Lacrimal System Flashcards

(67 cards)

1
Q

abnormal overproduction of tears
common response to ocular irritation

A

epiphora

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2
Q

epiphora is a common response to

A

ocular irritation

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3
Q

present in the conjunctival epithelium and produce the innermost mucous layer of the 3-layer tear film. Patients with conjunctivitis will often overproduce mucus, conventionally referred as mucoid discharge

A

goblet cells

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4
Q

a very common clinical sign with conjunctivitis

A

mucoid discharge

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5
Q

what is most commonly found is cases of KCS due to loss of aqueous portion of the tear film

A

mucopurulent discharge
-mucous overproduction, bacterial overgrowth and subsequent white blood cell recruitment
classic feature on KCS

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6
Q

why is there mucopurulent discharge in KCS cases

A

mucous overproduction, bacterial overgrowth and subsequent white blood cell recruitment
classic feature on KCS

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7
Q

infection or inflammation of any portion of the lacrimal system

A

Dacryocystitis

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8
Q

what is the path of drainage of the nasolacrimal system

A

1) Lacrimal puncta
2) Canaliculi
3) Lacrimal sac
4) Nasolacrimal duct
5) Nasal puncta

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9
Q

what makes the aqueous layer of the tear film *

A

orbital lacrimal gland
gland of the third eye lid

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10
Q

what makes the mucin layer of the tear film *

A

conjunctival goblet cells

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11
Q

what makes the lipid layer of the tear film

A

meibomian glands

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12
Q

from innermost outermost, what are the layers of the tear film *

A

Mucin: binds serous layer to cornea (innermost)

Aqeuous: majority of tear function (middle)

Lipid(outer layer)
increases surface tension
slwos tear evaporation

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13
Q

What are the 7 functions of the tear film?

A

1) smooth ocular surface for refraction of light
2) Lubrication of ocular surface and eyelids
3) Remove metabolic by-products from corneal surface
4) Provide oxygen and nutrients to the corneal surface
5) Give white blood cells access to the conjunctiva
6) Remove debris and foreign material from the ocular surface
7) Defend ocular surface from pathogens

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14
Q

What is the afferent nerve of the lacrimal system

A

Trigeminal V- ophthalmic branch
corneal and conjunctival afferents

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15
Q

What is the efferent nerve of the lactrimal system

A

parasympathetics (from VII)

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16
Q

Nasolacrimal flush

A

used to assess the nasolacrimal system
-use 23-27g metal cannula, tom cat catheter or IV catheter and saline
-Can canulate uppoer or lower puncta
-Obserbe flow out opposite puncta and nares or swallowing
-Topical anesthesia is necessary may need general anesthesia

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17
Q

How long does it take for the fluorescein dye to travel from the eye to the nares

A

30seconds to 5 minutes in dogs and cats

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18
Q

How do you perform a Jones test

A

1) instill fluorescein into the eye
2) Lower head/nose
3) Observe fluorescein in the nares or oral cavity
4) 30 seconds to 5 min in dogs and cats

High unreliable in horses

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19
Q

What can you use to test the quantity of the tear film *

A

STT I measures lacrimal quantity
-basal and reflex tearing

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20
Q

STT II measures _________ *

A

only the basal tear production (after 1 drop of anesthetic)

