CLM - RGP Lens Maintenance - Week 3 Flashcards
What are six key solution requirements for RGPs?
Antimicrobial afficacy
Non-toxic to ocular tissues
Minimal effect on lens parameters
Simple
Convenient
Inexpensive
List two common types of RGP lens materials. Do they have small or large matrix pores? Do deposits remain on the lens surface or is this minimal?
Silicon-acrylates
Fluoro-silicon acrylates
-small matrix pores
-deposits remain on the lens surface
What effect does the silicon component of a RGP lens have on its wettability?
Decreases wettability
How often are RGPs replaced?
Yearly
List two kinds of RGP cleaning solutions.
Daily cleaners
Protein removers
What is a suitable rinsing solution for an RGP?
Preserved saline solution
Are RGP disinfection solutions specific for RGPs? What is it used for (2) and what two additional agents does it contain?
Solutions are specific for RGPs
Contains wetting and viscosity enhancing agents
Are hydrogen peroxide solutions suitable for RGPs?
Yes
Do multipurpose soltutions exist for RGPs?
Yes
What does a wetting agent produce, what does this act as a buffer for (name what this effect is called), and what does it improve and ultimately reduce?
Produces an even distribution of tears over the CL surface
Acts as a mechanical buffer between the lens and the eye - cushion effect
Improves biocompatibility of the contact lens, reducing deposition
Do wetting agents provide comfort?
Yes, initial comfort
What do viscosity enhancing agents do and do they contribute to the cushion effect? Do they also contribute to the detergent/cleaning of the lens?
Increases contact time of solution on the lens/ocular surface
Lubricates and cushions
Doesnt contribute to cleaning
List the six steps in RGP lens care routine.
Handwashing
Surface cleaning
Rinsing
Disinfection
Enzymatic cleaning
CL case care
Are cleaners with isopropyl alcohol ideal for cleaning RGP lenses? Explain.
No, it removes mucin, but repeated use will change lens parameters and possible crack them
In what two types of RGP lenses are abrasive surfactants/detergents contraindicated?
Hyper-Dk and plasma-treated lenses
What is the purpose of the CL rinsing step? Explain why.
Flushes loosened debris
Cleaners are toxic to the corneal epithelium
What is benzalkonium chloride effective against (2)?
Bacteria and fungi
Benzalkonium chloride’s efficacy is enhanced when combined with what compound?
EDTA
Does benzalkonium chloride bind to hydrogel materials?
Yes
What is essential if using chlorhexidine digluconate and why? What does it have limited efficacy against?
Surface cleaning, because it readily binds to mucus
Not very effective against yeast/fungi
Is chlorhexidine digluconate combined with EDTA?
Yes
Is thimerosal a better antibacterial or antifungal? What is it often combined with?
Antifungal
Often combined with chlorhexidine digluconate
List four complications of thimerosal and whether or not it is commonly used.
Conjunctival swelling
Limbal injection
Infiltrates
SPK
Rarely used
What is EDTA and what does it inhibit? Does it cause irritation/allergy?
Chelating agent, inhibiting bacterial growth
What is benzyl alcohol used for (2) and what is needed if using it?
Effective for lipid removal and good antimicrobial activity
Careful rinsing is essential
What do enzymatic/protein cleaners remove?
Removes bound insoluble protein
What happens to the immunogenic potential of bound protein with age?
It increases
What should always be done before and after using a protein/enzmatic cleaner?
Always surface clean before and after enzyme treatment
What should CL cases be washed with? What can be used to scrub it?
Scrub with a toothbrush or cotton bud and use saline
How often should CL cases be replaced?
Every three months
What are rewetting/comfort drops used for, and what three things do they do?
Used to rewet the lens surface while in the eye
Stabilises the tear film
Aids in the removal of mucus/debris
Rinses away trapped debris
List one advantage and two disadvantages of mutlipurpose solutions.
Enhances compliance
Compromised efficacy
Increased sensitivity in some patients
Are multipurpose solutions often more or less viscous than other solutions?
More viscous (actually it’s lower viscosity)
Is it ok to mix and match different brands?
Best not
What should be done to RGPs used on patients with known infectious diseases?
Dispose them
What is the standard routine in-office RGP disinfection protocol for a trial lens?
Surfactant 30 seconds
Rinse with sterile saline
Soak in 3% hydrogen peroxide for min 3h or sodium hypochlorite (0.4%) for min 30m or 0.5% for 5m
Rinse with sterile saline
Store dry
Surface clean and rinse prior to use
If a patient uses hairspray, should it be used before or after RGP lens application? What about cosmetics?
Before
Apply cosmetics after
Can eyeliner be applied if using RGP lenses?
Yes but shouldnt be applied to the inner lid margin
Hw should RGPs be stored by the patient?
In a disinfecting solution - or as recommended by the manufacturer
When should patients clean and disinfect their lenses before putting it on?
If stored for more than a week
