Stains and Artificial Tears

Question 1

What is fluorescein available as?

Modality and concentration

Answer 1

Strips (1mg per strip)
1 or 2% Minims
0.25% with Proxymetacaine 0.5%
0.25% with Lidocaine 4%

Question 2

What are the indications for using fluorescein?

Answer 2

Checking staining (due to CL use or to check integrity of cornea for other reasons)
Check RGP fit
TBUT
Applanation tonometry
Schirmer tests
Fluorescein angiography
Assessing naso-lacrimal drainage

Question 3

Why should a Wratten #12 filter be used in addition to a cobalt blue filter when viewing fluorescein staining?

Answer 3

Fluorescein has a max absorption of ~490nm and a max emission of ~530nm
A cobalt blue filter has a max transmission of 390-410nm, so anything else is absorbed (so not seen)
A Wratten filter transmits 530-660nm when used in conjunction with a cobalt blue filter, meaning the full emission of fluorescein can be seen and a better view of staining results

Question 4

What is Rose Bengal available as?

Answer 4

Discontinued in UK
1% minims
Rosettes (strips)

Question 5

What are the indications for using Rose Bengal and Lissamine green?

Answer 5

Assessing ocular surface integrity
e.g. dendritic ulcers
Dry eye
Pressure areas for CL wearers

Question 6

What is Lissamine Green available as?

Answer 6

1.5mg strips

Question 7

What filter should be used with Lissamine green?

Answer 7

Wratten #25 (red)

Question 8

What structures do Rose Bengal and Lissamine Green stain?

Answer 8

Dead tissue, mucous strands (and clothes)

Question 9

How do artificial tears help in dry eye?

Answer 9

Reduce symptoms
Increase lubrication
Restabilise the tear film
Protect the cornea from dessication

Question 10

What are the components of artificial tears and what do they do?

Answer 10

Buffer (regulates pH)
Saline (regulates osmolarity)
Preservative (maintains stability)
Viscolisers (increases viscosity and lubrication)

Question 11

How does saline regulate osmolarity?

Answer 11

By reducing or increasing the osmolarity of the tear film - the chosen drop will have a higher or lower osmolarity than the tear film, and introducing it will help to return the tear film to a normal osmolarity.

e.g.most dry eyes have a hyperosmolar tear film, so the drops would help

Question 12

What component within saline helps to regulate osmolarity?

Answer 12

NaCl (Sodium Chloride)

Question 13

What component within the buffer helps to regulate pH?

Answer 13

Borate, bicarbonate or phosphate

Question 14

What level of Benzalkonium chloride can be toxic to the cornea and destabilise the tear film?

Answer 14

0.01%

Question 15

What viscolisers can be used in eye drops?

Answer 15

Hypromellose
Carmellose
Hydroxyethylcellulose
Propylene glycol
Polyvinyl alcohol (PVA)

Question 16

What viscoliser is used in eye gels?

Answer 16

Carbomer

Question 17

What viscolisers can be used in ointments?

Answer 17

Liquid paraffin
White soft paraffin
Yellow soft paraffin

Question 18

What is acecytlcysteine? Which product is it in?

Answer 18

Mucolytic agent in Ilube

Question 19

How do liposome sprays work? What’s it’s active ingredient? Give an example product.

Answer 19

Sprayed onto closed lids from ~10cm, and the lipid diffueses into the tear film and promotes tear film.
Active ingredient: phosphatidylcholine from soylecithin
e.g. Optrex ActiMist, Eye Logic

Question 20

How does oil in water emulsion work? What’s it’s active ingredient? Give an example product.

Answer 20

Supplements the lipid layer, reducing tear film evaporation
Active ingredient: soybean oil and natural phospholipids
e.g. Emustil

Question 21

How do low-osmolarity artificial tears work? What’s it’s active ingredient? Give an example product.

Answer 21

Reduce hyperosmolarity in dry eyes
Active ingredient: CMC
e.g. TheraTears

Question 22

How do polyethylene glycols work? What’s it’s active ingredient? Give an example product.

Answer 22

Form a polymer in the tear film
Active ingredients: Polyethylene glycol, propyleneglycol, borate, hydroxypropyl galactomannan, HP Guar (mucomimetic - prevents corneal dessication). Preserved by polyquad.
e.g. Systane

Question 23

What advantages do sodium hyaluronate drops have? Give an example product.

Answer 23

High viscosity
Better residency on tear film
e.g. Hycosan
Vismed
Hyabak
Hylo-Tear
Hylo-Forte

Question 24

Which products have bottles which contain pressurised system with valves?

Answer 24

Hylo-Tear and Hylo-Forte (Scope)

Question 25

Which product has a dispenser which contains a 0.2μm antibacterial filter?

Answer 25

Hyabak (Thea)

Question 26

What other products may be used to improve the tear film stability?

Answer 26

Omega 3 supplements
Immunomodulatory drugs (e.g. Ikervis increases tear film production)

Question 27

When is Ikervis indicated? What’s it’s active ingredient?

Answer 27

Severe keratitis due to dry eye, no other treatment successful
Active ingredient: 0.1% Ciclosporin

Question 28

What forms do medicinal eyewashes come in?

Answer 28

Minims of Saline
Normasol (sodium chloride 0.9%, 25 ml or 100 ml sachet)

Question 29

What should you be wary of with comfort eyewashes?

Answer 29

‘Random’ ingredients, so hard to know what effect it’s having on the px.