Lecture 2 - Care and maintenance Flashcards
what function do all lens care systems have?
cleaning, rinsing, and disinfection of lenses
what does CRADLE stand for?
clean rinse and disinfect lenses every time
what are some peroxide based soft lens care systems?
oxysept, clear care, peroxi clear, AO sept
what are some GP lens care products?
all from Boston line of products and Menicare plus
what is a preservative?
added to a product to prevent bacterial contamination or undesirable chemical changes
what is a buffer?
(normal pH of tears 6.5-7.6) resist unwanted changes in pH and prevent deterioration
what is a surfactant?
serve as cleaners (especially towards protein) and wetting agents - sequesters through micelles
what is a stabilizing agent?
opposite of catalyst - chemical that inhibits reaction of two or more other chemicals
what is an enzyme in a solution?
catalyst that work to lower the activation energy of a reaction
what is a CL deposit?
any surface coating/contaminant that is not flushed/wiped from lens by tears and blinking or care procedures/solutions
what is CLARE?
contact lens induced acute red eye (conjunctival/limbal injection)
what are 2 water borne bacteria that can adhere to CL?
pseudomonas and acanthamoeba
what is the difference between the Andrasko grid study and the IER matrix study? (B&L studies)
the Andrasko had a shorter time (2 hours vs. 3 months for IER)
if the solution says “no rub” can you get away without rubbing the lenses?
no - rinsing alone doesn’t detach adherent/penetrating fungi
why might solutions contain EDTA?
may be used to enhance microbial activity of the preservatives and soften the water ions to enhance cleaning activity
what are the levels of efficacy for antimicrobial activity?
sterilization (kills/eliminates all agents)
disinfection (kills/removes some or all resident pathogenic organisms)
preservation (kill/inhibit growth of selected microorganisms)
what are some alcohol based daily cleaners?
sereine XS, Walgreens XS, and Sof/Pro2 XS
what is an enzymatic cleaners?
effective in removing protein coatings and breaking protein bonds - Papain, pancreatin, and subtilisin
what is a soaking solution?
maintain hydration, prevents contamination and helps maintain clean surface by solubilizing debris
what are some disinfecting preservative components in solutions?
BAK, chlorhexidine, thimerosal, dymed and polyquad
can you use generic hydrogen peroxide to clean lenses?
no - has impurities
what is the minimum time to soak a hydrogen peroxide based solution?
minimum 3 hours in 3% (bacterial = 10-15min, fungi = 60min, and acanthamoeba = 3-6hours)
how often should you replace a hydrogen peroxide based case?
3 month intervals = about 100 uses
what are the tablet based systems that use chlorine tablets?
alcon softab and sauflon aerotab
how long do you soak lenses in chlorine tablet solutions?
4 hours (dissolved in unpreserved saline)
what is a wetting agent?
creates film to provide comfort and is pH compatible (nearly isotonic)
what is a lubricating solution?
rehydrates, rewets, on-eye cleaner
what is a rinsing solution?
usually 0.9% NaCl (saline) with neutral pH (7.0-7.4)
what is the difference between MPS (multipurpose solution) and MPDS (multipurpose disinfecting solution)?
convenience and marketing driven - MPDS had additional testing to get the “D”
both have wetting, soaking and cleaning agents
how often should you replace soft lens cases?
every 1-3 months - and advise inverted storage to prevent biofilm concerns
is sterilization a characteristic of a contact lens system?
no - only disinfection
what material is added to a CL to improve oxygen permeability?
silicone
what material is added to a GP lens to improve wetability?
fluorine
