Ophthomology Flashcards
What are some unique anatomical features of the equine eye?
Horizontal elliptical pupils, laterally positioned globes, corpora nigra, paurangiotic retinal vascular pattern, Stars of Winslow
What are some potentially requirements to perform an equine ophthalmic exam?
Restraint, sedation, topical anesthetic, nerve block
Which motor nerve do you block for an ophthalmic exam?
Auriculopalpebral nerve. Branch of CN VII
Where are the three points that the auricopalpebral nerve can be blocked?
- ) highest point of zygomatic arch
- ) caudal to bony process of frontal bone of zygomatic arch
- ) caudal to posterior ramus of mandible
What sensory nerve do you block for an equine ophthalmic exam?
Frontal (supraorbital) nerve block
What is the most common cause of blindness in horses? What is it called in laymen’s terms?
Equine recurrent uveitis (ERU). Moon blindness
T/F: There is only one cause for ERU.
False. There are many!
What is the pathogenesis of moon blindness in equine?
Invasion of antigen into eye -> deposition of Ag/Ab complexes -> continued presence of antigen (hence the recurrence)
T/F: The continued presence of live infectious organisms are needed for ERU disease
False. Just the antigen!
What are some clinical signs for active uveitis?
Aqueous flare, miosis, corneal edema, hyphema, hypopyon
What are some clinical signs for chronic uveitis?
Posterior synechia Iris hyperpigmentation Granula iridica atrophy Secondary cataracts Vitreal degeneration Retina edema and degeneration Retinal detachment
What are some lesions/scars you may witness in a fundus exam on a horse with chronic uveitis?
Chorioretinitis scar, bullet-hole scarring, butterfly lesions
How would you treat band keratopathy on a horse with chronic uveitis?
keratectomy or DBD
What signs of chronic uveitis can cause blindness?
Corneal edema, cataract, synechiation, 2ary glaucoma, retinal detachment
What are some work-ups you would want to perform to diagnose a horse with uveitis?
physical exam, deworm history, CBC, chem,
Titers: lepto, toxo, lyme, brucella
What are your treatment goals for horses with uveitis?
preserve vision, decrease pain, minimize any permanent damage, prevent recurrence, treat underlying cause (if possible)
What is a good systemic NSAID to use for a horse with uveitis?
Flunixin meglumine
What is a good systemic corticosteroid to use on a horse with uveitis?
Prednisolone, dex
What is a good systemic antibiotic to use on a horse with uveitis?
doxycycline
What mydriatic would you want to use for a horse with uveitis?
Atropine 1%