Ophthalmology Flashcards
What are the uses of proparacaine/tetracaine?
Topical local anesthetics
How does fluorescein stain work?
Stains the exposed stroma because the defect makes it hydrophilic. A normal cornea is lipophilic, so if fluorescein stain(hydrophilic) gets through, you know there is a defect
It will also stain mucous
What are you blocking with an auriculopalpebral nerve block?
You are blocking the motor function of the auriculopalpebral nerve to the orbicularis oculi which prevents blinking
What is the onset and duration of tropicamide?
Onset is 20-25 minutes
Duration: 4-6 hours for small animals, up to 12 hours for horses
Where do you give topical medications?
Anterior segment disease
Conjunctival and corneal epithelium = barrier
Where do you give subconjunctival medications?
Bypasses corneal epithelium for transcorneal absorption
Diffuses directly into cornea and sclera
Where do you give systemic medications?
Retina
Choroid
Periocular and retrobulbar tissues
Where do you give intracameral medications?
Anterior chamber
Where do you give intravitreal?
Endophtalmitis
What are the 5 most common routes used to treat ocular disease?
Topical Subconjunctival Systemic Intravitreal Implants
What are the pros and cons of tobramycin?
Pros:
Staph susceptible
Least epitheliotoxic
More effective against Pseudomonas than gentamicin
Cons:
Strep is not susceptible which is the cause of most ulcers
What are the pros and cons of gentamicin?
Pros:
Good for gram negative infections
Conjunctivitis, blepharitis, and dacryocystitis
Cons:
Epitheliotoxic
0.3% inadequate for serious bacterial keratitis (but it can be fortified with parenteral formulations)
What are the pros and cons of ofloxacin?
Pros: Great corneal penetration Now less expensive Available as a generic formulation Useful for infected ulcers
Cons:
Overuse encourages resistance
What are the pros and cons of Bacitracin/neomycin/polymyxin B?
Pros:
Excellent first choice
Bactericidal
Effective against many pseudomonas spp.
Cons:
Some resistance
What are the pros and cons of cefazolin?
Pros:
Great for staph and strep
Great for ulcers that are progressive because it gets the staph and strep that other drugs can’t get
Cons:
Don’t have a topical formulation (though it is easy to make)
Which medications are anti-proteases?
Anticollagenase agents:
Tetracyclines
EDTA
Serum
What is keratomycosis?
Corneal fungal infection that mostly occurs in horses
What are the common antifungals?
Azoles:
Fluconazole
Itraconazole/DMSO (compounded)
Voriconazole (intracorneal or subconjunctival)
Polyenes:
Natamycin
Nystain (poor)
Amphotericin B (intracorneal or subconjunctival)
Imidazoles:
Miconazole (compounded)
Ketoconazole
Silver sulfadiazine
What are the 2 best steroid preparations for getting high concentrations into the eye?
Prednisolone acetate 1% (gold standard)
Dexamethasone alcohol
Which steroid preparations will not be well-absorbed through intact cornea?
Dexamethasone sodium phosphate
Hydrocortisone
What are the contraindications/precautions against topical ophthalmic use of a steroid?
Should not be used when the cornea is compromised
Can cause adrenocortical suppression especially in dogs less than or equal to 15 kgs
What are indications for using topical NSAIDs?
Minor intraocular inflammation:
—Lens induced uveitis
—Mild anterior uveitis (especially in cats- chronic management)
—Allergic conjunctivitis
Pain control (post-operative, corneal, uveitis)
Less side effects
Necessary when there is corneal compromise
What are 5 topical NSAIDs?
Flubiprofen Diclofenac Ketorolac Nepafenac (new) Bromfenac (new)
How does mannitol work to help treat glaucoma?
Causes rapid decrease of IOP with 1-2 hours if it works
Dehydrates the vitreous
What are the primary indications for latanoprost?
Primary glaucoma in dogs
What is the mechanism of action of latanoprost?
Decreases pressure quickly and increases uveoscleral outflow
What is the drug class of latanoprost?
Prostaglandin analogue
What are indications for timolol?
Primary and secondary glaucoma
What is the mechanism of action of timolol?
Reduces IOP by 3-5 mmHg
What is the drug class of timolol?
β-blocker
What is the indication for dorzolamide?
Primary or secondary glaucoma
What is the mechanism of action for dorzolamide?
Decrease production of aqueous humor
What is the drug class of dorzolamide?
Carbonic anhydrase inhibitor
