Final: Ophthalmology - Cornea, Uvea Flashcards Preview

SAM 2 scs RUSVM > Final: Ophthalmology - Cornea, Uvea > Flashcards

Flashcards in Final: Ophthalmology - Cornea, Uvea Deck (71)
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1

What occurs because epithelialization occurs more rapidly than stromal healing resulting in a non-staining depression in the cornea?

Facet formation: Loss of corneal stoma with intact overlying epithelium

2

What causes blue opacity of the cornea?

Corneal edema

3

What is 360deg deep corneal neovascularization that is pathognomic for uveitis?

Ciliary flush/neovascularization

4

What is one cause of white corneal opactiy and is a sign of active inflammation, which is often painful and signifies an ocular emergency?

WBC corneal infiltration

5

What is the brown or black discoloration resulting from chronic corneal irritation and/or ulceration, commonly caused by corneal ulceration from feline herpes virus?

Feline Corneal Sequestrum

6

What are the 4 factors that allow the cornea to stay clear?

1. It is avascular 

2. Non-myelinated nerves

3. Dehydrated (Epithelium= barrier to tear film, Endothelium= active pump and barrier to aqueous humor)

4. Ordered cell arrangement

7

How long does epithelial healing take, even with complete loss? How long does stromal healing, resulting in fibrosis, take? How long does it take for a descemtocele to heal?

Epi: 7 days or less

Stoma: Days to weeks

Descemetocele: Weeks to Months

8

What is causing the focal edema seen here (inside the dotted circle)?

Anterior lens luxation

9

Generalized corneal edema can occur from a reduction in ________ cell numbers. This can occur due to canine adenoviral hepatitis or be an aging change. 

Endothelial

10

T/F: Canine glaucoma and uveitis can cause generalized corneal edema.

True

11

What are the 2 patterns of corneal vascularization that cause a red corneal opacity?

Superficial vessels 

Deep vessels (ciliary flush/Crown of Thorns)

12

How long does it take from the insult for vessels to start growing (i.e. for neovascularization to occur)? How quickly do they progress and toward what do they grow?

3 days

1mm per day

Toward the stimulus

13

What does a chronic stimulant irritating the cornea cause? (It is common with indolent ulcers)

Granulation tissue formation (dense, raised collection of superficial vessels)

14

T/F: When neovacularization of the cornea occurs, the superficial vessels progress more slowly than the deep ones.  Deep corneal vesssels also cross the limbus while superficial vessels do not.

False, deep neovascularization progresses slower and deep vessels do not cross the limbus 

15

What are the 3 variations of white corneal opacities? What do they look like?

WBC infiltration- yellow or green hue

Fibrosis - gray or wispy features

Crystalline or chalky white - mineral or lipid, dystrophy or degeneration

16

What characterized WBC infiltration of the cornea? What does it indicate?

PAIN

Signals corneal infection (also associated w/uveitis)

 

17

Is corneal fibrosis painful?

No

It is caused by disordered collagen scattering light

18

What is causing these white opacities?

a. Calcium (left), Lipid (right)

b. Fibrosis (left), Calcium (right)

c. Lipid (left), Fibrosis (right)

d. Lipid (left), Calcium (right)

d. Lipid (left), Calcium (right)

Caused by dystophy or degeneration 

19

What are the 2 broad causes for brown or black corneal opacities?

Pigment (melanin) in the epithlial or endothelial layer

Feline corneal sequestrum

20

This is a dog who is undergoing treatment for KCS. What are the arrows A, B, and C indicating?

A. Fibrosis/scarring

B. Superficial vessels

V. Epithelial pigment

21

What is the only cause for tan or greasy punctate? What disease process is this pathognomic for?

Keratic precipitates (cellular and fibrinous adhesions to the endothelial surface)

Uveitis

22

A superficial corneal ulcer describes a loss of the corneal ________ without any loss of corneal ________. A simple or uncomplicated corneal ulcer heals in ____ days while a complex or complicated corneal ulcer heals in ____ days.

A superficial corneal ulcer describes a loss of the corneal EPITHELIUM without any loss of corneal STROMA. A simple or uncomplicated corneal ulcer heals in <7 days while a complex or complicated corneal ulcer heals in >7 days.

23

What is the canine-specific form of complex corneal ulceration in which the epithelium fails to adhere to the stroma? What breeds get this?

Indolent Ulcer / Spontaneous Chronic Corneal Epithelium Defect (SCCED)

Boxers

24

What nerve, in addition to certain cytokines, causes direct stimulation of the ciliary body inducing spasm, pain, and disruption of the blood ocular barrier? What is this condition called?

Trigeminal nerve

Reflex uveitis 

25

What is the softening of the cornea due to collagenolysis from an infection?

Keratomalacia 

"Melting Corneal Ulcer"

26

What bacteria is most commonly the trigger for collagenolysis?

Pseudomonas

27

What is a devitalized portion of corneal stoma called?

Sequestrum

28

What breed is most commonly affected by Pigmentary Keratitis?

Pug

Presence suggests superficial infection

29

What are the 4 brachycephalic risk factors for corneal ulcers?

Ocular prominence

Decreased corneal sensitivity

Adnexal abnormalities

Tear film abnormalities

30

Why should you never use any type of topical steroid in cases of ulcerative keratitis (2 reasons)?

Delayed healing

Enhanced corneal destruction