Ophthamology Flashcards
what muscles open the eye?
levator palpebrae superioris (skeletal m)
mullers m (smooth m)
what produces the lipid part of tear film?
meibomian glands
what produces the mucin/mucous portion of tear film?
conjunctiva
what produces the aqueous part of the tear film?
lacrimal gland 70%
gland of the 3rd eyelid 30%q
what muscles does the oculomotor n control?
dorsal rectus
ventral rectus
medial rectus
ventral oblique
levator palpebrae superioris
what muscles does the abducens n control?
lateral rectus
retractor bulbi
what muscle does the trochlear n control?
dorsal oblique
what makes up the fibrous tunic?
cornea
sclera
what makes up the vascular tunic?
choroid
ciliary bodies
iris
what makes up the nervous tunic?
retina
optic n
what are the five layers of the cornea? which are hydrophobic or hydrophilic?
epithelium - hydrophobic
bowman layer (not in dog/cats)
stroma - hydrophilic
descemet’s membrane - hydrophobic
endothelium
what are the four reasons the cornea is clear?
- regularity of collagen fibers
- very low cellularity
- lack of blood & lymph vessels
- relative dehydration
what makes the cornea an obstacle for drug delievery?
it is relatively dehydrated
what “bends the light” to provide the most refractive power of the eye
tear film
how is the shape of the globe maintained?
aqueous humor in the anterior chamber
what produces the aqueous humor?
ciliary bodies
what cones do dogs have?
blue
yellow-green
makes them deuteranopia (red-green colorblind)
what tapetum do dogs, cats, humans and ruminants have
holangiotic
what tapetum do rabbits have
merangiotic
what tapetum do equine and elephants have
paurangiotic
what tapetum do birds and reptiles have
anagiotic
what cranial n causes Horner’s syndrome?
none - loss of sympathetic tone
purpose of frontal n block in equine?
block sensation of upper lid and cornea
purpose of auriculopalpebral n block in equine?
block motor of upper lid (blink)
what are the retinal reflexes?
PLR
Dazzle
what are the retinal responses?
menace
maze testing
red cornea?
blood
white and whispy cornea?
fibrosis
blue cornea?
edema/fluid
black cornea?
pigment/melanin or sequestrum in cats
sparkly white cornea?
lipid or mineral
what does the present of flare mean?
protein in anterior chamber
what do you use to dilate the eye
tropicamide
what do you use to numb the eye
proparocaine
normal Schirmer tear test?
species?
location?
15 mm / min
not in cats
lateral 2/3 of inferior eyelid
what does the fluorescein stain evaluate
ulcers
tear film
Jones test (nasolacrimal patency)
Seidel’s test (leakage)
normal IOP
8-25 mmHg (no more than 3-5 mmHg discrepancy between eyes)
when is IOP elevated? decreased?
elevated with glaucoma
decreased with uveitis and old age
definition:
squinting of the eye
blepharospasm
definition:
swelling of lids
blepharitis
definition:
inability or incomplete blinking
lagophthalmos
definition:
where the upper and lower eyelids meet (nasal and lateral)
canthus
definition:
region under the eyelid (where foreign bodies get trapped)
fornix
definition:
excessive tearing
epiphora
what findings might you have with a dog with a facial n paralysis?
absent menace & palpebral
intact facial sensation
KCS “neurogenic dry eye”
no tear production
xeromycteria (1/2 nose dry)
causes of facial n paralysis
idiopathic (most common)
trauma
infection
neoplasia
iatrogenic
hypothyroidism
nasopharyngeal polyps
what treatment is for immune mediated blepharitis “staphylococcal blepharitis”
oral steroid (1mg/kg/day)
oral antibiotic (cephalosporins)
NOT topical meds
what is trichiasis? clinical signs?
normal hair touching the eye
vascular keratitis
treatment for trichiasis?
lubrication
cryotherapy
blepharoplasty surgery
what is distichia? source and clinical signs?
modified hair follicles at lid margin
source: meibomian glands
dogs are not clinical
clinical signs of ectopic cilia?
irritated eyes and corneal ulceration
treatment for distichia and ectopic cilia?
manual epilation
cryosurgery
radiofrequency epilation
surgical excision
causes of entropion
congenital/inherited
spastic
cicatricial
fat loss/atrophy
treatment for entropion?
temp tack
HA filler injection
surgery (holtz, wedge, blepharoplasty)
ectropion treatment
surgical correction
what is eyelid agenesis in cats?
congenital defect of dorsal lateral lid
treatment for eyelid agenesis in cats?
lubricating drops
cryotherapy
robert-bishner
lip to lid blepharoplasty
most common canine eyelid masses
meibomian gland adenoma
papilloma
melanoma
MCT
SCC
treatment for common canine eyelid masses?
- debulk and cryotherapy
- wedge resection
common feline eyelid masses
SCC
fibrosarcoma
MCT
lymphoma (1* & 2*)
basal cell carcinoma
apocrine hydrocystoma
most common eyelid tumors in horses
SCC
sarcoid
melanoma
fibrosarcoma
lymphoma (2*)
most common eyelid tumors in bovine
SCC
most common tumor of feline, equine and bovine? association?
SCC
lack of pigment and UV exposure
where do SCC commonly occur
lower eyelid
third eyelid
lateral limbus
if a dog had an eyelid laceration/wedge resection, what suture/pattern would you use in SQ? skin?
SQ - 4-0,6-0 braided suture
skin - 4-0,5-0 nylon figure 8 at lid margin + simple interrupted or cruciate to finish
treatment for follicular conjunctivitis?
self limiting
can give neopolydex if irritation/discharge
cause of plasmoma? treatment?
immune mediated - atypical pannus
cyclosporine or topical steroid
treatment of cherry eye?
morgan pocket technique
large giant breed with something similar to cherry eye is most likely what?
scrolled cartilage
treatment for scrolled cartilage?
removal of bent cartilage
thermocautery
most common location of SCC
lateral canthus
treatment of eye neoplasia
surgical excision - often curative
