
34
Q

Which portion of the orbit are at greatest risk of orbital fractures?

A

Dorsal orbital rim & zygomatic arch

35
Q

What would be the clinical appearance of a horse with an orbital fracture?

A

Facial asymmetry
Blepharedema
Periocular lacerations
Conjunctival hyperemia
Chemosis
SQ emphysema

36
Q

What are the causes of orbital fractures?

A

Rearing in a confined space
Kick to the face
Colliding with a stationary object

37
Q

How does orbital fat prolapse occur?

A

Orbital fat herniates through weakened episcleral fascia or as a result from trauma

38
Q

What is the clinical appearance of orbital cellulitis?

A

Exophthalmos
Blepharedema or blepharitis
Severe conjunctival swelling
Elevated third eyelid
Mucoid ocular discharge
IOP: normal or elevated

39
Q

How do we diagnose orbital cellulitis?

A

Palpation
Sinus percussion
Imaging
Teeth evaluation

40
Q

Treatment for orbital cellulitis?

A

Systemic antimicrobial agents
Aggressive NSAIDs
Topical lubricants
Drainage of abscess (+/-)
Removal of FB (+/-)
Enucleation

41
Q

What are the most common orbital neoplasias?

A
  1. Neuroendocrine tumors
  2. Extra-adrenal paranglioma
  3. Nasal and orbital adenocarcinoma
  4. Sarcoma, lymphoma, SCC
42
Q

Diagnosis of orbital neoplasia?

A
  1. Imaging
  2. Biopsy
  3. FNA
43
Q

Treatment of orbital neoplasia?

A
  1. Exenteration
  2. Radiation/Chemo
  3. Euthanasia

Equine Clinical Practice Exam 1 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions