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Equine Med and Surgery II > Lecture 9: Equine Ophthalmology > Flashcards

Lecture 9: Equine Ophthalmology Flashcards

1
Q

Horses visual field is __degrees

A

350

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2
Q

Retina contains rods and cones in a __ ratio

A

9:1

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3
Q

rods sensitive to __light and ___

A

dim light, motion detection (night vision)

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4
Q

cones sensitive to ___, responsible for __vision

A

bright light, color vision

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5
Q

what colors do horses see

A

blue, green, yellow

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6
Q

define Epiphora

A

tearing (pain)

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7
Q

define blepharospasm

A

squinting (pain)

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8
Q

foals less than __weeks do not have menace

A

2-3 weeks

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9
Q

what CN do PLR test

A

2 and 3

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10
Q

what CN do you test for palpebral reflex

A

5 and 7

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11
Q

what CN do you test with menace

A

2 and 7

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12
Q

what CN do you test with dazzle

A

2,3, and 7

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13
Q

Identify 1-3

A
  1. Tapetum
  2. Non-tapetum
  3. Optic disk
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14
Q

what are the black dots that arrow pointing to

A

stars of Winslow

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15
Q

what IV sedation used for eye exam and what dose

A

xylazine at 150-250mg for 1000lb horse

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16
Q

what blocks are used on eye and what do they block

A

auriculopalpebral- motor to orbicularis oculi
Supraorbital nerve- sensory to medial 2/3 upper eyelid

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17
Q

Identify blocks 1-2

A
  1. Auriculopalpebral
  2. Supraorbital
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18
Q

what diagnostic test do you do on every horse, every time with eye problem

A

fluorescence stain

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19
Q

fluorescein stain adheres to __

A

corneal abrasions

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20
Q

Schirmer tear test must be done prior to ___ and ___

A

any medications in the eye, prior to sedation with alpha-2 that increase lacrimation

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21
Q

when is the schirmer tear test indicated

A

Chronic ulcerations or dry cornea

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22
Q

<__mm on schirmer tear test is deficient

A

10

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23
Q

what is normal IOP

A

16-30mmHg

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24
Q

consistently high IOP indicates __

A

glaucoma

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25
Q

consistently low IOP indicates __

A

inflammation/uveitis

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26
Q

IOP should be performed __ with normal head position after ___ application

A

unsedated, proparacaine

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27
Q

when should you test IOP

A

chronic eye problems, corneal edema, buphthalmos

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28
Q

Rose bengal retention indicates a defect in ___

A

mucin layer of the tear film

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29
Q

__ulcers at very early stages may be negative to fluorescein but positive to rose bengal

A

fungal

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30
Q

when should you do rose bengal test

A

chronic eye problems, especially with deficient schirmer

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31
Q

when doing nasolacrimal flush maximum of __cc per side otherwise can cause bleeding

A

20cc

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32
Q

what do you use to dilate the eye. How long to dilate and how long last

A

tropicamide 1%, 20 minutes to dilate, lasts 8-12hrs

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33
Q

you should get corneal ulcer culture prior to any ___in eye

A

medications, including proparacaine

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34
Q

what do you use for corneal culture

A

cotton swab

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35
Q

how is corneal swab diagnostic and therapeutic

A

debriefs necrotic debris off ulcer allowing it to heal more rapidly

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36
Q

what do you examine with ultrasound of eye

A

cornea, lens, retina, iris, ciliary body, corpora nigra, optic nerve, and peri orbital structures

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37
Q

normal or abnormal eye ultrasound

A

normal

38
Q

normal or abnormal eye- what wrong

A

Thickened lens- sclerosis
Detached retina

39
Q

normal or abnormal eye- what wrong

A

Cataract

40
Q

in what scenarios do you want to refer eye for diagnostic procedures

A

tonopen, slit lamp, electroretinogram, CT, MRI

41
Q

what wrong

A

superficial ulcer

42
Q

what wrong

A

melting ulcer

43
Q

what wrong

A

abscess

44
Q

what wrong

A

keratitis

45
Q

what wrong

A

viral keratitis

46
Q

t or f: ulcerations should be treated aggressively no matter how mild

A

true

47
Q

what is typical healing time of uncomplicated corneal ulcer

A

7-10 days

48
Q

ulcers are considered non healing if it takes longer than __

A

7-10 days

49
Q

Tear film proteinases normally ___, what are the two tear film proteinases

A

detect and remove damaged cells in cornea

Matrix metalloproteinase (MMP) and neutrophil elastase (NE)

50
Q

bacterial and fungal pathogens upregulate production of ___ which cause further inflammation and degradation of corneal stroma resulting in ___

