Week 4 - RGP CL Care

Question 1

Which groups of people are RGP’s better for?

Answer 1

• Those with an astigmatism, as they offer a more rigid fitted lens
• People with eye conditions that cause irregularity to the shape
• SCLs wearers who find their vision is not sharp enough

Question 2

What is the characteristics of RGP Material?

Answer 2

• Small matrix
• Deposits remain on lens surface
• Complex surface chemistry
• Silicone element decreases wettability

Question 3

What is the purpose of care and maintenance?

Answer 3

• Cleans lens
• Good vision
• Good comfort
• Safe lens wear by
- minimising deposit accumulation
- decreasing microbial contaminants
- increasing lens wettability

Question 4

What are the 7 techniques for care and maintenance?

Answer 4

1. Cleaning solutions
2. Rinsing solutions
3. Disinfecting solutions
4. Protein removers (weekly)
5. Rewetting lubrication solution
6. Lens storage case

Question 5

What is the purpose of cleaning RGP lenses?

Answer 5

• To remove loosely-bound foreign matter, cell debris, protein, lipid, mucous, cosmetics, etc.
• These would be toxic to the ocular surface if instilled to the eye directly. Communication with patient really important

Question 6

What are the 3 functions and types of solutions for rinsing RGP lenses?

Answer 6

1. To remove daily cleaner, loosened deposits and microorganisms
2. Rehydrated lens
3. Dissolve enzyme tablets

Types:
• Saline (non/preserved)
• MPS

Question 7

What is the function of disinfecting?

Answer 7

Function
• Physical or chemical process that destroys pathogenic microorganisms
•Kills or deactivates microbes left on the lens including:
~ Bacteria
~ Viruses
~ Fungi
~ Amoeba
• Restores and maintains lens hydration

Question 8

What are the Types of disinfecting systems?

Answer 8

• Heat (thermal unit, microwave) - rare
• Chemical
~ Oxidative - hydrogen peroxide, H2O, (very effective, good for px with allergies) or chlorine
~ Cold chemicals - lots of disinfectants inc. benzalkonium chloride (BAK), chlorhexidine (CHX), thiomerosal, dymed, polyquad

Question 9

what are “one set” and “two step” hydrogen peroxide-based disinfection?

Answer 9

• One step (e.g. EasySept, AOSept)
- Catalytic disc
- Delayed-release neutralising tablet

• Two step
- Dilution
- Catalytic disc
- Neutralising agents (after disinfection)
- Catalase (enzyme, catalyses H202 breakdown to H20 + 02)

Question 10

How long should hydrogen peroxide-based infections be left?

Answer 10

• Recommended minimum 3 hours in 3% H202
- Bacteria 10-15mins
- Fungi 1hr
- Acanthamoeba 3-6hrs
• Powerful cleaning and disinfecting. Good for atopic Px and those with preservative allergies
• AO Sept has added agent for comfort

Question 11

What are protein removers?

Answer 11

Function:
• To aid in removing/loosening tightly bound protein deposits

Enzymes include:
- papain
- Ultrazyme
- Universal
• subtilisin
- pronase
- pancreatin

• Done weekly
• Lenses should be cleaned & rinsed after enzymatic treatment
• Also covered in the SCL care lecture

Question 12

What is Rewetting and soakings functions?

Answer 12

Function:
• Disinfection, wetting and storage
• To alleviate insufficient lubrication from tear film
• Rehydrate
• Flush debris
• Maintain wettability

Composition
• Anti-microbial agents
• Wetting agents
• Viscosity-enhancing agents
• Buffer
• Salts

Question 13

What is proper lens care and storage?

Answer 13

• CL should be stored in a clean case with fresh disinfecting solution
- Should be replaced monthly (ideally)
• Should always rub lenses with new solutions
• Air dry case