SCL Solutions - Part 2 Flashcards
What solution component assists in removal of lipid?
Surfactant
What solution component assists in removal of protein?
Chelating agents (Hydranate, sodium citrate…)
Deposition on SiHys
Small amount of protein (most denatured)
Increased lipid
(Reduced surface wettability)
What materials showed most lipid deposition?
Senofilcon (OASYS)
Balafilcon (PureVision)
What materials showed least lipid deposition?
Lotrafilcon A (Focus N&D)
What percentage of bacteria will rinsing the lens remove?
90%
What percentage of bacteria will rubbing and rinsing the lens remove?
99%
Of SiHy lenses, which has most silicone exposed on lens surface?
PureVision
How to fix problem of lipid deposits on SiHy lenses
- Switch back to Hydrogel
- Daily disposables
- Solution w/ more surfactant (better wettability)
How does contact angle relate to wettability?
Lower contact angle, better tear spreadability
More wettable lens
What lenses have been found to interact w/ PHMB in solutions?
SiHys and FDA group II
more hydrophobic lenses
When is corneal staining induced by solutions the WORST?
After 2 hours
How does the “staining grid” work?
Each grid represents 30 px’s
Lens in solution overnight
Lens inserted, taken out after 2 hrs
Checked for staining
What does a percentage on the staining grid mean?
Percentage of the cornea that shows staining
What are the trends seen in the Staining Grid?
B&L (Renu) solutions show more corneal staining after 2 hrs. Worst w/ Softlens, Proclear, Purevision, O2 Optix.
What did the IER Matrix Study do?
Looked at lenses randomly after min 3 mod wear (more true to life)
What does a percentage in the IER study show?
Percentage of Px’s w/ abnormal corneal staining
What are the trend of the IER study?
Greater corneal staining in patients using polyquad (opti-free) products over a long period of time.
**Renu wasn’t included in this study…
What is PATH?
Preservative
Associated
Transient
Hyperfluorescence
How does PATH work?
PHMB taken up in lens, and leaked onto the eye
NaFlu adheres to PHMB
Transient, irrelevant observation
Is there a link between staining and MK?
NOPE.
Increased use of MPS and SiHy lenses, yet no increase in MK rate.
How can you avoid the problem of corneal staining in SiHy’s?
Switch to peroxide soln (no preservatives!)
Daily disposables
