Diagnostic Dyes

Question 1

Three main diagnostic dyes

Answer 1

Fluorescein
Lissamine Green (p)
Rose Bengal (p)

These are medical devices when strips. Have CE marking

Question 2

What do u know about fluorescein sodium aka FlNa

Answer 2

Hydroxyanthese
Pharmacy only 
PH indicator 
1- corneal integrity
2- rgp fitting. Tho soft can be done to if u use special form- fluoroxon
3-tbut
4-nasal duct patency
5-applanation tonometry

Question 3

How does fluorescine actually work????

Answer 3

It’s initially orange- then with dilation due to tears it turns yellow/green. Intact epithelium has a high lipid content and resists Water soluble Fl. a corneal abrasion allows Fl to reach around Bowmans membrane. Greater conc of AH gives a more green as more alkali. Cobalt blue light gives enhanced view- as peak absorption between 485-500nm. And used alongside yello rattan filter as this absorbs excess blue dispersed light. As epithelial surface regenerated the green disappears-rate- monitor recovery of cornea.

Question 4

Any side effects of fluorescine ?

Answer 4

Anaphylaxis shock perhaps on angiography- 10%fl
However for topical 2% fl it is v rare
Always do history before administration
Ask have they ever had an allergic reaction
More importantly any anaphylaxis ?

Question 5

Why is fl good in paper strip form

Answer 5

Four reasons-

1. Fl is susceptible to resistant virulent pathogen pseudomonas aeruginosa- strip form is less
2. As u use it on damaged corneas. Strip has less chance of spreading bacteria
3. Economical
4. In strip therefore no preservatives needed. As sometimes fl inhibits preservative

Question 6

Forms of fluoreceine

Answer 6

Minims - 1/2%
Paper strip- bio glow - 1mg
Can be with 0.25 fl minim mixed with anaesthetic - proxymetacine 0.5% and lydocaine 4%
Also high molecular form for cl available- fluoroxon- 0.5mg- this is a strip tho
In USA single dose of 0.35% in aq form

Question 7

What’s lissamine green used for. What does it stain

Answer 7

Assessment for dry eye. Espesh in cl wearers with skin conditions.
Stains comjuctiva. Unless severe dry eye then may also stain cornea. Stains dead and devitalised cells. Similar to rose Bengal but less stinging. Also stains lipid like structures such as mucous strands and can be used in infiltrate keratitis.

Question 8

Lissamine green instillation

Answer 8

Put adequate amount, about 10ul
Give like a min to absorb for optimum staining. No more than four
Do one eye at a time as fades quickly
Can use red wrattan filter 25

Question 9

What’s rose Bengal

Answer 9

Xanthene Dye to identify conjunctival lesions of keratoconjunctivitis sicca which is inter limbus palpebral staining. Or stains dead and devitalised cells in the cornea conjunctival epithelium and mucous. Actually stains the cells and cell nuclei. Not used as much anymore due to stinging

Question 10

Any adverse reactions of rose Bengal?

Answer 10

Stings like a bitch and excess lacrimal reflex can go onto ur cheeks. And stain it bright red. Who wouldn’t want that, would be a nice little blush.

Question 11

How is rose Bengal available

Answer 11

No longer a 1% minim form

But 1.3mg rose glow strip is available