Ophthalmology Flashcards
what motor nerve block can be used for the eye?
auricopalpebral block
what primary eye diseases are seen in cattle?
infectious bovine kerato-conjunctivits (new forest eye)
bovine iritis (silage eye)
squamous cell carcinoma
what causes new forest eye?
Morexella bovis
what antibiotics are used to treat new forest eye (Morexella bovis)?
beta lactams
what are the clinical signs of new forest eye?
lachrymation
blepharospasm
white spot in conjunctiva (keratitis)
ulcers
neovascularisation from inside of eye
how is new forest eye treated?
eye ointment - cloxacillin based
subconjunctival injection - oxytetracycline
suture eyelid closed
why is it advised to keep animals with new forest eye indoor?
they are photophobic
what are the risk factors for new forest eye?
flies and habitat (woodland)
dust/chaff
UV light
viral pneumonia
what is bovine iritis also known as?
silage eye
what causes bovine iritis?
immune reaction to antigens of listeria
what are the clinical signs of bovine iritis?
constricted pupil
patchy corneal opacity
glaucoma
white floccules in anterior chamber
vascularisation
how is bovine iritis treated?
subconjunctival injection - atropine, dexamethasone and oxytetracycline
what breed are predisposed to squamous cell carcinomas?
herefords
what is a major risk factor for squamous cell carcinoma development?
UV exposure
how are SCCs of the eye treated?
removal of eye/third eyelid
what nerve block is used for enucleation?
retrobulbar
what can foreign bodies in the eye lead to?
keratitis
what is malignant catarrhal fever infection of cows typically associated with?
co grazing of cattle with sheep
what are the clinical signs of malignant catarrhal fever?
persistant pyrexia
depressed (encephalitis)
nasal/mouth erosions
enlarged lymph nodes
respiratory signs
diarrhoea
(immune mediated vasculitis)
what eye lesions are associated with malignant catarrhal fever?
conjunctivits
eyelid oedema
blepharospasm
corneal opacity
what causes IBR?
bovine herpes virus 1
where does IBR infectious stay as a latent infection?
trigeminal ganglion
how are vaccine used for IBR?
IM or intra-nasal with the possibility to vaccinate in the face of an outbreak
what are the clinical signs of IBR?
pyrexia
conjunctivitis and serous discharge
corneal oedema
nasal lesions/discharge
severe milk drop
what are the clinical signs of listeriosis?
encephalitis
circling
unilateral facial paralysis - dry eye, ear droop…
depressed
retracted mean response
what is used to treat listeriosis?
oxytetracycline or penicillin
what lesion of the eye is associated with BVD?
cataracts
what eye lesion is associated with septicaemia?
hypopyon
what are some possible causes of blindness?
CCN
lead poisoning
vitamin A deficiency
twin lamb disease
what are some risk factors for cerebrocortical necrosis?
thiamine (vit B1) deficiency
young growing cattle/sheep
dietary change/high energy diet
what are some clinical signs of CCN?
star gazing
no menace response
PLR is present
nystagmus and convulsions
opistothonus
how can CCN be treated?
thiamine supplement
diet change
what are the clinical signs of lead poisoning?
no menace response
dilated pupils
tremors/convulsions
what is used to treat lead poisoning?
EDTA and magnesium
what are the clinical signs of vitamin A deficiency?
night blindness
no menace response
dilated pupils
oedema of optic disc
