Brainscape's Knowledge GenomeTM

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


See full index

RUSVM SAM II > Cornea > Flashcards

Cornea Flashcards

1
Q

what keeps the cornea dehydrated

A

epithelium - barrier to tear film

endothelium - active pump and barrier to aqueous humor

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

what 4 factors keep the cornea clear

A

avascular

non-mylinated nerves

dehydrated

ordered cell arrangement

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

how long does epithelialization take to occur

A

7 days or less (even wirh complete epithelial loss)

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

stromal healing results in _____

A

fibrosis/scarring

this takes days to weeks

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

what is a facet

A

non-staining depression in the cornea

Often, the epithelium often slides over remodeled stroma before it becomes level with surrounding epithelium

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

how long does it take a descemetocele take to heal

A

weeks to months

why referral and surgical repair is recommended

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

blue corneal opacity =

A

edema

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

2 possible causes of blue corneal edema

A

epithelial barrier disruption - tear film entry into hydrophilic stroma

endothelial barrier/pump disruption

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

3 ways endothelial barrier/pump can be disrupted

A

focal loss

generalized reduction in number

generalized reduction in function - glaucoma, uveitis

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

what causes red corneal opacity

A

corneal neovascularization

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

2 sources of red corneal opacity

A

superficial neovascularization

deep neovascularization

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

superficial neovascularization occurs with

A

KCS, eyelid conformation or hair abnormalities, superficial corneal ulcers

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

how long does it take for superficial neovascularization to occur

A

3 days from insult to start growing vessels

progress ~ 1mm per day

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

what is an indication of chronic stimulation leading to superficial neovascularization

A

granulation tissue causing a dense raised collection of superficial vessels

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

what are ghost vessels

A

non-perfused, empty vessels

occurs when stimulus/irritant has been removed

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

what is ciliary flush and when does it occur

A

360º deep neovascularization

occurs with uveitis

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

white corneal opacity with grey or wispy features indicates

A

fibrosis

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

white corneal opacity with yellow or green hue indicates

A

white blood cell infiltration

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

white corneal opacity that is crystalline or chalky indicates

A

mineral or lipid - dystrophy, degeneration

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

WBC infiltrates detected or not detected

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

characterisitics of WBC infiltrate

A

painful

associated with severe corneal disease

often associate with uveitis

signals corneal infection

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

this corneal opacity is due to

A

corneal fibrosis

dull white; corneal scar from previous corneral laceration

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

characteristics of corneal fibrosis

A

non painful

corneal scarring from previous keratitis

involves contracture of lamellar stromal collagen

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

what is causing the opacities in the pictures below

A

cyrtalline white - corneal lipid degeneration

chalky white - corneal calcific degeneration

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

corneal degeneration

A

can be lipid or mineral

secondary to: primary corneal disease or systemic disease

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

corneal dystrophy

A

most often lipid

27
Q

2 causes of brown or black corneal opacities

A

pigment (melanin) - epi/endothelial

feline corneal sequestrum

28
Q

what dis?

A

feline corneal sequestrum

29
Q

epithelial corneal pigment

A

origin - conjunctival melanin

occurs as a result of chronic keratitis

esp. in brachycephalic breeds

30
Q

endothelial pigment

A

origin - uveal (iris) melanin

occur congenitally (persistent pupillary membranes) or aquired (anterior synechial and uveal cysts)

31
Q

what is the only cause of tan or greasy punctate in the cornea

A

keratic precipitates

32
Q

what is the classic pattern of keratic precipitates

A

clear of precipitates dorsally

small precipitates at mid cornea

larger and larger precipitates as you move ventrally

33
Q

this is helpful

A

but seriously…look at it

34
Q

4 brachycephalic risk factors for corneal ulcers

A

ocular prominence

decreased corneal sensitivity

adnexal abnormalities

tear film abnormalities

35
Q

T/F topical steroids can be used in the treatment of ulcerative keratitis

A

False!

never use any types of topical steroid in cases of ulcerative keratitis, cause delayed healing and enhanced corneal destruction

