Lecture 10: Equine ophthalmology II Flashcards
What wrong
Iris cyst
what wrong
glaucoma
What wrong
cataract
what wrong
Synechiae
what is a common cause of blindness in horses
equine recurrent uveitis: aka moon blindness
what breeds are predisposed to equine recurrent uveitis
appaloosas and European warm bloods
what is the cause of equine recurrent uveitis
immune mediated with multiple etiologies: lepto, toxoplas,a, brucella, streptococcus, E. Coli, R. Equi, visceral larval migrans, viral infections
what genetic mutation is seen in appaloosas with recurrent uveitis
TRMP1 gene on ECA1
MCH ELA on ECA 20
what are the goals of equine recurrent uveitis care
preserve vision, decrease pain, minimize recurrence
what is the tx for equine recurrent uveitis
- Corticosteroids (neopolydex)
- NSAIDS
- Cyclosporine
- Atropine
- Vitrectomy
- Intravitreal gentocin injection
t or f: hydrocortisone is good drug to tx equine recurrent uveitis
false- does not penetrate cornea
how does a vitrectomy work to tx equine recurrent uveitis
removes all fibrin, inflammatory cells, and debris trapped in vitreous to improve vision and delay progression
what are some complications from intravitreal gentocin injection
hemorrhage, cataracts, retinal degeneration
what are cataracts
lens opacities associated with various degrees of blindness
t or f: the rate of progression and development of blindness from cataract can be predicted
false!
what is nuclear or lenticular sclerosis
cloudiness of the lens nuclear starting at 7-8yrs old but shouldn’t interfere with vision
what are the tx for cataracts
- Extracapsular cataract sx- lens is removed
- Phacoemulsification cataract sx- lens emulsified and aspirated (quickest return to fx and comfort)
what is glaucoma
group of diseases that result in alterations of aqueous humor dynamics that cause increase in OP resulting in damage to retinal ganglion cells and optic nerves
what are some signs of glaucoma
- Bupthalmos
- Haabs stria
- Corneal edema
- Loss of vision
what is indicated by black arrow and what is that a sign of
Haab’s stria- sign of glaucoma
what is the tx for glaucoma
- Dorzolamide: Topical carbonic anhydrase inhibitor:
- Pilocarpine: topical Miotic
- Timolol- topical beta blocker
- Anti-inflammatory ens
what is exophthalmos
normal sized globe that is being pushed forward by space occupying lesion in orbit
what most commonly causes exophthalmos
retrobulbar abscess/cellulitis or neoplasia
what wrong
exophthalmos
exophthalmos or buphthalmos: unilateral or bilateral
buphthalmos
buphthalmos vs exophthalmos: eye is pushed forward, excessive conjunctiva visible
exophthalmos
buphthalmos vs exophthalmos: third eyelid elevated
exophthalmos
bupthalmos vs exophthalmos: diameter of cornea enlarged
bupthalmos
bupthalmos vs exophthalmos: normal IOP
exothalmos
what is coloboma
full thickness holes in iris
what wrong
coloboma
iridial cysts are hallmarks of hereditary ___ of __horse
anterior segment abnormalities or Rocky Mountain horse
what wrong
chorioretinitis
what are some causes of chorioretinitis
infectious agents, immune mediated uveitis, trauma, vitamin E deficiency, vascular disease
what are some lesions associated with chorioretinitis
- Focal bullet hole
- Black lightening
- Butterfly lesions of optic nerve
what is tx for chorioretinitis
- Systemic NSAIDS
what mutations/coloration is associated with congenital stationary night blindness
two copies of specific white spotting pattern mutation known as leopard complex spotting- symmetrical whiter pattern centered over rump
what are some signs of congenital stationary night blindness
visual impairment in dim light with normal vision during daylight
mutation in what gene causes congenital stationary night blindness
calcium ion channel gene known as TRPM1 gene
what is tx for congenital stationary night blindness
no tx
what is dacryocystitis
inflammation of nasolacrimal duct and gland
what are some signs of dacryocystitis
ocular discharge
what is tx for dacryocystitis
flush with saline +/- lidocaine +/- steroids
if fail to flush dacryocystitis what do you do
perform dacryocystorhinogram with radiopaquew solution
how do you sx tx dacryocystitis
nasolacrimal punctua or duct agenesis- create fistula between lacrimal lake and nasal cavity