A

Matrix metalloproteinase and neutrophil elastase, resulting in melting ulcer

51
Q

__should be considered likely in every ulcer

A

infection

52
Q

what are good topical antibiotics for corneal ulcers

A

TAO, ciprofloxacin, tobramycin

53
Q

___is great for beta hemolytic streptococcus corneal ulcers

A

cefazolin

54
Q

__ and ___ are good for gentamicin resistant pseudomonas

A

ciprofloxacin and amikacin

55
Q

in corneal ulcer treatment, how do you prevent collagenolysis

A
  1. serum- antiproteinase activity against MMP and NE
  2. Acetylcystein 5-10% and EDTA 0.17%
56
Q

how do you decrease inflammation/uveitis in tx of corneal ulcer tx- how do they work

A
  1. Atropine 1%- stabilizes blood-aqueous barrier, reducing protein leakage, stops pain from ciliary muscle spasm, reduce synechiae formation
  2. NSAIDS: reducing uveal exudation and pain, reduce uveitis
57
Q

fungi in corneal ulcers have affinity for __

A

descemets membrane

58
Q

if you see a deep ulcer what do you need to tx with

A

anti-fungal

59
Q

what is tx against fungal ulcer

A

natamycin, miconazole, itraconazole/DMSO, fluconazole, silver sulfadiazine, voriconazole

60
Q

which antifungal has best corneal penetration

A

voriconazole

61
Q

what medications do you put in sub palpebral lavage line

A
  1. Cefazolin
  2. Tobramycin
  3. Serum
  4. Atropine
  5. Diflucan
62
Q

if a corneal ulcer fails to heal in 7-10 days what do you do next

A

Cytology to rule out resistant infection

63
Q

If a cytology from non-healing ulcer is negative then what is likely the cause

A

indolent from microscopic hyaline membranes that form on ulcer bed and slow epithelial healing

64
Q

if you have a clean cytology- what treatment can you do to promote healing

A

keratectomy/keratotomy debridement

65
Q

how does debridement promote healing

A

removing necrotic tissue and microbial detritus speeds healing and minimizes scarring

66
Q

what are conjunctival grafts used for

A

management of deep melting ulcer, large corneal ulcers, descemetoceles or perforated corneal ulcers/iris prolapse

67
Q

how do conjunctival grafts help with healing

A

supplies immediate blood supply and physically stabilizes the eye

68
Q

conjunctival grafts with result in permanent ___ that will inhibit __

A

scarring to cornea that will inhibit vision

69
Q

What blocks are performed for enucleation

A

Supraorbital, auriculopalpebral, retrobulbar

70
Q

describe the enucleation procedure

A
  1. Tarsorrhaphy- exenteration includes muscles
  2. Enucleation of globe alone
  3. Close skin
71
Q

full thickness corneal or scleral perforations are associated with ___, __ and ___

A

iris prolapse, shallow anterior chamber, and hyphema

72
Q

what is Seidel tests

A

using large amount of stain can see aqueous humor flowing out of laceration. Gentle pressure on the globe may be required to observe flow

73
Q

what is tx for corneal lacerations/perforations

A
  1. Small lacerations may heal medically
  2. Large lacerations may require sx
  3. Traumatic corneal perforation with extension extrusion of intraocular contents should be enucleated
74
Q

what is a common cause of viral keratitis

A

EHV-2

75
Q

what are some signs of viral keratitis caused by EHV-2

A

epiphora, conjunctivitis, blepharospasm, linear and punctuate corneal opacities

76
Q

what wrong based on stain uptake

A

viral keratitis- EHV-2

77
Q

what is tx for viral keratitis

A
  1. Topical NSAIDS- diclofenac, flurbiprofen
  2. Topical antivirals- valacyclovir, idoxuridine
78
Q

what is the cause of eosinophilic keratoconjunctivitis

A

immune mediated from environmental allergens or parasites

79
Q

what are some signs of eosinophilic keratoconjunctivitis

A

corneal granulation tissue with predominant eosinophils, blepharospasm, epiphora

80
Q

what is tx for eosinophilic keratitis

A

topical steroids, cetirizine

81
Q

what is ddx for eosinophilic keratoconjunctivitis

A

SCC

82
Q

what wrong- lots of eosinophils observed

A

eosinophilic keratoconjunctivitis

83
Q

what is immune mediated keratitis

A

chronic corneal opacity without corneal ulceration or significant uveitis

84
Q

what are the 4 types of immune mediated keratitis

A
  1. Epithelial
  2. Superficial stroma
  3. Deep stromal
  4. Endothelitis
85
Q

what is tx for immune mediated keratitis

A
  1. Cyclosporine
  2. Topical NSAIDS
86
Q

what is prognosis for immune mediated keratitis

A

guarded

87
Q

A stromal abscess vision threatening sequela to __

A

corneal ulcer

88
Q

most stromal abscesses involving descemets membrane are __

A

fungal

89
Q

aggressive medical therapy against stromal abscess should improve in 2-3 days, if no response then consider __

A

sx removal and corneal graft

90
Q

all painful eyes should be ___

A

stained with fluorescein

91
Q

what drugs are contraindicated when ulcer is present

A

corticosteroids

92
Q

topical anesthetics should not be used in treatment of corneal uclers as they __. __ is toxic to corneal epithelium

A

delay epithelial healing, proparacaine

Equine Med and Surgery II (15 decks)

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