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Flashcards in Diagnostic Stains Deck (50)
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1

what type of light do diagnostic stains emit?

lower energy (longer wavelength) - molecule will absorb highest energy (shortest wavelength)

2

are diagnostic stains acidic or basic?

can be either but not neutral

3

Is fluorescein water or oil soluble? and where is it ionized?

water soluble and ionized in the tears (hydrophilic)

4

When will fluorescein be able to enter the cornea (lipophilic)?

cornea will be compromised (not intact) - dry eye, abrasion, ulcer, lesions - tight junctions are broken = corneal staining

5

what is absorption of fluorescein for tissue and blood?

excited by 493nm (cobalt blue) and 465nm in bloodstream

6

why does the blood need a higher energy to become excited?

binding in the blood to albumin and RBC's reduces the activity

7

what is the emission of fluorescein?

520nm (yellow/green color is seen)

8

what color of fluorescein is seen on the tear film?

orange/yellow/green --> need to enhance with a wratten filter

9

what is seidel's sign?

used to assess the presence of anterior chamber leakage through the cornea from a penetrating injury (will see fluorescent green in bowman's membrane or aqueous humor)

10

what is quenching?

some atoms or molecules can facilitate non-radiative transitions to ground state (occurs without emitting photo - steals the energy)

11

which anesthetic causes the least amount of quenching? what about the most?

least = BAK + benoxinate
middle = proparacine
most = tetracaine

12

what happens to IOP readings with fluorescein quenching?

intensity is diminished - underestimation of IOP

13

how can fluorescein detect an ulcer?

penetration below basement membrane of corneal epithelium - exposes the stroma = dye will disperse 360 in eye

14

how can fluorescein detect an alkaline burn?

chemicals/molecules will precipitate by biding with a salt and deposit in the lower fornix - will stain will dye

15

how can fluorescein evaluate tear break-up time (TBUT)?

after complete blink - look for the first randomly distributed dark spot in tear film (interval = TBUT)

16

how can fluorescein be used to evaluate RGP CL adaptation?

anywhere you see dye it is trapped under the lens - not in absolute contact with the eye (need different lens if no dye is seen)

17

how do you use a Wratten filter when elvauating RGP fit?

filter is required over the light source

18

how can fluorescein be used to diagnose a tear duct obstruction/epiphora?

use with a Jones test

19

how is fluorescein used with aniline dye from indelible pencils?

it is an antidote - methyl violet spreads through ocular tissues and is precipitated by 2% sodium fluorescein

20

how can you measure aqueous humor production with fluorescein?

patient drinks dye --> goes into bloodstream and to the eye (watch appearance in anterior chamber)

21

how can fluorescein be used to distinguish between viral keratitis caused by herpes simplex or herpes zoster?

dye highlights the filaments
simplex = bulb-like ends
zoster = thin ends

22

How is fluorescein used in angiography?

used to visualize structural defects, vascular pathology, tumors, RPE thinning, CME, AMD (10-15 sec to arrive at retina)

23

After administering fluorescein to antecubital vein, what do you watch for on the fundus photos?

any areas of pooling in the macula = diabetes, AMD, Stargardt's disease and tumors

24

What are HMW (high molecular weight) fluorescein formulations used for?

used with soft CL because they can stain with LMW - the HMW are too large to be absorbed by the lens

25

What are some examples of topical fluorescein formulations?

Fluoracaine + proparacine, Fluress + benoxinate, and Flu-Glo (strips)

26

What are some examples of HMW fluorescein formulation?

Fluoresoft PF and Fluora-safe + benoxinate and SoftGlo

27

What allergies should you avoid giving fluorescein to?

ester anesthetics - PABA

28

What are some common adverse reactions to topical fluorescein?

string, irritation, redness, dermatitis, nausea and headaches

29

What pregnancy category is fluorescein?

C

30

What are some serious adverse reactions to topical fluorescein?

corneal hypersensitivity, epithelial keratopathy, seizures, CNS depression, anaphylaxis