Unit 1 - Conjunctiva and Cornea Flashcards
What are the functions of the conjunctiva?
Lines the eyelids and sclera and allows movements
Source of tear film mucin
Conjunctival associated lymphoid tissue
Conjunctiva is clear, ____ tissue with thin branching _____.
mobile, vessels
What are the bacterial flora of the conjunctiva?
Gram + aerobes
When evaluating the conjunctiva, what should you be evaluating for?
Evaluate the bulbar and palpebral surfaces for injected vessels, bleeding, swelling, masses, foreign bodies, etc
When evaluating the sclera what should you be looking for?
Evaluate for episcleral vessel congestion, masses, etc
What are ways that the conjunctiva can respond to ocular or systemic disease?
Hyperemia, chemosis, color change, lymphoid follicles, ocular discharge
What color change can the conjunctiva go through in cases of ocular or systemic disease?
Extreme pallor, icterus, and/or subconjunctival hemorrhage
Serous ocular discharge = _________
Mucoid/mucopurulent ocular discharge = ________
Purulent ocular discharge = _________
epiphora
KCS
bacteria
What can cause ‘red eye’?
Conjunctival hyperemia or episcleral injection
Conjunctival hyperemia is due to (surface/deep) disease and episcleral injection is due to (surface/deep) disease.
surface, deep
T/F - Primary conjunctivitis is more common than secondary
False - it is very rare, secondary is the most common presentation
What can cause primary conjunctivitis?
Foreign bodies, infection, and/or allergies
What is the most important step to treating conjunctivitis?
ID and address the underlying cause
How is bacterial conjunctivitis treated?
Topical antibiotic QID - make sure to do a STT to check for KCS first
How is conjunctivitis due to allergies or conjunctival pocket syndrome treated?
Topical gel lube and saline eye rinsing
What is another term for neonatal conjunctivitis?
ophthalmia neonatorum
What is neonatal conjunctivitis?
Infection behind closed puppy/kitten eyelids (this is prior to normal lid opening)
How is neonatal conjunctivitis treated?
Separate eyelids, flush eyes, antibiotic ointment QID, +/- lube
Benign or malignant?
Conjunctival melanoma
Hemangioma
Mast Cell Tumor
Subconjunctival fat prolapse
Conjunctival melanoma - malignant (not at eyelid or limbus)
Hemangioma - benign
Mast cell tumor - benign
Subconjunctival fat prolapse - benign
How are conjunctival hemangiomas and mast cell tumors treated?
Excise and freeze the base
What miscellaneous ‘disease processes’ can happen to the conjunctiva?
Dermoid, inflammatory nodules, foreign bodies, and KCS
The cornea is a smooth, clear, and physically ______ window that has major ______ function.
tough, refractive
‘A _____ cornea is a happy cornea’
moist
What are the layers of the cornea?
Epithelium, stroma, Descemet’s membrane, and Endothelium
The corneal epithelium is _____philic and provides ______ function.
Lipophilic; barrier
The corneal stroma is ____philic, adheres _____, and is composed of collagen, keratocytes, and GAGs.
hydrophilic; fluorescein
Descemet’s membrane is _____philic.
lipophilic
What is the role of the corneal endothelium?
It maintains ‘dehydrated’ clear cornea
What are the many things that can cause an abnormal corneal appearance?
Superficial vs. deep vascularization (red)
Granulation (pink)
Leukocytes (white, cream, yellow)
Corneal scarring (white/gray +/- vesses or synechia)
Corneal edema (white or blue)
Pigment (brown)
Sequestrum (brown or black)
Foreign body (dark or any color)
Rough or dull surface defects
Superficial or deep neovascularization?
Superficial
Superficial or deep neovascularization?
Deep
What can cause corneal ulcers?
Injury, conformational issues, eyelash disorders, and acquired conditions
What injuries can cause corneal ulcers?
Trauma, foreign body, chemical or thermal insult
What conformational issues can cause corneal ulcers?
Entropion, macropalpebral fissure, lagophtalmos, nasal fold trichiasis
What eyelash disorders can cause corneal ulcers?
Ectopic cilia, distichia (rarely)
What acquired conditions can cause corneal ulcers?
Keratoconjunctivitis sicca, facial nerve paralysis, eyelid masses, eyelid injuries, indolent ulcer, exposure, anesthesia, herpesvirus, Moraxella bovis, and others
A.
Ectopic cilia
B.