36
Q

what consitutes a superficial corneal ulcer

A

loss of epithelium with no stromal loss

37
Q

simple “uncomplicated” superficial corneal ulcers

A

superficial corneal ulcer that heals in 7 days or less

38
Q

causes of superficial corneal ulcers

A

irritants - foreign body, tear film abnormalities, adnexal abnormalities

infection - herpes (cats)

trauma

39
Q

treatment of simple superficial corneal ulcers

A

e collar!

broad spectrum antibiotics 3-4x/day

atropine 1-2x/day or until pupil stays dilated

recheck in 5-7 days

40
Q

3 possible causes of complicated/complex corneal ulcers

A

indolent ulcer

persistent irritant (underlying cause has not been identified/treated)

infection

41
Q

Indolent ulcers (aka spontaneous chronic corneal epithelial defect) signalment/ history

A

middle age to older dogs - NOT CATS

boxers

corneal ulcer that won’t heal - will take months is left untreated

42
Q

diagnosis of indolent ulcers

A

test epithelium with cotton tiped applicator

normal epithelium will not debride easily

43
Q

treatment of indulent ulcers

A

debridement! - reset relationsho between epithelium and stroma

once debrided - treat typucally similar to simple superficial corneal ulcers

44
Q

what is the most important part of your approach to corneal ulcers

A

trying to find and treat the underlying cause (if possible)

45
Q

3 possible infectious causes of complex corneal ulcers

A

FHV-1 - Most Common

early bacterial (cats and dogs)**

early fungal (cats and dogs)**

**This is where we transition into deep corneal ulceration as bacteria especially have affinity for stroma**

46
Q

what features indicate which complex category this dog’s eye falls into

A

fluorescein “halo” - staining under the epithelial edge

indicates indolent ulcer

47
Q

what is the most likely cause of this cats complex ulcer

A

Herpes!

most common cause of non-healing ulcer in a cat is FHV-1

48
Q

why should you never perform ASP, GK, or DBD on cats with corneal ulcers

A

feline corneal sequestrum often occurs

49
Q

T/F ASP, GK, or DBD should never be performed on infected ulcers

A

True

risks a severe progression of the infection

50
Q

what is the most common ophthalmic condition seen in practice that will require a decision of whether or not to refer to specialist

A

deep (stromal) corneal ulcer

51
Q

99% of deep (stromal) corneal ulcers have ______

A

corneal infection

bacterial or fungal (mostly horses)

52
Q

collagenolysis

A

enzymatic destruction or corneal collagen

53
Q

keratomalacia

A

softening or “melting” of corneal stroma due to collagenolysis

from bacterial/fungal and neutrophil enzymes

54
Q

3 most common bacteria involved in deep corneal ulcers

A

Staphylococcus spp.

Streptococcus spp.

Pseudomonas aeruginosa - most common cause of melting

55
Q

what is an important identifying feature of stromal ulceration

A

reflux uveitis

56
Q

clinical signs of reflex uveitis

A

miosis

aqueous flare

diffuse corneal edema

hypopyon or hyphema

57
Q

necessary diagnositics for deep corneal ulceration

A

STT - more important in normal eye

fluorescein stain

topical anthesia

cytology

aerobic culture

tonometry - avoid in fragile eyes

58
Q

treatment of deep corneal ulceration

A

e-collar

antibacterial therapy

anti-collagenase therapy

reflux uveitis and pain management

+/- surgical management and referral

59
Q

antibiotics used to treat deep corneal infections

A

cephalosporins

neomycin polymixin B Gtamicidin

fluroquinolones and aminoglycosides

high frequency of application (q1-2hrs)

60
Q

3 indications for oral antibiotics with deep stromal ulcers

A

ulcer has become vascularized

cornea is close to perforation or has perforated

iatrogenic vascularization

61
Q

anti-colagenase therapy options

A

autologous serum

1% EDTA solution

10% N-acetycysteine

at lease every 2-4 hours

62
Q

pain management from reflux uveitis

A

atropine - paralyzes ciliary body (tx until pupil is dilated; 1-2x per day)

+/- oral anti-inflammatory and pain management (NSAID, tramadol)

63
Q

3 guidelines for referral/surgical repair

A

ucler has 50% or greater stromal depth

ulcer is failing aggressive medical therapy

descemetocele or perforation

64
Q

what dis?

A

Pannus aka chronic superficial keratitis

raised granulaton tissue

RUSVM SAM II (20 decks)

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