Lecture 5 contact lens care, solutions and teaches Flashcards
What is included in a multi-purpose solution?
BUFFERS (borate, phosphate, citrates): maintain PH
OSMOLARITY AGENT (NaCl): role in comfort
CHELATING AGENT (EDTA): antimicrobial preservative
COMFORT AGENTS: increases wettability
SURFACTANTS (poloximine)
ANTIMICROBIAL AGENTS: reduces microbial pathogens
PROTEIN MANAGEMENT AGENTS
What is the difference between cleaning and disinfecting?
cleaning: using surfactants and protein removing agents
-rub and rinse
-aim is to remove deposits
disinfecting: using biocides and antimicrobial agents
-sterilisation,preservation and disinfection
How do surfactants work?
Adsorption
They have hydrophobic and hydrophilic ends. Hydrophobic ends attach to debris on lens.
Displacement
Hydrophilic ends attract water which helps to lift debris of lens
Solubilization
More surfactants attach rinsing debris away
What is the disinfecting process?
Sterilisation
Solution and bottle are sterile and manufacturing stage, but lens is not sterile
Preservatives
Intended to prevent growth of microorganism in bottle
Disinfection
Chemical -process occurs in the case-killing microbes to a safe level for the lens
What microorganisms must a solution kill?
-candida albicans
-fusarium Solani
-serratia marcescens
-pseudomonas aeruginosa
-staphlyococcus aureus
What is the stand-alone test?
How can a solution be classified?
solution goes through test without rub and rinse. Without the extra step.
*stand-alone classification: meets primary standards
*Can be used for non-compliance patients
*If solution doesn’t meet primary standard, it is secondary standard. Rub and rinse step HAS to be included as part of the disinfecting requirement.
*Rub and rinse is a necessity for the non-stand-alone
What are the pros of single preservative multipurpose solutions?
What preservative is usually used?
*Cost effective and generally successful
Consumer friendly/convenient
PHMB
How do unpreserved multipurpose solutions work?
*Based on chlorite ion in the solution
*While solution is in the bottle, it is preservative free
*When it comes out the bottle, solution encounters microbes and transforms into chlorine dioxide (disinfectant). Reaction needs stabilisation so there is a trace amount of hydrogen peroxide to stabilise reaction.
*When it is out of the bottle, it turns into saline and oxygen so can go back onto the eye
*Expensive to make
What dual preservative multipurpose solutions can yuo get?
BioTrue by Bausch and lomb
pure moist by alcon
Who would you recommend hydrogen peroxide solutions too?
*Hypersensitive patients/atopic patients
*Patients prone to allergic response/intolerance to preservatives
*patients who have always used it
*Option for RGP’s
*Non-compliance patients
*People who don’t wear lens daily. They won’t be disinfecting lenses daily. The multipurpose solutions still have antimicrobial activity after a day. peroxide turns into oxygen and saline in the morning. Prolonged killing rate doesn’t happen when using peroxide solutions.
How do hydrogen peroxide solutions work?
- need neutralisation for peroxide
- hydrogen peroxide is in case
- you get a fizzy reaction
- leave it for 6 hours
- solution turns back into saline after chemical reaction
- no preservatives
- NO RUB AND RINSE
What are widely used hydrogen peroxide solutions?
AoSept
OxySept
EasySept
What solutions do you get for RGPs?
Bausch and lomb:
Boston cleaner
Boston conditioner
Boston multi purpose
What does the cleaner solution do in RGP wear?
-removes accumulated film, deposits
-has a visibility indicator (milky white) which needs to be rinsed off with saline
What does the conditioner solution do in RGP wear?
*Conditioner soaks and disinfects lens. it’s the solution you use to apply lens.
*Conditioning solution is thicker solution as it must cushion a Harder surface.
