FITTING SiHy CL Flashcards
Prime motivation for developing silicone-based Ot materials
O2 permeability (Dk)
why is SiHy better thatn hydrogel
Better oxygen permeability
increase CL transmissibility = increase corneal oxygenation
eliminate adverse outcomes of CL wear
year when SiHy was discovererd
1998
Extended wear is prone to
hypoxia
Pervaporation staining thwarted use of obvious combination which are
high water and low transmissibility
Higher water content, more
permeable
elastomer
flexible
acrylate
plastic
when was polysiloxane hydrogels are patented
Jan 1979
WHEN
SiHy CL patent issued to tanaka of TOYO CL COMPANY
FEB 1979
WHAT YEAR
B&L released PureVIsion: balafilcon A - based on Tanaka’s and Kunzler & Ozark’s earlier work
1998
WHAT YEAR
GALYFICON A
2003
WHAT YEAR
SENOFILCON A
2005
FIRST GENERATION SIHY
Focus night and day
Purevision
SECOND GENERATION SIHY
Acuvue Advance
PureVIsion 2 HD
Acuvue Oasys
O2OPtic/AirOptix
THIRD GEN SIHY
Biofinity
PremiO
Avaira
T OR F
SIHY IS MORE PRONE TO PROTEIN DEPOSIT THAN LIPID
F
SIHY IS MORE PRONE TO LIPID THAN PROTEIN
WHAT IS LCP
LENS CARE PRODUCT
T OR F
HYDROGEL HYPOXIA RELATED CONDITIONS ARE SIGNIFICANTLY LOWER THAN SIHY
F
SIHY SIGNIFICANTLY LOWER
WHICH IS MORE DIFFICULT TO MANUFACTURE
SIHY OR HYDROGEL?
SIHY
ability of water to move through CL material - required for on-eye lens movement & ocular health
HYDRAULIC PERMEABILITY
T/F
hydrogels have hydraulic permeability. SiHy CLs do not
T
T/F
SiHy lenses inherently < wettable due to hydrophobic lens surface
T
WHICH MANUFACTURING TECHNIQUE IS NOT USED WITH CURRENT SIHY CL
SPIN CASTING
T/F
DRYNESS SENSATION IS LESS OF A PROBLEM WITH SIHY CLS
T
SIHY CLS ARE UITED TO ALL MODES OF WEAR WHICH ARE
DD
DW
FW
EW
CW
CHEMISTRY OF SIHY CLS
polyDiMethylSiloxane (pDMS)
DiMethylAcrylAmide (DMAA)
Tris(trimethylsiloxysilyl)PropylVinyl Carbamate
N-CarboxyVinyl Ester
Poly(dimethylsiloxy) di(silylbutanol) Bis(Vinyl Carbamate) (PBVC)
Propenyl group
