Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

(2) Tri A - Contact lenses > Week 11 - SCL Care > Flashcards

Week 11 - SCL Care Flashcards

1
Q

Why do we bother with lens hygiene?

A

• reduce the number of microorganisms that accumulate on the lenses with wear
• minimise the risk of infection with contact lenses
• cleaning solutions can also improve comfort by conditioning and wetting the lens surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What challenges do CL solutions face before being approved for use?

A

• Tested for ability to protect vs organisms:
- Pseudomonas (lens associated keratitis)
- Serratia (nun-ulcerising keratitis and endopthalmitis)
- Staphylococcus (microbrial keratitis - 25%)
- Candida (yeast infections)
- Fusarium (common fungus in 1st world)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What other challenges do CL solutions face?

A

• MRSA (methicillin-resistant Staphylcoccus aureus) - CL solutions have varying degrees of efficacy
• Acanthomoeba (amoeba) - found in tap water, very stubborn to kill in their cyst form. CL solutions have varying degrees of efficacy. Good compliance helps!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What 5 things must all solutions have in common?

A

• Sterile, stable at room temperature
• Harmless (relatively) to eye if accidentally instilled
• Have no adverse effects on contact lens materials
• Compatible with any other solutions
• Self-sterilising

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What 3 steps are there to cleaning SCLs?

A
  1. Cleaning
  2. Rinsing
  3. Disinfecting / Storage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is cleaning specifically?

A

• To clean debris from the lens
• To reduce deposit build up
• Important to include a lens “rub” step in cleaning regime to mechanically remove debris and deposits (oils, proteins,
“biofilm”)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the lenses cleaned with?

A

• Surfactant (surface-acting agent): poloxamer
• Hydrophilic and hydrophobic ends in molecule
• Hydrophobic interacts with debris to form micelles, hydrophilic reacts with water
• Effective against lipids and inorganic deposits
• Enhances lens wettability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is rinsing?

A

• To clear the debris away that has been dislodged by the cleaning
• Prior to disinfection
• This can be done with MPS (multi-purpose solution) or sterile saline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is Disinfecting taken place, how is it done?

A

• Neutralise all microbes present on CL
• Different disinfectants take different lengths of time: check label
• Typically done overnight (once a week for EW)
• Refers to keeping solution in bottle safe, not just lenses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 3 terms associated with antimicrobials, and their definitions?

A
  1. Sterilisation: the solution is sterile: BUT the solution does not sterilise lenses.
  2. Preservation: the preservatives present in the solution that prevent growth of micro-organisms in the bottle.
  3. Disinfection: the reduction of the level of micro-organisms to a level that is safe for the ocular surface without damaging the contact lens. This occurs in the contact lens case.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are some examples if Biocides used in CL solutions?

A

• PHMB
• PAMB
• PQ-1
• MAPD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are Multi-purpose solutions (MPS)

A

• The most convenient and common design
• Used for cleaning, rinsing and disinfecting
• Research showed apart for some fungal isolates, MPSs performed adequately (99.9% viability reduction) on FDA test-panel organisms
• Most CL companies have MPS options
- So do some of high street companies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

MPS Steps - Bausch and Lomb example…

A

• Place 3 drops of MPS each side of lens, rub for 20s
• Rinse each side 5s with MPS
• Place cleaned lens in case, fill with fresh fluid at least 4hrs - discard solution from case after each use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the Hydrogen Peroxide CL system?

A

• Very different from MPS
• Hydrogen peroxide has broad antimicrobial activity - 3% concentration
• Destroys pathogens by oxidation, by denaturing protein; damaging membranes
• Preservative free!
• Requires catalyst to neutralise hydrogen peroxide, turning to water
• Disinfection takes 6hrs overnight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 7 steps for REMOVING lenses with hydrogen peroxide?

A
  1. BEFORE handling your contact lenses wash, rinse, and dry hands
  2. Remove R lens and place into R basket, Carefully close the basket. Repeat for left eye.
  3. Rinse each eye in lens holder for 5s with peroxide
  4. Fill lens case up with peroxide solution
  5. Place lens holder in case, close cap securely. Solution will bubble.
  6. Allow 6hrs to soak, do not shake/turn upside down the case
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 4 steps for inserting lenses with hydrogen peroxide?

A
  1. BEFORE handling your contact lenses wash, rinse, and dry hands
  2. When 6hrs pass, open cap and take out lens holder
  3. Lenses can be rinsed with sterile saline prior to insertion
  4. After applying your lenses onto the eyes, discard all used, remaining one step peroxide solution from lens case, and leave it open to air dry
    ( If lenses stored for more than 1 day, will require disinfection)
17
Q

What happens if Hydrogen peroxide not left to neutralise?

