Cornea Flashcards
Define ciliary flush.
360 degree deep corneal neovascularization that is pathognomonic for uveitis
Define cornea edema.
The only ‘blue’ opacity
Often appears heterogenous or fluffy
What are the two mechanisms that generate cornea edema?
Epithelial disruption - focal
Endothelial disruption - diffuse
Define corneal fibrosis.
Corneal scarring
Results from stromal collagen contracture and appears as a dull, wispy white
Define corneal fibrosis.
Corneal scarring
Results from stromal collagen contracture and appears as a dull, wispy white
Non-painful
Define corneal dystrophy or degeneration.
Dystrophy most often involves corneal lipid and appears glittery/shiny
Degeneration most often involves calcium and appears gritty or chalky
Define descemetocele.
Stromal ulcer reaches the depth of Descemet’s membrane
Corneal epithelium and stroma are lost
Define deep corneal neovascularization.
This vessel pattern occurs in response to deep disease processes
Define facet.
Loss of corneal stroma with intact overlying epithelium
Occurs because epithelialization progresses more rapidly than stromal healing
What is the most common cause of corneal ulceration in cats?
Herpesvirus
Define keratitis.
Inflammation of the cornea
Define keratic precipitates.
Cellular adhesions to the endothelium and are pathognomic for uveitis
Tiny dots from the mid-portion of the cornea that become larger and denser in the ventral cornea
Define limbus.
360 degree junction between the cornea and the sclera/conjunctiva
Define superficial ulcer.
Loss of epithelium only
Define superficial corneal neovascularization.
This vessel pattern occurs in response to superficial disease processes
Corneal vessels only appear with?
Keratitis
What are the four factors that keep the cornea clear?
Avascular
Non-myelinated nerves
Dehydrated
Ordered cell arrangement
What pathologies are most likely to cause focal edema?
Superficial ulcers
Anterior lens luxations
Endothelial dystrophy (early)
What pathologies are most likely to cause diffuse edema?
Glaucoma
Stromal ulcers
Uveitis
Endothelial degeneration
Endothelial dystrophy (advanced)
What can occur with bullous keratopathy?
Spontaneous corneal ulceration
With dorsal superficial neovasculartization, what should you think of?
KCS
What are the most common causes of deep neovascularization?
Uveitis
Deep corneal ulceration
What are the three variations of corneal opacities?
White with yellow or green hue - white blood cell infiltration
White with gray or wispy features - fibrosis
Crystalline or chalky white - mineral or lipid, dystrophy or degeneration
What is a sign of stromal healing?
Fibrosis
What are the two common causes of epithelial pigment?
KCS
Pigmentary keratitis
Ocular surface irritation
Treat with cyclosporine or tacrolimus
What causes endothelial pigment?
Uveal cysts or tissue endothelial adhesion
Less common
Where would you see keratic precipitates? What are they pathognomotic for?
Ventral
Uveitis
When would you expect a simple ulcer to heal?
5-7 days
What is the most common type of superficial ulcer?
Indolent Ulcer - boxers
What must you do for the treatment of indolent ulcers?
Debridement
How long should you wait minimum before debriding an indolent ulcer again?
At least 14 days
Stromal corneal ulcerations are
Emergencies
What are the most common bacteria for a stromal corneal ulcer?
Staph
Strep
Pseudomonas
What is the most common cause of a melting ulcer?
Pseudomonas
What are the identifying features of stromal corneal ulceration?
Inappropriate level of reflex uveitis
Severe corneal edema
White blood cell infiltration
Deep corneal vessels and episcleral injection
Visible stromal loss or disruption
Malacia
What breeds are predisposed to Pannus?
German shepherds
Greyhounds
What is the recommendation for Pannus?
Goggles for UV protection
Cyclosporine