Exposure, KCS, trauma, chemical, thermal, M. bovis, etc
C.
Nasal fold trichiasis
D.
Foreign body behind third eyelid
E.
Entropion
What clinical signs are associated with corneal ulcers?
Blepharospasm
Epiphora
Rubbing at eyes
Enophthalmos
Elevated third eyelid
‘Red eye’
Corneal edema, blood vessels (BV), infiltrates, melting
Corneal defect or surface irregularity
Reflex uveitis
What is associated with reflex uveitis?
Miosis, aqueous flare, hypopyon, fibrin, and photophobia
What is used to diagnose corneal ulcers?
History, complete ocular exam, fluorescein stain, +/- Rose bengal stain
If a corneal ulcer is present, how will fluorescein act when placed on the eye?
the stain will adhere to the exposed stroma
What does the Seidel test do?
It demonstrates corneal perforation or leakage
How does the Seidel test work?
Apply the stain (do not rinse) and then assess for aqueous leakage diluting stain as lighter green gravitational flow
Describe a superficial corneal ulcer.
Loss of corneal epithelium only
Describe a stromal corneal ulcer.
Some of the stroma is missing as well - superficial, midstromal, and deep stromal
What is a desmetocele?
Loss of epithelium and stroma to Descemet’s membrane
Superficial or deep?
Superficial
Superficial or deep?
Deep
Superficial or deep?
Deep - desmetocele
Superficial or deep?
Deep
Superficial or deep?
Superficial
Superficial or deep?
Superficial
Superficial or deep?
Deep
Superficial or deep?
Superficial
Superficial or deep?
Deep
Superficial or deep?
Superficial
Superficial or deep?
Deep
A superficial ulcer will have a _______ corneal curvature.
normal
A stromal corneal ulcer will look like what on examination?
Corneal flattening or some indentation
A desmetocele will look like what on examination?
severe indentation (and stain + edge)
Simple or infected?
simple
Simple or infected?
infected
Simple or infected?
simple
Simple or infected?
infected - melting cornea
Simple or infected?
infected
Simple or infected?
infected
Simple or infected?
infected
Simple or infected?
unsure
Simple or infected?
infected - fungal
What are some findings consistent with ruptured ulcers?
The perforation site may be bulging
It is sealed with fibrin, blood, and iris
Other possible findings - hyphema, shallow anterior chamber, low IOP +
Seidel test
Treatment of corneal ulcers varies based on what?
Underlying cause, depth, chronicity, +/- infected, +/- melting
Treatment for simple/uncomplicated ulcers aims to do what?
Prevent infection, reduce pain, and facilitate healing
What is used to prevent infection in simple corneal ulcer management?
Prophylactic topical antibiotic - TID and QID
What are some broad spectrum topical abx options for simple corneal ulcer management?
Neomycin/PolymyxinB/Bacitracin ointment, Neomycin/PolymyxinB/Gramicidin solution, Tobramycin solution, oxytetracycline ointment
When is a topical ointment base abx for simple corneal ulcer management preferred?
For superficial ulcers (especially if due to KCS), conformational issues, or eyelash disorders
When is a drop abx preferred for simple corneal ulcer management?
When the patient is incooperative
What can be used to reduce pain in simple corneal ulcer management?
Topical atropine 1% solution or ointment - SID-BID or systemic NSAID or gabapentin
What is used to facilitate healing in simple corneal ulcer management?
E-collar +/- ophthalmic lubricant
When should simple corneal ulcers be rechecked?
in 3-5 days
If a simple corneal ulcer does not heal within 7-10 days, what may that mean?
The underlying cause persists, the ulcer is infected, it is an indolent ulcer
Change the diagnosis not the antibiotic
What diagnostic testing can be done for complicated corneal ulcers?
Culture and sensitivity and/or cytology
What are the preferred abx for gram + infected complicated corneal ulcers?
Chloramphenicol or fortified 5% cefazolin
What are the preferred abx for gram - infected complicated corneal uclers?
Aminoglycosides - Tobramycin
Fluoroquinolons - Ciprofloxacin (good gram + coverage also)
How often should abx be given for infected complicated corneal ulcers?
Initially every 1-2 hours, then every 4 hours if not worsening
Minimum of 6x per day
How are complicated corneal ulcers due to reflex uveitis treated?
Atropine drip SID-BID, oral NSAID +/- gabapentin
What should be used to treat melting ulcers?
Anticollagenases
What is the preferred anticollagenase for melting ulcers?
