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

Final: Ophthalmology - Cornea, Uvea Flashcards

1
Q

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

A

Facet formation: Loss of corneal stoma with intact overlying epithelium

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2
Q

What causes blue opacity of the cornea?

A

Corneal edema

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3
Q

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

A

Ciliary flush/neovascularization

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4
Q

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

A

WBC corneal infiltration

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5
Q

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

A

Feline Corneal Sequestrum

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6
Q

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

A
  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
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7
Q

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?

A

Epi: 7 days or less

Stoma: Days to weeks

Descemetocele: Weeks to Months

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8
Q

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

A

Anterior lens luxation

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9
Q

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

A

Endothelial

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10
Q

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

A

True

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11
Q

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

A

Superficial vessels

Deep vessels (ciliary flush/Crown of Thorns)

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12
Q

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?

A

3 days

1mm per day

Toward the stimulus

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13
Q

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

A

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

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14
Q

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.

A

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

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15
Q

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

A

WBC infiltration- yellow or green hue

Fibrosis - gray or wispy features

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

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16
Q

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

A

PAIN

Signals corneal infection (also associated w/uveitis)

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17
Q

Is corneal fibrosis painful?

A

No

It is caused by disordered collagen scattering light

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18
Q

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)

A

d. Lipid (left), Calcium (right)

Caused by dystophy or degeneration

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19
Q

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

A

Pigment (melanin) in the epithlial or endothelial layer

Feline corneal sequestrum

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20
Q

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

A

A. Fibrosis/scarring

B. Superficial vessels

V. Epithelial pigment

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21
Q

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

A

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

Uveitis

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22
Q

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

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.

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23
Q

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

A

Indolent Ulcer / Spontaneous Chronic Corneal Epithelium Defect (SCCED)

Boxers

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24
Q

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?

A

Trigeminal nerve

Reflex uveitis

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25
Q

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

A

Keratomalacia

“Melting Corneal Ulcer”

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26
Q

What bacteria is most commonly the trigger for collagenolysis?

A

Pseudomonas

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27
Q

What is a devitalized portion of corneal stoma called?

A

Sequestrum

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28
Q

What breed is most commonly affected by Pigmentary Keratitis?

A

Pug

Presence suggests superficial infection

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29
Q

What are the 4 brachycephalic risk factors for corneal ulcers?

A

Ocular prominence

Decreased corneal sensitivity

Adnexal abnormalities

Tear film abnormalities

30
Q

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

A

Delayed healing

Enhanced corneal destruction

31
Q

What is the most important part of your approach to corneal ulceration (if possible)?

A

Find the underlying cause (irritants, infection or trauma)

32
Q

What is the treatment protocol for simple/uncomplicated corneal ulceration?

A

E-collar

Broad-spec topical ABs (NPB, NP-Gramicidin, Erythromycin, Terramycin)

Atropine (until pupil stays dilated)

33
Q

What is the first step in treating an indolent ulcer? What purpose does this serve?

A

Debridement

(First w/cotton swab, followed by either 1. Anterior stromal puncture 2. Grid keratotomy or 3. Diamond burr debridement)

To reset the relationship between the epithelium and stroma

34
Q

What are the 3 potential causes for complex/complicated ulcers?

A

FHV-1 (cats only)

Early bacterial infection

Early fungal infection

35
Q

T/F: Diamond burr debridement (DBD) is the best choice to treat cats with corneal ulceration.

A

FALSE, never perform ASP, GK, or DBD on cats - often causes sequestrum

36
Q

What are the 3 most common bacteria that cause corneal infection?

A

Staphylococcus (gr +, aerobic cocci)

Streptococcus (gr+, aerobic cocci)

Pseudomonas aeruginosa (gr -, facultative anaerobic rod)- causes melting

37
Q

What is this?

A

Descemetocele

38
Q

What are the 4 reasons why we see more descemetoceles relative to any other type of deep corneal ulcer?

A
  1. Loss of epithelium (trauma, FHV-1, eyelid abnormalities…)
  2. Breaches defense and susceptibility to infection
  3. Stoma is extremely sensitive to proteases from bacteria/fungi/neutrophils
  4. Progression of collagenolysis through the stroma is rapid (<24h)
39
Q

Which 2 of these diagnostics are NOT indicated/necessary to diagnsose a deep/stomal ulcers?

STT

Fluoroscein

Topical anesthesia

Cytology

Aerobic culture

Tonometry

A

STT - less imporant in the affected eye, more important in the normal eye

Tonometry - avoid in fragile eyes

40
Q

What are the 3 indications for parenteral antibiotics when a deep ulcer is present?

A
  1. The ulcer has become vascularized
  2. Cornea is close to perforation or has perforated
  3. Iatrogenic vascularization (e.g. Flap surgery)
41
Q

What are the 3 options for anti-collagenase therapy?

A
  1. Autologenous (or equine) serum
  2. 1% EDTA solution
  3. 10% N-acetylcysteine
42
Q

What are the 3 guidelines for referral or surgical repair of a deep ulcer?

A
  1. Ulcer has 50% or greater stomal depth
  2. Ulcer is failing aggressive medical therapy
  3. Descemetocele or perforation
43
Q

What procedure has been done here and what purpose did it serve? What is a disadvantage of this surgery?

