Dry eye

Question 1

tear film: SECRETARY SYSTEM is composed of

Answer 1

lipid phase- OUTER layer- stops evaporation, increases surface tension,lubricates the eyelid
meibomian glands
glands of zoll-eyelashes
glands of meiss- deficiency leads to blepharitis
aqueous phase- middle layer0 supplies o2- contains lysozymes- washes away debris- main lacrimal gland
glands of wolfing
glands of krause
mucus phase- conjuctival goblet cells
crypts of hence
superficial coneal epithelial cells

Question 2

tear film: distributary system is composed of:

Answer 2

wiper effect towards punctae and drainage system
tear film- production- 1.2ul/min
vol- 7ul
turnover every 5min
eyelids- blinking distributes the tears
tear meniscus- along lower lid- reservoir

Question 3

tear film- execratory system

Answer 3

drainage- tears move thorugh punctae to caniculai and then to lacrimal duct. lacrimal sac, pumping from lid action,
evaporation- 10% of aqueous evaporates
however lipid layer prevents evaporation

Question 4

whats the point of a tear film:

Answer 4

optical properties- smooth optical surface for good va
for nutrition
to remove waste- mechanical
for transparancy
antibacterial- lysozyme
lactoferin
immunoglobulins
allow cl to move- leave it be comfortable

Question 5

what is dry eye

Answer 5

disorder of the tear film- due to tear deficiency or excessive evaporation- damage to ocular surface
discomfort, visual instability and tear film instability
also increased osmorality and inflammation

Question 6

How does neural stimulation- lead to dry eye

Answer 6

a disruption in the neural stimulation-
tear secretion as a response to external stimuli- parasympathetic and sympathetic system
decreasing corneal sensitivity- diabetes, herpes zoster, long term cl, sjorgens also decreases tears

Question 7

does dry eyes lead to inflammation

Answer 7

yes.
did u wish all this card said was yes.
sorry theres more to the answer hahaha
u can get
inflammatory cell infiltration
activation of ocular surface epithelium- increased expression of adhesion molecules and inflammatory cytokines also in test fluid
increased activity of matrix degrading enzymes

Question 8

how would u do a tear film assessment

Answer 8

1. H&S-age/gender, systemic conditions, atopy, med, environment, smoking. sx bilateral?
   2.Secretion/ volume of tears- schemers strip, phenol read test, meniscus height, fl clearance
   3.staining- rose bengal, florecine, lissamine green- NEW METHOD- Alcian blue- stains mucous and connective tissue
   4.stability/ tear quality- TBUTwith fl, niTBUT, tearscope, meniscus shape
   5.blink/ surface action
   6.solute analysis
   also do examination of lids and lashes- check for blepharitis/ mgd/ acne
   does this px close lids fully

Question 9

whats the lid wiper

Answer 9

lid ege-0.4-0.6mm- over ocular surface- 8000x

irritation and damage if tear film depleted

Question 10

phenol red test

Answer 10

dry eye examination- string in lower conjuctival sac
with ph indicator
ph of tears changes string-
10 second quick test
less reflex tearing

Question 11

schirmers test

Answer 11

for dry eye
reflex tearing
strip of paper
cheaper
put in lower conjuctiva
measured for 5 mins- av 30mm
WHATMAN filter paper, WHATMAN you say WHATMAN, omg WHATMAN- better not forget this on the test

Question 12

why would u look at tear meniscus

Answer 12

tear quality
dry eye assessment
maybe u just wanted to check out a tear meniscus
look at central height- should be 0.3 and regular

Question 13

what can help with dry eye

Answer 13

In short: Artificial tears/ lubricating agents
In long:
Hydroxypropyl Methylcellulose (HPMC)

Carboxyl Methylcellulose (CMC)

Demulcent

Polyvinyl Alcohol (PVA)

Glycerine

oils/gels

ointments

clarymist

vitamin A

Fatty oils

omega 3

antiinflammatory

cortico- steroids

hormones

if due to Mgd/blepahritis- treat that?

if can’t blink properly- treat them

punctal plugs

refit cl- duh

Question 14

Kerato-conjuctivitis sicca

Answer 14

exposure keratitis 
cause by dry eye
kerato means cornea involved
conjuctivitis sicca- no cornel involvement
sterile punctate keratitis

Question 15

whats the different TBUT

Answer 15

with fl- 15 seconds

a non invasive technique- like tearscope- more so 45 seconds

Question 16

whats the thickness of a lipid layer

Answer 16

between 20-200 nm

reflections from anterior and posterior tear film- produce interference patterns- which change with the thickness

Question 17

stuff about the tearscope

Answer 17

cold light source
reflected image of tear film surface
interference pattern
NiTBUT
tear meniscuc
uses scattered light- thickness is implied- not actually measured
but can look at tear thinning

Question 18

how does a cl affect the tear film

Answer 18

-it splits the tear film
-reduced tbut
-soft cl reduces lipid layer
and RGP completely removes it- omg- RGPs are so mean- i feel u lipid layer x

these things could reduce cl wear- as get uncomfortable, reduce va, redness, unhappy px

Question 19

whats Flourecine

Answer 19

ph indicator
as bowman’s layer is alkali- gets in here-green
tears are normally acidic- yellow

also fitting rgp
for soft cl- use fluroxen- high molecular weight- for HEMA- less fluorescence

BAD points- evil fl- susceptible to pseudomonas- resistant to many antibiotics- and usually used for corneal lesions-
also inhibits preservatives

Question 20

pterygium can also be due to dry eye

Answer 20

no note- just learn that yeah babesss

Question 21

corneal sensitivity

Answer 21

v sensitive
from periphery- and radiate centrally- inferior more than superior
affected by diurnal, age, iris, race, colour, pregnancy, menstruation

affected by cl use

• aesthesiometer- used to asses sensitivity