Stains and Artificial Tears Flashcards
What is fluorescein available as?
Modality and concentration
Strips (1mg per strip)
1 or 2% Minims
0.25% with Proxymetacaine 0.5%
0.25% with Lidocaine 4%
What are the indications for using fluorescein?
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
Why should a Wratten #12 filter be used in addition to a cobalt blue filter when viewing fluorescein staining?
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
What is Rose Bengal available as?
Discontinued in UK
1% minims
Rosettes (strips)
What are the indications for using Rose Bengal and Lissamine green?
Assessing ocular surface integrity
e.g. dendritic ulcers
Dry eye
Pressure areas for CL wearers
What is Lissamine Green available as?
1.5mg strips
What filter should be used with Lissamine green?
Wratten #25 (red)
What structures do Rose Bengal and Lissamine Green stain?
Dead tissue, mucous strands (and clothes)
How do artificial tears help in dry eye?
Reduce symptoms
Increase lubrication
Restabilise the tear film
Protect the cornea from dessication
What are the components of artificial tears and what do they do?
Buffer (regulates pH)
Saline (regulates osmolarity)
Preservative (maintains stability)
Viscolisers (increases viscosity and lubrication)
How does saline regulate osmolarity?
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
What component within saline helps to regulate osmolarity?
NaCl (Sodium Chloride)
What component within the buffer helps to regulate pH?
Borate, bicarbonate or phosphate
What level of Benzalkonium chloride can be toxic to the cornea and destabilise the tear film?
0.01%
What viscolisers can be used in eye drops?
Hypromellose
Carmellose
Hydroxyethylcellulose
Propylene glycol
Polyvinyl alcohol (PVA)
What viscoliser is used in eye gels?
Carbomer
What viscolisers can be used in ointments?
Liquid paraffin
White soft paraffin
Yellow soft paraffin
What is acecytlcysteine? Which product is it in?
Mucolytic agent in Ilube
How do liposome sprays work? What’s it’s active ingredient? Give an example product.
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
How does oil in water emulsion work? What’s it’s active ingredient? Give an example product.
Supplements the lipid layer, reducing tear film evaporation
Active ingredient: soybean oil and natural phospholipids
e.g. Emustil
How do low-osmolarity artificial tears work? What’s it’s active ingredient? Give an example product.
Reduce hyperosmolarity in dry eyes
Active ingredient: CMC
e.g. TheraTears
How do polyethylene glycols work? What’s it’s active ingredient? Give an example product.
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
What advantages do sodium hyaluronate drops have? Give an example product.
High viscosity
Better residency on tear film
e.g. Hycosan
Vismed
Hyabak
Hylo-Tear
Hylo-Forte
Which products have bottles which contain pressurised system with valves?
Hylo-Tear and Hylo-Forte (Scope)
Which product has a dispenser which contains a 0.2μm antibacterial filter?
Hyabak (Thea)
What other products may be used to improve the tear film stability?
Omega 3 supplements
Immunomodulatory drugs (e.g. Ikervis increases tear film production)
When is Ikervis indicated? What’s it’s active ingredient?
Severe keratitis due to dry eye, no other treatment successful
Active ingredient: 0.1% Ciclosporin
What forms do medicinal eyewashes come in?
Minims of Saline
Normasol (sodium chloride 0.9%, 25 ml or 100 ml sachet)
What should you be wary of with comfort eyewashes?
‘Random’ ingredients, so hard to know what effect it’s having on the px.
