large animal ophth

Question 1

some differences from small animals

Answer 1

closed, more laterally placed orbits-almost 360 degree visual field

globes flattened in anterior-posterior axis

strong orbicularis oculi muscle

corpora nigra

ovoid pupil

retinal vascular patterns and optic nerve shape

Question 2

equine NDL

Answer 2

runs from medial canthus to point rostral and dorsal to infraorbital foramen

~30 cm, 4-5mm diameter

nasal punctum on floor

Question 3

equine fundic exam

Answer 3

paurangiotic

Question 4

ruminant and camelid fundus

Answer 4

holangiotic

Question 5

additional equipment needed

Answer 5

lidocaine 2%-auriculopalpebral block

sedation-detomedine, xylacin, butorphanol

Question 6

auriculopalpebral block

Answer 6

sq lidocaine 2^

onset within 5 mins, 60-90 m akinesia

three sites: caudal to posterior ramus of mandible, dorslal to highest point of zygomatic arch, on zygomaticus arch caudal to bony process of frontal bone

Question 7

NLD obstruction and flushing

Answer 7

clin sxs: epiphora, mucopurulent d/c, negative Jones test

causes: sinusitis, dental dz, trauma, FB

retrograde flushing of NLD

Question 8

conjunctivitis

Answer 8

chemosis and hyperemia

seen in almost all eye diseases

dx: fluorescein stain, Flushing lacrimal duct, C&S, palpation, bx, imaging
tx: treat primary cause or underlying cause

Question 9

entropion in foals

Answer 9

most common ocular abn

usually lower lateral eyelid

usually secondary to systemic dz-cachexia, deh, maladjustment–>enophthalmos, genetics

temp correction-tacking sutures

ophthalmic lubrication

Question 10

entropion in adult horses

Answer 10

conformational entropion rare

cicatricial and blepharospastic entropion

phthisis bulbi

Question 11

ectropion in adult horses

Answer 11

rare

Trauma and cicatricial

complication: corneal ulceration, chronic keratitis, conjunctivitis
tx: sx correction

Question 12

Equine SCC

Answer 12

most common neoplasia-locally invasive, potentially mets, eyelid, third eyelid and limbus

appaloosa, draft horses, lightly pigmented horses

erosive plaques and crusts to fleshy masses with variable infl, necrosis and ulceration

dx/tx- incision or excisional bx, cryotherapy, surgical excision, third eyelid removal, keratectomy/conjunctivectomy, CO2 laser ablation

recurrence high

prevention: fly mask with UV filter

Question 13

equine periocular sarcoids

Answer 13

fibroblastic cutaneous tumors

locally invasive

younger horses

all breeds

high risk of recurrence

Question 14

uncomplicated corneal ulcer in horse

Answer 14

epiphora, blepharospasm

pos for fluorescein stain

tx: topical abx, serum, atropine, systemic anti-infl

recheck 5-7days

Question 15

complicated corneal ulceration in horses

Answer 15

higher likelihood of secondary fungal inf

cyto and bacterial/fungal culture crucial

tx: topical abx, antifungal, serum, atropine, systemic anti-infl

Question 16

keratomycosis

Answer 16

aspergillus and Fusarium most common

penetrate deeply-often infiltrating Descemet’s membrane

therapy expensive and time consuming