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21
Q

Schirmir tear test interpretation

A

15-25mm = Normmal range
10-14mm = suspect low tears
<10mm = inadequate tears

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22
Q

What does STT I measure

A

basal + reflex tearing

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23
Q

why should you not touch the tip of the strip

A

lipids on fingers may prevent tear absorption

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24
Q

how hsould you keep the schirmer tear test in

A

keep in middle of lower eyelid +/- close lids for 1 minute

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25
What is normal Schirmer tear test I production in dogs
15mm wetting / 60 seconds
26
What is normal Schirmer tear test I production in horses
> 10mm/60 sec
27
What is normal Schirmer tear test I production in cats
>5mm/60 seconds
28
How do you assess the quality of the tear film
Tear Film Break Up Time -Apply fluorescein stain to cornea -hold lids open and prevent blinking -should take at least 20 seconds for tear film to break up and dark regions to form in normal eye abnormal tear film breaks up too quickly or too slowly Indication of mucin quality in the tears
29
Tear Film Break Up Time is an indication of
mucin quality in the tears
30
In Tear Film Break Up Time, how long should it take for the tear film to break up and drak regions to form in normal eye
at least 20 seconds abnormal tear film breaks up too quickly or too slowly -indication of mucin quality in the tears
31
What does the Rose Bengal stain do
Stains devitalized or degenerated epithelial cells as well as mucous filaments
32
What is the phenol red thread test
75mm long thread that is a pH indicator 15 second test alkaline tears turn the thread red Dogs: 34mm +/- 4.5 Cats: 24mm +/- 2.23 measureas tears in inferior cul de sac
33
__________ tears turns the phenol red thread test red
alkaline
34
tear overflow can result from
1) overproduction - irritation 2) decreased drainage - obstruction must evaluate which part of system is dysfunctional in order to devise most effective treatment (lacrimal glands or 3rd eyelid, canaliculi and sac, nasolacrimal duct)
35
flow of tears onto the face as a result of decreased drainage or increased production of tears
epiphora
36
why do tears turn brown on the face
porphyrins
37
do dogs have more meibomian glands on upper or lower lid
upper > lower
38
what portion of the tear film does the schirmir tear test test?
aqueous portion
39
What causes increased tear production
very non-specific sign of ocular pain may result from intraocular disease or ocular surface disease rule out nasolacrimal drainage problem, then look for reasons of excessive tearing -foreign body? abnormal cilia?
40
What might cause decreased outflow?
1) Punctal atresia- congenital abnormality need to surgically break down the membrane over the puncta 2) Dacryocystitis- obstruction of nasolacrimal system by foreign object or inflammation may require aggressive lavage, advanced imaging
41
is acute epiphora tend to be from increased tear production or reduced outflow
increased production - some sort of irritation to the eye
42
punctal atresia
congenital abnormality need to surgically break down the membrane over the puncta
43
obstruction of nasolacrimal system by foreign object or inflammation
dacryocystitis
44
What are the clinical signs of dacryocystitis
epiphora or mucoid discharge negative Jones Test
45
How do you treat dacryocystitis
-topical antibiotic/anti-inflammatories -Placement of a nasolacrimal stent while duct is healing (prevent structure/stenosis) -May require aggressive lavage/ irrigation while lifting the puncta (beware might cause fibrosis if done a lot over time)
46
How can tear film abnormalities lead to cornea cell damage and inflammation
decreased oxygen and other nutrients to cornea and conjunctiva (increased waste)
47
What is the most common form of Keratoconjunctivitis sicca (KCS) **
quantitative -deficiency of aqueous layer -dogs most frequently affected
48
qualitative Keratoconjunctivitis sicca (KCS)
deficency of mucus or lipid layers harder to diagnose- USe TFBUT test treat with hyaluronic acid based drop or gel to stabilize tear film
