Lacrimal disorders and dry eye evaluation Flashcards
what is ephiphora
normal amount of tear production w/ impaired tear drainage
what is lacrimation
over secretion or production of tears
what does the jones test measure
tests patency/blockages btwn the puncta and inf meatus of the nose
- check puncta all the way to nasolacrimal duct if open, doesnt tell you location but identify presence of blockage
- fl in eye and have pt blow nose in tissue and look for staining
what does the regurgitation test check
patency btwn puncta and lacrimal sac
-fl in eye, pull lower lid, locate puncta and press on nasolacrimal sac
what is dacryocystitis
infection of the lacrimal sac and/or obstruction of the naso-lacrimal duct
what can dacryocystitis lead to
pre-septal cellulitis
what glands are involvd in the lipid layer
meibomian glands
gland of zeiss
what is the purpose of the lipid layer
what is it composed of
- stabilizes tear film
- reduces evaporation of aqueous component
- outer layer
- composisition of cholest, fatty acids, phospholipds
- lowers surface tension of tear film=> draw water into and thickens aqueous
deficiency of the lipid layer is from
lid problems
contact lenses
-bells palsy
-MGD
what is the aqueous layer produced by
lacrimal gland and accessory lacrimal gland of kraus and wolfring
what is the thickest layer of tear film
aqueous 7-8 microns in thickness
what is the composition of the aqueous layer
salts proteins glucose lactate water soluble molec
what is a deficiency of the aqueous layer from
decrease in lacrimal gland tear production
trauma
what is the aqueous responsible for
basic aqueous secretion, major portion of tear film
- carrying nutrients and oxygen towards cornea
- lysozymes prevent infections from reaching cornea
what is the mucin layer produced by
goblet cells with crypts of henle, gland of manz
what is a deficiency of the mucin layer caused by
vitamin A
trachoma
lasik surgery
what does the mucin layer do
converts corneal ep from hydrophobic to hydrophilic
what is the contempory model of tear film
one continuous layer
varying amounts of mucin throughout tear film w/ higher conc on bottom (mucin layer)
why is elevated tear osmolarity a characteristic of dry eye
goblet cell number is decreased, which decresaes mucin, which decreases aqueous, lipid, lysozymes which all affect osmolarity
what is the role of gycocalyx
helps bring mucin to the corneal surface
what mucin help to create gycocalyx
mucin 1, 4, 16
what are the risk factors to dry eye
- age: atrophy of meidb glands, decrease in hormone production: androgens
- hormonal regulatios: adrogens in lacrimal gland/meib glands and an immuno-suppreive effect (women)
- environmental factors: air dryness, near task, altitude, smoking
- systemic disease: sjogren’s syndrome (triad symptoms, severe dry eye, mouth, rheumatoid arthritis)
what is the neurotrophic theory
severing of nerves in corneal stroma, takes 3 months to regnerate and may contribute to lack of sensory input back to lacimal and accessory lacrimal glands
what are the theories of lasik contributing to dry eye
- neurotrophic theory: severing nerves in corneal stroma lacrimal and accessory lacrimal glands affected
- suction ring during lasik: disrupts goblet cells at limbus, decrease mucin production
what are the underlying causes of dry eye
evaporative: alters ocular surface=> low grade infl
inflammatory: low grade infl in tears and ocular surface, infl cytokines and T cells in lac glands and conj
patients with what diseases are twice as likely to have dry eye
blepharitis
meibomianitis
classfying bleph as ant are what diseases? post?
ant: staph bleph
seborrheic blph
post: meibomian dys
what is the relationship btwn dry eyes and: allergies, bleph, eye drops/dry eye disease, conjunctivitis
- allergies: loss of goblet cells
- bleph: impairment of lipid laer=> inc rate of tear evap
- eye drops and eye dieases: preservatives are cytotoxic
- viral conjunctivitis: loss of goblet cells, release of cytokines
what are the inflammatory mediators in dry eye
cytokines and leukotrines
in lid evaluation for dry eye, what are you looking for
- examin lid margin (bleph, mgd_
- inf corneal staining, blinking patterns
- evaluate blink rate and tear flow (dec w/ prolonged near work, incomplete blinking)
- examine lacrimal drainage (steonsis of puncta, blockage of nasolacrimal duct)
- lid apposition abnormalities (ectropian)
what is lagophthalmos
inability of lid closure
what is the normal tear meniscus height
0.2-0.5mm in height and smooth
what does schirmer’s test test for
tear volume of reflex and baseline tears
>10mm in 5 min is normal
what does schirmer’s 2 test test for
use anesthetic so only test baseline tears
5mm in 5 min
what is the norm for phenol red test
> 13mm + or - 4mm 15 sec
OR
10mm in 15 sec
what is the norm for TBUT
20-30 sec
15-20 young
10 in aging
cl wearers less TBUT, keep environment in mind
what kind of staining will a superficial punctate keratitis give
isolated loss of ep cells, small diffuse
what kind of staining will a moderate to severe dry eye give
coalesced areas of ep cell loss, punctate erosions when lose large areas of ep cells
what will give a geographic area of fl staining
large area of cell loss, very severe dry eye
what does rose bengal and lissamine green stain?
which works better
stains dead ep cells and mucin
rose bengal picks up on dead cells on cornea better
-lissamine green is less toxic to cells , less cytotoxic
how does filamentary keratitis show up
“filaments”
dead cells wrapped w/ mucin, on advanced dry eye
