Schirmer Tear Test

What is the lipid layer and where is it?
- outer layer
- from sebaceous (Meibomian) glands lining eyelids
What is the water layer and where is it?
- middle layer
- from tear (lacrimal) glands
What is the mucus layer and where is it?
- inner layer
- from goblet cells in conjunctiva
What are the different causes of KCS?
- autoimmune (immune system tries to destroy the tear glands)
- congenital (defective tear glands)
- trauma
- drug reaction
- viral infections
- hormone imbalance
- idiopathic
What does KCS stand for and what is it?
- Keratoconjunctivitis sicca
- dry eye
What is STT?

standard measurement of aqueous tear production
What do we use STT for?
- to evaluate animals with ocular discharge and irritation
- to diagnose KCS
- to evaluate a patient with epiphora (tear overflow) - to determine if increased volume or decreased outflow is the problem
What does STT stand for?

Schirmer Tear Test
Is interpreting the STT difficult?

yes
When we are interpreting the STT what must it correlate with?

the clinical signs
What can cause tear production to vary?
- stress
- animals are stressed in the vet clinic so it can affect the test
Why should we do repeated STT?

to evaluate if it is transient or permanent KCS
When we do repeated tests, why do we need to use the same brand for each repeated test?

because the different brands vary in absorbency
How do we perform the STT?
- remove excess mucopurulent discharge prior to testing (a dry cotton tipped swab may be used)
- strip is bent at notch and placed over lower lid
- keep strip in place for 1 minute
- then measure the amount of wetting in millimeters
What unit of measurement do we use for STT?

mm/min
What are the normal values for the STT in dogs and cats?
- dogs: equal to or greater than 15
- cats: equal to or greater than 16.9
What is marginal or early subclinical KCS?
- dog: 11 - 14
- cat: 5 - 11
What is mild to moderate KCS?
- dog: 6 - 10
- cat: 5 - 11
What is severe KCS?
- dog: <5
- cat: <5
What are the two ways to treat KCS?
- medical
- surgical
What are the medical ways to treat KCS?
- artificial tears
- cyclosporine
What are the surgical ways to treat KCS?
- parotid duct transposition
- superficial keratectomy
What is the purpose of artifical tears?
- keep the eye moist
- slightly viscous
How do we use artificial tears?

apply at least every 2 hours
What is cyclosporine?
- stimulates tear production
- powerful immune system response suppressor - restores natural tear production
What product is cyclosporine?

Optimmune
How do we use cyclosporine?

ointment put in eyes twice a day
When we apply the cyclosporine to the eye what does it do?

prevents the immune system from destroying the tear glands
Does cyclosporine affect the rest of the patient's immune system?

no
Is cyclosporine effective if tear glands have been comletely destroyed?

no
What does a parotid duct transposition do?
- move rostral end of parotid salivary durt to conjunctiva
- patient is literally "spitting in his own eye"
What are some complications of parotid duct transposition?
- not enough saliva
- runny eye at mealtime
- dental tartar in eye
When would we do a parotid duct transposition?

only if medical treatment does not work
What can chronic KCS cause?

can cause pigment to accumulate on the surface of the cornea
When do we do superficial keratectomy?

for chronic KCS and only if KCS is under control at the time of surgery
How do we do a superficial keratectomy?

outer layer of the cornea can be removed to get rid of the pigment that accumulates on the surface of the cornea

Author

kris10leejmu

179465

Card Set

Schirmer Tear Test

Description

Clinical Practice ll

Updated

2012-10-24T00:56:43Z

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