Lecture 2 - Care and maintenance

Question 1

what function do all lens care systems have?

Answer 1

cleaning, rinsing, and disinfection of lenses

Question 2

what does CRADLE stand for?

Answer 2

clean rinse and disinfect lenses every time

Question 3

what are some peroxide based soft lens care systems?

Answer 3

oxysept, clear care, peroxi clear, AO sept

Question 4

what are some GP lens care products?

Answer 4

all from Boston line of products and Menicare plus

Question 5

what is a preservative?

Answer 5

added to a product to prevent bacterial contamination or undesirable chemical changes

Question 6

what is a buffer?

Answer 6

(normal pH of tears 6.5-7.6) resist unwanted changes in pH and prevent deterioration

Question 7

what is a surfactant?

Answer 7

serve as cleaners (especially towards protein) and wetting agents - sequesters through micelles

Question 8

what is a stabilizing agent?

Answer 8

opposite of catalyst - chemical that inhibits reaction of two or more other chemicals

Question 9

what is an enzyme in a solution?

Answer 9

catalyst that work to lower the activation energy of a reaction

Question 10

what is a CL deposit?

Answer 10

any surface coating/contaminant that is not flushed/wiped from lens by tears and blinking or care procedures/solutions

Question 11

what is CLARE?

Answer 11

contact lens induced acute red eye (conjunctival/limbal injection)

Question 12

what are 2 water borne bacteria that can adhere to CL?

Answer 12

pseudomonas and acanthamoeba

Question 13

what is the difference between the Andrasko grid study and the IER matrix study? (B&L studies)

Answer 13

the Andrasko had a shorter time (2 hours vs. 3 months for IER)

Question 14

if the solution says “no rub” can you get away without rubbing the lenses?

Answer 14

no - rinsing alone doesn’t detach adherent/penetrating fungi

Question 15

why might solutions contain EDTA?

Answer 15

may be used to enhance microbial activity of the preservatives and soften the water ions to enhance cleaning activity

Question 16

what are the levels of efficacy for antimicrobial activity?

Answer 16

sterilization (kills/eliminates all agents)
disinfection (kills/removes some or all resident pathogenic organisms)
preservation (kill/inhibit growth of selected microorganisms)

Question 17

what are some alcohol based daily cleaners?

Answer 17

sereine XS, Walgreens XS, and Sof/Pro2 XS

Question 18

what is an enzymatic cleaners?

Answer 18

effective in removing protein coatings and breaking protein bonds - Papain, pancreatin, and subtilisin

Question 19

what is a soaking solution?

Answer 19

maintain hydration, prevents contamination and helps maintain clean surface by solubilizing debris

Question 20

what are some disinfecting preservative components in solutions?

Answer 20

BAK, chlorhexidine, thimerosal, dymed and polyquad

Question 21

can you use generic hydrogen peroxide to clean lenses?

Answer 21

no - has impurities

Question 22

what is the minimum time to soak a hydrogen peroxide based solution?

Answer 22

minimum 3 hours in 3% (bacterial = 10-15min, fungi = 60min, and acanthamoeba = 3-6hours)

Question 23

how often should you replace a hydrogen peroxide based case?

Answer 23

3 month intervals = about 100 uses

Question 24

what are the tablet based systems that use chlorine tablets?

Answer 24

alcon softab and sauflon aerotab

Question 25

how long do you soak lenses in chlorine tablet solutions?

Answer 25

4 hours (dissolved in unpreserved saline)

Question 26

what is a wetting agent?

Answer 26

creates film to provide comfort and is pH compatible (nearly isotonic)

Question 27

what is a lubricating solution?

Answer 27

rehydrates, rewets, on-eye cleaner

Question 28

what is a rinsing solution?

Answer 28

usually 0.9% NaCl (saline) with neutral pH (7.0-7.4)

Question 29

what is the difference between MPS (multipurpose solution) and MPDS (multipurpose disinfecting solution)?

Answer 29

convenience and marketing driven - MPDS had additional testing to get the “D”
both have wetting, soaking and cleaning agents

Question 30

how often should you replace soft lens cases?

Answer 30

every 1-3 months - and advise inverted storage to prevent biofilm concerns

Question 31

is sterilization a characteristic of a contact lens system?

Answer 31

no - only disinfection

Question 32

what material is added to a CL to improve oxygen permeability?

Answer 32

silicone

Question 33

what material is added to a GP lens to improve wetability?

Answer 33

fluorine