A

Conjunctival pedicle flap

To provide immediate tectonic strength, provide blood supply for parenteral AB tx, provides serum for anti-collagenolysis

Disadvantage: Can cover the visual axis (i.e. blindness)

44
Q

What is going on here?

A

Pannus aka Chronic Superfcial Keratitis

Note raised granulation tissue and pigment

45
Q

What features indicate simple vs complex superficial ulcers between the eye in 1 and the eye in 2?

A
  1. Simple/uncomplicated: No evidence that ulcer is indolent, has an underlying irritant, or is infected
  2. Complicated: Early bacterial infection; early episcleral injection, severe edema, deep vessels
46
Q

Given that neither of these ulcers have healed within the expected time frame, what features indicate which variation of complex ulcer is present in eye 1 and eye 2?

A
  1. Superficial vessels, stain seen under epithelial edge, loose epithelium with folding = Indolent (Debridement indicated)
  2. Moderate episcleral injection, turbid anterior chamber (flare), diffuse corneal edema, marked miosis, stain seen under epithelial edge = Early bacterial infection (Do not do ASP, GK, or DBD)
47
Q

What are the most common clinical signs associated with uveitis?

A

Aqueous flare

Keratic precipitates

Ciliary flush

Fibrin development

Hypopyon

Hyphema

(Hypotony (decr IOP) = acute uveitis)

48
Q

What is a diagnostic plan for uveitis?

A

MDB: history, exam, CBC/chem, UA, rads, 4Dx (or if cat FIV/FeLV and Toxo), fungal titer

(If hyphema present: BP, PTL count, coag panel)

49
Q

What is the treatment plan for uveitis?

A

Topical corticosteroids (unless has ulcers)

Topical NSAIDs (unless has ulcers)

Systemic corticosteroids (if vision loss imminent due to inflammation of nerve)

Mydriatics (Atropine)

50
Q

What are the 3 components of the uvea?

A

Iris

Ciliary body

Choroid

(Uvea= Greek for grape)

51
Q

What defines uveitis?

A

Breakdown/inflammation of the blood-occular barrier

52
Q

Inflammation of the iris and ciliary body is termed _____ uveitis or ________. Inflammation of the choroid is termed ______uveitis, which usually occurs with retinal inflammation and is thus termed ________. Inflammation of the whole uvea is termed ______.

A

Anterior

Iridocyclitis

Posterior

Chorioretinitis

Panuveitis

53
Q

What is the pathopnomic sign of anterior uveitis in which proteins and cells are suspended in the anterior chamber? What does its presence signal?

A

Aqueous flare

Active inflammation

54
Q

What is the pathognomic sign for uveitis referring to 360deg deep corneal neovascularization? The vessels arise from the ciliary body and deep episcleral vessels.

A

Ciliary flush

55
Q

What pathognomic sign of uveitis is often responsible for synechia?

A

Fibrin

56
Q

What is the settling down of WBCs dependenly in the anteior chamber called?

A

Hypopyon

57
Q

What causes the iris to bulge forward like a donut? What is this called?

A

360deg posterior synechia

Iris bombe

58
Q

What is hyphema and what does it indicate?

A

Blood settling in the anterior chamber

Indicative of large breakdown in the blood ocular barrier

(can be caused by uveitis, hypertension and coagulopathies)

59
Q

What does atropine induce which is useful in alleviating pain from uveitis due to ciliary body spasm?

A

Paralysis of the ciliary body

60
Q

What is the vascular layer of the eye?

A

Uvea

61
Q

What are the 2 components of the blood ocular barrier?

A
  1. Blood-aqueous barrier
  2. Blood-retinal barrier
62
Q

Inflammation during uveitis is driven by prostaglandins. What else are prostaglandins responsible for (name 3 things)?

A

Miosis

Decreased IOP

Iris hyperpigmentation

63
Q

What is the Tyndall Effect?

A

Proteins and cells which leak into the anterior chamber (aqueous flare) causing light to scatter through a turbid environment

64
Q

What is normal IOP?

A

10-20 mmHg

65
Q

What are some common sequelae to chronic uveitis?

A

Cataracts

Secondary lens luxation- cats

Secondary glaucoma

Retinal detachment

Phthisis bulbi

66
Q

What is the most common cause of blindness from uveitits?

A

Secondary glaucoma

67
Q

What are the 2 categories of the causes of canine uveitis?

A

Exogenous (e.g. trauma, reflex uveitis)

Endogenous (e.g. lens-induced, infection, neoplasia, metabolic, auto-immune)

68
Q

What is the most common primary canine uveal neoplasm? What is the most common DDx for this mass?

A

Melanocytoma

Uveal cyst (= free floating, use retroillumination or see if it floats to ddx)

69
Q

What causes “Roman nose” and granulomatous chorioretinitis?

A

Cryptococcosis

70
Q

What is the most common feline uveal tumor? What are the 4 criterion that can assist in diagnosis?

A

Diffuse Iris Melanoma

  1. Rapid progression (weeks-months)
  2. Texture is ‘velvety’
  3. Dyscoria due to invasion of the musclature
  4. Pigmented cells floating in anterior chamber
    * Only histopath (enucleation) can confirm diagnosis*
71
Q

What drugs do all cases of uveitis need?

A

Anti-inflammatories

SAM 2 scs RUSVM (14 decks)

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