Flashcards in CL Care and Maintenance Deck (25):
FDA Group 1
Low water content, non-ionic
FDA Group 2
High water content, non-ionic
FDA Group 3
Low water content, ionic
FDA Group 4
High water content, ionic
why do we have silicon in lenses?
great affinity for oxygen; increases transmissibility of oxygen to our eyes
con of silicon
hydrophobic (repels charged particles and attracts uncharged particles)?
what lens does not belong into any of the FDA groups?
Dailies Total 1
charged and attracts oppositely charged particles
fda group mneumonic
Fluorine advantage to lenses
attracts water and keeps lens moist; reason why we choose lenses with Fluorine
What filter makes staining easier to visualize?
why do we need to rub the lens?
! Rinsing alone does not detach adherent/penetrating fungi
! Micro-organisms are not the only ‘concern’
! other lens contaminants also require removal
! finger-borne contaminants (←lens handling)
! inevitable surface deposition needs to be contained
! a clean lens is usually more comfortable
! Lens wettability is enhanced
is unpreserved normal saline ok to use for lens care?
Any process that kills or eliminates transmissible agents
The killing and/or the removal of some or all resident pathogenic organisms
The killing, and/or the inhibition of growth, of selected micro-organisms
WHAT IS A CLEANING SOLUTION?
Contains cleaners which are ionic or nonionic surfactants.
EDTA may be used to enhance microbial activity of the preservatives and soften the water by removing ions which also enhances the cleaning activity.
Mild abrasives may be added Opti-Free.* Usually not meant for use in the eye. Visibly tinted e.g., Boston Advance
daily cleaner function action
Emulsify or solubilize contaminants and/or loose foreign matter on lens surfaces
WHAT IS A SURFACTANT?
A surfactant cleaner lowers surface tension and emulsifies lipids, oils and other materials.
Prophylactic daily use to prevent deposits.
Rub vs No Rub (Mechanical cleaning vs Rinse only)
lipids anchor onto hydrophobic lens or epithelium and consequently brings water with them
WHAT IS AN ENZYMATIC CLEANER?
• Effective in removing proteinaceous coatings.
• Proteolytic enzymes (breaks down protein bonds)
• Papain (papaya-based enzyme/meat tenderizer)
• Pancreatin (hog pancreas derived enzymes protease,lipase & amylase)
• Subtilisin (extracellular enzyme produced by B. licheniformis)
ENZYMATIC PROTEIN REMOVERS PANCREATIN
! Protease (protein), lipase (lipid) and amylase (polysaccharides)
! Pig pancreas derivative
! Cleaning efficacy similar to papain
ENZYMATIC PROTEIN REMOVERS
SUBTILISIN A & B
! Derived from Bacillus bacteria
! Low toxicity; used in food products
! Less specific binding characteristics
! May be more effective than papain
WHAT IS A SOAKING SOLUTION?
Maintains hydration, prevents contamination from microorganisms, helps maintain a clean surface by solubilizing debris
Usually not meant for use in the eye