Opthalmic Flashcards
Which is preferred for ophthalmic use - topical or systemic? Why?
Topical
-increases local concentration and decreases systemic absorption
Why may systemic drugs not reach parts of the eye?
- BBB
- blood is coming from back of eye - can be difficult for the drugs in blood stream to reach front of eye
How many drops, typically, in dogs and cats, should you use with an ophthalmic drug?
ONE!
into the conjunctival sac
How many minutes should you wait between eye drops?
5 mins
Which ANS branch controls the pupil size more?
PSNS
What is the contraction of the iris sphincter muscle called? Which ANS branch mainly controls this?
- miosis
- PSNS
What is the contraction of the iris dilator muscle called? Which ANS branch controls this?
- mydriasis
- SNS
Which ANS branch has more input in aqueous humor production?
SNS
2 parasympathomimetic mystics…
which is direct, which is indirect?
pilocarpine - direct
phyostigmine - indirect
What is pilocarpine used for?
diagnosing PSNS lesions
-lasts 2-6 hours
What is phyostigmine used for?
increasing uveoscleral draininage
What are the two main parasympatholytic mydriatics?
Atropine (direct acting)
Tropicamide (direct acting)
Which drug can cause cycloplegia?
Atropine (blurred vision)
Which has a faster onset and shorter duration: Atropine or Tropicamide?
TROPICAMIDE: onset in 15-30 mins, lasts 6-12 hrs
Atropine - onset in 1 hr, lasts 120+ hrs
What is Atropine used for, opthalmically?
- decreasing pain associated with corneal or iris disease (uveitis)
- break up synechiae in uveitis
T/F. Atropine should be used with primary glaucoma.
FALSE! Atropine should NOT be used with primary glaucoma
Why do horses panic when given ophthalmic atropine?
cycloplegia / blurred vision
T/F. Atropine can cause cats to froth at the mouth.
True. d/t bitter taste
What is Tropicamide used for?
- tdilate pupi for opthalmic/fundic exam
- prevent adhesions after cataract surgery
What is phenylephrine? What species does it work best in?
- sympathomimetic mydriatic
- directly acts on alpha 1 receptors
- DOGS
Which drug can be used to diagnose and treat Horner’s syndrome?
Phenylephrine
Which category do Timolol, Dorzolamide, Brinzolamide, and Latanoprost fall under?
aqueous humor formation and flow
What is Cosopt?
timolol plus dorzolamide - manages glaucoma in dogs
What is timolol used for? Which receptors does it influence?
- decrease aqueous humor formation (glaucoma mgmt and prevention in other eye)
- nonselective beta antagonist
Which drugs are topical carbonic anhydrase inhibitors?
dorzolamide and brinzolamide
What is Latanoprost used for? What species?
-treating glaucoma and decreasing IOP in DOGS
Which ophthalmic drug would you use for emergency management of glaucoma?
Latanoprost
What are the 3 layers of a tear film?
mucin
water
lipid
What is Cyclosporine? What does it do?
- lacrimogenic (topical immunomodulator)
- treat canine KCS / dry eye, stimulates tear production
Which drug is also referred to as Optimmune and is used to treat canine dry eye?
Cyclosporine
Which anti-inflammatories should NOT be used with diabetes?
Topical glucocorticoids (Dexamethasone and prednisolone)
Which anti-inflammatories would you use on the eye if a higher local concentration was desired? (and low systemic concentration)
-NSAIDs (topical) - Flurbiprofen, Diciofenac
Which ophthalmic antibiotics should NOT be used in CATS?
Bacitracin or Polymyxin B (d/t anaphylactic reactions)
Which drug is used to treat severe cases of herpes-related keratitis in cats and horses?
Gancyclovir
Which drug is used to treat fungal keratitis/conjunctivitis?
Natamycin
What is Proparacaine/Alcaine? What is the MOA of proparacaine?
- topical anesthetic –> anesthesia on ocular surface
- blocks sodium channels to prevent axonal depolarization, decreasing corneal sensation
What do you use proparacaine for? What is its onset and duration?
- decrease corneal sensation for diagnostic evalulation / tonometry
- onset 1 min, duration 10-15 mins