Serum/plasma given every 1-2 hours
Other options: EDTA, N-acetylcysteine, tetracycline abx
What novel ulcer therapy option promotes healing of severe and melting ulcers, is helpful with complicated and neurotrophic ulcers, and is given TID?
Vetrix Eye Q Amniotic Eye Drop
What systemic antibiotics can be given for complicated corneal uclers? What is the caveat to using systemic antibiotics?
Clavamox or Doxycycline
Only aids ulcer if vascular supply is present
What is contradicted for treatment of corneal ulceration?
Topical steroids, topical nonsteroidals, or topical anesthetics (only okay for initial exam)
When is surgical treatment of complicated corneal ulcers warranted?
If midstromal or deeper, worsening condition, or prolonged pain
What are the surgical options for complicated corneal ulcers?
Corneal cross-linking, conjunctival graft, collagen graft, corneaconjunctival transposition, and corneal transplant
What should be avoided surgically when treating corneal ulcers?
Third eyelid flap or temporary tarsorrhaphy
What are the advantages to surgical treatment of corneal ulcers?
More thorough ulcer debridement
Immediate tectonic support
Possible blood supply
Faster healing
Less aggressive medical therapy needs
What are the disadvantages to surgical treatment of corneal ulcers?
Requires general anesthesia
Potentially more scarring
Added expense
What are some other names for indolent ulcers?
Refractory ulcer, Boxer ulcer, and SCCED
What is an indolent ulcer?
Superficial ulcer with loose epithelial edges
What is the signalment for indolent ulcers?
middle-aged to older dogs
How is an indolent ulcer diagnosed?
Signalment, history of failed healing with appropriate therapy and no infection or other persisting cause, and the classical appearance
What is the classical appearance of indolent ulcers?
Epithelial defect only, loose margins, and does not extend into the stroma
How can an indolent ulcer be treated?
Thorough debridement with cotton-tipped applicators
Keratotomy
Superficial keratectomy (most effective)
What are the general non-surgical management methods for indolent ulcers?
Standard ulcer medications (topical antibiotic, atropine, and pain control) and E-collar
What are some additional optional therapies (non-surgical) to treat indolent ulcers?
Contact lens, tetracycline antibiotic, serum QID, 5% NaCl TID, and PSGAGs QID
When should indolent ulcers be rechecked after treatment has been initiated?
10-14 days +/- repeat
IF there is severe vascularization, what can be added to the treatment protocol for indolent ulcers?
Cyclosporine or tacrolimus BID
Corneal foreign bodies are commonly what?
Plant material
If a corneal foreign body is superficial, how should it be treated?
Apply a topical anesthetic and remove with hydropulsion or cotton swab
If there is a deep or penetrating corneal foreign body, what should be done?
REFER
After removal of a corneal foreign body, what should be done treatment-wise?
Treat as a corneal ulcer
Topical abx 4-6x/day
Topical atropine solution SID-BID
Systemic NSAID and/or gabapentin PO
E-collar
What is chronic superficial keratitis also known as?
Pannus
What is the signalment for chronic superficial keratitis?
German shepherd type breeds and Greyhounds
Young adult to middle-aged
What is chronic superficial keratitis?
Progressive inflammatory disease of the cornea and conjunctiva
Usually bilateral +/- symmetrical, immune-mediated, and there is a UV light factor
What clinical signs are associated with chronic superficial keratitis?
Corneal neovascularization, pigmentation, and scarring
Starts laterally and moves medially across the cornea
Can cause blindness +/- thickened and depigmented third eyelid
What is atypical pannus (plasmoma)?
Chronic superficial keratitis with third eyelid involvement without corneal change
It is a lymphocytic-plasmacytic conjunctivitis
What does plasmoma look like?
There is a depigmented margin of the third eyelid and a thickened, cobblestone surface
How is chronic superficial keratitis diagnosed?
Signalment and appearance
No other cause of CS (rule out KCS)
Cytology
How is chronic superficial keratitis treated?
Topical steroid QID x 2-4 weeks with tapering
Topical cyclosporine or tacrolimus BID (taper to SID)
Reduce UV exposure
Client education
+/- Lifelong therapy
What topical steroid is recommended for chronic superficial keratitis management?
Prednisolone acetate or dexamethasone
What is the physiologic cause of exposure keratitis?
A disorder of tear coverage or distribution
What are the corneal manifestations of exposure keratitis?
