CLM - RGP Lens Maintenance - Week 3

Question 1

What are six key solution requirements for RGPs?

Answer 1

Antimicrobial afficacy
Non-toxic to ocular tissues
Minimal effect on lens parameters
Simple
Convenient
Inexpensive

Question 2

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?

Answer 2

Silicon-acrylates
Fluoro-silicon acrylates
-small matrix pores
-deposits remain on the lens surface

Question 3

What effect does the silicon component of a RGP lens have on its wettability?

Answer 3

Decreases wettability

Question 4

How often are RGPs replaced?

Answer 4

Yearly

Question 5

List two kinds of RGP cleaning solutions.

Answer 5

Daily cleaners

Protein removers

Question 6

What is a suitable rinsing solution for an RGP?

Answer 6

Preserved saline solution

Question 7

Are RGP disinfection solutions specific for RGPs? What is it used for (2) and what two additional agents does it contain?

Answer 7

Solutions are specific for RGPs

Contains wetting and viscosity enhancing agents

Question 8

Are hydrogen peroxide solutions suitable for RGPs?

Answer 8

Yes

Question 9

Do multipurpose soltutions exist for RGPs?

Answer 9

Yes

Question 10

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?

Answer 10

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

Question 11

Do wetting agents provide comfort?

Answer 11

Yes, initial comfort

Question 12

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?

Answer 12

Increases contact time of solution on the lens/ocular surface
Lubricates and cushions
Doesnt contribute to cleaning

Question 13

List the six steps in RGP lens care routine.

Answer 13

Handwashing
Surface cleaning
Rinsing
Disinfection
Enzymatic cleaning
CL case care

Question 14

Are cleaners with isopropyl alcohol ideal for cleaning RGP lenses? Explain.

Answer 14

No, it removes mucin, but repeated use will change lens parameters and possible crack them

Question 15

In what two types of RGP lenses are abrasive surfactants/detergents contraindicated?

Answer 15

Hyper-Dk and plasma-treated lenses

Question 16

What is the purpose of the CL rinsing step? Explain why.

Answer 16

Flushes loosened debris

Cleaners are toxic to the corneal epithelium

Question 17

What is benzalkonium chloride effective against (2)?

Answer 17

Bacteria and fungi

Question 18

Benzalkonium chloride’s efficacy is enhanced when combined with what compound?

Answer 18

EDTA

Question 19

Does benzalkonium chloride bind to hydrogel materials?

Answer 19

Yes

Question 20

What is essential if using chlorhexidine digluconate and why? What does it have limited efficacy against?

Answer 20

Surface cleaning, because it readily binds to mucus

Not very effective against yeast/fungi

Question 21

Is chlorhexidine digluconate combined with EDTA?

Answer 21

Yes

Question 22

Is thimerosal a better antibacterial or antifungal? What is it often combined with?

Answer 22

Antifungal

Often combined with chlorhexidine digluconate

Question 23

List four complications of thimerosal and whether or not it is commonly used.

Answer 23

Conjunctival swelling
Limbal injection
Infiltrates
SPK
Rarely used

Question 24

What is EDTA and what does it inhibit? Does it cause irritation/allergy?

Answer 24

Chelating agent, inhibiting bacterial growth

Question 25

What is benzyl alcohol used for (2) and what is needed if using it?

Answer 25

Effective for lipid removal and good antimicrobial activity

Careful rinsing is essential

Question 26

What do enzymatic/protein cleaners remove?

Answer 26

Removes bound insoluble protein

Question 27

What happens to the immunogenic potential of bound protein with age?

Answer 27

It increases

Question 28

What should always be done before and after using a protein/enzmatic cleaner?

Answer 28

Always surface clean before and after enzyme treatment

Question 29

What should CL cases be washed with? What can be used to scrub it?

Answer 29

Scrub with a toothbrush or cotton bud and use saline

Question 30

How often should CL cases be replaced?

Answer 30

Every three months

Question 31

What are rewetting/comfort drops used for, and what three things do they do?

Answer 31

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

Question 32

List one advantage and two disadvantages of mutlipurpose solutions.

Answer 32

Enhances compliance
Compromised efficacy
Increased sensitivity in some patients

Question 33

Are multipurpose solutions often more or less viscous than other solutions?

Answer 33

More viscous (actually it’s lower viscosity)

Question 34

Is it ok to mix and match different brands?

Answer 34

Best not

Question 35

What should be done to RGPs used on patients with known infectious diseases?

Answer 35

Dispose them

Question 36

What is the standard routine in-office RGP disinfection protocol for a trial lens?

Answer 36

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

Question 37

If a patient uses hairspray, should it be used before or after RGP lens application? What about cosmetics?

Answer 37

Before

Apply cosmetics after

Question 38

Can eyeliner be applied if using RGP lenses?

Answer 38

Yes but shouldnt be applied to the inner lid margin

Question 39

Hw should RGPs be stored by the patient?

Answer 39

In a disinfecting solution - or as recommended by the manufacturer

Question 40

When should patients clean and disinfect their lenses before putting it on?

Answer 40

If stored for more than a week