Damage to which facial nerve can cause the inability to blink and corneal ulceration?
Facial nerve (CN 7)
How long does an uncomplicated corneal ulcer take to heal?
Days (usually <5)
How long must a corneal ulcer be present to be considered complicated?
> 7d
How do you treat a complicated corneal ulcer?
Conjuntival flap
How do you diagnose the cause of a melting corneal ulcer?
Swab for cytology and culture
Which feline virus can manifest in ocular signs such as conjunctivitis, ulcers, and eosinophilic keratitis?
Feline herpesvirus (feline viral rhinotracheitis)
What type of ulcers appear with feline herpesvirus?
Dendritic (linear)
How do infected corneal ulcers appear?
Melting
What does a melting ulcer indicate?
Deepening of ulcer into stroma
What is the most common cause of bacterial keratitis that is also usually the cause of a melting corneal ulcer in horses?
Pseudomonas (gram neg rod)
How do you treat a melting corneal ulcer in a horse?
TOPICAL tobramycin (aminoglycoside) for gram neg TOPICAL cefazolin for gram pos (Staphylococcus)
How might guttural pouch mycosis result in corneal ulceration?
Facial nerve paralysis
What are underlying causes of corneal ulcers?
Trauma, anatomical malformation, ectopic cilia, neuro deficits, inadequate tear production
What is ectopic cilia?
Cilia arising from palpebral conjunctiva
What is distichiasis?
Cilia from the meibomian gland openings @ eyelid margin
What is trichiasis?
Hairs from a normal location in contact w/cornea
What is a corneal ulcer?
Break in the corneal epithelium
How do you dx a corneal ulcer?
Fluorescein stain
A particular type of superficial corneal ulcer that typically is non-healing/chronic, a hyaline acellular zone prevents the epithelium from adhering to the underlying stroma
Spontaneous chronic corneal epithelial deficits (SCCED) - aka indolent ulcer
What is the only type of corneal ulcer that benefits from debridement?
Spontaneous chronic corneal epithelial deficit (SCCED) - aka indolent ulcer
What type of uveitis does a corneal ulcer cause?
Reflex uveitis
What should you never use in the eye if a corneal ulcer is present?
Steroids
What are the three types of corneal ulceration that can be dx via the pattern of fluorescein stain uptake?
Dendritic, indolent, descemetocele
How will fluorescein stain uptake with a dendritic ulcer?
Linear
What type of dye is fluorescein stain?
Hydrophilic
What layer of the eye will fluorescein stain bind to?
Stroma
Loss of epithelium w/o stromal loss and heals in 7d or less is what type of corneal ulcer?
Simple superficial
What causes simple superficial corneal ulcers?
Irritants, trauma, FHV-1
Focal corneal edema and an ulcer margin that is very crisp indicates what type of corneal ulcer?
Superficial
Complicated epithelial ulcer that does not heal properly
Indolent ulcer (SCCED)
Why will an indolent (SCCED) ulcer take months to heal without treatment?
Lacks epithelial adherence to stroma
Relationship at the epithelial/stromal interface is abnormal b/c hemidesmosomes don’t properly reform @ ulcer site
Indolent ulcer (SCCED)
Which dog breed is predisposed to indolent ulcers?
Boxers >5yo
How will fluorescein stain appear for an indolent ulcer?
Halo under/around ulcer margin
Are indolent ulcers superficial or deep?
Superficial
What is the most common ophthalmic condition you will see in GP that may require referral?
Deep corneal ulcer
What are most deep corneal ulcers and descemetoceles caused by?
Infection (Staph, Strep)
What is the most common cause of keratomalacia (melting ulcer) in dogs and cats?
Pseudomonas
How might CN 5 cause a corneal ulcer?
CN 5 plugs into cornea and uvea so if one is irritated the other will probably be angry too
What is the hallmark sign of a deep corneal ulcer?
Inappropriate level of reflex uveitis (severe miosis)
Jello around the cornea and WBC infiltrate indicate what type of ulcer?
Deep corneal ulcer
What pain medication can you use to do an exam on a deep corneal ulcer?
Proparacaine
How do you treat a deep corneal ulcer?
Cephalosporins + aminoglycosides q1-2h for 48h
Atropine for pain management
What medication should you add to a melting ulcer treatment regimen?
Anticollegenase (1% EDTA)
When is surgery recommended for a deep corneal ulcer, perforation, or descemetocele?
If >50% of stromal loss or if severe infection
How do you surgically repair a deep corneal ulcer, descemetocele, or perforation?
Conjunctival pedicle flap/360* conjunctival flap
What is an important px factor for a deep corneal ulcer?
Indirect PLR
A positive Seidel test indicates what?
Active aqueous leakage
What type of deep corneal ulcer is most commonly seen?
Descemetocele
What is a descemetocele?
Deep stromal ulcer
The iris may be prolapsed and the cornea may have a wrinkled appearance with what type of ulcer?
Perforation
How long does it take for corneal vascularization to occur after the corneal has ulcerated?
2-3d
How quickly do corneal vessels grow toward a corneal ulcer?
1mm/d toward the defect
How will fluorescein stain uptake with a descemetocele?
Donut/ring