Roughened corneal surface, corneal edema, vascularization, pigmentation, scarring, and corneal ulceration
What are the many possible causes of exposure keratitis?
Exposure during anesthesia, eyelid deformaties, facial nerve paralysis, macropalpebral fissure, lagophthalmos, exophthalmos, buphthalmos, proptosis
How is exposure keratitis diagnosed?
Complete ophthalmic examination - CN testing, baseline diagnostic tests, assess eyelid apposition and closure, corneal status, and globe retropulsion
How is exposure keratitis managed?
Ocular lubrication, therapy based on causative agent, and prevention of further corneal changes and vision loss
In what breed group is pigmentary keratitis common in?
brachycephalic dogs
What is pigmentary keratitis a response to?
chronic irritation or inflammation
What are possible underlying causes of pigmentary keratitis?
KCS, chronic superficial keratitis, chronic ulcerative disease, hairs rubbing cornea, and lagophthalmos
How is pigmentary keratitis diagnosed?
Signalment and pattern and adnexal exam
What medications can be used to treat pigmentary keratitis?
Lube and cyclosporine or 0.5% tacrolimus (preferred) BID
Topical steroids if BV present and NO ulcer risk
What surgeries can be used to treat pigmentary keratiits?
Cryotherapy or strontium beta-irradiation to thin pigment
Keratectomy if blinded
What is corneal dystrophy?
An inherited, nonpainful, bilateral central/paracentral opacification
T/F - Corneal dystrophy is an age related change that affects vision
False - it is not age related and does not affect vision
When maginifying the cornea of a patient with corneal dystrophy, what does it reveal?
Sparkling corneal opacities
What is juvenile corneal dystrophy?
Congenital subepithelial faint opacities of the cornea that are hazy, grayish-white, mosaic and usually located in the interpalpebral fissure
T/F - Juvenile corneal dystrophy is nonpainful and no treatment is needed.
True - it should resolve by ~10 weeks of age
What is corneal degeneration?
Corneal opacities with other ocular/intraocular pathology
___________ exacerbate deposition in patients with corneal degeneration.
Corticosteroids
How can corneal degeneration result in a corneal ulcer?
The dense mineral plaques may slough resulting in a corneal ulcer
How is corneal degeneration managed?
Address underlying issues, +/- topical EDTA 1-2% BID-QID to bind calcium, +/- keratectomy and corneal/conjunctival graft
What are some other less common corneal opacifications?
*Not on test*
Perilimbal lipid deposits, superficial punctate keratopathy, lipid keratopathy, macular corneal dystrophy, florida spots, and infectious crystalline keratopathy
How are perilimbal lipid deposits diagnosed?
*Not on test*
labwork with a thyroid panel
In what breeds is superficial punctate keratopathy common in?
*Not on test*
Shelties and Daschunds
Superficial punctate keratopathy is (painful/nonpainful) +/- fluorescein stain uptake.
*Not on test*
painful
How is superficial punctate keratopathy treated?
*Not on test*
Topical cyclosporine BID long-term
What causes lipid keratopathy?
*not on test*
Corticosteroid use
In what breeds is macular corneal dystrophy common in?
*not on test*
Labradors
Where (geographically) are Florida spots common in?
*not on test*
Tropical and subtropical areas
How is infectious crystalline keratopathy treated?
*Not tested*
BV or surgery
What is endothelial dystrophy?
Endothelial cell loss of the cornea
What clinical signs are associated with endothelial dystrophy?
Corneal edema that starts laterally, progresses and intensifies, and is bilateral but commonly not symmetrical initially
It is not painful unless ulcers are present
T/F: Endothelial dystrophy is acquired.
False - it is inherited most often in Boston terriers, dachshunds, and chihuahuas
What is endothelial degeneration also known as?
Old dog disease
What clinical signs are associated with endothelial degeneration?
corneal edema with possible bulla formation that can lead to recurrent ulcers and discomfort
What is the preferred medication for endothelial dystrophy or degeneration management?
5% NaCl ointment TID + abx if ulcers are present
What is the preferred surgical treatment for endothelial dystrophy or degeneration? Other options?
Preferred - thin conjunctival graft (Gunderson flap)
Other - thermokeratoplasty, corneal transplantation, Descemet’s stripping endothelial keratoplasty (best option for repaired vision, but is being investigated)
What are some ‘other’ corneal pathologies that were not discussed?
Epithelial inclusion cyst, dermoid, leukoma, and nodular granulomatous episclerokeratitis
