Lacrimal and Conjunctiva Flashcards
what produces soluble mucin that mixes with aqueous?
conjunctival goblet cells
what is a normal value in a dog for a schirmer tear test?
> 15 mm/min
what are common immune-mediated KCS breeds?
cavalier king charles spaniel
west highland white terrier
american cocker spaniel
english bulldog
lhasa apso
pug
which glands are abnormal in lipid deficiency?
meibomian glands
what can cause mucin deficiency?
conjunctivitis
allergies
diabetes mellitus
what can cause KCS in cats?
herpes
eyelid agenesis
what are some calcineurin inhibitors?
cyclosporine
tacrolimus
others
when is the maximal effect of calcineurin inhibitors seen?
6-8 weeks
how long do cyclosporine implants increase schirmer tear test?
10-11 months
are antibiotics usually necessary?
no, unless ulcer
what can be done for an imperforate punctum?
can surgically open
what is dacryocystitis?
purulent discharge from puncta
when is conjunctival pigmentation concerning?
raised
what are some infectious causes of conjunctivitis in cats?
felines herpesvirus-1
chlamydophila/Chlamydia felis
Mycoplasma spp
how can you treat feline herpesvirus-1?
antivirals
topical hyaluronic acid lubricants
supportive care
which oral antivirals can we use in cats?
famciclovir
what are the functions of the tear film?
oxygen and nutrients for cornea
lubrication
protection, immune function
optical clarity
what is the thickest layer of the tear film?
aqueous layer
what is the function of the aqueous layer?
hydrates, nourishes cornea
what do thee corneal and conjunctival epithelium produce?
insoluble mucin- glycocalyx
binds tears to ocular surface
what are some signs of tear film deficiency?
mucoid discharge
dry corneal surface
conjunctival hyperemia
corneal changes
discomfort
corneal ulceration
blepharitis
decrease in vision
how can you diagnose tear film deficiency?
ocular exam
schirmer tear test
ocular stains
tear film breakup time
what decreases schirmer tear test?
general anesthesia
proparacaine
atropine
illness
what schirmer tear test value is severe KCS?
<5mm/min
what is a tear film breakup time?
fluorescein stain and manually keep eyelids open
dog <20sec is mucin deficiency
is immune mediated KCS unilateral or bilateral?
bilateral
when should you be suspicious of a dog with KCS?
unilateral
very young
acute onset
dermatologic disease
nasal signs
what is neurogenic KCS?
parasympathetic disruption
unilateral, acute, severe
what drugs induce KCS?
sulfa antibiotics
etodolac
both in dogs
what dogs can have lacrimal gland aplasia?
yorkies
what can cause lipid deficiency?
allergies/atopy
blepharitis
chemical burns
what can cause mucin deficiency (loss of conjunctival goblet cells)?
conjunctivitis
allergies
diabetes mellitus
how is KCS treated?
periocular hygiene
calcineurin inhibitors
lubricants
antibiotics
steroids?
pilocarpine
surgery
what do calcineurin inhibitors do with KCS?
lacrimogenic effect
improve mucin quality
decrease inflammation, corneal pigment, vascularization
when is the maximal effect of calcineurin inhibitors?
6-8 weeks
what are the adverse effects of calcineurin inhibitors?
rarely periocular hair loss, topical irritation
ocular squamous cell carcinoma
when is pilocarpine (parasympathomimetic) useful for KCS?
neurogenic KCS
what are treatments for qualitative KCS with lipids?
warm compress
omega 3 supplements
treatment of underlying disease
what are some mucin tear supplements?
hyaluronic acid/hyaluronate
methylcellulose
what are the three pathways for tear drainage?
via nasolacrimal system
evaporation
overflow onto face
what is jones test?
apply fluoroscein to eye and monitor nares
passive test
in whom is dacryocystitis (purulent discharge from puncta) common?
rabbits
what cells make up the conjunctiva?
columnar epithelium
goblet cells
what can cause conjunctivitis in dogs/
follicular conjunctivitis
allergies/atopy
conformation
environmental
what can cause infectious conjunctivitis in dogs?
canine distemper virus
leishmania
thelazia
what is pathognomonic of feline herpesvirus 1?
dendritic ulcers
where does feline herpesvirus 1 persist?
in trigeminal ganglion
what should you avoid with feline herpesvirus 1?
topical anti-inflammatories
why can we not use oral antivirals other than famciclovir in cats?
acyclovir causes bone marrow suppression
valacyclovir causes bone marrow suppression and fatal hepatic/renal necrosis
