SCL care Flashcards
(15 cards)
steps to cleaning
- cleaning
- rinsing
- disinfecting and storage
Cleaning
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
cleaning solution
Surfactant (surface-active agent) used to clean the lens
Composed of both hydrophilic and hydrophobic ends in the molecule structure
Hydrophobic ends cluster around debris to form micelles. The free hydrophilic ends are then able to react with water, and the micelle can then be whisked off the lens surface
Effective against lipid and inorganic deposits, but have limited effect against bound or denatured proteins
Also enhance lens wettability
Rinsing
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
Disinfecting
The step required to neutralise all microbes that may be present on the CL
Different disinfectants take different lengths of time to disinfect, must check labelling on solution bottle
Typically this is done overnight (or ideally once a week for extended wear)
Also refers to keeping the solution in the bottle safe, not just the lenses
Saline is not a suitable disinfecting agent
3 terms associated with antimicrobials:
Sterilisation
Preservation
Disinfection
disinfecting steps
Sterilisation – the solution is sterile i.e. no organisms can survive, they have all been killed off. BUT the solution does not sterilise lenses.
Preservation – the preservatives present in the solution that prevent growth of micro-organisms in the bottle.
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.
Multipurpose solution
The most convenient and common design of SCL solution i.e. all parts of the care regime are in one bottle
Used for cleaning, rinsing and disinfecting
Research showed that except for some fungal isolates, MPSs performed adequately (99.9% viability reduction) on FDA test-panel organisms
Most of the CL companies have various MPS options available
So do some of the multiple high street companies and supermarkets
how to use MPS steps
Place 3 drops of the solution on each side of the lens and rub gentally for 20s
rinse each side for 5 seconds
place n fresh solution and soak fo atleast 4 hours
replace lens case once a month
Hydrogen peroxide steps cleaning
BEFORE handling your contact lenses wash and rinse your hands thoroughly, then dry
Remove the lens from your right eye and place into the right basket (marked: R) of the open lens holder. Carefully close the basket. Remove the lens from your left eye, place into the left basket and close it carefully.
Thoroughly rinse each lens while in the lens holder for 5 seconds with fresh one step peroxide solution.
Fill the lens case up to the marked line with fresh one step peroxide solution. Do not underfill or overfill the lens case.
Place the lens holder inside the lens case and close the cap securely (do not overtighten). The solution will start to bubble. Ensure the lens case is in an upright position and that your lenses are fully immersed.
Allow your lenses to soak for at least 6 hours or overnight prior to applying onto the eyes. Do not shake the lens case or turn it upside down during the disinfection process.
Hydrogen peroxide insertion steps
BEFORE handling your contact lenses wash and rinse your hands thoroughly, then dry
Only after a period of at least 6 hours of neutralization, open the cap and take out the lens holder
Lenses can be rinsed with sterile saline prior to insertion
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
Addatives in solution preservative
Thiomersal
Benzalkonium chloride (BAK)
Polyquad
Polyhexamethylene biguanide (PHMB)
Polyaminopropyl biguanide (PAPB)
addatives in solution and viscosity enhancers
PVA (polyvinyl alcohol)
Methyl Cellulose
Hypromellose
addatives in solution tonic 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.
NaCl (sodium chloride)
KCl (potassium chloride)
Addatives in solution buffers
Borate
Phosphate
Bicarbonate
other addatives
Chelating agents – prevents lens deposits (binds free ions such as calcium and magnesium) & disinfectant antimicrobial activity
Ethylenediamine tetra-acetic acid (EDTA)
Colouring agents
Very rare in modern solutions
Mild Abrasives – enhance the mechanical stripping of debris and proteins from the lens surface
Polymeric beads
Sterile water / saline
