Lecture 10 - Lacrimal system and Dyes Flashcards
What is the main function of tears?
Lubrication between eyelids and globe, Atmospheric oxygen for cornea, removes debris and contains ANTIBACTERIAL substances
What are the three layers of the tear film?
LAM Lipid (outermost layer) - delays evaporation and provides lubrication - Meibomian
Aqueous (Middle) - water layer - Lacrimal
Mucin (inner) - Mucous layer - “ADHESION to Cornea” - Goblet cells
What is the production mechanism for the tear system?
Basic and Reflex blink
What is the distribution mechanism for the tear system?
Blinking and lids
What is the drainage mechanism of the tear system?
Nasolacrimal
How much is lost to re absorption and evaporation?
25%
Reflex secretion _____ the volume in reponse to a stimulus?
Increase
What CN carries Afferent nerve fibers?
CN 5
What is the Efferent CN?
CN 7
What are the 3 components for corneal reflex?
Lacrimation, Miosis (EW) and Blinking (Facial Nucleus)
What does epiphora mean?
Overflow of tears
What is another name for tear meniscus?
Tear prism
What is the normal TMH?
0.2mm tall
Note: It is good to start in the initial scanning of the lids to look at the TMH. During the exam there will be tearing, thus giving you an abnormal reading
If you see foamy or soapy tears, what deficiency could that be?
MGD
What type of test do you check for tear production?
Schirmer 1 and 2
Note: This tests for both reflex and basic
What test do you use for distribution?
TBUT
What test does the Jones dye test 1 and 2 look for?
Drainage issues
In schirmer 1, how much time should you wait for the process?
5 minutes
How many minutes do you use for Schirmer 2?
2 minutes
What type of liquid do you put fluorescein strips?
Saline
Where do you place a fluorescein strip?
lower cul de sac
What do you tell your pt when you would like to conduct a TBUT test?
Give 2 good blinks and hold for as long as you can
When you notice that immediately after blinking, you notice there is immediate evaporation. What has occurred?
Mucin layer is inadequate
What type of dye would you use for Jones 1
Fluorescein w/ no anaesthetic
When you notice a bright glow when using fluorescein, what could that mean?
epithelial cell loss
You notice SPK staining all over the eye, what could be the cause?
Viral infection or Medicamentosa
How would SPK be dispersed with an individual with dry eyes?
Usually IP but can be inferiorly
What is bell’s phenomenom?
Upward rotation of globe on lid closure
If you would like to evaluate palpebral conj, what type of diagnostic stain do you use?
NaFL
What type of stain do you use when you want to observe devitalized corneal tissue?
Rose Bengal
What are the three advantages of Lissamine Green compared to Rose Bengal?
Less toxic
Doesn’t last as long
Doesn’t sting as much
When preforming a corneal sensitivity test, what cranial nerve damage is usually the first sign?
CN V
What area of the eye do you touch with a cotton wisp?
Central cornea
Note: If you see a bend in the cotton wisp, that is positive damage to the CNV
What is Seidel’s sign?
There is a leakage of aqueous streaming thru.
“water fall”