A
  • Stinging
  • Burning
  • Corneal damage
18
Q

How is the CL case cared for MPS?

A

• When the lenses removed, the case should be emptied of the current solution
• The case should then be rinsed out with the MPS solution or saline (not water)
• Make sure no residual lens solution is allowed to dry on the case, shake the lens case after rinsing
• Then the lens container and the lids should be left to air dry face down on a clean tissue before the lid is put back on (no towels)
• The lens case should be replaced ideally every month

19
Q

How is the CL case cared for hydrogen peroxide?

A

• Once lenses are removed from the baskets, discard any remaining solution from the lens case
• Rinse the case with the peroxide solution or saline over a sink/basin
• Leave the lid off the case to air dry

20
Q

What are the additives in solutions: Preservative and viscosity enhancers??

A

• Preservatives - maintain sterility of solution.
- BAK, PAPB etc
• Viscosity enhancers - thicken the solution
- PVA, methyl cellulose etc

21
Q

What are the additives in solutions: Tonicity adjusters and Buffers?

A

• Tonicity Adjusters: to maintain the ideal contact lens salt solution of 0.9% sodium chloride. Too low and the cornea may swell, too high and it may dry.
- NaCI (sodium chloride)
- KCI (potassium chloride)

• Buffers - to stabilise the pH between 7.0 and 7.4
• Borate, Phosphate, Bicarbonate

22
Q

What are the additives in solutions: Chelating agents, colouring agents, mild abrasives and sterile water/saline?

A

• Chelating agents - prevents lens deposits (binds free ions such as calcium and magnesium) & increases disinfectant antimicrobial activity
• Colouring agents; very rare modern day
• Mild abrasives: enhance the mechanical stripping of debris and proteins from lens surface (i.e polymeric beads)
• Sterile Water/Saline

23
Q

Can patients have allergies to CL solutions and what can be done?

A

• Patients can be allergic to their CL solution
• Presents in the same way as most ocular allergies - itching, lacrimation, hyperaemia and peri-ocular swelling
• Usually this is due to the preservatives

• So what can we do?
- Temporarily discontinue lens wear
- There are “gentle” solutions that are marketed for sensitive eyes
- Hydrogen peroxide cleaning system
- Daily disposable lenses

24
Q

What are Re-Wetting drops used for?

A

• Not part of every CL wearer’s care routine
• Often used in those who have CL-related discomfort (ocular pathology ruled out)
• Always consider a refit if it is in the patient’s best interests
• Re-wetting drops will give temporary relief
• Drain from the ocular surface quickly
• They attempt to mimic the natural tears that have evaporated quickly due to the presence of the CL

25
Q

What are common ingredients for Re-Wetting drops?

A

• Sodium Hyaluronate
• Sodium chloride (saline)
• Povidone
• Hypromellose (hydroxypropyl methylcellulose)
• Carboxymethy|cellulose

26
Q

What are Deposits and what are their effects?

A

• Protein, lipids, mucins, polysaccharides can build up on lenses
• More common when lenses are replaced less regularly
• Increase irritation, bacterial binding, potential for infection and incidence of CLPC
• Decrease comfort, decrease visual acuity, decrease CL life

27
Q

What substances might a soft CL protein removal solution contain and their use schedule?

A

• Papain - protease that binds to CL materials (plant material)
• Pancreatin - protease, lipase (porcine)
• Subtilisin A or Subtilisin B - protease derived from bacteria

• Frequency of remover depends on how quickly build up appears

28
Q

What steps are done before disinfection, regarding deposits?

A

• BEFORE DISINFECTION: Lenses soaked in MPS or saline with enzyme dissolved in solution - 15 min to overnight (depends on manufacturer’s recommendation)
• CLs should be rubbed & rinsed thoroughly in MPS or sterile saline after protein treatment
• Usually protein removal needs to be followed by disinfection

29
Q

What steps are done during disinfection, regarding deposits?

A

• DURING DISINFECTION: Protein remover tablet placed in peroxide after case is filled but before the CLs immersed or neutralising tablet added
• Processing time is governed by the peroxide system’s disinfection
recommendations
• Lenses should be rubbed and rinsed thoroughly with fresh sterile saline after protein treatment immediately before lens insertion

30
Q

What are some common mistakes in SCL care?

A

• Not rubbing the lenses
• “Topping up” contact lens solution
• Not changing CL case each month
• Tap water being used for any part of the care regime
• No hand washing
• Not leaving the solution the correct length of time for disinfection
• Using the incorrect solution
• Using expired solution

(2) Tri A - Contact lenses (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions