Final: Ophthalmology - Cornea, Uvea Flashcards by Sarah Sabler

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

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What causes blue opacity of the cornea?

Corneal edema

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

Ciliary flush/neovascularization

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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

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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

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

It is avascular
Non-myelinated nerves
Dehydrated (Epithelium= barrier to tear film, Endothelium= active pump and barrier to aqueous humor)
Ordered cell arrangement

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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

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

Anterior lens luxation

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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

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

True

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

Superficial vessels

Deep vessels (ciliary flush/Crown of Thorns)

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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

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

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

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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

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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

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

PAIN

Signals corneal infection (also associated w/uveitis)

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Is corneal fibrosis painful?

It is caused by disordered collagen scattering light

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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

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

Pigment (melanin) in the epithlial or endothelial layer

Feline corneal sequestrum

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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

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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

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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.

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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

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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

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

Keratomalacia "Melting Corneal Ulcer"

What bacteria is most commonly the trigger for collagenolysis?

Pseudomonas

What is a devitalized portion of corneal stoma called?

Sequestrum

What breed is most commonly affected by Pigmentary Keratitis?

Pug ## Footnote *Presence suggests superficial infection*

What are the 4 brachycephalic risk factors for corneal ulcers?

Ocular prominence Decreased corneal sensitivity Adnexal abnormalities Tear film abnormalities

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

Delayed healing Enhanced corneal destruction

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

Find the **underlying cause** (irritants, infection or trauma)

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

E-collar Broad-spec topical ABs (NPB, NP-Gramicidin, Erythromycin, Terramycin) Atropine (until pupil stays dilated)

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

**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

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

**FHV-1** *(cats only)* _Early_ **bacterial** infection _Early_ **fungal** infection

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

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

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

***Staphylococcus*** (gr +, aerobic cocci) ***Streptococcus*** (gr+, aerobic cocci) ***Pseudomonas aeruginosa*** (gr -, facultative anaerobic rod)- causes melting

What is this?

Descemetocele

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

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)

Which 2 of these diagnostics are NOT indicated/necessary to diagnsose a deep/stomal ulcers? STT Fluoroscein Topical anesthesia Cytology Aerobic culture Tonometry

STT - less imporant in the affected eye, more important in the normal eye Tonometry - avoid in fragile eyes

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

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

What are the 3 options for anti-collagenase therapy?

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

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

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

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

**_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**)

What is going on here?

**Pannus** aka Chronic Superfcial Keratitis ## Footnote *Note raised granulation tissue and pigment*

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

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**

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?

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)**

What are the most common clinical signs associated with uveitis?

Aqueous flare Keratic precipitates Ciliary flush Fibrin development Hypopyon Hyphema (Hypotony (decr IOP) = acute uveitis)

What is a diagnostic plan for uveitis?

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)

What is the treatment plan for uveitis?

Topical corticosteroids (unless has ulcers) Topical NSAIDs (unless has ulcers) Systemic corticosteroids (if vision loss imminent due to inflammation of nerve) Mydriatics (Atropine)

What are the 3 components of the uvea?

Iris Ciliary body Choroid *(Uvea= Greek for grape)*

What defines uveitis?

Breakdown/inflammation of the blood-occular barrier

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 \_\_\_\_\_\_.

Anterior Iridocyclitis Posterior Chorioretinitis Panuveitis

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

Aqueous flare Active inflammation

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

Ciliary flush

What pathognomic sign of uveitis is often responsible for synechia?

Fibrin

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

Hypopyon

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

360deg posterior synechia Iris bombe

What is hyphema and what does it indicate?

Blood settling in the anterior chamber Indicative of large breakdown in the blood ocular barrier (can be caused by uveitis, hypertension and coagulopathies)

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

Paralysis of the ciliary body

What is the vascular layer of the eye?

Uvea

What are the 2 components of the blood ocular barrier?

1. Blood-aqueous barrier 2. Blood-retinal barrier

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

Miosis Decreased IOP Iris hyperpigmentation

What is the Tyndall Effect?

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

What is normal IOP?

10-20 mmHg

What are some common sequelae to chronic uveitis?

Cataracts Secondary lens luxation- cats **Secondary glaucoma** Retinal detachment Phthisis bulbi

What is the most common cause of blindness from uveitits?

Secondary glaucoma

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

Exogenous (e.g. trauma, reflex uveitis) Endogenous (e.g. lens-induced, infection, neoplasia, metabolic, auto-immune)

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

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

What causes "Roman nose" and granulomatous chorioretinitis?

Cryptococcosis

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

**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*

What drugs do all cases of uveitis need?

Anti-inflammatories

Final: Ophthalmology - Cornea, Uvea Flashcards

(71 cards)