Ophthalmology Flashcards
What are the typical signs for corneal ulcers?
- acute onset conjunctival hyperemia
- corneal edema
- blepharospams
- epiphora or purulent ocular discharge
- days to weeks old: corneal neovascularization
- possible: reflex uveitis
What are the layers of the cornea?
- epithelium
- bowman’s layer
- stroma
- descemet membrane
- endothelium
What layer is penetrated/affected in a deep ulcer?
stroma
What is the treatment protocol for stromal ulcers?
- topical antibiotics
- antiproteolytic therapy (plasma,serum, EDTA, acetylcysteine)
- topical cycloplegic agent (atropine, cyclopentolate)
- oral analgesics
At what percentage stromal loss is surgical stabilization of corneal ulcers recommended?
equal to or greater than 50% stromal loss
When are oral antibiotics indicated for corneal ulcers?
if ulcer perforated or perforation is suspected
What are the main 3 signs seen with glaucoma?
- vision loss
- corneal edema
- episcleral injection
What are typical signs of glaucoma in cats?
typically secondary in cats
* visible anterior lens luxaiton
* hyphema
* miosis despite increased IOP
* diffuse or focal iris thickening
other signs (related to underlying disease) - trauma, inflammation, systemic disease
What is latanoprost and what is a contraindication for it?
- prostaglandin analogue
- increases outflow of aqueous humor through the uveoscleral outflow
- used for open-angle glaucoma
contraindication: anterior lens luxation, uveitis, or in cats (doesn’t work well)
most commonly used for canine primary glaucoma
What are Dorzolamide and Timolol and how do they work for glaucoma?
Dorzolamide (topical)
* carbonic anhydrase inhibitor (CAi)
* inhibits the HCO3- formation and secretion into the posterior chamber which is necessary for aqueous humor production
* other CAi: acetazolamide, methazolamide (both oral)
Timolol (topical)
* beta blocker
* reduces aqueous humor production but MOA not fully understood
* can cause bradycardia and mild miosis
What is the IOP treatment target for glaucoma?
< 20 mm Hg
in acute glaucoma, when patient’s pressure does not improve within several hours, what is the next step to prevent vision loss?
- mannitol administration
- aqueous paracentesis
Which breeds are predisposed to anterior lens luxation?
terrier breeds - predisposed to lens instability
What is the most common cause of anterior lens luxation in cats?
chronic uveitis
How can you confirm the diagnosis of Horner’s syndrome?
apply 1% phenylephrine ophthalmic solution - should resolve within 20-60 minutes