49
How do you treat qualitative Keratoconjunctivitis sicca (KCS) *
hyaluronic acid based drop or gel to stabilize tear film
50
What causes Keratoconjunctivitis sicca (KCS)*
#1) T cell mediated destructionof lacrimal tissue * 2) Metabolic disease: Diabetes mellitus, Cushigns 3) Drug induced: Sulfa antibiotics, Etodolac (NSAID), atropine (temporary) 4) Infectious: Canine distemper, FHV-1 5) Congenital hypoplasia/aplasia of lacrimal gland 6) Cherry eye 7) Iatrogenic - removal of 3rd eyelid 8) Anesthesia 9) Neurogenic (CN VII- parasympathetic deficit, ear infection) 10) Radiation 11) Trauma
51
What are the clinical signs of Keratoconjunctivitis sicca (KCS)*
Decreased lubrication Decreased corneal clarity Increased corneal and conjuncntival irritation Decreased antimicrobial activity Increased corneal and conj. infection
52
What metabolic diseases cause Keratoconjunctivitis sicca (KCS) *
Diabetes mellitus Cushings
53
What drugs induce Keratoconjunctivitis sicca (KCS) *
Sulfa antibiotics Etodolac (NSAID) Atropine (temporary)
54
infectious causes of Keratoconjunctivitis sicca (KCS)
canine distemper virus FHV-1
55
What are the clinical signs of KCS **
Mucoid, ropy tenacious discharge Conjunctival hyperemia/ conjunctivitis Corneal vascularization Corneal pigmentation Corneal fibrosis Corneal ulceration Lacluster corneal surface Blepharitis Loss of vision
56
How do you diagnose Keratoconjunctivitis sicca (KCS) **
-Decrease in STT values -Clinical signs: Mucoid, ropy tenacious discharge Conjunctival hyperemia/ conjunctivitis Corneal vascularization Corneal pigmentation Corneal fibrosis Corneal ulceration Lacluster corneal surface Blepharitis Loss of vision
57
How do you medically treat Keratoconjunctivitis sicca (KCS) *
LAAT Lacrimostimulants Antibiotics Anti-inflammatories (if not ulcers) Tear Replacement
58
What are lacrimostimulants used to treat Keratoconjunctivitis sicca (KCS) *
Topical Cyclosproin A 0.2% or Tacrolimus 0.01-0.02% (more potent) function to inhibit T cells from infiltration and destroying lacrimal gland Tacrolimus >>>> Cyclosporine generally TID 6-8 weeks to reach efficacy * Add on Pilocarpine for neurogenic KCS
59
For treatment of Keratoconjunctivitis sicca (KCS), how long does it take Cyclosproin A 0.2% or Tacrolimus 0.01-0.02% to reach effiacacy *
6-8 weeks to reach effiacacy
60
What do you use to treat neurogenic KCS
Pilocarpine additionally to Cyclosporine A or Tacrolimus - helps stimulates parasympathetic system (CN VII) innervation to lacrimal gland
61
helps stimulates parasympathetic system (CN VII) innervation to lacrimal gland
Pilocarpine
62
For Keratoconjunctivitis sicca (KCS), what should you do if the dog presents with conjunctivitis or corneal ulcer is present *
Topical antibiotic -Tobramycin -Terramycin -Neomycin and Polymyxin B Sulfates and Bactricin (Tripe Antibiotic)
63
How should you treat Keratoconjunctivitis sicca (KCS) inflammation if the cornea doesnt have an ulcer *
Anti-inflammatories - if keteraitis is present but no corneal ulcers -Topical NSAID: Diclofenac -Topical Steroid: NeoPolyDex > Prednisone Acetate
64
For Keratoconjunctivitis sicca (KCS), why is topical Neopolydex better than prednisolone acetate when there is no ulcer present but keratitis?
Prednisolone has good chamber and enters the anterior chamber Dexamethasone only works surfacely at the cornea
65
What should you use as tear replacement in Keratoconjunctivitis sicca (KCS) cases *
gel or ointment preferable (longer lasting) more frequent administration until tear stimulant has reached efficacy (every 2-3 hours in severe cases)
66
Surgical treatment options for Keratoconjunctivitis sicca (KCS) *
1) Parotid duct transposition- duct from parotid is rerouted up to eye (palpebral conjunctiva) creates spit eyes- ends with lots of calcium deposits 2) Subconjunctival silicone cyclosporine implant - well tolerated in dogs, for dogs not responsive to topic CsA ESMC iplant controlled signs of KCS in horse Eliminates the need for topical medication Need to be changed every year also used for some pannus
67
What is a side effect of parotid duct transposition
calcium deposits in the eye